Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
337 AM EDT Sun May 19 2024

Valid 12Z Sun May 19 2024 - 12Z Tue May 21 2024

...Increasing severe weather and excessive rainfall threats over the
Central U.S. into early next week...

...Sweltering heat continues across South Florida and southern Texas while
expanding into the southern High Plains...

An energetic upper-level pattern will bring a couple rounds of storms to
the central U.S. for Sunday and Monday. On Sunday, moist return flow
following a warm front moving northward through the Plains and ahead of a
dryline over the High Plains will provide more than enough instability to
trigger robust thunderstorm development over the Central Plains.
Increasing upper-level winds will promote supercells with the threat of
large hail and a few tornadoes. Storms are also expected to grow upscale
into one or more organized convective systems, bringing a heightened
threat for potentially widespread, significant damaging winds later Sunday
evening. As such, the Storm Prediction Center has issued a Moderate Risk
of severe weather (level 4/5). Storm chances will shift northeastward into
the Upper Midwest overnight Sunday and into the Great Lakes by Monday
following an initial upper-wave/accompanying surface frontal system. An
amplifying long-wave trough over the West will help to enhance lee
cyclogenesis over the High Plains bringing another chance of storms to the
Central Plains/Missouri Valley by Monday evening. The Storm Prediction
Center has included a Slight Risk (level 2/5) for the threat of some more
damaging winds and large hail, and possibly a tornado. Some locally heavy
downpours will also be possible, particularly from the Central Plains into
the Upper Mississippi Valley Sunday and the Central Plains once again
Monday, with an isolated chance of flash flooding. 

The active upper-level pattern will also bring some precipitation chances
to the Northern/Central Rockies and eastern Great Basin over the next
couple of days. Rainfall should generally remain light to moderate, though
some locally heavier storms will be possible especially over Wyoming on
Monday. Some snow is expected for higher mountain elevations. To the east,
an area of low pressure lingering just off the Atlantic coast of the
Southeast with a trailing frontal boundary moving through Florida will
bring more showers and thunderstorms to the area Sunday. Storm chances
will decrease overnight Sunday and into the day Monday from north to south
as the front pushes southward, expected to clear the coast by Tuesday
morning.

Intense Summer-like heat will continue over portions of South Florida and
from southern Texas into the southern High Plains the next couple of days.
Highs in the 90s with high humidity values for areas closer to the coast
will bring heat indices into the 105-110 degree range, with a Heat
Advisory in effect for South Florida Sunday. While not as humid,
temperatures will soar into the 100s further inland into west Texas/the
southern High Plains. Some record-tying/breaking temperatures are
possible. While not as hot, conditions will still be well above average
more broadly across the central/eastern U.S. Highs in 80s will be common,
even into more northerly locations like the Great Lakes and the interior
Northeast. One exception will be where onshore flow keeps things a bit
cooler along the East Coast, with highs in the 60s and 70s expected from
coastal New England south into the Mid-Atlantic and coastal Carolinas.
Highs over the Pacific Northwest/northern Rockies will remain cool Sunday
behind a cold front, with highs in the 50s and 60s. These cooler
temperatures will spread southward into the Great Basin Monday. Highs in
the 80s and 90s are forecast south of the front over the Southwest.
    
Putnam

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