Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
301 PM EDT Tue Sep 28 2021

Valid 00Z Wed Sep 29 2021 - 00Z Fri Oct 01 2021

...Severe thunderstorms possible across portions of the Mid-Atlantic
today...

...Record breaking warmth and critical fire weather forecast across the
Northern Plains...

...Increasing chances for thunderstorms and heavy rain found throughout
the central and southern Plains through midweek...

The upper level jet pattern across the Lower 48 remains highly amplified
with strong ridging across the Upper Mississippi River Valley; while a
compact upper low exists across southeast Canada/New England blocks and
squeezes this ridge as the air masses push off the Northern Pacific
presses eastward.  In the east, a cold front will continue to drop
southward through the  Mid-Atlantic into the Carolinas.  Today, along and
ahead of this front, there is potential for strong thunderstorms with
isolated severe weather possible including large hail and damaging winds. 
The Storm Prediction Center has issued a Slight Risk (level 2/5) of severe
weather between northern Virginia and southern New Jersey.  Behind the
front, more fall-like temperatures will occur, perhaps a tad cold over New
England by Thursday when highs only eek out the upper 50s/low 60s (about
5-10 degrees below normal).

At the peak of the upper-level ridge, ahead of the advancing Pacific cold
front, the Northern High Plains of Wyoming, Montana and the Dakotas are
likely to experience high winds and low humidity in combination with very
high temperatures supporting the potential for Critical fire weather
conditions and Red Flag Warnings.  These extreme temperatures are likely
to continue breaking records with a large portion of the central to
northern High Plains being over 90 degrees, or about 20-30 degrees above
normal.  By Wednesday, the cold front will push into the Plains and bring
relief, but portions of Upper Mississippi Valley stretching from Minnesota
to Missouri/Illinois will remain in the upper 80s to low 90s; about 15-25
degrees above normal.  The front is expected to slow/stall across the
northern Plains, and while temperatures fall a bit further on Thursday,
they will be still be 10-20 degrees above normal across the same areas. 

The aforementioned cold front currently in the Rockies will press eastward
into the Central Plains but slow its eastward advancement by mid-week;
however, the colder maritime air mass will continue to filter southward
across the central then southern Rockies.  The upper-level jet will also
help to press drier air out of the Mexican Plateau in advance of the cold
front across the Southern High Plains toward the Lower Mississippi Valley
given strengthening return of deeper Gulf moisture.  This will aid an
increased showers and thunderstorms across the southern Plains with the
main concern will be heavy rainfall rates and potential for isolated to
widely scattered instances of flash flooding. While severe thunderstorms
are not out of the question across central Texas into W Oklahoma in
proximity to the dry line and eventually cold front by Thursday.

Gallina


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