525
FXUS01 KWBC 231903
PMDSPD

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
303 PM EDT Mon Sep 23 2024

Valid 00Z Tue Sep 24 2024 - 00Z Thu Sep 26 2024

...Much needed rains possible from the Ohio Valley into the
Central to Southern Appalachians, Upper Tennessee Valley and
Mid-Atlantic...

...Rains from the developing tropical system in the western
Caribbean may begin to affect the Florida Keys and South Florida
on Wednesday...

...Much above average temperatures continue across the West into
the Northern Plains and across the Gulf Coast into the Southeast...

The large scale mid to upper level flow across the Lower 48 will
continue to amplify over the next few days, comprised of a
deepening upper trof from the eastern portions of the Plains into
the Mississippi Valley, a building upper ridge across the interior
West and the strengthening and re-positioning of an upper ridge
off the Southeast coast.  This amplification will be leading to
impactful weather event over the next several days across large
portions of the U.S.

The initial impacts will be in the form of an expanding area of
moderate to heavy rainfall potential from the Mid-West into the
Lower Lakes, Ohio Valley, Upper Tennessee Valley, Central to
Southern Appalachians into the Mid-Atlantic.  Much of these areas
are currently experiencing severe to exceptional drought
conditions, with the expected 1 to 1.5 inch plus rainfall amount
over the next two days bringing some relief to these drought
conditions.  With the dry conditions across these areas, river
flooding will be unlikely.  However, there is still at least a
marginal risk of isolated flash flooding with the expected heavy
rainfall amounts, especially if they occur over urbanized regions.

More significant impacts to the above mentioned amplifying pattern
will be the weakening of the mid to upper level ridge across the
Gulf coast as the upper trof amplifies over the Lower Mississippi
Valley and the upper ridge rebuilds off the Southeast.  This in
turn will be creating a path in the atmosphere, between the
amplifying upper trof over the Lower Mississippi Valley and the
re-positioning upper ridge off the Southeast coast, for the
northwest movement of the developing tropical system over the
northwest Caribbean toward the Yucatan Straits Tuesday into early
Wednesday, and then a more north northeast track into the eastern
Gulf Wednesday into Thursday.  While the current official track of
this system from the National Hurricane Center keeps the center of
the storm well to the west of the Florida Keys, the outer bands of
precipitation and squally weather on the east side of the storm
may begin to affect the Florida Keys and South Florida on
Wednesday.  Additional major impacts from this storm likely across
portions of Florida into the Southeast Thursday and Friday.
Please refer to the National Hurricane Center for the latest
updates on this system.

The amplifying upper ridge across the interior West will be
supporting widespread much above average temperatures over the
next few days across nearly all of the West and into the Northern
Plains.  High temperatures across these regions are forecast to be
as much as 10 to 20 degrees above average.  Above average
temperatures also likely across the Gulf Coast and into the
Southeast.  While temperatures are forecast to be much above
across these areas over the next few days, there are not expected
to be many record highs.  However, more numerous record high
morning temperatures are possible both Tuesday and Wednesday
morning along the West coast and from portions of the southern
Mid-Atlantic into the Southeast and Florida.

Oravec


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




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