Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
400 PM EST Thu Dec 12 2013
Valid 00Z Fri Dec 13 2013 - 00Z Sun Dec 15 2013
...Winter storm to impact parts of the Midwest, northern Appalachians and
New England with snow and ice...
...Heavy lake effect snow showers to end, only to be followed by more snow
from an approaching storm system this weekend...
...Warm up coming for the northern High Plains...
The big story over the lower 48 will be with a developing storm system
which should begin to take shape over the Southern Plains and Mississippi
Valley on Friday. At the surface, bitter cold temperatures currently
remain north of an arctic front draped across the northern tier of the
United States, but as an upper level disturbance emerges into the Southern
Plains from the Southwest on Friday, the cold air across the North will
begin to quickly sag southward with the leading edge reaching West Texas
by Friday evening. Meanwhile, warm and moist air from the Gulf of Mexico
will advect northward ahead of the surface low with light showers
transitioning into a steady moderate rain by Friday night in the Lower
Mississippi Valley. With sub freezing temperatures still in place at the
surface, light freezing rain is expected with the onset of precipitation
Friday morning across portions of the Ozarks along the northern fringes of
the precipitation shield.
Overrunning light to moderate snow will expand north and east Friday night
into Saturday across the Midwest and Ohio Valley with several inches
possible by the time snowfall ends on Saturday. Locations across the Gulf
Coast States should see a steady rainfall with embedded thunder at times,
especially for southern portions of the region. Cold air will be banked
along and east of the Appalachians as the storm system makes its way east
on Saturday with a wintry mix likely for locations from Washington, D.C.
to Philadelphia and New York. The details are still being ironed out, but
interior sections of the Northeast should see a significant snowfall from
this storm system by the time the weekend is over.
Localized heavy snows downwind of Lakes Erie and Ontario are forecast to
come to an end with the passage of a cold front tonight, which will
disrupt the low level wind fetch across the lakes and preventing band
organization. More scattered in nature snowfall is anticipated with the
frontal passage with light accumulations possible before the
aforementioned storm system approaches.
Out over the western U.S., as mid level ridging attempts to build back in
across the West Coast, a downslope flow regime should set up over the
northern High Plains. The result will be gusty winds with high
temperatures steadily rising from Friday through the weekend.
Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php