148
FXUS01 KWBC 271920
PMDSPD

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
320 PM EDT Mon Jul 27 2026

Valid 00Z Tue Jul 28 2026 - 00Z Thu Jul 30 2026

...Risk for severe thunderstorms and flash flooding will spread
from the Great Lakes/Ohio Valley to the Northeast over the next
few days; Moderate Risk of Excessive Rainfall for the northern
Mid-Atlantic/southern New England Tuesday...

...Dangerous heat wave continues over parts of southern U.S. into
this week...

...Active monsoonal moisture fuels thunderstorms over the Four
Corners Region, Rockies, and High Plains...


Scattered to widespread thunderstorms are forecast into this
evening across the Great Lakes and south into the Ohio Valley as
upper-energy rounds a trough along the East Coast and frontal
boundaries help force storm development. Plentiful
moisture/instability as well as sufficient upper-level shear has
led to an Enhanced Risk of severe weather (level 3/5) from the
Storm Prediction Center. Clustering/potentially organized
thunderstorms will bring a threat for damaging winds, possibly
significant, as well as some large hail and possibly a tornado.
Plentiful moisture in place will also bring a threat for heavy
rainfall, with a Slight Risk of Excessive Rainfall (level 2/4) in
place focused on eastern Illinois and northwestern Indiana, where
some scattered instances of flash flooding are possible. More
isolated instances will remain possible elsewhere through the
region.

On Tuesday, additional upper energy will help to both strengthen
the trough, leading to a closed low aloft, as well as
reinforce/strengthen the eastward progressing frontal system. The
combination of intense upper forcing more reminiscent of Fall than
Summer and warm, anomalously moist air flowing in from the
Atlantic will lead to widespread, very heavy rainfall producing
storms from the Carolinas north through the Appalachians,
Mid-Atlantic, and into New England. The greatest concentration and
potential for multiple rounds of storms is expected to focus on
portions of the northern Mid-Atlantic/southern New England where a
Moderate Risk of Excessive Rainfall has been included (level 3/4)
for the threat of scattered to numerous and potentially
significant instances of flash flooding. A broader Slight Risk
(level 2/3) across the Mid-Atlantic/southern New England covers
more scattered instances of flash flooding with isolated instances
possible elsewhere through the region. Additional severe
thunderstorms will be possible as well particularly across the
Carolinas and central/southern Mid-Atlantic where the SPC has
included another Slight Risk for the threat of damaging winds as
well as some hail and a few tornadoes. The focus will shift a bit
further to the northeast and into southern New England on
Wednesday where another Slight Risk of Excessive Rainfall is in
effect for additional scattered instances of flash flooding.

An active Monsoonal pattern remains in place over the Four Corners
Region as well as portions of the central Rockies and adjacent
High Plains. Daily rounds of thunderstorms will bring locally
heavy downpours with at least an isolated risk of flash flooding.
There is now a Slight Risk of Excessive Rainfall in effect for
portions of eastern Arizona, western/northern New Mexico, and
eastern Colorado for Tuesday as suppression of the upper-ridge
will allow for more widespread thunderstorms and rainfall leading
to a few more scattered instances of flash flooding. Urban areas
as well as burn scars will remain most sensitive to additional
heavy rainfall. Elsewhere, daily thunderstorm chances will
continue across portions of Florida and the Gulf Coast, with
isolated flash flooding possible.

A dangerous heat wave will settle over portions of the southern
U.S. this week as a broad and strong upper-ridge remains in place.
High temperatures in the mid- to upper 90s, locally into the low
100s, as well as oppressive humidity will lead to heat indices in
the 105-115 degree range. This will result in areas of Major to
Extreme HeatRisk (levels 3 and 4 out of 4), indicating a level of
heat dangerous to anyone without adequate cooling or hydration.
Conditions will also remain hot across much of the Interior West
with highs in the 90s and Desert Southwest with highs in the 100s
to low 110s. Conditions will be more variable further north over
the central U.S. including the central/northern Plains where
various frontal passages as well as some storm chances will help
to keep temperatures down locally, but some highs in the 90s to
100 will continue, particularly across the northern Plains.
Meanwhile, temperatures will be much more mild for Summer over the
Northeast and Pacific Northwest with highs mainly in the 70s and
80s.


Putnam

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




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