Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
411 PM EDT Thu Aug 16 2018
Valid 00Z Fri Aug 17 2018 - 00Z Sun Aug 19 2018
...Slight risk of severe thunderstorms and flash flooding over parts of
the Central/Southern Plains and the Middle/Lower Mississippi Valley...
...Monsoonal rains bring flash flooding concerns to the Southwest...
...Fire Weather Concerns continue across the western U.S....
A quasi-stationary front currently extends from coastal New England
southwestward through the Great Lakes, Middle Mississippi Valley and into
the Southern Plains. Warm moist unstable air from the Gulf of Mexico is
flowing northward towards this frontal boundary, allowing for scattered to
numerous showers and thunderstorms along and ahead of the front. This
boundary is expected to slowly shift eastward heading into the weekend, as
will the best shower and thunderstorm potential. The Storm Prediction
Center has outlined a region encompassing northeast Oklahoma, southeast
Nebraska, southwest Missouri, and far northwest Arkansas as being in a
slight risk for seeing severe thunderstorms today through tonight. The
Weather Prediction Center has also outlined an area along the frontal
boundary from the Southern Plains to the Tennessee Valley as being in a
slight risk of seeing excessive rainfall and flash flooding through
tonight. This slight risk of excessive rainfall will shift eastward into
Kentucky and southern Indiana for Friday. Flash flood watches and warnings
are currently in effect for portions of Oklahoma. Flash Flood watches are
also in effect across north-central Kentucky and south-central Indiana
ahead of the approaching system. Given the strong pull of warm air into
the region, Heat Advisories are also in effect for portions of the
Southern Plains and the Lower Mississippi Valley.
Meanwhile, monsoonal moisture is making its way into the Southwest.
Excessive rainfall is likely here through tonight, as is outlined by the
Weather Prediction Center's slight risk forecast which encompasses much of
the region. Flash Flood Watches and Warnings are also ongoing here. This
same airmass will cause widespread fire weather concerns across other
portions of the West. Scattered thunderstorms are expected across much of
the western U.S., however a very dry near-surface layer will prevent most
of the moisture from making it to the ground. Any lightning that occurs
out of these storms could easily induce new wildfires, plus thunderstorm
winds could cause them to quickly spread. Red Flag Warnings and Fire
Weather Watches are currently in effect across much of Oregon, Idaho,
southeast Washington and western Montana as a result. Furthermore, ongoing
wildfires continue to pollute the air with extensive amounts of smoke. Air
Quality Alerts remain in effect across central California, as well as much
of Oregon, Washington, Idaho, and northwest Montana.
Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php