Good Evening:
Last week we spoke about the things we know, the things we know are not known, and the things that we don't know we don't know.
There are still plenty of things we don't know we don't know, but the things we know (or don't know) are becoming better known.
For instance, we see that our next storm -- to arrive immediately after the relatively weak (but still) wet) storm affecting us now will bring cold temperatures aloft, but nothing too chilly at lower levels. This means periods of rain mixed with graupel/hail. This storm will be arriving from our west, as higher heights (NAO) build over Greenland - meaning that initially the ridge trough couplet (west to east, respectively) will be located at first too far to the west -- so the lower levels in the next storm will be moderated by the warm sea.
In contrast, we now have indications that the storm that should follow Shabbat or early next week will arrive from the north (as Siberian air makes its way southward). Our current forecasts show a 60/40 in split in favor of extremely cold temperatures aloft. This means that the forecasts are clustering around either a cold, snowy "solution" to the equations that describe our future weather or a warmer solution, with a lean toward the colder forecasts. However, there is less certainty about lower level temperatures. Still, many ensemble members show temperatures below freezing at least at some point during the storm.
So, we know that we can be more positive about the possibility of our first snow (in the Jerusalem area) early next week, but there are still a lot of unknowns (just how directly the storm arrives from the north) and even unknowns we don't know -- besides model errors, how many people want snow or don't want snow, which can sometimes tip the balance.
Barry Lynn
Sunday, December 30, 2018
Thursday, December 27, 2018
Weather It Is (Things We Know: Or will it Snow?)
Good Afternoon:
I am sure that many readers appreciate the heavy rainfall, but more it must be satisfying to know that winter in Israel can still feel like winter's past!
To understand what may be in store for us next week, we need to review a bit of history.
"Reports that say that something hasn't happened are always interesting to me, because as we know, there are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns—the ones we don't know we don't know."
Mr. Rumsfeld was far more prescient than he possibly knew. He might just have been speaking about the weather, if not the weather we "expect' next week.
Here are the things we know: We know that the global weather forecasts are showing the possibility of the coldest weather in many years to arrive next week. We also know that there will be prolonged and heavy precipitation over several days. Lastly, we know that there is no "flip-side" to the forecasts. We're not seeing an equal number of equally unusually warm vs unusually cold forecasts within the global ensemble. It's either winter as usual or winter as we've not known it for many years (perhaps going back to the time when snow fell in Tel-Aviv in 1950 (see: https://en.wikipedia.org/wiki/Snow_in_Israel).
However, there are many known unknowns. For example, there is something referred to as the North Atlantic Oscillation. It has no significance by itself, but a negative NAO index indicates a weather pattern that can produce strong storms, but storms that drop down west of Cyprus, and then move across the sea. This means that these storms warm up in their lower levels too much for any heavy snow in the Jerusalem area. While half our forecasts are indicating abnormally cold air towards the end of next week, the other half are not. . We just don't know how strong a "Ridge" of warm air will build over Greenland (a negative NAO) -- which will determine not only how much cold air arrives earlier versus later in the week, but just how much of our precipitation falls as snow.
We also have unknown, unknowns: we often assume that when the forecast synoptic pattern of the global forecast indicates certainty (> 90%) then we can confidently use a higher resolution forecast model to forecast the details of the upcoming weather event. However, there are unknown errors and non-linear interactions that can grow to even create variability in an otherwise "certain" synoptic forecast pattern. This can turn what looks like a sure snow event into a missed forecast, and even our higher resolution forecasts can't correct for that (as they depend on the information they receive from the global model).
So, we left with uncertainty, but "hope" too (if you like snow). In any case, I can state with near certainty that a lot of people will be following the weather over the next several days and hoping for Jerusalem snow.
I am sure that many readers appreciate the heavy rainfall, but more it must be satisfying to know that winter in Israel can still feel like winter's past!
To understand what may be in store for us next week, we need to review a bit of history.
After the attack of "9/11," former United States Secretary of Defense Donald Rumsfeld stated:
"Reports that say that something hasn't happened are always interesting to me, because as we know, there are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns—the ones we don't know we don't know."
Mr. Rumsfeld was far more prescient than he possibly knew. He might just have been speaking about the weather, if not the weather we "expect' next week.
Here are the things we know: We know that the global weather forecasts are showing the possibility of the coldest weather in many years to arrive next week. We also know that there will be prolonged and heavy precipitation over several days. Lastly, we know that there is no "flip-side" to the forecasts. We're not seeing an equal number of equally unusually warm vs unusually cold forecasts within the global ensemble. It's either winter as usual or winter as we've not known it for many years (perhaps going back to the time when snow fell in Tel-Aviv in 1950 (see: https://en.wikipedia.org/wiki/Snow_in_Israel).
