Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
400 AM EDT Sun Jul 21 2024

Valid 12Z Sun Jul 21 2024 - 12Z Tue Jul 23 2024

...A break in the heat continues from the Plains to the East Coast but
more triple-digit high temperatures expected for the western U.S....

...Scattered thunderstorms continue across the South and Southeast will
gradually lift northeast into the Mid-Atlantic and southern New England
during the next couple of days...

...Monsoonal thunderstorms linger across the Four Corners region into the
Great Basin...

...A cold front will bring new rounds of thunderstorms across the northern
tier states through the next couple of days...

A cool air mass settling in across the eastern two-thirds of the country
will offer an extended reprieve from the intense heat through the next few
days.  Afternoon high temperatures will only reach into the 70s and 80s
today from central U.S. eastward through the Atlantic coast with the
exception of the Sunshine State and the coastal plain of Georgia and South
Carolina, and near the nation's capital where highs will be in the 90s. 
In contrast, the heat across the western U.S. is expected to persist, with
high temperatures once again exceeding 100 degrees across much of the
region.  The interior Pacific Northwest will feel the heat exceeding 110
degrees at the hottest locations by this afternoon along with little
overnight relief.  Daily highs across the Southwest will remain in the
110s.  Please continue to practice heat safety in this persistent and
prolonged heat wave in the western U.S. as we head into the new week.  A
Pacific cold front will approach the West Coast on Monday, lowering the
heat only slightly for inland sections.  By Tuesday, the front is forecast
to push farther inland into the Pacific Northwest.  In response, the heat
ahead of the front will begin to shift eastward toward the northern High
Plains while a cooling trend will begin near the coast.

The slow-to-evolve upper-level pattern that is sustaining the heat in the
western U.S. and the relatively cool conditions farther east will also
keep a front nearly stationary across the South and into the Mid-Atlantic
region.  This front will help focusing and triggering more scattered
thunderstorms from the Gulf Coast to the Southeast through the next few
days.  The expansive cloud cover throughout the South into the East Coast
will keep daytime highs capped generally in the mid-upper 80s, which is
several degrees below normal.  Under this pattern, the weak upper trough
will slowly lift northeastward, bringing an increasing chance of showers
and thunderstorms into the Mid-Atlantic and southern New England during
the next couple of days.

For the Four Corners region into the Great Basin, monsoonal moisture will
continue to support on-and-off thunderstorms through the next couple of 
days.  These storms will keep an elevated threat for isolated to scattered 
flash flooding and severe weather, which may result from the strongest of 
the storms.  Across the northern tier states, a cold front arriving from
central Canada will bring new rounds of thunderstorms from the northern
Plains to northern New England during the next couple of days with
temperatures averaging near or slightly above normal through the next
couple of days.

Kong


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