Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
443 PM EDT Sun Mar 16 2014
Valid 00Z Mon Mar 17 2014 - 00Z Wed Mar 19 2014
...A late season winter storm is expected to affect the Central
Appalachians and Mid-Atlantic through Monday...
...Accumulating snows are in the forecast across the Northern Plains/Upper Midwest...
The pattern will be rather active during the period with a St. Patrick's
Day snowstorm slated for the Central Appalachians and Mid-Atlantic region.
The event has just begun to unfold with an expansive area of moderate to heavy precipitation from the Gulf Coast up into the Lower Ohio Valley/Upper Tennessee Valley.
With a dome of high pressure building across the Great Lakes, low-level northerly winds will provide the cooling necessary to drop temperature to near/below the freezing mark overnight.
Snows will overspread the region this evening and continue through Monday afternoon with several inches possible once the system clears the Mid-Atlantic coast.
While forecast models are still ironing out the precise details of the storm, the current forecast from the WPC winter weather desk suggests a widespread 6 to 8 inches of snow from eastern West
Virginia through northern Virginia and into the Delmarva Peninsula.
While snow will be the primary threat along the northern side of the precipitation axis, a mixture of sleet and freezing rain is possible from the Upper Tennessee Valley into the Southern/Central Appalachians and Piedmont Range.
While wintry precipitation will dominate across the higher latitudes, it
will be quite the opposite along the Eastern Gulf Coast where heavy rain and severe weather is possible.
A strong cold front advancing eastward should continue to intercept abundant moisture resulting in fairly hefty rainfall rates.
Training convection has already occurred earlier in the day with the potential looming into the overnight hours.
In addition to the flash flood risk, forecast parameters appear sufficient for severe thunderstorm development.
This will particularly be the case during the afternoon/evening where surface heating will be maximized.
The threat should continue through at least midday Tuesday before the cold front exits the Florida peninsula.
A broad upper ridge currently situated over the Desert Southwest/ Central Great Basin is expected to flatten out as a sharp mid-level wave tracks into the Pacific Northwest by late Sunday night.
Strong onshore flow against the local topography will produce heavy rain across coastal locations with snow across the Cascades and into the Upper Intermountain West/Northern Rockies.
The activity will spread into the Northern Plains/Upper Midwest by Monday evening and continuing into the overnight hours.
The current forecast suggests 4 to 8 inches possible over Minnesota
accompanied by localized higher amounts.