The Weather Prediction Center

Short Range Forecast Discussion

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Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
327 PM EDT Wed Jun 29 2022

Valid 00Z Thu Jun 30 2022 - 00Z Sat Jul 02 2022

...Locally heavy rain and isolated flash flooding remains possible
across the Southeast, Gulf Coast, and Southwest...

...Severe thunderstorms to potentially impact the northern Plains
today; severe threat moves into the northern Great Lakes and
Midwest on Thursday...

...Hot temperatures to take hold of the Northern Plains this
afternoon, then advance east into the Great Lakes on Thursday and
eventually the Northeast by Friday; seasonally cooler temperatures
to arrive to close out the week along the West Coast...

A typical summer pattern setting up across the country is expected
to largely remain intact as the calendar closes on June and flips
over to July. A broad upper-level ridge and lingering stationary
boundary draped across the southern U.S. will continue to trigger
additional scattered thunderstorms along the Gulf Coast and into
the Southeast. Rich atmospheric moisture content and light
steering winds aloft set the stage for an environment conducive
for slow-moving thunderstorms containing torrential downpours and
frequent lightning, similar to the last few days. Storms that
remain stationary for a longer duration have a greater chance of
causing flash flooding. Additionally, urbanized locations are more
prone to ponding water over mostly impervious surfaces. In the
western Gulf of Mexico, the National Hurricane Center continues to
monitor a wave of low pressure that currently has a 40% chance of
development over the next 48 hours. Regardless of whether it
becomes a named system or not, tropical downpours associated with
this feature are forecast to edge north and west toward the Texas
coastal areas beginning this evening. As the wave moves ashore on
Thursday, the coverage of heavy showers and thunderstorms will
increase over southeast Texas with an increased threat for
Excessive Rainfall rates. As a result, a Slight Risk has been
issued for areas along the southeast Texas coast and in the
southwestern suburbs of Houston. The other regions under the
threat of locally heavy rainfall and flash flooding are located
across the Southwest and central Rockies. Monsoonal moisture
remaining in place is likely to trigger additional showers and
thunderstorms across Arizona today. By the end of the work-week,
an upper level disturbance passing through the central Rockies
will help funnel moisture northeastward into Colorado and
eventually the central Plains. Even though much of this region
could use the rainfall, downpours in these areas can quickly turn
dangerous and lead to flash floods. For these reasons. a pair of
Marginal Risks are in place from portions of the Four Corners
region on Thursday to the Central Plains on Friday.

Farther north, a cold front swinging across the north-central U.S.
will have the potential to spark severe weather through tonight.
The areas most at-risk for severe storms are across the Dakotas
and far northwestern Minnesota, where the SPC has issued a Slight
Risk (level 2/4) of severe storms. Damaging wind gusts and large
hail are the most likely hazards, with a few tornadoes also
possible. The Marginal severe threat shifts eastward along the
cold front on Thursday and into a region stretching from the
central Plains to the Upper Great Lakes. There is no designated
Marginal area for Friday as of now, but there is an expansive
general thunderstorms area that stretches almost coast-to-coast.
This further highlights the kind of typical summer weather pattern
setting in for the first days of July.

Ahead of the aforementioned cold front and associated thunderstorm
activity, sizzling heat is forecast across much of the
central/northern Plains this afternoon. Highs are expected to
reach into the upper 90s and triple digits from the central High
Plains to South Dakota, which equates to around 20 degrees above
average. Critical Fire Weather is also anticipated along with the
brief but intense heat. Red Flag Warnings have been issued for
parts of northeast Colorado, northwest Kansas, central/western
Nebraska, and south-central South Dakota. The axis of the hottest
conditions versus normal shifts east on Thursday to include a
large portion of the country, stretching from the Big Bend of
Texas and across Midwest into the Great Lakes and northern
Mid-Atlantic. Highs will be in the 90s for most of these regions
with some triple digit heat possible in the central High Plains.
By Friday, stifling heat returns to the Northeast where highs in
the 90s will average 10-20 degrees above normal. Areas that can
expect seasonally cooler daytime highs include the Southeast and
the Four Corners region where diurnally-driven showers and
thunderstorms should produce enough cloud cover to keep daytime
highs capped to slightly below normal levels. Despite the slightly
cooler highs in the Southeast, elevated dew points will keep heat
indices topping out in the mid 90s through week's end. Meanwhile,
an approaching Pacific trough ushers in cooler conditions to the
West Coast starting Friday and temps are forecast to remain on the
cooler than normal side through the first weekend of July.

Mullinax

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




Last Updated: 327 PM EDT Wed Jun 29 2022