However, there are many known unknowns. For example, there is something referred to as the North Atlantic Oscillation. It has no significance by itself, but a negative NAO index indicates a weather pattern that can produce strong storms, but storms that drop down west of Cyprus, and then move across the sea. This means that these storms warm up in their lower levels too much for any heavy snow in the Jerusalem area. While half our forecasts are indicating abnormally cold air towards the end of next week, the other half are not. . We just don't know how strong a "Ridge" of warm air will build over Greenland (a negative NAO) -- which will determine not only how much cold air arrives earlier versus later in the week, but just how much of our precipitation falls as snow.
We also have unknown, unknowns: we often assume that when the forecast synoptic pattern of the global forecast indicates certainty (> 90%) then we can confidently use a higher resolution forecast model to forecast the details of the upcoming weather event. However, there are unknown errors and non-linear interactions that can grow to even create variability in an otherwise "certain" synoptic forecast pattern. This can turn what looks like a sure snow event into a missed forecast, and even our higher resolution forecasts can't correct for that (as they depend on the information they receive from the global model).
So, we left with uncertainty, but "hope" too (if you like snow). In any case, I can state with near certainty that a lot of people will be following the weather over the next several days and hoping for Jerusalem snow.
Barry Lynn
Monday, December 24, 2018
Weather It Is (Rainy with Some Ice)
Good Evening:
As we head into the end of the month, we've arrived at an almost: an almost (Jerusalem) snow storm.
Tomorrow, the winds will switch to the southwest at all levels of the atmosphere, bringing with them dry and warmer air, as well as dust. However, by Wednesday, the winds are forecast to switch back to the west by northwest, and temperatures will plummet. With the plummeting temperatures will come plenty of moisture, such that rain should return from the north to the northern Negev, and last into Friday, if not Shabbat.
On Thursday, forecast mean ensemble temperatures with this storm will be close to zero at 850 mb, and close to -10 C at 700 mb. This will combine with average temperatures at 500 mb close to -25 degrees. For snow to fall in Jerusalem, though, we need temperatures two to three degrees colder than the mean values just mentioned. It seems unlikely that we will reach these values, even if the coldest forecasts among the set of 20 forecasts actually occurs. Hence, while there is a chance of wet snow/rain on Thursday, it will more likely be rain mixed with ice pellets.
One might think that after our weather active November and December that January might take a few days off to bring us a bit more sun and warmth. However, the long range forecast shows cold (Israeli winter) weather continuing the first two weeks of January with periods of precipitation within.
We'll keep you posted.
Barry Lynn
As we head into the end of the month, we've arrived at an almost: an almost (Jerusalem) snow storm.
Tomorrow, the winds will switch to the southwest at all levels of the atmosphere, bringing with them dry and warmer air, as well as dust. However, by Wednesday, the winds are forecast to switch back to the west by northwest, and temperatures will plummet. With the plummeting temperatures will come plenty of moisture, such that rain should return from the north to the northern Negev, and last into Friday, if not Shabbat.
On Thursday, forecast mean ensemble temperatures with this storm will be close to zero at 850 mb, and close to -10 C at 700 mb. This will combine with average temperatures at 500 mb close to -25 degrees. For snow to fall in Jerusalem, though, we need temperatures two to three degrees colder than the mean values just mentioned. It seems unlikely that we will reach these values, even if the coldest forecasts among the set of 20 forecasts actually occurs. Hence, while there is a chance of wet snow/rain on Thursday, it will more likely be rain mixed with ice pellets.
One might think that after our weather active November and December that January might take a few days off to bring us a bit more sun and warmth. However, the long range forecast shows cold (Israeli winter) weather continuing the first two weeks of January with periods of precipitation within.
We'll keep you posted.
Barry Lynn
Monday, December 17, 2018
Weather It Is (Stormy Times)
Good Afternoon:
While the weather outside is pretty tranquil, there is a cool breeze and a definite chill in the air. You know things are serious when my Wife asks if it is going to snow.
Unlike me, she is a native Israel and very "in-tune" with the weather -- so long as she doesn't get confused by anything I might tell her.
There will be a series of storms in the next couple of weeks as storms move in from our northwest, before exiting to our east. There is even a hint of potentially a more significant storm as we move into the last week of December, with cold air arriving directly from the north. We've been seeing various members of the GEFS show temperatures below freezing at 850 mb the last week of December, which is necessary for snow to fall in the central mountains. In fact, you can see exactly that on the enclosed graph that shows the 850 mb temperatures over the next couple of weeks. Note that all members of the ensemble (each member is a line) indicate that the temperatures will be falling through the first half of the two week period (this coming week). Then, about half the members remain pretty much the same, but a quarter warm up and a quarter of them get even colder with some forecasts going below freezing. (Actually, the first week of January also looks to be cold, based on the CFS (the Climate Forecast Systems Model)).
