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FXUS01 KWBC 210815

PMDSPD



Short Range Forecast Discussion

NWS Weather Prediction Center College Park MD

400 AM EDT Tue May 21 2024



Valid 12Z Tue May 21 2024 - 12Z Thu May 23 2024



...An increasing threat of severe weather and excessive rainfall

as well as high winds expected to overspread the northern Plains

and upper Midwest today through tonight and into Wednesday

morning...



...Severe weather and heavy rain threat will emerge across the

southern Plains to the mid-Mississippi Valley on Wednesday...



...Cool conditions with periods of shower and high elevation snow

chances from the Rockies to the Pacific Northwest...



...Well above average temperatures across the central Plains will

be replaced by cooler conditions but summer-like weather expected

to continue across the southern Plains to the Northeast...



A persistent weather pattern will continue to send energetic and

fast-moving weather systems onshore from the Pacific Ocean into

the Northwest through the short-range forecast period.  These

systems will tend to intensify as they reach into the mid-section

of the country.  One such system is developing and tracking toward

the northeast across the central Plains this morning.  The threat

of severe weather and heavy rain will be expanding toward the

upper Midwest by tonight along with increasingly windy conditions

when the low pressure system is forecast to become quite deep and

intense.  Thunderstorms that erupt ahead of a potent cold front

may contain damaging wind gusts, large hail, and a few tornadoes,

from the central Plains to the Great Lakes, and especially over

Iowa, where the Storm prediction Center has issued a Moderate Risk

of severe thunderstorms for later today.  Heavy rain may also lead

to scattered instances of flash flooding through tonight across

the upper Midwest.  The center of the system will begin to move

into southern Canada by Wednesday morning with the heavy rain

threat quickly decreasing across the Great Lakes but the winds

will take extra time to subside there.



As the low pressure system begins to move away into southern

Canada on Wednesday, the trailing cold front will become nearly

stationary across the southern Plains where the next phase of

severe weather and excessive rainfall is forecast to emerge.  It

appears that these threats will expand toward the mid-Mississippi

Valley Wednesday night where thunderstorms will tend to become

slow-moving.



Meanwhile, cool and unsettled weather underneath a 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 today.  Another upper trough

will then bring the next round of mountain snows and low-elevation

rain into the Northwest on Wednesday before overspreading the

northern Rockies by early on Thursday where snow levels could drop

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.



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.



Kong/Snell





Graphics available at

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



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