Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
359 PM EDT Thu Apr 18 2019

Valid 00Z Fri Apr 19 2019 - 00Z Sun Apr 21 2019

...Severe thunderstorms and flash flooding expected for the Lower
Mississippi and Tennessee Valleys through Thursday night, shifting to the
Eastern Seaboard on Friday as a strong cold front moves east...

...Precipitation chances will increase in the Northwest as a cold front
moves through...

An upper-level trough/low that is particularly deep for this time of year
will move from the Plains into the Mississippi Valley and into the Ohio
Valley over the next couple of days. This trough will drive a cold front
through the central and eastern U.S., and widespread rain and
thunderstorms are expected along and ahead of it as a plume of moist air
from the Gulf of Mexico streams in. Through Thursday night, a Moderate
Risk of excessive rainfall/flash flooding is in place for portions of the
Lower Mississippi and the Tennessee Valley as heavy rain is expected to
continue. In terms of severe weather, an Enhanced Risk of severe
thunderstorms is in effect from the Storm Prediction Center for these
areas and for the Central Gulf Coast. High winds and tornadoes are both
possible in these areas. On Friday and Friday night, the severe and flash
flood threats will shift eastward with the cold front. An Enhanced Risk of
severe weather is in place for the southern Mid-Atlantic and Southeast,
and the Mid-Atlantic region and parts of the Northeast will have a Slight
Risk of flash flooding in effect. Heavy rain will remain a possibility in
the Northeast on Saturday.

A cold front is forecast to move southeastward through the Pacific
Northwest Thursday night, the Northern Great Basin on Friday, and into the
Northern Rockies and Central Great Basin on Saturday. Light to moderate
precipitation will spread across these areas with the front. While the
highest elevations could see snow, heavy snow is not expected through
Saturday. Rainfall totals are forecast to be a half inch to an inch in
lower elevations.   

Temperature-wise, record high minimum temperatures are expected to be
widespread on Friday morning across the Eastern Seaboard ahead of the
approaching cold front, and again on Saturday morning in the Mid-Atlantic
and Northeast. Behind the cold front on the other hand, high temperatures
of 10 to 20 degrees below average are forecast for the Ohio and Tennessee
Valleys on Friday, spreading into the Southern Appalachians on Saturday.
The West will see much above average temperatures on Friday, with record
high minimum temperatures likely there as well, and warm temperatures
should spread into the Plains on Saturday. The cold front coming through
the northwestern U.S. is expected to cool high temperatures down to a few
degrees below average there on Saturday.

Tate

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