Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
359 PM EDT Sat Aug 18 2018
Valid 00Z Sun Aug 19 2018 - 00Z Tue Aug 21 2018
...Active weather continues for the East Coast...
...Heavy rainfall expected to impact parts of the Plains and Mississippi
Valley through the remainder of the weekend...
...Air quality will remain a concern across portions of the Western U.S.,
as well as across the Upper Midwest...
A cold front stretching from New England to the southern Plains will be
the focus for showers and thunderstorms throughout the south and east
through the remainder of the weekend. The best thunderstorm activity will
be along the frontal boundary as warm moist air pulling in from the Gulf
of Mexico clashes with a colder airmass moving in from the north. The
northeastern portion of the front is expected to continue shifting
southeast and off the Atlantic Coast through tomorrow, tapering off rain
chances across the Northeast. But for today, portions of the coastal
northern Mid-Atlantic region are within a Flash Flood Watch.
Meanwhile, a deepening low pressure system over the Southern Plains will
ramp up the frontal system here as it begins shifting northeastward for
Sunday and the first part of the work week. The Storm Prediction Center
has outlined an area across the Panhandles of Texas and Oklahoma, as well
as far northeast New Mexico and southeast Colorado as being in a slight
risk for severe weather through tonight. A Severe Thunderstorm Watch is in
effect for eastern Colorado and northeast New Mexico through this evening.
There is also a slight risk for excessive rainfall and flash flooding for
much of this same region issued by the Weather Prediction Center. The
slight risk for excessive rainfall will shift with the deepening low
pressure center towards the eastern Plains for Sunday, and into the Middle
Mississippi Valley, Ohio Valley, and Upper Great Lakes for Monday as it
begins to interact with another cold front dropping in from Canada.
Marginal risks for severe weather will also accompany portions of this
system during this time.
Fire weather concerns continue across the western U.S., with impacts
spreading across the northern U.S. as well. Red flag warnings remain in
effect through late this evening for southwest Wyoming and central Utah
due to a combination of high winds, low humidities, and the threat of low
precipitating thunderstorms sparking new wildfires. A Dense Smoke Advisory
is in effect for north-central Montana due to nearby wildfires.
Furthermore, Air Quality Alerts remain in place across portions of the
West and Northwest, including much of the Northern Great Basin, due to
smoke pollution. Large wildfires in south-central Canada are also
advecting smoke southward, resulting in Air Quality Alerts for much of
Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php