Weather It Is (Afternoon Update)

Good Afternoon:

Winter Storm Warning for Snow and Extreme Cold

The morning WRF (high resolution model) update (from 0  UTC GFS data) suggests that the highest amounts of snow should fall in the Gush Etzion area this afternoon and night (up to 20 cm).  Amounts of 5 cm or less are predicted for the Jerusalem area, with higher amounts on mountain peaks surrounding.

The  0/6 UTC GFS is still showing a large precipitation amount with the onset of the coldest air at 500 mb early tomorrow morning into early afternoon.  However, our highest resolution model doesn't show this to the same extent.

If the overnight values verify correctly, the GFS and its ensemble shows the potential for various amounts of convective precipitation during the morning hours on Tuesday.  Somewhat colder temperatures are also seen than previously forecast.  Hence, there could be higher amounts of snow in the Jerusalem area than the WRF  (high resolution model) predicts with its last update.

The amount of precipitation on Tuesday into Wednesday night will depend upon the formation of a small low pressure system just off our coast.  The GFS ensemble is suggesting southeasterly winds, which could wrap around moisture off the Mediterranean and into the central areas.  The WRF spins this low pressure just off the central coast.  If the position is a bit more to the north, then snow amounts will be higher than forecast late Tuesday morning into Wednesday evening.

Any precipitation (even light) late Tuesday afternoon into Wednesday afternoon will cause a fluffy accumulation.  Roads will be quite icy as temperatures fall to or below freezing from late this afternoon onward (outside of Jerusalem), and at night in snow in Jerusalem.

Because of the potentially cold temperatures Tuesday and Wednesday night, slush on roads and running water on roads will freeze into ice, making for extremely hazardous conditions.

A clarification. The IMS web site suggests a prolonged period of snow in Jerusalem, but they are, apparently, only predicting light amounts overall.

The cold will last into Friday.

Barry Lynn