Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
301 PM EDT Tue Jul 25 2023

Valid 00Z Wed Jul 26 2023 - 00Z Fri Jul 28 2023

...Excessive Rainfall & severe thunderstorms to continue this afternoon in
the Northeast and Mid-Atlantic...

...Another round of severe weather to unfold across the Upper Midwest
today and the in the Great Lakes by Wednesday...

...Expansive heat wave to take hold of the Northern/Central Plains and
Upper/Middle Mississippi Valley through mid-week, reaching the East Coast
the second half of the week...

...Air Quality Alerts remain in effect across the Midwest and Upper Great
Lakes due to Canadian wildfire smoke; Critical Fire Risk across
Northern/Central Great Basin on Wednesday...

A pair of upper level disturbances will be the catalysts for rounds for
strong-to-severe storms from the Upper Midwest to the Northeast through
Thursday afternoon. Focusing on the first upper level feature over the
Northeast today, it is already responsible for intense storms from the
northern Chesapeake Bay to New England. The Weather Prediction Center
(WPC) has a Slight Risk for Excessive Rainfall in place over the I-95
megalopolis that encompasses the DC/Baltimore metro areas to as far north
and east the NYC metro area. Meanwhile, the Storm Prediction Center (SPC)
has a more expansive Slight Risk area that covers the DelMarVa Peninsula
on north to Connecticut and southern New England. Both national centers'
Slight Risk areas highlight the threat for severe storms that could
produce damaging winds, large hail, tornadoes, and flash flooding. As of
2:30PM EDT, there was as many as 43 million people under a Severe
Thunderstorm Watch from the DC/Baltimore area to southern New England.
Thunderstorms will likely contribute to travel delays in these affected
areas this afternoon. Storms will dissipate later tonight and result in
drier conditions heading into early Wednesday morning.

Farther west, another upper level disturbance is set to produce more
severe weather in parts of the Northern Plains and Upper Midwest. SPC has
a large Slight Risk area that includes the eastern Dakotas, northern
Nebraska, southwest Minnesota, and northwest Iowa. Damaging winds, large
hail, and tornadoes are all possible in these areas. By Thursday, the fast
moving upper level disturbance and a frontal system at the surface will
race east into the Great Lakes. The confidence in severe weather is
greater in parts of the central Great Lakes, prompting SPC to issue an
Enhanced Risk (threat level 3/5) for southern Michigan, northern Indiana,
and northwest Ohio. The Slight Risk currently includes the Chicago and
Cleveland metro areas. Damaging winds and tornadoes are the most
concerning modes of severe weather, although storms could also contain
large hail. WPC also has a Slight Risk for Excessive Rainfall for most of
Michigan, including the Detroit metro area. By Thursday, portions of the
Northeast contending with severe storms today may see another round of
severe storms Thursday afternoon. Elsewhere, there are Marginal Risks for
Excessive Rainfall in parts of the Southwest today and Thursday due to
daily rounds of monsoonal thunderstorms. In South Florida, there is a
Marginal Risk on Thursday as heavy thunderstorms could result in flash
flooding around the more populated areas of South Florida.

In other news, the expansive upper level ridge of high pressure over the
Southwest and Southern Plains will work in tandem with a building Bermuda
High to cause sizzling temperatures from southern California to the East
Coast by Thursday. Daytime highs will soar into the triple digits each day
in the Desert Southwest, while a growing footprint of 100+ degree highs
takes hold of the Nation's Heartland. Sultry heat indices are forecast to
stick around throughout the South and eventually make their way into the
Mid-Atlantic by Thursday where heat indices are likely to exceed 100
degrees. At this time, Excessive Heat Warnings are in place in the Desert
Southwest and Lower Colorado River Valley, while Heat Advisories are more
common in the Great Plains, Southern California, the Middle Mississippi
Valley, and South Florida.

Lastly, Air Quality Alerts remain in place across portions of northern
Minnesota and the Great Lakes due to smoke from Canadian Wildfires causing
unhealthy air quality in these regions. Farther west, the combination of
gusty winds, parched fuels, and low RH values will be supportive of
Elevated to Critical Fire Weather conditions over the northern Great
Basin. Isolated thunderstorms and their associated lightning strikes could
also pose a threat to ignite additional fires in extreme northeast
California, northwest Nevada, and southeast Oregon.

Mullinax


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