Saturday, January 31, 2015

Weather It Is (Confused? Don't Be!)

Good Evening:

We're being asked to vote for the "Zionist Camp" (Labor), which actually contains very few Zionists. We're being told to trust Tzipi Livni; one whose lack of success in foreign affairs (including supporting the Gaza disengagement) encourages the opposite.

Now, the weather is also turning heads.  It was quite warm, and then it was winter-like cold (even though it never really was that cold). Soon it will warm up, but by mid week (or so) it will cool off again, only to warm up even more by Shabbat and early next week.

Then, just when you might think it safe (even though it is only early February) to put away the boots, winters coats, gloves, scarves, and long underwear, not to mention the thermal sheets, the winter comforter, let alone the portable radiators, it will turn much colder.

While we can't see how long winter will last, we do see a high probability of winter returning mid the following week with a period of rain.  We also see a 25% chance of a more "bone-chilling" cold (or at least the kind of cold that reminds New Yorkers (or their ilk) of home.

All of this weather begins with a broad trough of low pressure over western and Northern Europe.  The main area is over Finland and as the days progress smaller atmospheric waves will rotate around it.

As the entire system shifts slowly to the east, the southern and northern streams within this wave pattern will compete between them.  A merging of the two as they approach our area will bring winter back (with more alacrity) -- otherwise, just expect cooler temperatures and a period of rain.

Shavua Tov,

Barry Lynn

Thursday, January 29, 2015

Weather It Is (Feeling Good, Feeling Human)

Good Evening:

I once heard an esteemed Rabbi comment that times may have changed, but people haven't.

Indeed.

Rather than dreaming about peace, we should accept that there will always be some segment of humanity that try or may even succeed to murder some other segment of it.

To them, humane means to steal, rape, and murder, and their religion (at this time in human history: Islam) tells them to feel good about it.  Imagine that: one can do all of these terrible things and feel guilt free!  They say that armies are good places for those with homicidal tendencies to excel, well so are groups like "DASH," Hizbollah, and Hamas.

Strong low pressure centered north of Finland will continue to maintain its cold grip on most of Europe. Early next week, a storm entering from the eastern Pacific will drive around the southern perimeter of this system and draw very cold air as far south as Italy and Greece.  As it does so, the system will begin to elongate and shift towards the east, as a ridge of higher pressure noses into western Europe.

Between 6 and 9 days from now, the system will begin to approach the eastern Mediterranean and soon there after things may begin to get interesting.  It is about 10 to 14 days out that we see a 25% for our next winter storm.

Stay tuned, and remember that not every human is "humane."

Barry Lynn

Tuesday, January 27, 2015

Weather It Is (On the Edge)

Good Morning:

There is a broad area of higher pressure over the eastern Atlantic and a broad area of low pressure over Europe.  We're on the edge of the area of low pressure.  The whole pattern is forecast to remain pretty much in place for the next week or so.

From time to time,  weak areas of low pressure will bring some high clouds and possibly a light shower.   The next weak system will bring much cooler temperatures during the several days.

Early next week, the high pressure area may move eastward a bit, while the trough over Europe "sharpens" up a bit.  This will drag much colder air into central Europe, while bringing much warmer air into our area by mid-next week.

The progression of the sharpening low-pressure trough will determine the evolution of our weather about two weeks from now.  It will eventually bring colder weather, but there is not enough information to say just how cold or how wet.

Until then, people may grumble that spring or even summer has arrived, and wonder where went winter.

Barry Lynn

Sunday, January 25, 2015

Weather It Is (Clarification)

Good Afternoon:

The weather map shows a large area of storm weather, which will slowly consolidate over northern Europe, where it will become quite cold as the week progresses.

While some of this cold air will seep southwards and bring a bit of rain here, we are most likely to stay on the fringes of this system. True, weak low pressure will give a wintry appearance, but there is nothing to get excited about.

Based on the number of people who have asked if it will snow next week, I can only say: probably not.  I never say never because even "Mr. Bond" regretted those words.

Even so, snow is not a very likely occurrence here. We can write about it, think about, and even talk about, it, but we're not building a baseball field here, so I doubt they (the snowflakes) will come.

Barry Lynn

Friday, January 23, 2015

Weather It Is (Pooh's Tickle)


Good Morning:

You might have one time read the Pooh stories. You might remember a rather snowy day where Pooh and Piglet sang a song to stay warm.

The more it snows (Tiddely-Pom)

The more it goes (Tiddely-Pom)

The more it goes on snowing (Tiddely-Pom)

And nobody know (Tiddely-Pom)

How cold my toes (Tiddely-Pom)

How cold my toes are growing (Tiddely-Pom Tiddely-Pom Tiddely-Pom Tiddely-Pom)



Certainly after a late night cup of hot chocolate one might find ones thoughts turning to those of snow, and so it was that I found myself in the middle of dream.  In this dream, the forecast was for snow in the north and so I was downstairs looking at weather maps and wishing that for once our forecasts might be wrong.  
As morning broke, my oldest daughter came downstairs and asked me what I was doing.  After I gave a brief weather briefing, she exclaimed "but look outside!"  Indeed, there was snow outside and the more often I looked the more snow there was.  Beautiful, heavy -- but not to wet - snow. Snow that covered everything, everywhere, from the cars in the lots to field in the valleys and up the hills on the other side.  If only I could have slept a bit longer.
I hid this dream from my wife, of course, who doesn't like snow.
Looking at the weather maps, we see a relatively shallow wavy pattern.  There is relatively mild air over the eastern Atlantic, extending as far north to England, somewhat cooler winter air over central Europe and the Mediterranean, and unusually warm air over our neck of the woods -- the eastern Mediterranean states (one might even take  a selfie of Lebanon and Israel together to get the picture -- if you know what I mean).  
However, change is in the air.  The shallow-wavy pattern should slowly widen and elongate as an area of strong low pressure in the northern Jet stream moves in off the Atlantic ocean and enters the southern Jet Stream shallow trough over central Europe.  Our very mild air will be pushed back to the east and colder air will filter in from the west. The cold air will enter will definitely make itself felt by mid week, but he change towards  more wintery (rainy) weather will be gradual and it may take another week before the pattern deepens and moves far enough east to push more than somewhat cold winter air our way -- that is rain.  
Right now, we see temperatures falling to daytime highs of 5 to 10 C in the mountains and a slow increase in moisture during the next week.  The temperatures will be cold and it may be damp.
While one might as a result  feel a "tickle" -- or a feeling that this must end in snow (as temperatures at 850 mb cool even more) -- the knowledgable will know that this tickle is not nearly as strong as the one Pooh feels when 11 AM rolls around and he heads back home for a snack of honey.  It will get cold but not that cold -- at least not by the end of next week.
Ironically, the change in our weather pattern will occur -- as noted -- with a merging of the northern and southern Jet streams.  However, it appears that the real cold air will only be peripherally available even to the northern Jet stream.  In fact, our sometimes source of wintertime snow cold (western Russia/Siberia) is unusually warm.  The temperature-weather pattern in a way resembles a global warming world. 
Since this is a slowly evolving system, there is time for change, and we do see some snow potential the week after next.  However, the rain may also come to a premature end as temperatures slowly warm.  In fact, this is more likely -- regardless of how our story began.
In the meantime, let's enjoy the end of our winter-break.
Shabbat Shalom,
Barry Lynn






