550
FXUS01 KWBC 201914
PMDSPD

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
314 PM EDT Mon May 20 2024

Valid 00Z Tue May 21 2024 - 00Z Thu May 23 2024

...Continued severe weather and excessive rainfall threats over
parts of the central U.S. into mid-week...

...Cool conditions with periods of shower and high elevation snow
chances from the Rockies to the Pacific Northwest...

...Well above average and summer-like temperatures to start the
week from the central/southern Plains to the Northeast...

An energetic upper-level pattern featuring multiple shortwaves
emitting from a broader long-wave trough over the western U.S.
will continue a period of active weather throughout the central
U.S. this week. Showers and thunderstorms are already pushing
eastward across the Great Lakes this afternoon ahead of a leading
system over the Upper Midwest. By tonight, a developing surface
cyclone over the central High Plains in response to a deeper
shortwave ejecting into the Plains will spark numerous
thunderstorms from northeast Colorado through Nebraska and Iowa.
These storms may contain damaging wind gusts, large hail, and a
few tornadoes, which has prompted an Enhanced Risk (level 3/5) for
severe thunderstorms from northeast Colorado to central Nebraska.
Heavy rain may also lead to scattered instances of flash flooding
tonight for parts of Iowa. This low pressure system is expected to
remain compact and strengthen as it progresses into the Upper
Midwest on Tuesday. Once again the threat of severe weather and
heavy rain will be associated with this system throughout the
Midwest and Great Lakes. Thunderstorms are expected along and
ahead of a cold front as it extends southward into the southern
Plains, with widespread moderate to heavy rain north of a warm
front including parts of Minnesota, Wisconsin, and northern Iowa.
The Storm Prediction Center has issued a Moderate Risk (level 4/5)
for severe thunderstorms from south-central Iowa to northwest
Illinois in order to capture the threat of damaging wind gusts and
the potential for a few strong tornadoes. As the aforementioned
low shifts into southwestern Ontario Wednesday morning
(potentially at record strength for the month of May) and the
attached cold front slides into the Mid-South and southern Plains,
heavy rainfall remains a concern where this frontal boundary comes
to a crawl. A Slight Risk (level 2/4) of Excessive Rainfall is in
effect between northeast Texas and eastern Oklahoma to the lower
Ohio Valley as thunderstorms could be slow-moving and contain
intense rainfall rates.

Cool and unsettled weather underneath the broad upper trough is
anticipated to remain locked-in over the Northwest and Rockies
through at least midweek. Snow is possible into the higher
elevations of Wyoming and Colorado on Tuesday before winter
weather chances enter the northern Rockies on Wednesday, with snow
levels possibly dropping to around 7000 feet. High temperatures in
these regions are also expected to remain on the cooler side and
10 to 25 degrees below average.

Meanwhile, for areas south and east of the main storm system
impacting the central U.S. this week, highs are expected to soar
above average and into potentially record-breaking territory for
certain spots. Widespread highs into the 80s and low 90s are
forecast from the Midwest and Deep South to the Northeast through
Wednesday, with mid-to-upper 90s and triple digits in parts of
South Texas and the southern High Plains. This heat could be
particularly dangerous for people dealing with a loss of power in
parts of Texas. Warm overnight temperatures will offer little
relief and high humidity could also lead to heat index readings
over 110 degrees.

Snell

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

$$