Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
333 PM EDT Tue Jul 19 2022

Valid 00Z Wed Jul 20 2022 - 00Z Fri Jul 22 2022

...Dangerous heat to continue through midweek across the south-central
U.S., building into the Northeast on Wednesday...

...Severe thunderstorms possible into portions of the Ohio Valley on
Wednesday and New England on Thursday...

...Monsoonal moisture to bring locally heavy rains and isolated flash
flooding across portions of the Southwest, Great Basin and Southern
Rockies...


Scorching heat will remain a major weather story over at least the next
few days throughout much of the south-central U.S. and extending into
other parts of the Nation as a stagnant upper-level ridge hovers over the
Southwest. Looking ahead to Wednesday, highs well into the triple digits
will once again impact the southern Plains and lower Mississippi Valley
with upper-90s extending into the lower Ohio Valley. Additionally, low
temperatures will be very warm and only dip into the upper 70s or low 80s,
which can exacerbate the dangers of heat due to a lack of substantial
cooling. Even though this is (on average) around the warmest time of the
year, these temperatures are forecast to run nearly 15 degrees above
average in some spots. In fact, several daily high temperature records
could fall across Texas and northern Louisiana on Wednesday. Elsewhere,
steamy temperatures into the 90s will also be felt into the Mid-Atlantic
and Northeast, as well as the central and northern Plains. Heat indices up
to around the century mark across the Northeast have prompted Heat
Advisories to be issued from Philadelphia to Boston. Excessive Heat
Warnings and Heat Advisories also remain in effect across much of the
south-central part of the country.

Periods of severe weather are possible through Thursday as well, mostly
across the northern tier states. A potent upper-level low is forecast to
cross over the Upper Great Lakes on Wednesday and help spark scattered
thunderstorms into the Ohio Valley. A few storms could turn severe,
producing damaging wind gusts, large hail, and isolated tornadoes. SPC has
issued a Slight Risk (level 2/5) of severe thunderstorms from southeast
Michigan through much of Ohio into eastern Indiana and northern Kentucky.
By Thursday, the severe weather threat is expected to shift along the cold
front as it progresses east-southeastward. SPC has issued a Slight Risk of
severe weather across New England and parts of central
Alabama/Mississippi, with damaging wind gusts anticipated to be the
primary hazard. Along with the severe weather threat in these locations,
isolated thunderstorms may contain intense rainfall rates capable of
producing localized flash flooding.

For the Southwest, monsoonal moisture over the region is anticipated to
continue leading to daily chances for isolated flash flood concerns over a
broad area. A Marginal Risk (level 1/4) of Excessive Rainfall has been
issued for Wednesday across much of the central Great Basin, Southwest,
and central/southern Rockies. By Thursday the threat is expected to
consolidate a bit and remain over the Southwest and parts of New Mexico
and Colorado. Areas within and near recent burn scars, as well as slot
canyons and saturated terrain are most at risk to rapid runoff.

Snell

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