Wednesday, January 21, 2015

Weather It Is (Being Optimistic)

Good Morning:

There is often told a joke: "what is the difference between a Jewish Pessimist and a Jewish optimist?"  The pessimist says that it can't get any worse, while the optimist says yes it can.

I am reminded about this when answering some readers' comments/questions.  For example, all I have to do is mention the word "snow" and suddenly everyone thinks it will snow.  For instance, we see in our crystal ball (the "Global Ensemble") that it should stay mild until late Shabbat, but that temperatures will start downwards soon after.  We see that there is a high probability of rain after mid-next week, and... we see a 15% chance that the end of the two week period will bring our next snow.

So, here is what happens.  The Jewish optimists will say:  "those 3 ensemble members (15%) must be right and the other 17 must be wrong."  The right way (i.e, to be a Jewish realist) is to say that there is a small chance of snow, and we'll have to wait and see.

In the meantime, I request anyone planning a simcha or other event check with me beforehand so that we don't actually schedule the next snowstorm on the wrong day.  Once we get closer to the event (assuming it happens -- as I am an optimist), it will be much harder to make any changes to the weather pattern.  On the other hand, while we're still far away from our next "big" storm, small changes we make to the dials on our "weather-machine" can make a big difference.

Barry Lynn

Saturday, January 17, 2015

Weather It Is (Taking Stock)

Good Evening:

Someone today asked me if we might see the sun.  He feels like it has been raining just about every day.  Compared to last year, he's correct. I've recorded more than 30 days of rain so far this year.

We've had approximately 330 ml of precipitation in Efrat and other areas are (also) above normal (so far) for the year.  I actually enjoy the rain, which has come in the form of snow twice (and wet snow on one Saturday night).  Last year, we had about 270 ml in the big storm, (and all over just a few days) and then nothing really until March.

However, the weather (or winter) will take a break and it is going to not only be sunny but five to 10 degrees warmer than the past several days.  Will we see shorts proliferating around streets of our towns?  Or, will folks remember that it may be "warm," but it's not going to be springtime hot.

The warmer weather will last until mid-week or so, and then we'll turn our attention to a developing system in the Mediterranean. This system will "try" to phase with colder air of the northern Jet-Stream.  Might the month end on a snowy note?  It will at least turn colder.

Barry Lynn

Friday, January 16, 2015

Weather It Is (Winter -- A Thing of The Past)

Good Afternoon:

Our latest storm will produce rain over north central Israel this afternoon.  Late tonight, moisture will wrap in from the northwest and impact the central and southern areas with rain into the morning. There is a slight chance of ice pellets towards noon.

After this storm passes, the persistent trough in our neighbourhood will retrograde (move westward) and this will allow for comparatively mild wintertime temperatures. The mild temperatures will persist, quite possibly into next week.

We see our next hint of winter weather about 10 to 14 days out.  Will it be snow? At the moment, there is a 15% chance.  We'll have to see how the storm develops.

Shabbat Shalom,

Barry Lynn

Wednesday, January 14, 2015

Weather It Is (Our Weather and Predicting Snow in Jerusalem)

Good Afternoon:

The "mid-week" storm we spoke about last week will arrive later today. It will arrive as light to moderate rain in most of the country. Temperatures aloft (at 500 mb) will be cooling off to comparatively cold levels by Thursday afternoon; however, the available moisture will be less. Hence, there is the possibility of a light wet snow at the higher elevations, but little or no accumulation is expected. Moreover, surface temperatures will probably be too warm in most locations (except the Hermon) for snow to accumulate as well, regardless of precipitation amounts. 

Another storm will arrive on Shabbat. It should produce more precipitation. Right now, there is only a 10% chance of snow with this storm (except on the Hermon, where snow chances are higher).

Late next week, there is the possibility for a more significant winter storm.

Barry Lynn

Here is our our latest thoughts on predicting snow in Jerusalem.  


Prepared by Dr. Barry Lynn: Weather It is, LTD, Efrat, Israel

Over the last several years, our weather has been unusually snowy. Using our high-resolution forecast model with a general picture of the synoptic (general) weather pattern has allowed us to achieve unparalleled success in forecasts of snowfall accumulation.  


Nevertheless, we over-predicted the snow amounts from the first January snowstorm of 2015 in the center of the country, where there was only about 30% of the snow minimally forecast.  Comparing our high resolution forecast from last year's December snow to this year's January snow provides us with enough data to be able to better utilize the high resolution forecast data going forward. That is, we expect to further improve our forecast predictions of snow amounts by better utilizing the high resolution data in the future.


Last year, the high resolution model data forecast a lot of snow in a very favorable snow environment.  This year, the high resolution forecast predicted relatively small snow accumulations compared to last year, even though the synoptic environment was again highly favorable for snow. The high resolution forecast became available about 12 hours before the start of the snow in the north (where our forecast was very good), and the following discussion might have mentioned that the latest forecast indicted reduced snowfall forecast amounts. 

Given the analysis below, it is now obvious that there was higher likelihood of less snow (even though there was significant amounts) in the neighborhoods of Jerusalem and Gush Etzion) than last winter's December snowstorm. 

The attached "pdf" shows our analysis of last year's and this year's snow events. For those of you are interested, I will summarize it here.

Figure 1: The forecast snow amounts in December 2013 are quite high compared to those in January 2015.  Only Neve Ativ and Sefad were forecast in this January storm to have snow amounts similar to what fell in last winter's storm in Jerusalem and Gush Etzion. This should have been the most obvious indication that snow amounts were to be less in the high elevations location in the  center of the country.

