Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
338 PM EDT Thu Jun 22 2023

Valid 00Z Fri Jun 23 2023 - 00Z Sun Jun 25 2023

...South-central heat wave persists from southern New Mexico into portions
of central/southern Texas...

...Risk for flash flooding and severe weather across much of the Plains
Friday and Saturday...

...Wet and cool start to Summer continues for the East Coast...

A persistent upper-level ridge centered over the south-central U.S. will
remain in place through the forecast period, continuing the heat wave that
has plagued the region for much of this month. High temperatures Friday
and Saturday across much of southern New Mexico and into portions of
western, southern, and central Texas will range between 105 to 110. Highs
closer to the Gulf Coast will be in the upper 90s to low 100s, but
dewpoints in the 70s will contribute to heat indices of 105-115, locally
as high as 120. Several additional daily record-tying/breaking highs are
possible. In addition, anomalously warm, near record-tying/breaking low
temperatures will bring little relief from the heat at night. A southward
sagging cold front and associated precipitation has brought some brief
relieve to northern portions of Texas as well as Oklahoma and into the
Lower Mississippi Valley. But this will be short lived, as the ridge will
build back northeastward Saturday with highs soaring back into the mid 90s
to low 100s. The hot conditions combined with incoming stronger winds
mixing down aloft as well as low humidity and dry antecedent conditions
have prompted a Critical Risk of Fire Weather from the Storm Prediction
Center for much of New Mexico Friday and Saturday.

To the north, an upper-level trough will pass northeastward across the
northern/central Plains, providing lift aloft and encouraging lee
cyclogenesis at the surface, helping to better organize a low
pressure/frontal system from lingering frontal boundaries over the region.
The upper-level and low-level forcing along the organizing fronts, as well
as a strong low level jet advecting plenty of moisture northward, will
combine to promote the development of widespread, organized showers and
thunderstorms, with the potential to produce several inches of heavy
rainfall. There are Slight Risks (level 2/4) of Excessive Rainfall in
place for portions of the northern High Plains/northern Plains Friday and
further east into the Upper Midwest on Saturday as some isolated to
scattered instances of flash flooding will be possible. Severe weather is
also expected, and the there is an Enhanced Risk (level 3/5) of Severe
Weather from the Storm Prediction Center over portions of the central High
Plains among a broader Slight Risk (level 2/5) covering much of the High
Plains. Moist, upslope flow combined with cooling temperatures aloft will
lead to sufficient CAPE for vigorous thunderstorm development with the
potential to produce large hail and damaging winds, as well as isolated
tornadoes. Additional severe storms are possible on Saturday ahead of a
cold front pushing east across the Missouri Valley, with a Slight Risk for
large hail as well as some damaging winds.

An upper-level low over the eastern U.S. as well as a lingering frontal
boundary will keep temperatures unseasonably cool for the start of Summer
and shower and storm chances up into the weekend. Some locally heavy
downpours will be possible, but dry antecedent conditions across much of
the Northeast will keep any flash flood related risk low. One exception
will be along the central to eastern Gulf Coast, where deeper Gulf
moisture and clustering storms along the frontal boundary over a region
that has seen much more rainfall the past few days has prompted a Slight
Risk of Excessive Rainfall for some scattered instances of flash flooding.
High temperatures Friday and Saturday will range from the mid-70s in the
Ohio Valley and southern New England to the low to mid-80s in the
Mid-Atlantic and Southeast. On the other hand, outside of the influence of
the upper-level low, the Great Lakes/Midwest and northern New England will
be above average, with highs in the upper 80s to low 90s. In the West,
showers and storms should be mostly limited to portions of the Northern
Rockies, with some locally heavy rainfall possible. Temperatures across
the region will similarly be below average with an upper-level trough over
the region, with mostly 70s and low 80s expected outside of the Desert
Southwest, where highs will be in the 90s to low 100s.

Putnam


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