Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
405 PM EDT Fri Apr 19 2019

Valid 00Z Sat Apr 20 2019 - 00Z Mon Apr 22 2019

...Severe thunderstorms and areas of heavy to excessive rainfall will be
likely across the Mid-Atlantic and Southeast through this evening...

...Locally heavy rain and some flooding concerns will exist across the
Northeast on Saturday...

...New storm system moving into the West will bring some unsettled weather
and cooler temperatures while the Plains see much warmer temperatures this
weekend...

A strong upper level low and associated trough crossing the Tennessee
Valley this evening through tonight will lift northeast across portions of
the central and southern Appalachians along with the upper Ohio Valley on
Saturday. This will drive a cold front across much of the Mid-Atlantic
states and Southeast through tonight as low pressure lifts up north up
west of the Appalachians. The front will then pivot slowly up across the
Northeast by late Saturday and into Sunday as the aforementioned upper low
begins to slow down and meander over the Mid-Atlantic region through the
weekend.

In the short-term, widespread showers and thunderstorms, are expected
across a large area of the East through this evening and well into the
overnight hours from the Mid-Atlantic states south to the Florida
Peninsula. Much of this region has already been highlighted for a threat
of severe weather, including severe thunderstorms that will be capable of
producing damaging wind gusts and a few tornadoes. The area of greatest
concern will be across the Carolinas and northward up across central and
southern Virginia where the Storm Prediction Center has placed this region
in a Moderate Risk of severe weather. Already several Tornado Watches are
in effect. In addition to the severe weather threat, many of these areas
will see heavy to locally excessive rainfall, and as a result the Weather
Prediction Center has highlighted a Slight Risk of excessive rainfall
across areas of the Mid-Atlantic and Southeast. Locally several inches of
rain will be possible, and thus there will be concerns for some flash
flooding. On Saturday, as the front pivots up across the Northeast, the
threat of heavy rain will lift northeast as well, and there will be some
additional concerns for runoff problems and flash flooding. This will
include areas of far northern New England in particular where there is a
melting snowpack in place. On Sunday, there will still be a fair amount of
unsettled weather from the Mid-Atlantic up across the Northeast with
shower activity lingering, but the threat of heavy rain and severe weather
will come to an end.

Across the West, a cold front associated with an upper trough moving into
the Pacific Northwest will drop southward into the Great Basin and the
northern Rockies by Saturday. On Sunday, this front will continue to
advance south across the Intermountain West while also advancing east out
across the northern and central Plains. Low pressure will be developing in
the lee of the Rockies on Sunday, and this will help drive plenty of warm
southerly flow up across the Plains ahead of the front which will result
in temperatures being well above normal. Some areas over the central and
northern Plains will see high temperatures reaching well into the 80s with
temperature over 20 degree above average for these locations. The Pacific
Northwest and parts of the Great Basin should cool behind the
aforementioned front, and there will also be an extensive area of
cloudiness and some precipitation as well stretching from the Great Basin
east across the central and northern Rockies and gradually out across the
northern High Plains through Sunday. Precipitation amounts should be
generally light to moderate, and there will be some very modest snow
accumulations possible over the high terrain of the Rockies.

Orrison

Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php