Figure 2: Almost 50% of the total precipitation in the Old City was suppose to accumulate as snow in last winter's storm.  Less than 20% of the total was to accumulate as snow in this January's storm, and there was less than half the total amount of precipitation in this year’s storm compared to last winter’s storm. Moreover, surface temperatures were forecast to be near or below freezing in the December Storm, but not in this year's January storm.

Figure 3: The hourly rate of precipitation in the Old City was much higher in the last winter’s December storm than in this year's January storm. Moreover, the snow rate was a much higher fraction of the total precipitation rate (assuming a 1 ml to 1 cm of precipitation to snow ratio).

Figure 4: This shows the same information as Figure 3, but for Efrat (Gush Etzion) where there was more snow in December's storm and in January's storm than in the Old City.  The hourly rates of precipitation were similar in both locations, but the fraction of snow to precipitation was higher. Our analysis showed that this was due to colder forecast surface temperatures in Gush Etzion than in Jerusalem's Old City.  The observations confirmed this analysis.

Figure 5: This shows precipitation and snow rates for Neve-Ativ and Sefad for this January's storm.  The precipitation rates were higher than in the center. Moreover, the snow rates were higher in each location than in the center. In Neve-Ativ, the ration of snow to precipitation was almost 1 to 1.

In summary: the high resolution forecasts appear to be a very useful tool for snowfall prediction-- even more useful than a general analysis of the synoptic situation – especially for the prediction of relative snow amounts in Jerusalem and location in the north from storm to storm. 

Further analysis showed that using the model to predict snow might lead to an error with a factor of 2 in the forecast snow amounts, while using the synoptic picture in combination with forecast precipitation amounts can lead to an error in order of magnitude (10 times).

Barry Lynn





Monday, January 12, 2015

Weather It Is (The Winter of Our Disconent)

Good Morning:

My wife made a quick trip to the doctor's office yesterday morning.  The doctor felt obligated to tell her that because of the snow her day was really, really busy -- too busy.  One can imagine why she told my wife.

My wife said that she had a headache from the snow.  Then, she said ("tongue in check")  she had an allergy to to snow and since I like snow, she must be allergic to me.

I have to say that the past week was quite full of pressure. I felt especially bad telling people that it would snow on the night of their son's (or daughter's) wedding night, and even worse when it didn't snow as much as "advertised."

Moreover, many people had requests for the storm: more snow, less snow, rain to wash the snow away.  I couldn't keep up with it all.  With weather, the truism "that you can never please all of the people all of the time" is true.

Keeping in mind that our past forecasts of snow accumulation have been very accurate (and that our predictions for snow amounts in other locations for this storm were also so).... In regard to improving our forecasts, we have to be careful to distinguish between the general picture (which may portend doom), and the specific picture that may not be quite so bad. Fortunately, a post-storm investigation shows that on the day of the storm our highest resolution forecast was reasonably able to predict the subtleties of the snow accumulation patterns. Now that I am better appreciate this, I will be better able to use the forecast model to provide even more accurate snow predictions (or at least this is the plan).

This winter has been above normal on the wet side, and it certainly is off to a snow-good start. In fact, this Wednesday brings another chance of snow -- at least in the high elevations of Jerusalem and Gush Etzion, as well as the north.  When we get more details, we'll report them.  However, it may turn out to be just a window snow, as the temperatures may not be cool enough for sticking snow in most places other than the far north and Golan.

Looking almost two weeks out, we see a hint of an even bigger and stronger event. Now, wouldn't that be something.

Barry Lynn

Barry Lynn

Sunday, January 11, 2015

Weather It Is (1:43 AM: Dynamic Cooling)

There was a bit of snow on the windows in Efrat, but not it is just rain (and warmer, too).
Good late night.

I woke up with a start.  Actually, I went to bed with the latest forecast showing snow in Metula, Safed (less) the Golan (more), the mountains north of Jerusalem, and possibly in the best elevations of Gush Etzion.

So, what is going on? The cold of the last few days has been a little slow to leave, but also the storm is very intense and undergoing what is called "dynamic cooling." (http://www.srh.noaa.gov/topics/attach/html/ssd98-10.htm). This is what happens from a sharp decrease in pressure.

We see the impacts of dynamic cooling in the 700 and 500 mb temperature traces, as well as the 500 mb height fields.

What does this mean for those of us on the "border" of rain/snow in the center.  We really are right on the border in Gush Etzion/Jerusalem.  A half degree downwards could make a difference (and surface temperatures here are just 1 C). So, hard to tell what it will be, but I wouldn't mind a surprise in the morning -- even if this surprise is not  the likely scenario.  Still, the storm will peak in the next few hours so it will be interesting, and our snow model shows a light snow accumulation.

Snow on Wednesday is still possible and may have gotten a bit more likely in the high elevations of Gush Etzion, the Galil, and Golan.

Barry Lynn

Saturday, January 10, 2015

Weather It Is (Heavy Rain)

Good Evening:

After a very snowy late Friday afternoon in Efrat (6 inches/15 cm), our weather will change back to a more typical winter time pattern (or at least what used to be typical and is more frequent this year): rain. 

It was an amazing snow event, and the snow fell at more than an inch an hour.  Overall, the precipitation amounts were predicted quite well by the model (about 12 ml), with the last third or so falling as a dry, fluffy, fast accumulating snow.  The snow came in bands -- almost like a "lake-effect" snow (e.g., lake effect snow from Lake Erie) -- as extremely cold air overlay the relatively warm sea-surface temperatures.  The gradient in temperatures between the 850 mb level and the sea-surface may have been as high as -24 C (20 C to - 4 C).  With extremely cold temperatures at 700 mb (-15 C) and 500 mb (-30 C), the moisture was able to fuel very strong convective clouds that led to white out conditions in the area of the central mountains. 

The snow started to accumulate at a rapid rate from about 3:30 onwards (and especially after 4:30 P.M) as temperatures fell to 0 (and then below).  After the snow stopped, I noted a -3 C temperature on our weather station.

Otherwise, a strong low pressure area will spread heavy rain into the coastal regions tonight and the center of the country towards morning.  The rain will spread to the south on Sunday morning.  Rain will probably cause flooding in low lying areas and in stream/river beds. 

The system should pass through Sunday afternoon.

