Weather It Is (Getting Closer)

Good Afternoon:

Those of us who are optimists might be hoping that the probability of snow will increase to near 100% by Thursday night/Friday.  However, there are probably those (also optimists) hoping the opposite.

What we see is that a ridge of high pressure will ride up into northern Europe; conversely, a sharp trough will develop on its eastern flank, and this means that the gates of winter will open as far south as the eastern Mediterranean.

Concurrently, a storm moving across the southern jet stream along the Mediterranean sea will couple link up with the source of cold air creating the necessary dynamical and isentropic lifting needed to produce a bout of rain and possibly snow.

The coldest temperatures should arrive late Friday and Friday night, when temperatures at 850 mb will fall a degree or so below freezing.  We expect the cold lower level temperatures to persist until Saturday (Shabbat afternoon).  There is a 15% chance that temperatures will return to below freezing levels very early in the week.

At 700 and 500 mb, some of the ensemble members show that temperatures are forecast to be just barely cold enough for good snow development, while a large number of ensemble members do not. This is a bit of an unusual situation. Again, there is 15% chance of strong forcing arriving early next week.

Looking at the forecast precipitation amounts, we see a lot of variability.  This means that we're still not settled on the amount of cold aloft.  Without it, there will be rain, but much less likelihood of heavy rain/accumulating snow (now, about 30%).

Strong, possibly damaging, winds are forecast from Thursday afternoon into Friday night.

Today a Red Sea Trough will pass by to our southeast, bringing some rain to the southern Arava. Tonight our cold weather system will approach and bring a broad area of rain from Netanya south to Ashkelon and east through Efrat to the Dead Sea Basin. Five to 10 mm of rain are expected.

The rain should return towards evening and through Thursday night we expect 25 to 50 mm in an area focused from Ashkelon eastward through Jerusalem/Hebron into the Dead Sea Basin.

The forecast for Friday's possible snow event remains unclear.  We'll be wise to wait until we see actual snow/rain amounts from our high resolution forecasts.

Otherwise, snow is expected in the Hermon, beginning tomorrow (Wednesday). Moreover, we look to be entering a wet pattern next week.  The very cold air is forecast to be lurking just to our north and  there is an active southern jet stream. We e still have the possibility of a cold-storm to follow this week's storm arly next.

Barry Lynn