Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
351 PM EDT Sun Aug 19 2018
Valid 00Z Mon Aug 20 2018 - 00Z Wed Aug 22 2018
...Heavy rainfall and strong thunderstorms expected to impact parts of the
Plains, Midwest and Mississippi Valley over the coming days...
...Air quality will remain a concern across portions of the Western U.S.
and the Upper Midwest...
A strengthening low pressure system is currently located across the
Central Plains, with a cold front extending south into the Southern
Plains, and a warm front extending eastward into the Lower/Mid Mississippi
Valley and Ohio Valley. This system will continue to push eastward as it
strengthens during the first part of the work week. A strong influx of
warm and moist air from the Gulf of Mexico is aiding in heavy rain
production and strong to severe storms near this system. Meanwhile,
another cold front originating from Canada will continue to quickly dive
southward, bringing with it a much cooler airmass. These two systems are
currently in fairly close proximity to one another, and will continue to
interact with one another in the coming days, exasperating the storm and
heavy rain potential. The Weather Prediction Center has issued a slight
risk for excessive rainfall through tonight across a large north-to-south
oriented region stretching from the Northern Plains and Upper Midwest
southward into the Lower Mississippi Valley. This slight risk region will
shift eastward with the low pressure and frontal systems for Monday and
Tuesday. On Monday it will encompass portions of the Mid/Northern
Mississippi, Ohio, and western Tennessee Valleys. On Tuesday the slight
risk region will encompass an area from the Lower Great Lakes to the
central Appalachians. Meanwhile, a flash flood watch is currently in
effect through Monday morning for eastern Nebraska and southwest Iowa.
Preemptive flash flood watches are also in effect across portions of
southeast Wisconsin and southern Louisiana. The Storm Prediction Center
also has a slight risk for severe storms through tonight for an area
including northwest Arkansas and southwest Missouri. This slight risk area
will also shift eastward over the next couple of days, encompassing many
of the same areas as was outlined by the Weather Prediction Centers risk
for excessive rainfall.
Fire weather remains a concern across the western U.S. The combination of
high winds and low humidities may contribute to igniting wildfires as we
head into the work week. Several fire weather watches are currently in
effect, including portions of Utah, Washington, and Montana. Due to the
smoke pollution from ongoing wildfires, Air Quality Alerts remain in place
for large portions of Oregon, Washington, Idaho, and all of Montana.
Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php