Weather It Is (Winter Storm Warning)

Good Evening:

A major winter storm will impact our area over the next several days.

Warnings for flooding, gale force winds, heavy dust (south), and  heavy snow.

Already, temperatures are falling at all the critical levels of the atmosphere: 850 mb, 700 mb, and 500 mb.

About 8 A.M this Sunday morning, temperatures at 500 mb will reach about -25 C, -10 C at 700 mb, and 0 C at 850 mb.  Were we to stop there, this would just be another wet storm -- but we won't.

Temperatures at 850 and 700 mb will continue to drop during the day in advance of a more significant 500 mb trough.

From about midnight Monday/Tuesday morning the temperatures at 500 mb will plummet and herald a significant precipitation event, with heavy snow affecting mountainous areas.

There is a 75% chance that temperatures at 500 mb will be -30C or below and this means thundersnow storms, possibly extending over a period 36 to 42 hours long (from Monday night), and not ending until Wednesday evening.  The cold at lower levels, moreover, will last even longer and temperatures may not rise above freezing until Friday morning.

From Saturday night until Monday night (prior to the arrival of the "big" event), there will be 50 to 100 mm of rain along the central mountain spline, with 25 to 50 mm covering wide areas and even 10 to 25 mm extending all the way down to the Ramon crater.  This means plenty of water for river and stream flow -- at high levels -- even before the onset of the major snow event.

Regarding possible snow accumulation amounts in the central mountains. There is a 15% chance that snow will briefly cover the ground tomorrow morning in Jerusalem. Otherwise, wet snow in the early Sunday morning is quite possible in Gush Etzion where periods of snow during the day are shown on our highest resolution model to produce a few centimetres of snow.  However, temperatures will be mostly above freezing, so conditions should not become too slippery. Sunday night, the high resolution model shows higher snow amounts in Gush Etzion and mountains north of Jerusalem. Temperatures will fall close to freezing so roads could become snow covered and icy.

In Jerusalem, there is the beginning of a light snow accumulation at night.  However, temperatures don't fall close to freezing until sometime Monday night, so travel in the city should not be a problem.

In the northern mountains, snow will also accumulate moderate amounts, with heavy amounts on the Hermon and Golan.  Light snow amounts are shown in Safed.

Winds: Becoming Gale force until Sunday night.

Dust: There will be heavy dust in southern areas continuing into Monday morning.

Barry Lynn