Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
451 PM EDT Sat Mar 15 2014
Valid 00Z Sun Mar 16 2014 - 00Z Tue Mar 18 2014
...A threat for severe weather exists along the Gulf Coast states during
the weekend...
...A late season winter storm should affect the Lower Ohio/Upper Tennessee
Valleys and into the Mid-Atlantic...
...Heavy snow across the Pacific Northwest and Northern Rockies is
expected...
Upper energy currently organizing across the Southern High Plains has
helped fuel an extensive area of showers and thunderstorms across
Texas/Oklahoma this afternoon. As the system shifts its focus eastward,
the threat for severe weather will continue as the air mass downstream
will be rather moist and unstable. The Storm Prediction Center has
highlighted an area from far east Texas along the Central/Eastern Gulf
Coast states for an enhanced threat for severe thunderstorms through
Monday morning. The progressive nature of the cold front should limit the
threat for flash flooding this weekend while high pressure builds in
behind bringing high temperatures down to the low 50s for Monday.
While the action across the southern states will feature precipitation in
liquid form, it will be quite the contrary for locations to the north from
the Lower Ohio/Upper Tennessee Valleys eastward to the Mid-Atlantic and
upper Carolinas. With a strong surface high settling across the Great
Lakes region, northerly winds will sufficiently lower the temperatures
over the region of interest. Much of the precipitation expected will occur
in association with the upper disturbance affecting the southern U.S. The
northern extent of this precipitation shield will be comprised of mixed
precipitation before shifting to all snow as temperatures cool late Sunday
night and into early Monday. In spite of the forecast being only 24 to 36
hours out, there still is uncertainty with the exact axis of snow, ice,
and sleet. At this point, the WPC winter weather desk suggests the
heaviest snowfall amounts will be over the Central Appalachians and
extending eastward into the Mid-Atlantic/Delmarva Peninsula. Expected
totals may range from 6 to 12 inches with the higher accumulations more
into the higher terrain. South of the area of snowfall will be an
extensive region of freezing rain which is forecast to extend from lower
Missouri eastward into the Central/Southern Appalachians and Piedmont. For
the latest information on the possible winter storm, please visit the WPC
Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php
With a large upper ridge anchoring the southwestern U.S., zonal flow above
this dome of high pressure will allow a series of impulses to affect the
Pacific Northwest and Northern Rockies the next couple of days. Initially
it will mainly be a rain event across western Washington except for the
higher elevations of the Cascades. As the flow begins to amplify offshore
by late Sunday night, much colder air will work its way southward from
western Canada which will quickly lower snow levels. Through Monday
evening, expect the highest snow accumulations across the Washington
Cascades where 1 to 2 feet will be possible.
Rubin-Oster
Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php