729
FXUS01 KWBC 201945
PMDSPD

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
344 PM EDT Sat Jul 20 2024

Valid 00Z Sun Jul 21 2024 - 00Z Tue Jul 23 2024

...A break in the heat continues for much of the Heartland but
dangerous heat will build across the interior Pacific Northwest
this weekend and into next week...

...Scattered thunderstorms continue across the South and Southeast
as monsoonal thunderstorms linger across the Four Corners region...

...Scattered thunderstorms over the central Plains today will
gradually shift into the southern Plains by Monday while a cold
front will bring new rounds of thunderstorms across the northern
tier states...

An cooler than normal air-mass that has settled in throughout much
of the Heartland will stick around not only for the remainder of
the weekend but into the first half of the upcoming week. After
seeing some parts of the Lower Missouri River Valley registering
daytime highs only in the 70s, a cold front will continue to
advance south tonight through the Southern Plains. By Sunday,
daytime highs in the 70s and 80s (as low as 15 to 20 degrees below
normal in the southern High Plains) will be common from central
New Mexico to as far east as the Middle Mississippi River Valley.
Meanwhile, a stalled frontal boundary over the Mid-South is
responsible for daily rounds of showers and storms. The expansive
cloud cover throughout the South will keep daytime highs capped
generally in the mid-upper 80s, which is several degrees below
normal (lone exception is Florida and south Texas where highs will
be in the 90s on Sunday). The footprint of unusually cool
temperatures for late July will persist in the Southern and
Central Plains through Monday.

While cooler than normal temperatures envelope much of the
Heartland, dangerous heat will be a mainstay in the West through
early next week. The experimental HeatRisk product depicts Major
to Extreme heat risks from parts of the Lower Colorado River
Valley and Mojave Desert to as far north as the Snake River Plain
and Columbia River Basin. Some daily record highs and warm minimum
temps are likely to be broken in these areas with the interior
Northwest most likely to witness the bulk of the record heat.
Major HeatRisk levels return to California`s Great Valley by
Monday and look to expand throughout the center of the Golden
State by Tuesday. Overall, these areas can expect highs in the 90s
to 100s with little relief overnight thanks to lows in the 60s and
70s. Those in affected areas should stay hydrated, limit outdoor
activities, and use fans when air conditioning is not available.

This stagnant weather pattern will make for a stormy southern tier
of the U.S. into next week. An elongated frontal boundary will
spark numerous showers and storms from the Southern Rockies and
Plains to the Southeast and Mid-Atlantic through Monday. Today,
SPC does have a couple Marginal Risk areas(threat level 1/5) in
the Southeast and in both the Southern and Central High Plains.
However, an unusually high concentration of moisture aloft is
supporting a rather wide area for Excessive Rainfall potential.
WPC has issued a couple Slight Risks (threat level 2/4) for parts
of the southern Mid-Atlantic and in both central New Mexico and
southeast Arizona. A Marginal Risk (threat level 1/4) for
Excessive Rainfall include much of the Four Corners region, the
central Plains, and the Southeast. This will be a common theme for
both Sunday and Monday with Slight Risks posted in parts of the
Southwest on Sunday and in both the Southern Rockies and Southern
Plains. The Marginal Risk areas each day are expansive,
encompassing much of the Southern U.S. and portions of the
southern Mid-Atlantic. Lastly, a frontal system will trigger
scattered showers and storms across parts of the Midwest this
afternoon and Sunday. Hit-or-miss showers and storms will remain
in the forecast across the Midwest and Great Lakes early next
week.

Mullinax


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