Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
350 AM EDT Fri Sep 20 2019
Valid 12Z Fri Sep 20 2019 - 12Z Sun Sep 22 2019
...Remnants of Imelda to bring heavy rain and possible flash flooding
across the Southern Plains and Arklatex region today...
...Severe thunderstorms and flash flooding possible in the Northern Plains
today and Central Plains on Saturday...
...Early season snow likely across the Northern Rockies...
Tropical Depression Imelda has dissipated, but its remnants will still
bring heavy rain and possible flash flooding to portions of the Southern
Plains and Arklatex region today. A Slight Risk of excessive rainfall is
in effect, where 1 to 3 inches of rain is forecast. This comes after over
40 inches of rain fell in parts of southeast Texas during the last four
days. Please refer to WPC's latest storm summary for a list of the highest
rainfall totals from the storm.
Meanwhile, a low pressure system will make gradual progress from the
Rockies, to the northern Plains, to Ontario over the next few days. An
associated cold front will push into the Plains today and tonight. This
front should lead to thunderstorms in the northern and central Plains both
today and Saturday. Some of the storms could be severe, with large hail
and damaging winds the primary threats. The Storm Prediction Center has
issued a Slight Risk for severe thunderstorms across the Northern Plains
today and the Central Plains Saturday. Flash flooding will also be
possible, especially on Saturday and Saturday Night in portions of the
Central Plains as the front begins to interact with lingering moisture
from Imelda. Rainfall amounts in excess of 3 inches are forecast from
central Kansas into northern Missouri. This has prompted a Moderate Risk
of excessive rainfall to be issued.
Colder air will continue to push through the western states behind the
cold front, and this is expected to lead to accumulating snow in the
higher elevations of the interior Northwest, particularly in Idaho,
Montana and Wyoming above 8000 feet elevation. Winter Weather Advisories
have been issued across these regions, where up to a foot of snow is
possible. High temperatures will be as much as 15-25 degrees below average
in these areas.
Ahead of the cold front, high temperatures will be above average in the
Plains and Central U.S., with the warmth spreading to the East Coast this
weekend. Temperatures will be most above average in the Great Lakes, with
highs into the 80s and lows in the mid-to-upper 60s on a widespread basis.
Those temperatures are more typical of average conditions in mid-summer in
Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php