So, are you an optimist or a pessimist, and how shall we define that? Perspective and historical background is everything. "Some like it cold, some like it hot, and some like it in the pot, 9 days old."
In any case, it is interesting to note the perspective of Saeb Erekat, the so-called foreign minister of the "State of Palestine." Responding to Australia recognizing "West Jerusalem" as Israel's capital he said: "“All of Jerusalem remains a final status issue for negotiations, while East Jerusalem, under international law, is an integral part of the occupied Palestinian territory" (italics added) see: https://www.timesofisrael.com/erekat-slams-australian-recognition-of-west-jerusalem-as-israels-capital/). What he says might be construed as a contradiction, or he simply means "what is mine is mine and what is yours is mine" (https://torah.org/learning/pirkei-avos-chapter5-13/). It's amazing how well Mr. Erekat knows Jewish religious texts, for someone who denies that Jerusalem was ever part of Jewish history or that the Jewish Temples ever existed. Or perhaps he is just a wicked man, as so aptly described in Pirkei Avot (Ethics of our Fathers).
Barry Lynn
While the weather outside is pretty tranquil, there is a cool breeze and a definite chill in the air. You know things are serious when my Wife asks if it is going to snow.
Unlike me, she is a native Israel and very "in-tune" with the weather -- so long as she doesn't get confused by anything I might tell her.
There will be a series of storms in the next couple of weeks as storms move in from our northwest, before exiting to our east. There is even a hint of potentially a more significant storm as we move into the last week of December, with cold air arriving directly from the north. We've been seeing various members of the GEFS show temperatures below freezing at 850 mb the last week of December, which is necessary for snow to fall in the central mountains. In fact, you can see exactly that on the enclosed graph that shows the 850 mb temperatures over the next couple of weeks. Note that all members of the ensemble (each member is a line) indicate that the temperatures will be falling through the first half of the two week period (this coming week). Then, about half the members remain pretty much the same, but a quarter warm up and a quarter of them get even colder with some forecasts going below freezing. (Actually, the first week of January also looks to be cold, based on the CFS (the Climate Forecast Systems Model)).
So, are you an optimist or a pessimist, and how shall we define that? Perspective and historical background is everything. "Some like it cold, some like it hot, and some like it in the pot, 9 days old."
In any case, it is interesting to note the perspective of Saeb Erekat, the so-called foreign minister of the "State of Palestine." Responding to Australia recognizing "West Jerusalem" as Israel's capital he said: "“All of Jerusalem remains a final status issue for negotiations, while East Jerusalem, under international law, is an integral part of the occupied Palestinian territory" (italics added) see: https://www.timesofisrael.com/erekat-slams-australian-recognition-of-west-jerusalem-as-israels-capital/). What he says might be construed as a contradiction, or he simply means "what is mine is mine and what is yours is mine" (https://torah.org/learning/pirkei-avos-chapter5-13/). It's amazing how well Mr. Erekat knows Jewish religious texts, for someone who denies that Jerusalem was ever part of Jewish history or that the Jewish Temples ever existed. Or perhaps he is just a wicked man, as so aptly described in Pirkei Avot (Ethics of our Fathers).
Barry Lynn
Saturday, December 8, 2018
Weather It Is (Rainy Weather Continues)
Good Evening:
It's not often that I get to bask in the accolades of my admirers -- there aren't many and they don't all live in the same place. Still, it was nice to know that I've done a good job this year both forecasting the weather and arranging for quite a number of stormy days (we've got to sell an interesting product).
Fortunately, like a hitter on a hot streak, the rainy and wintry weather is forecast to continue through this coming week. The next substantial rain will result from a large amplified ridge (over western Europe) combining with a deep trough over the Mediterranean. It should arrive by Tuesday/Wednesday, and may be followed by another storm early the following week (but there is also the possibility that warmer and drier air could end our rainy streak).
It's raining while I write this blog, and it has generally been raining over a large portion of the country from about Jerusalem northward for a couple of days. You probably heard that over 150 mm of rain fell in places closer to the coast, flooding streets and even buildings. What was interesting about this storm was just how long it basically stayed in one location, with persistent heavy rain areas just north of areas with lighter amounts of rain (we had "just" 25 mm).