Looking ahead, there is a chance for more winter (snow) weather on Wednesday.  The chance of snow in the higher elevations of the center is 40%.

Barry Lynn

Friday, January 9, 2015

Weather It Is (Latest Update)

Latest forecast.

The storm should continue to produce light precipitation throughout the day.  Surface temperatures are now forecast to fall below freezing about in the Jerusalem area sometime around 5 P.M, when there may be a coating of snow that will remain into the night and ice the roads.

In Gush Etzion, temperatures should fall below freezing around 4 P.M, when the light precipitation will be more likely to stick and produce a coating to several centimeters that will remain into the night.

Barry Lynn

Weather It Is (7:23 AM Update: Certainty/Uncertainty)

Quick Update at 7:23 AM:

My favorite words: "Abba it's snowing."  It is snowing in Gush Etzion.

Temperatures have dropped to near freezing and will continue downwards during the day (provided the sun doesn't peak through the clouds).

The last snow event produced about 15 cm here in Efrat, although almost 65 ml of precipitation was measured.  That is, we converted less than a quarter of the precipitation amounts to actual snow that was measurable.  Much of the accumulating snow fell in thunderstorms (or as "thundersnow").

Today, the temperatures at 850 mb and 700 mb will trending downwards, and will be 1 or 2 C cooler than in the last storm.  Hence, we are likely to convert a higher percentage of precipitation totals into accumulating snowfall.  On the other hand, since this snow will be mostly produced from altostratus and nimbostratus clouds (rather than cumulonimbus) -- as the atmosphere is not as unstable and the moisture source is less than in the previous storm.  As the precipitation rates will be lower than in the last storm,  the snow may "find" it harder to stick (or accumulate).  It all depends on the precipitation rate and surface temperatures.  The rate should be less than with part 1 of this storm, but the temperatures should be cooler.  So, the potential is there, but not easy to predict whether it will be realised -- other than that the roads may become treacherously dangerous.

As the coldest air arrives this afternoon at 500 mb, there will be the possibility for enhanced snowfall rates.

Barry Lynn


Good Morning:

We're certain that temperatures will continue their inexorable fall downwards today.  We're certain that it is going to get very cold -- downright cold.

We know that generally the storm forming in this extremely cold influx of air has some moisture associated with it.  We see patches of light to moderate precipitation on the radar. We know that generally 5-10 cm might fall in Jerusalem, and we know that 10-15 cm might fall in the area of Gush Etzion. However, we are far from certain that the precipitation will fall heavily enough to accumulate or exactly when it will change to snow.

We can only speak about potential, and of course -- we all live our lives according to what we hope is our potential.

Because it will be getting colder, and we see that the coldest air will arrive by early afternoon aloft -- travel is not advised today in the higher elevations of Jerusalem and Gush Etzion.

Travel south is also not advised as there may be flooding of rivers and stream beds.

Shabbat will start to see a warm up, and rain, or possibly snow changing to rain is expected Saturday night into Sunday.

Otherwise, possibly rain mid-week, and then not much of winter (nor spring) is seen afterwards -- just a break in the inclement weather.

Shabbat Shalom,

Barry Lynn

Thursday, January 8, 2015

Weather It Is (Snow/Extreme Cold + Summary)

Good Afternoon:

We all hope that the little things we do can make a difference -- little storms may think similarly.

The after effects of our powerhouse of a storm linger today, and there has been intermittent snow (in the higher elevations) and rain across the country. 

Yet, tonight and tomorrow's storm -- while of relatively small scope and impact -- may have profound affects on the central Jerusalem region (somewhat spared by the mega-storm). 

The weather will change tonight and it will bring remembrances of the "The Day After Tomorrow." In the movie: "The superstorm sucks vast quantities of frigid upper atmospheric air down to the surface, flash freezing any living thing caught outside" (http://www.wunderground.com/resources/education/thedayafter.asp).  

While not physically plausible the change in our weather to sub-freezing temperatures will feel extreme in the least. In fact, this is the first time I have seen the Global Forecast Systems (GFS) model (of relatively coarse resolution) produce below freezing temperatures in Efrat (by Saturday morning). 

While we know it is going to get cold, the wrinkle in the forecast is the precipitation amounts and the changeover to snow from Jerusalem Southwards. The moisture field with this storm is suppose to be from about the mountains of northern Jerusalem southward, while the GFS indicates that the heaviest precipitation amounts will be just south of Jerusalem.  

The temperatures at 850 mb should be about freezing early this evening and then drop to minus six! by tomorrow evening. The temperatures at 700 mb should drop from about -10 to -16 C during the same period.  The 500 mb temperatures will fall below -25 C by midnight tonight (Thursday).  With the cold temperatures and moisture field, we expect a change over to all snow (certainly by morning) and then it is on to the deep freeze. 

In terms of snow amounts, we should expect less to the north and more to the south. One might estimate 5 cm in Jerusalem, 10 or 15 cm in Gush Etzion and on the higher mountain ridges in the south. It all depends on the this relatively small scale storm and its moisture field translates into a precipitation pattern that affects real people. 

Other weather highlights: flooding in the Arava is a strong possibility. 

The storm predicted for Saturday night/Sunday is not well resolved yet by the forecast models.

I can infer that our snow predictions were quite good in the city of Sefad, the Galilee peaks, and the Golan (where 25-50 cm or more fell).

In Jerusalem, the failure of the models to correctly predict the late onset of the precipitation made a big difference in snow amounts: Jerusalem had 5 cm while out here in Gush Etzion there was 15 cm (about a third of what was predicted, but travel came to a stand still nevertheless).  Ironically, the forecasts prediction of light snow ahead of the big-push of moisture (delayed, of course) was quite good and made for a feeling that this was going to be a good forecast day.

Barry Lynn

Yedioth Ahronoth says that Jerusalem was disappointed by its few centimeters of snow, compared to the northern city of Safed, whose veteran residents said they don’t recall a snowfall like Wednesday’s (the city got 68 millimeters of precipitation).

Read more: The calm after the storm | The Times of Israel http://www.timesofisrael.com/the-calm-after-the-storm/#ixzz3OEuZzJq8
Follow us: @timesofisrael on Twitter | timesofisrael on Facebook


Weather It Is (The Storm Synopsis)

Good Morning:

There will be periods of snow in the higher elevations of Jerusalem and Gush Etzion this morning, but they will mix with rain from time to time.  Most of the precipitation will be in the center of the country.  There may be a light accumulation where temperatures remain near freezing.

