Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
312 PM EST Tue Feb 19 2019
Valid 00Z Wed Feb 20 2019 - 00Z Fri Feb 22 2019
...Significant winter storm for the Mid-Atlantic region on Wednesday...
...Heavy rain will continue a threat for flooding from the Lower
Mississippi Valley into the Ohio Valley...
...Heavy snow for portions of the Upper Midwest tonight/Wednesday...
...Continued cold and snowy west of the Continental Divide...
A large winter storm will affect locations from the Upper Midwest to the
East Coast beginning tonight. A dome of high pressure currently in place
across the Great Lakes region has set the stage for wintry precipitation
with temperatures near or below freezing from the Mid-Mississippi Valley
to the northern Mid-Atlantic region. As an upper level system lifts
through the Great Plains tonight, significant amounts of moisture will
spread north and east from the Gulf of Mexico. This moisture will meet
with cold air across the Upper Midwest where an area of low pressure is
forecast to develop and track across the Upper Mississippi Valley on
Wednesday. Widespread snowfall totals of 4-8 inches (locally higher) are
expected from eastern Nebraska into eastern Minnesota and northwestern
Wisconsin through the day on Wednesday. Temperatures will remain below
freezing through Thursday from the Dakotas into the Upper Mississippi
Valley, which translates into daytime highs generally 5 to 15 degrees
Meanwhile, snow will move from southwest to northeast into Ohio and the
Mid-Atlantic region late tonight, changing to a wintry mix of sleet and
freezing rain and eventually all rain for many. The time of changeover
will occur from southwest to northeast and depend on exact location but
will be delayed for locations near the central Appalachians where
significant ice accumulations near 0.25 inches along with 4-8 inches of
snow (locally higher) will be possible. Major cities along I-95 from
Boston to Richmond will likely see some from of frozen precipitation at
the onset before changing over to rain before ending Farther to the south,
heavy rain is expected to continue from the Lower Mississippi Valley into
portions of the Ohio Valley where an additional 1-3 inches of rain, on top
of already saturated ground, can be expected through Wednesday afternoon.
Flood and flash flood watches are already in effect for many of these
locations. Additional heavy rain is expected to begin for some of these
same locations impacted by flooding Thursday night.
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