One can see below a forecast from our ensemble, which showed heavy rain falling within a 3 hour period Thursday night from Ashdod north to Netanya. The forecast correctly depicted the sharp north to south gradient of the area of heavy rain, and it did so throughout the storm.
This is reassuring, and points out the usefulness of ensemble (multi-forecasts) that can correctly predict small scale, but very important differences in rainfall.
Have a good week, and Happy Chanukah.
Barry Lynn
It's not often that I get to bask in the accolades of my admirers -- there aren't many and they don't all live in the same place. Still, it was nice to know that I've done a good job this year both forecasting the weather and arranging for quite a number of stormy days (we've got to sell an interesting product).
Fortunately, like a hitter on a hot streak, the rainy and wintry weather is forecast to continue through this coming week. The next substantial rain will result from a large amplified ridge (over western Europe) combining with a deep trough over the Mediterranean. It should arrive by Tuesday/Wednesday, and may be followed by another storm early the following week (but there is also the possibility that warmer and drier air could end our rainy streak).
It's raining while I write this blog, and it has generally been raining over a large portion of the country from about Jerusalem northward for a couple of days. You probably heard that over 150 mm of rain fell in places closer to the coast, flooding streets and even buildings. What was interesting about this storm was just how long it basically stayed in one location, with persistent heavy rain areas just north of areas with lighter amounts of rain (we had "just" 25 mm).
One can see below a forecast from our ensemble, which showed heavy rain falling within a 3 hour period Thursday night from Ashdod north to Netanya. The forecast correctly depicted the sharp north to south gradient of the area of heavy rain, and it did so throughout the storm.
This is reassuring, and points out the usefulness of ensemble (multi-forecasts) that can correctly predict small scale, but very important differences in rainfall.
Have a good week, and Happy Chanukah.
Barry Lynn
Wednesday, December 5, 2018
Weather It Is (Special Weather Statement)
Good afternoon:
A strong and very moist storm will bring extremely heavy rains to central Israel, with heavy (but lighter rains both over northern and southern areas).
Forecasts show greater than 100 mm of rain over central Israel, including Jerusalem, from Thursday morning into Friday, which will most likely cause flooding of streets and streams.
Barry Lynn
A strong and very moist storm will bring extremely heavy rains to central Israel, with heavy (but lighter rains both over northern and southern areas).
Forecasts show greater than 100 mm of rain over central Israel, including Jerusalem, from Thursday morning into Friday, which will most likely cause flooding of streets and streams.
Barry Lynn
Sunday, December 2, 2018
Weather It Is (A Wet Chanukah)
Good Afternoon:
There's a mosquito in our room, my wife says. However, while she says she's heard it every night, I've only heard it once, and I've never seen it.
A while ago, it got so bad that we bought a Mosquito zapping light. That should have solved the problem, but mosquitos (unlike humans) evolve quickly and our particular brand of mosquito spent their time daring each other to fly as close to the light without getting zapped!
Fortunately for us, Mosquitoes don't wear fur coats, and when it soon turns quite chilly and wet all we need to do is sleep with the windows open and the heat off, and the Mosquito zapping light will look like the best place to be.
So, why am I writing about Mosquitoes? Because I didn't want to mention from the "get-go" that temperatures are already falling at upper levels of the atmosphere, and tomorrow afternoon will probably see our warmest temperatures for some time to follow. But, it's not just that, it's the wind and rain that will probably persist until the end of the week, if not the end of the Chanukah holiday. If you have plans to light outside, you'll probably need an umbrella, and possibly a blow torch to light those candles.
The wet, cold, and wind is "courtesy" of a large amplified trough, initially located over central Europe with an extension into the eastern Mediterranean. The trough is actually forecast to amplify further and open a connection into the Ukraine, Belarus, and the polar regions of Siberia -- which could bring our coldest air in quite some time just as we move from Chanukah into the middle of the month.
All this spells pretty much doom for the mosquito population until next year. While, I don't suppose one of "our" readers can help us with this, perhaps someone can explain some other mysteries I've had pertaining to communication among species.
For instance, cat owners have probably spent a good deal of their waking hours exchanging "Meows" with their cats, and I've always wondered just what was said during these conversations. I'd like to know what I'm saying, too! Keep in mind, that you hardly ever hear a cat say "Meow" to another cat, so we're probably talking communication on a very basic level -- more like "baby talk."
Speaking of which, babies like to talk, but really no-one knows what they are saying, except perhaps other babies. Realizing this, and realizing that I had a unique opportunity to decipher baby talk, I asked my then 2 + year old daughter (who had just learned to speak "real" words) just what her brother and sisters were "jabbing" about. Amazingly enough, she couldn't tell me -- she'd already forgotten baby talk.