The snow will mix with rain and change to light rain later this morning.  In other areas of Jerusalem, there will be just plain rain.

The next weather story is the extreme cold, which should begin to arrive after midnight and will probably bring a light covering of snow to the center mountains, including Jerusalem.  It will also freeze the water on the roads. The extreme cold will, of course, extend to the higher elevations of the north where snow fall was much more extensive.

Another storm will approach late Saturday. It will bring a lot of precipitation that may start as snow, or be a mixture of rain and snow.  It is more likely to be more rain than snow.

There is the possibility of another storm mid-week.  There is a small chance of snow with this system as well.

Barry Lynn

Wednesday, January 7, 2015

Weather It Is (Evening Update)

Good Evening:

The wind gusted to 76 km/h this evening in Efrat.  During the afternoon, there were periods of heavy snow, which accumulated about 4 inches (or about 10 cm).  This is about half what was expected by evening.  The forecasts consistently showed heavy precipitation during the noon time period, yet, storms along the coastal region dissipated (for the most part) before reaching the central mountains.  Hence, the lower snow and precipitation amounts.

The forecast for the rest of the night and morning is for periods of snow and cold temperatures.  Another 10 cm or so will probably accumulate in the higher elevations of Gush Etzion and Jerusalem.

Strong winds will become lighter by morning.

From midnight Thursday until Friday night the temperatures will fall by 3 or 4 C, freezing slushy roads.  Associated with the cold air push will be some light or moderate snow, with a light or moderate accumulation.  Driving in snow covered areas may become impossible by Friday morning/afternoon -- unless roads are cleared of snow and ice beforehand.

On Shabbat (Saturday), the temperatures will slowly warm as another storm approaches from the west. There should be a lot of moisture associated with this storm.  Right now, it looks like this storm may produce some wet snow/graupel that will likely change to rain, and possibly wash away much of the snow.  There is still some uncertainty with this storm -- as there may still be some phasing with the northern jet stream -- so it will have to be watched closely.

There is a 20% of another significant storm mid next week.

Barry Lynn

Weather It Is (Afternoon Update)

Good Afternoon:

Heavy snow occurred in the northern mountains during the night as forecast. This morning's heavy rain and extremely strong winds developed as forecast along the coast.  This morning's light snow occurred in the central mountains as forecast.  There was even a period of heavy snow in Jerusalem.

These early afternoon hours snowfall have not yet materialised.

Yet, the latest 4 km ensemble forecasts continue to show precipitation moving into our area and continuing through the night.  The 1.3 km forecast continues to show snow accumulation into Thursday morning. The overall synoptic pattern remains the same, with temperatures forecast to cool aloft during the next several hours.

With all that, it is apparent, however, that the forecast timing of the heavy precipitation into the central mountains has not been accurate. The total amounts forecast remains the same as before.

The question is: is this a matter of timing, or simply a change in wind directions that have pushed the heavier precipitation a bit further north?

Considering the consistency of the forecasts, we must conclude that the forecast timing of the system is off and that snow and very cold temperatures should still be expected.

Moreover, Friday's event is still highly probable and temperatures are suppose to be even colder than this storm (possibly a couple of degrees below freezing at the surface in many mountainous areas), where any water on the roads will freeze and snow will be hard to remove from the roads. However, it is not yet possible to forecast amounts of snow, although they should be lighter than forecast today.

The forecast storm for Saturday night remains unclear.  It will be cold enough for snow at higher levels (500 mb), but it may be too warm near the surface (850 mb).  A substantial amount of precipitation is expected with this storm.

There is a 30% chance of another storm mid next week.

Barry Lynn

Weather It Is (11:30 Update: A Personal Plane or Armageddon?)

Good late morning:

My wife told me last night that I should immediately withdraw my snowy forecast. She is afraid of a great embarrassment. It is fine to be married to me when I am correct, but the alternative? She has gone so far as to order me a personal (plane) transport so that I can be whisked away as soon as the sun peaks through the clouds.  Perhaps, she prefers to be on the plane. 

However, a quick glance at the radar shows a convex shaped squall line half way between Tel-Aviv and Jerusalem.  I believed this is called a Derecho, and it will arrive with fierce winds and heavy (snow) precipitation within the hour.

We had a gust of 66 km/h.  

Of course, I will better about things after I can go out and measure the snow. 

Otherwise, no change in the forecast.

Barry

Weather It Is (10 AM Update)

Good Morning (10 A.M):

The latest forecast data (from the 00 UTC update) confirms the original schedule for snow fall for Jerusalem, arriving with the heavy precipitation band between 11 AM and 2 PM. 

The lighter snow occurring now is simply the forerunner along the frontal system and arrival of sub-freezing temperatures.

Barry Lynn

Weather It Is (Early Wednesday Morning Update)

Good Morning:

***Heavy snow band may arrive in the center as early as 9 or 10 A.M.***

Previous.

Heavy, blinding snow on the way!

Temperatures at or below freezing.  Wind chill temperatures even colder (currently -5 C in Efrat).

The latest forecast shows a chance of light snow this morning after 8 A.M in the Jerusalem area.

IMS radar shows an intense trainband off the coast stretching through Haifa and into northern Israel.

This rain band will move into the coastal region this early morning and reach the northern central mountains between 8 and 11 A.M. There it will accumulate 10 cm or more of snow in three hours. It will then move southward into Jerusalem and Gush Etzion shortly thereafter.

The rain will be all snow, with the potential for between 10 and 20 cm broadly across the Jerusalem and Gush Etzion area between 11 AM and 2 P.M.  By this evening, accumulations will approach or exceed 25 cm broadly across the center region, with more snow tonight.  By Thursday morning, accumulations will likely double again to broadly 50 cm across the center.

Accumulations in Sefad will be 25-50 cm.  In the Golan: 50-100 cm.  On Har Hermon, > 1 meter.

Very strong winds during the day will create blizzard conditions.  Beware of your surroundings!

Heavy rains in the Jordan and Dead Sea Valleys will cause flooding from late morning onwards.  Flooding is likely in the Arava after noon and night.

Barry Lynn

Tuesday, January 6, 2015

Weather It Is (Tuesday Evening Blizzard Update)

Good Evening:

The forecast map shows a phasing of the northern (Europe) and southern (Mediterranean) jet streams.  This is unusual, and in some years never happens at all. In the previous four years, this has occurred at least once, and last year with great intensity.

