Weather It Is (Very Cold With Possible Snow)

Good Afternoon:

Highlights:

1) Very cold Tuesday with rain mixing with snow in the higher elevations of the Galilee and Jerusalem Mountains

2) Otherwise, 25 to 50 mm of precipitation generally along the coastal cities, and the central mountains.

3) Strong "River" flows in the northern Jordan Valley, and Negev.

This winter has been unusual in that we've been the recipient of a number of very heavy rain events in the last few weeks, in contrast to last year in which there were in contrast quite a large number of small rain events.  My supposition is that the relatively warmer than usual Mediterranean waters are contributing to the intensity of the rainfall.

Tonight, a storm off to our northwest will receive an influx of colder, polar air and then drop southward, with the upper low passing just to our east late tonight and tomorrow afternoon.  Cold air at lower levels flowing in behind the storms should allow for a transition to mixed rain and snow on Tuesday in the higher elevations.

Based on our high-resolution WRF forecast (with credit to the Department of Earth Sciences at the Hebrew University, Givat Ram, Jerusalem) rain and snow is expected in the area of Safed late tonight and Tuesday morning, with rain and snow in Jerusalem from late morning into Tuesday night.  Snow will also fall on the Hermon and Golan tonight into tomorrow, with up to about 30 cm in the highest elevations of the Hermon and about 5 cm lower down to (Neve Ativ).  Elsewhere, a very light, slushy accumulation is possible on colder car surfaces in the mountains of the Galilee and mountain tops of Jerusalem. Because temperatures will be near freezing, motorists should be aware that roads could be slippery.

Turning our attention to Friday's storm, it is clear at this time that the temperatures should be colder (at the surface) than with Tuesday's storm, and that the cold should last from Friday morning into late Shabbat.  The GEFS is showing a large spike in the precipitation rate as the the cold air arrives during Friday morning, Hence, an accumulating snow is more likely than with Tuesday's storm during the morning and early afternoon hours.

The big question mark is still whether the 500 mb trough will pass over us or to our east.  At the moment, the models are forecasting the upper level trough to pass just to our east, but yesterday, it was forecast to pass quite a ways further to our eaat.  There is still also a disagreement between the European Ensemble and the American Ensemble, and much of this disagreement revolves around the strength of low pressure over Spain, which will influence the trough, ridge wavelength.  The closer it passes to us, the more snow will likely accumulate.

For a great summary from one of the members of our Israel Winter Weather group, please see:

https://www.facebook.com/JerusalemWF/videos/194776091677307/

The temperatures should moderate after Friday's storm as we head into February.

Barry Lynn