Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
203 AM EST Wed Feb 20 2019
Valid 12Z Wed Feb 20 2019 - 12Z Fri Feb 22 2019
...Heavy rain and wintry weather will affect much of the eastern U.S.
through Thursday and additional snow expected out West...
A low pressure system originating from the Gulf of Mexico is gathering
strength and lifting northward towards the Ohio Valley and Great Lakes.
This is in response to an upper level trough and strong shortwave impulse
tracking across the Plains and Upper Midwest. Moisture is surging north
from Louisiana to the Ohio Valley and central Appalachians, and heavy rain
and some thunderstorms will continue in the warm sector of the low.
Rainfall amounts on the order of 1 to 3 inches are expected through Friday
morning across much of the Deep South as multiple rounds of rain fall over
the same areas, and widespread flash flood watches are in effect. River
flooding in the coming days will also be an issue.
Farther to the north in a colder airmass, snow will be prevalent across
the northern Mid-Atlantic region Wednesday morning with several inches of
accumulation likely. With strong warm air advection aloft expected during
the afternoon and evening hours, a transition to sleet and then rain is
expected for areas near and east of Interstate 95. Freezing rain is also
likely farther inland across western Virginia, West Virginia, western
Maryland, and into Pennsylvania since the low level sub-freezing
temperatures will be slower to erode for those areas. Significant icing
is also possible for some interior valley locations through Wednesday
Out West, high temperatures will continue to run 10-20 degrees below
average along and west of the Continental Divide through Thursday. Another
storm system is forecast to drop south from the Pacific Northwest tonight,
reaching the Southwest by Thursday morning. Additional snowfall totals of
over a foot are forecast for some of the major mountain ranges extending
from Washington and Oregon into Arizona and southwestern Colorado through
Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php