This year's storm at first glance is not as intense as last year, as the total moisture available to this storm is less. Moreover, it was thought that it would come in on Wednesday and be gone by Thursday.

However, temperatures will be quite cold as a massive front moves in off the coast tomorrow morning and sweeps through the coastal regions and up into the mountains. Hence, the precipitation will start as snow in the mountains and accumulate at the rate of two to three inches per hour over several hours, before moderating a bit.  However, even as the moisture flow moderates, the temperatures will be cooling to extremely cold levels aloft (-32 C at 500 mb), which will wring the atmosphere moisture in periodic convective bursts.  Hence, snow accumulations will be expected at night and will continue into a good part of Thursday.

This was suppose to be the end of story.  That is, the story would end when the phased trough would move off to the east and the northern jet stream decoupled from our southern stream (our cut-off low would weaken and dissipate).

Yet, an unusual weather pattern is forecast to develop where the cut-off low will move just off to our northeast east and start subsisting on and sending back our way frigid Siberian air.  This frigid air will slowly, but inexporably cool the lower atmosphere, and this cold layer will soon interact with another wave moving through the southern Jet stream to create another round of snow (likely accumulating) on Friday into Friday night.  Moreover, we're going to quite possibly repeat this pattern on Saturday night into Sunday, where moisture amounts may lead to an even more significant snow.

Lastly, our global ensemble suggest a 40% chance that another phasing of the north and southern streams may occur mid-next week.

Some might think that we're going from bad to worse, and then from worse to worst. Others might think this just a cap and a feather on their snowmen.

In either case: get ready for snow, high winds, and frigid temperatures that will make last year's storm seem a bit tame by comparison.

Please keep in mind that the snow won't announce itself, it will just come and come with a vengeance.

Barry Lynn

Weather It Is (Blizzard Warning, Heavy Rain, Gale Force Winds)



Here are the Warning and Advisories.


Advisories/Highlights (changes):

WINDS (Gale force)
High wind warning from Tuesday morning into Wednesday night along the coastal sections (north, central, and south), Galilee, and Golan.
Heavy Wind warning from Tuesday afternoon into Wednesday night in center. Strong winds in south.

RAIN
Tuesday Evening to Wednesday Morning:
North Coast (Carmel): 25-50 ml.
Golan/Hermon: 25-50 ml (snow; see below).
Wednesday to Thursday morning.
Central Coast: 25-50 ml 
Inland Plain: 50-100 ml
North Coast (inland): 50-100 ml (total).
Golan: 50-100 ml (snow; see below).
Hermon > 100 ml (snow; see below).

FLOOD WARNINGS:
Jordanian Valley late Tuesday night and Wednesday.
Dead Sea Valley: Wednesday and Thursday.
Arava: Wednesday and Thursday.

SNOW
Tuesday Night:
Golan: 25-50 cm.
Sefad: Rain to Snow (10 cm). (This is a change.)
Wednesday Morning until Thursday Morning:
Sefad/peaks : 25-40 cm (total).
Golan: 50-100 cm (total)
Hermon: > 1 m (total).
Jerusalem: 25-50 cm 
Gush Etzion: 35-70 cm.
Southern Peaks: 10 cm.

Otherwise:
Periods of snow on Thursday in the Center (some accumulation). 

A 70% chance of heavy snow on Friday in north and center, including Jerusalem.  Snow possible again on Saturday night or Sunday.

Barry Lynn

Monday, January 5, 2015

Weather It Is (High Wind Warning)

High Wind Warning in the north from mid-morning through Tuesday.

High Wind Warning in the center from mid-afternoon onwards, through Tuesday night.

Weather It Is (Blizzard Warning!)

Good Evening:

Heavy snow and gale force winds in the north (Safed, Galilee peaks, the Golan) will occur Tuesday night. The combination of heavy snow and strong winds means that blizzard conditions will occur in these areas Blizzard conditions will continue in the north on Wednesday.

The snow should arrive early-to-mid-morning Wednesday in Jerusalem and mid-to-late morning in Gush Etzion and accumulate 25 cm by mid-afternoon.

Because of the snow amounts and gale force wind schools should/must be cancelled in Jerusalem and Gush Etzion on Wednesday (even if the snow doesn't arrive by sunrise).  Snow amounts and winds will combine to quickly produce blizzard conditions during the day on Wednesday throughout the area. 

When the snow arrive in the morning, it will accumulate immediately, heavily, and make travel quite dangerous if not impossible within a very short time.

Expected snow amounts by early Thursday: 25-50 cm in Jerusalem. 35-70 cm in Gush Etzion.  25 cm in Safed by Wednesday morning. 25-50 cm in Safed by Thursday morning.  50-100 cm of snow by Thursday morning in the Golan and more than one meter on Har Hermon.

Snow will be accompanied by lightning at times.

Expect flooding in the Jordan Valley, Dead Sea Valley, and Arava

Barry Lynn

Weather It Is (Winter (Heavy Snow) Storm Update

Good Afternoon:

The day of the big storm approaches, or more accurately: the days of the big storm(s).

We have arrived within the window of the three day 4 km forecast and it is fearsome.

The chance of snow in the Golan Tuesday afternoon, night and Wednesday is 100%. The chance of snow in Sefad and the Galilee peaks is 100% Tuesday night and Wednesday.

The chance of snow in Jerusalem (from Wednesday morning) is 100% into late Wednesday night, Thursday morning.

Precipitation totals will range from 25 to 50 mm along the coast, to 50 to 100 mm in the central mountains and Galilee, and greater than 100 mm in the Golan.

This corresponds to 25 - 50 cm of snow in Jerusalem by Thursday morning, 35-70 cm of snow in the hills around Jerusalem and Gush Etzion (and the Galilee), and 50 to 100 cm of snow in the Golan, with more on the Har Hermon itself.

The storm is expected to arrive Tuesday afternoon and evening in the north and north central areas, where up to 25 to 50 cm of snow will fall by morning on the higher peaks (with more in the Golan). The precipitation should approach the Jerusalem area by about morning, but then retreat briefly to the its north.

Soon after, heavy snow should redevelop and move in the Central (Jerusalem) and South-Central Areas (peaks) during the morning and continue throughout the day and night.  The heaviest snow should be over by sometime late Thursday morning or night, but periods of snow will continue throughout the day.