I think it's a shame because if I could understand baby talk, then perhaps I could teach my wife how to understand me and vice-versa. Right now, the only word I really know in Hebrew is the word ("Meatzben") which means annoying, irritating, frustrating, and bothersome all in one word. She didn't tell me what it meant, but I could guess (and I've heard the word often enough to remember it well).
Of course, there's the small issue of understanding the nuances of how husband and wives speak to each other. For instance, the wife says: "honey, the garbage needs to go out," and the husband says: "I'll do it," which means I will do it (in the future) -- and that's where the trouble starts.
Fortunately, I now have a calendar where I get a "smiley" face for every day I behave like the ideal husband I wish to be, and I find its a great motivator.
On a final note: George H.W Bush passed away the other day. While he and his Secretary of State had disagreements with the Israeli government during his presidency (https://www.timesofisrael.com/how-lonely-little-george-h-w-bush-changed-the-us-israel-relationship/), various articles have documented how much he helped the Jewish people in their time of need (https://www.jpost.com/American-Politics/Bushs-Israel-legacy-A-mixed-bag-of-positive-steps-but-little-warmth-573296). Perhaps, with this in mind, he died peacefully in his sleep.
Chanukah Samaech!
Barry Lynn
There's a mosquito in our room, my wife says. However, while she says she's heard it every night, I've only heard it once, and I've never seen it.
A while ago, it got so bad that we bought a Mosquito zapping light. That should have solved the problem, but mosquitos (unlike humans) evolve quickly and our particular brand of mosquito spent their time daring each other to fly as close to the light without getting zapped!
Fortunately for us, Mosquitoes don't wear fur coats, and when it soon turns quite chilly and wet all we need to do is sleep with the windows open and the heat off, and the Mosquito zapping light will look like the best place to be.
So, why am I writing about Mosquitoes? Because I didn't want to mention from the "get-go" that temperatures are already falling at upper levels of the atmosphere, and tomorrow afternoon will probably see our warmest temperatures for some time to follow. But, it's not just that, it's the wind and rain that will probably persist until the end of the week, if not the end of the Chanukah holiday. If you have plans to light outside, you'll probably need an umbrella, and possibly a blow torch to light those candles.
The wet, cold, and wind is "courtesy" of a large amplified trough, initially located over central Europe with an extension into the eastern Mediterranean. The trough is actually forecast to amplify further and open a connection into the Ukraine, Belarus, and the polar regions of Siberia -- which could bring our coldest air in quite some time just as we move from Chanukah into the middle of the month.
All this spells pretty much doom for the mosquito population until next year. While, I don't suppose one of "our" readers can help us with this, perhaps someone can explain some other mysteries I've had pertaining to communication among species.
For instance, cat owners have probably spent a good deal of their waking hours exchanging "Meows" with their cats, and I've always wondered just what was said during these conversations. I'd like to know what I'm saying, too! Keep in mind, that you hardly ever hear a cat say "Meow" to another cat, so we're probably talking communication on a very basic level -- more like "baby talk."
Speaking of which, babies like to talk, but really no-one knows what they are saying, except perhaps other babies. Realizing this, and realizing that I had a unique opportunity to decipher baby talk, I asked my then 2 + year old daughter (who had just learned to speak "real" words) just what her brother and sisters were "jabbing" about. Amazingly enough, she couldn't tell me -- she'd already forgotten baby talk.
I think it's a shame because if I could understand baby talk, then perhaps I could teach my wife how to understand me and vice-versa. Right now, the only word I really know in Hebrew is the word ("Meatzben") which means annoying, irritating, frustrating, and bothersome all in one word. She didn't tell me what it meant, but I could guess (and I've heard the word often enough to remember it well).
Of course, there's the small issue of understanding the nuances of how husband and wives speak to each other. For instance, the wife says: "honey, the garbage needs to go out," and the husband says: "I'll do it," which means I will do it (in the future) -- and that's where the trouble starts.
Fortunately, I now have a calendar where I get a "smiley" face for every day I behave like the ideal husband I wish to be, and I find its a great motivator.
On a final note: George H.W Bush passed away the other day. While he and his Secretary of State had disagreements with the Israeli government during his presidency (https://www.timesofisrael.com/how-lonely-little-george-h-w-bush-changed-the-us-israel-relationship/), various articles have documented how much he helped the Jewish people in their time of need (https://www.jpost.com/American-Politics/Bushs-Israel-legacy-A-mixed-bag-of-positive-steps-but-little-warmth-573296). Perhaps, with this in mind, he died peacefully in his sleep.
Chanukah Samaech!
Barry Lynn
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