Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
333 AM EDT Fri May 19 2023

Valid 12Z Fri May 19 2023 - 12Z Sun May 21 2023

...Soggy and cool weather from the Great Lakes to the Northeast heading
into the weekend...

...Severe thunderstorms and flash flooding possible for the Southern
Plains into the Lower Mississippi Valley on Friday...

...Well above average, record-breaking warmth continues for interior
portions of the Northwest into the weekend...

A cold front stretching from the Great Lakes southwest through the
Central/Southern Plains and into the Rockies will continue southeastward
the next couple of days, helping to support widespread shower and
thunderstorm chances as well as keep temperatures on the cooler side for
mid- to late May. Rain chances will shift from the Lower Great Lakes, Ohio
Valley, and Middle Mississippi Valley Friday to the Northeast,
Mid-Atlantic, and Southeast on Saturday. Rainfall will be moderate to
locally heavy at times, particularly for coastal New England Saturday. A
low pressure system off the Carolina coast will also help to locally
enhance rainfall chances along the coast on Friday. High temperatures will
be cool behind the front, with mostly 60s expected across the
Central/Northern Plains and Upper Midwest. The low pressure system and
precipitation chances will also keep temperatures cool across the
Carolinas and into the Mid-Atlantic Friday, with low 70s generally in the
forecast. Temperatures will be warmer ahead of the front through the
Interior Northeast southwest into the Lower Great Lakes and Ohio/Middle
Mississippi Valley Friday, with 70s to low 80s expected, but will fall
into the upper 60s to mid-70s Saturday following the passage of the front.

Further southwest, storm development more parallel to the
east-northeast/west-southwest oriented front as it sags southward will
increase the chances for repeated rounds of rainfall over portions of the
Southern Plains. A pool of higher Gulf moisture over the region will also
help promote heavier rain rates. A Slight Risk of Excessive Rainfall has
been introduced centered over the ArkLaTex where the highest chance for a
few scattered instances of flash flooding due to this heavy rainfall
resides. In addition, the Storm Prediction Center has outlined a Slight
Risk of severe thunderstorms (level 2/5) for portions of the Southern
Plains. Strong enough winds aloft at the tail end of an upper-level trough
should provide enough shear for some organized thunderstorms with the
potential to produce a few instances of large hail and damaging winds, and
possibly a tornado. High temperatures will be a bit above average from the
Lower Mississippi Valley into the Southern Plains Friday with upper 80s to
low 90s expected. The cold front passing through will drop temperatures
well below average Saturday for most locations inland from the Gulf Coast,
with highs generally in the low to mid-70s.

Meanwhile, in the West, an upper-level ridge will remain in place keeping
temperatures above average for most of the region. The focus will once
again be on the interior Pacific Northwest/Great Basin/Northern Rockies
where highs Friday and Saturday will be running upwards of 15-25 degrees
above average. Temperatures will range from the upper 70s to mid-80s in
the Northern Rockies to the upper 80s to low 90s in the interior Pacific
Northwest and Great Basin. Many of these highs across the interior Pacific
northwest/Great Basin will be near record-tying/breaking levels, with
morning lows also being in record-tying/breaking warm low territory. The
one cooler spot in the West will be portions of the Central and Southern
Rockies, where a lingering frontal boundary as well as monsoon-like daily
showers and thunderstorms will keep precipitation chances up and
temperatures near to below average. Anomalously high moisture lingering in
the region may lead to some locally heavy downpours and isolated flash
flooding Friday, especially along terrain sensitive areas and dry washes.

Putnam

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