It is important to keep in mind that snow rates could be quite high, especially during the initial influx of frigid air Wednesday morning in the center of the country.

The extreme cold should linger into Shabbbat and there is a 35% chance of an additional (snow) storm on Friday afternoon and evening in the mountains of the north and central areas.

Gale force winds (with higher gusts) should develop Tuesday afternoon in the north and center. Strong winds and dust will cover the south to Eilat.

Expect flooding in the Jordan (Tuesday night) and Dead Sea Valleys (Wednesday), and Arava mid-Wednesday onwards.

Barry Lynn

Sunday, January 4, 2015

Weather It Is (Winter Storm: Sunday Evening Update)

Good Evening:

The details of our upcoming winter storm are slowly coming into focus, but only some of them.

For instance, we see that it will be generally cold enough for snow from the center to the north by around mid-night Tuesday night.  Our 4 km forecasts show that precipitation should overspread the area on Tuesday, but that precipitation with the coldest air will (or at least might) remain north of Jerusalem until about morning time.  Or, at least we can say that the heaviest precipitation is expected from Wednesday morning through Wedneday night from the north to the center (Jerusalem, Gush Etzion, and centre-south).

A heavy snow event is expected throughout the center, northern mountains, and Golan, with the snow starting Tuesday afternoon and night from the Golan into the Galilee.  Gale force winds will accompany the storm with higher gusts. Snow may fall on the southern mountains.

The cold air will remain entrenched into Friday morning, and steady snow should end around Thursday morning.

The forecast for Friday and Shabbat remains a bit unclear.  Another trough may try to build southward again and combine with another low moving in from the West on Friday.  Temperatures may cool at 500 mb potentially bringing another round of snow -- but the chance of snow is about 20%.  Rain is more likely on Friday and Shabbat.

The weather pattern looks like winter next week, with a higher chance of rain and possibly snow again next week.

Barry Lynn

Weather It Is (Winter Storm Warning)

Good Afternoon:

The chance of significant snow is 95% Tuesday night and Wednesday.

There is not much to update with today's forecast. We are still beyond the time period for which we can be anymore certain about snow amounts, and there is still some uncertainty in the strength of the developing 500 mb trough.

However, we can say that the chances for a return to a period of snow Friday Evening (Erev Shabbat) is now quite low.

It appears that the strongest synoptic scale forcing will occur on Wednesday as the coldest temperatures pass overhead at 500 mb. Winds will be very strong (Gale Force) Tuesday night and Wednesday.  There is a 75% chance that significant snow will continue to fall past midnight on Wednesday night.  There is a slight chance that significant snow will continue until Thursday morning, although periods of light snow are possible.

Surface temperatures in the southern, central and northern mountains will remain quite cold into Friday, and road surfaces might freeze and unfreeze at any time (depending on the exact local temperature).

Travel in the mountainous areas will likely be impossible without chains or four wheel drive vehicles.

Barry Lynn

Saturday, January 3, 2015

Weather It Is (Winter Storm Warning)

Good Evening:

The probability of (heavy) snow Tuesday night and Wednesday is now about 90%.

Today's rain arrived on schedule, and now most of the Global Ensemble Forecast System forecasts indicate a major winter (snow) storm on Tuesday night into Wednesday.

A ridge of higher pressure will shoot up into northern Europe and open the atmospheric gates for extremely cold air to plunge southward into the eastern Mediterranean Monday night and Tuesday. The cold air and energy from the northern jet stream will interact with a strong winter storm in the southern jet stream moving across the Mediterranean Monday into Tuesday.  This will cause a surface low to deepen rapidly on Monday and move into our area at about 995 mb (an intense winter storm for our part of the world) on Tuesday afternoon.

The snow amounts can only be predicted generally because we are still not within the forecast window of our high resolution models. Moreover, there is still some room for changes in the intensity of the storm as the two Jet streams complete their phasing. However, the general amounts indicate 10 cm or more (somewhat lower elevations), 20 cm in the Jerusalem hills and Safed, with possibly 30 cm in some higher locations (of Gush Etzion).  Snow should fall in the Golan, Galilee peaks, and Central Mountains and possibly in the mountains of the south.

Winds will increase on Tuesday afternoon and reach sustained speeds of 50 to 60 km/h with higher gusts.

Heavy rain should fall in the coastal regions (north to south) with the possibility of flooding in these areas and in the Jordan and Dead Sea Valleys.

The chance of heavy snow in the central mountains is 25% Tuesday evening, 90% Tuesday night, 90% Wednesday, and 60% Wednesday evening.  More moderate snow may continue into Thursday morning, and cold weather should remain at least into Friday. Again, exact details must wait until we can see them in our high resolution forecasts.  Snow is possible in Safed late Tuesday afternoon and more likely in the Evening.

Barry Lynn

Friday, January 2, 2015

Weather It Is (Not to be a "Nudnik")

Good Afternoon:

They say to be a good weather forecaster one has to be tenacious and very detailed oriented, or perhaps obsessed with details might be more appropriate.  My wife, though, had a different word for it, and the story begins here.

The other night I interrupted her moment of "solitude" with something I thought quite important.  While talking, one of our daughters came by with a request, to which I replied that she should have been in bed two hours before (instead of still wandering the house).  My wife -- being a teacher -- of much knowledge and wisdom remarked that "if the father is a 'nudnik' than the children are nudniks."

Now, I wonder about this.  There is a large debate in the scientific world about the importance of genes versus environment in raising children. I can tell you that my parents are not nudniks, and that I  never heard the word nudnik growing up -- and (actually) not until I was married.  This means that somehow I've spontaneously become a nudnik, and my children (or at least some of them) have now inherited (or rather acquired) this trait from me -- Aristotle and Lemarck not withstanding.

Well, if one must be one, one might as well take advantage of it and I seem to have a ready venue (weather) to express it.

There will rain developing from the north to south tonight and continuing on Shabbat .  Most of the rain will fall from late morning into Sunday along the coastal regions and in the center of the country..

The rain with the next winter system is expected to arrive late Tuesday and temperatures will quickly fall thereafter.  Although the  forecast picture remains a bit fuzzy, we see the likelihood of cold air arriving Tuesday night at lower and middle levels.  During the day on Wednesday, a very strong 500 mb trough will move through and create a period of heavy precipitation.  This may be relatively fast moving (12 hours) or develop and move more slowly (36 hours).  We still can't tell which type of system it will be.   The probability of a wintertime snow storm remains at 60%.

