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21-22

Winter Storm Threat: February 21-22 (Only/Final Call)

Lots of uncertainty with this system. How much precip. falls as snow before the changeover, timing of the changeover, rates during the daytime hours, etc. The only thing that’s not really in question will be the surface temperatures at the start of the storm. Cold, cold, cold.

20150221-22_MAsnow_final

Models overall show a little more potential to get higher totals than lower totals east of the Appalachians.

My brain is done. k bye.

Winter Storm Threat: Feb 21-22 (final call)

The morning update:

 
Temperatures are coming in colder than expected early across the northern half of the region as northerly winds take over. That means earlier/easier changeover to snow for many. This’ll be a fun one.

EDIT: Need to add that I also made a slight adjustment to the time constraints to better fit the storm period.

Winter Storm Threat: Feb 21-22 (only call?)

This forecast is for the second part of the two-part rain/snow event. What I have is not too different from what the models show now, save for some lesser amounts in northern MD. The changeover from rain to snow and the surface temperatures will be the biggest players in inhibiting snowfall totals. The models have probably underforecast the warmth in MD on Monday before the front makes its way through from north to south. However, once the changeover is made, moderate to heavy snowfall after a brief period of moderate sleet could lead to decent totals from DC northwards through central PA. The best combination of colder air and intense snowfall seems to be in southwestern PA, where a band of 4-8″+ is possible.

 
I also included a small area of 8-12″ for upsloping and cooler surface temperatures in the Appalachians in southern PA. The band of higher totals could shift north/south a bit depending on the placement of the low as it passes over the region.

EDIT: I may have to make some last minute changes to it if the temperatures stay colder in northern MD today. The 2-4″ and 4-8″ contours could creep further south!