Weather It Is (Winter Weather Warning; Winter Storm Watch)

Good Afternoon:


"Ya can talk, ya can talk, ya can bicker, ya can talk, ya can bicker, bicker, bicker, ya can talk, ya can talk...,"

"The piper pays him! Yes sir, yes sir, yes sir, yes sir.."

"But he doesn't know the territory!"

(From the "Music Man;" http://www.angelfire.com/musicals/thespia/mm/mmsongs.html).

We're only a day or so away from our first major winter storm -- and it may go down in the record books as a major snowstorm as well.

Because its Shabbat Eve, I won't belabour the point, but I can say that there has been a lot of talk, disagreement (bickering), and more talk, and we're all hoping to get "paid" in the end with a "good forecast."  And yet, even after all that is is hard to know the "territory."

 This is shaping up to be a tough, tough call, and when the going gets tough I fall back to the high resolution model -- but it extends only out to Sunday afternoon.  Still, the global ensemble (GEFS)  and longer rain GFS are showing copious amounts of moisture (rain) and a deepening winter chill coinciding with the heaviest rain.

Here's what we know.

Through Sunday afternoon:

Rain amounts: generally 25 to 50 mm, with higher amounts in the far north and possibly along the Askelon Jerusalem corridor. 

Winds: winds rising on Shabbat to Gale force by Sunday afternoon before decreasing into Monday.

Snow: Snow on the Hermon Shabbat and Sunday, and in the northern mountains, (mixed rain/snow) Jerusalem, and Gush Etzion late Saturday night into Sunday morning. There is a 20% of accumulating snow in Jerusalem, while a coating of snow is predicted in higher areas surrounding it.  The high resolution model is predicting around 5 cm in the Gush Etzion area. 

Dust: Heavy dust south of Beer Sheva, especially late Shabbat through Sunday.

Extended forecast:

Temperatures at 850 and 700 mb will remain around -1.5 and -11.5 throughout Sunday into Monday, but temperatures at 500 mb will rise to to around -23 C.  From Monday afternoon until Wednesday afternoon the mean temperatures at 500 mb will fall progressively to close to -29 C.  

While the mean 850 mb temperatures don't change much, there is a 60/40 chance that they will also cool progressively below the mean. At the same time, there is a 25% chance that there will be even greater cooling at 500 mb than the mean temperatures.  

Interestingly, the 700 mb level temperatures do not show much variability, and the simplest explanation is that a massive moisture flux will produce heavy wet snow from Monday afternoon until Wednesday Evening, with the cold near the surface lasting into Thursday and possibly Friday.

So, here's where we leave it for Monday into Thursday:

Expect gusty winds, heavy, heavy rain (in the coastal plain, Kinneret basin (> 100 mm, possibly 200 mm)), and wet snow in the northern mountains (of course on the Hermon and Golan), and higher areas surrounding Jerusalem, and Gush Etzion.  Expect flooding rains in the Jordanian and Dead Sea Valleys.

However, there is the opportunity for an historic, heavy, wet snow that bring all traffic and travel to a standstill for several days.

More, God willing, after Shabbat.

Shabbat Shalom,

Barry