Overall, the chance of a significant snow Tuesday night is 25%, while the chance of snow on Wednesday is 60%.  The snowfall may vary from as much as 12 hours (on Wednesday) to possibly 36 hours into Thursday morning.  Temperatures look to continue  to be quite cold from Wednesday morning and may actually become even colder Thursday morning when there is a possibility of another round of precipitation (most likely snow -- but we need to see later forecasts to be more sure about this). In any case, roads should remain snow and ice covered into Friday (assuming the snow occurs to its possible potential).

Shabbat Shalom,

Barry

Weather It Is (An Early Morning Update)

Good Morning:

The forecast for Shabbat remains the same: rain amounts generally 25 to 50 mm, with most of the rain falling on Shabbat into Sunday.  Occasional gusty winds and lightning in stronger storms.

The latest forecast has pushed the timing of our next  possible winter snow storm into Wednesday, with only a small chance of snow beginning Tuesday night.  However, if the storm develops earlier than this, than it is more likely to be rain (see below).

The likelihood of snow still remains about 60%, as much about the development of the next storm remains unclear. As mentioned, the key to a heavy snowfall is a strong interaction of the northern jet stream with the developing storm in the southern Jet stream. A strong development will lead to lots of cold (Siberian) air moving southward into our area, leading to intense surface low development just off our coast in the far eastern Mediterranean.

Lesser development means that there will only be rain with this next storm (which would fall mostly on Tuesday and Tuesday night).  Some phasing of the streams would mean heavy rain Tuesday night changing to mixed rain and snow on Wednesday.  A complete phasing means that there will be heavier amounts of snow of around 20 cm, which would occur most likely on Wednesday into Thursday.  The last scenario is the most likely.

Shabbat Shalom,

Barry Lynn

Thursday, January 1, 2015

Weather It Is (A Winter Storm Clarification)

Good Evening:

Everyone is talking about it -- next week's snowstorm -- but it necessary to step back a moment.

As I wrote before, the development of a snowy winter storm depends on the phasing of the northern and southern jet streams on Tuesday.  Some of the uncertainty in the forecast may be because the northern system is originating from a relatively data sparse region. On the other hand, two days before our next storm system we still see some large differences in the strength of the 500 mb trough (which is necessary to develop a strong surface low) that is moving in from a region with greater data availability.

Right now, there is a 60% chance of a significant snow storm Tuesday night into late Wednesday.  The snow is more likely after midnight and most likely on Wednesday.

The important point is that 40% of the forecasts do not show a significant snow storm, or 4 out of 10 times we have a situation like this there would be no significant snow.

We need to wait 1-2 days to see how the probabilities change (or, how the jet stream phasing progresses in the forecasts), and then until a day or two before to be more exact about snow amounts (assuming we get this far).

So, it is okay to be excited, but "not" okay to change plans yet -- unless absolute necessary (or possible without too great an expense).

Barry Lynn

Weather It Is (Winter Storm Afternoon Update)

Good Afternoon:

There are two storms that should impact the State of Israel late this week and next.

The first will arrive in the north on Friday, but most of the rain with this system should fall Shabbat morning, afternoon and evening. Total amounts will be generally between 25 to 50 mm in the central and northern coastal regions, with greater than 50 mm in the far north.  Amounts in the center should be around 25 mm.  There will be occasional wind gusts greater than advisory levels and lighting/hail in the stronger storms.  Snow amounts of 10-25 cm are expected on the Hermon.

Our next storm is expected to arrive Tuesday evening and last into Wednesday.  Right now, there is about a 60% chance of significant snow in the higher elevations of the Golan, Galilee, and central mountains, including Jerusalem.  There is a 30% chance of sustained gale-force winds Tuesday night into Wednesday morning, with lightning likely in convective storms, including snow bands.

We're still six to seven days away from this event, and there is still a lot of uncertainty in the development of the 500 mb trough, which depends on the phasing of the northern and southern Jet Streams.  The higher amounts of rain and snow refer to forecast scenarios in which there is greater phasing of these Jet streams (e.g., 25 cm). In the worse scenarios, significant snow will fall well into Wednesday and temperatures should remain at or below freezing in the higher elevations into Thursday.

On late Monday, we expect to be able to see with our 4 km forecast more clearly how much snow will fall with this event.  On Tuesday morning, we will be able to provide even more exact amounts by combining our 1.3 km forecast with the 4 km ensemble output.

Barry Lynn


Weather It Is (A Snowman, Some Pressure)

Good Morning:

Of course, there are many folks who want to build a snowman.

https://www.youtube.com/watch?v=6ZOI1yUGPBQ

or the classic ("Frosty The Snowman"): https://www.youtube.com/watch?v=vjscH2WBWjw


Of course, there are those who don't want anything of the kind, and I hear from of them ("him") often.

Last night, my wife came downstairs in her "deerskin" boots.  When I noticed she said: "I heard it's going to snow next week.  Why does it have to snow? I hate snow."

How can it be you ask?  What would our marriage be like if it snowed more often?

Then, she heads out and says: "it's raining!"  You're forecast is broken.

My daughter asked me if we would have school on Wednesday.  My son says that everyone asks him if it will snow -- and now it better snow or else.

I'd like to escape.  Remember, there is a chance it won't snow and I really don't want to be around if it doesn't.  After all, there are people I know, people I know by sight, and people who I know by e-mail. So, I may just head off to Sunny Florida.  If it rains there, I will head over to Hawaii. If the waves are too large, I'll head down to Australia. Of course, I might be eaten by a crocoliles, so there really is no escape.

Escape from winter, that is.  Our weather maps show rain on Shabbat, with a small possibility of mixed rain and snow Shabbat afternoon, but more likely hail in strong thunderstorms.

We can see now that snow chances are up to about 70% for late Tuesday afternoon into Wednseday morning.  The precipitation amounts predicted by the GFS ensemble are quite large, so even though this may be a single day event, snow amounts could be relatively high (but less than last year by half, most likely).  Temperatures should remain cold at 700 mb through the afternoon, so lighter snow may continue through then.  Temperatures at the surface will remain cold through Thursday, so icing conditions are likely through then as well.

Still, keep in mind that we're not certain about this event, but the latest chances for snow are certainly higher than they were yesterday.

The next forecast will tell us more.  I may then write next time from a warmer climate.

Barry Lynn