Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
410 PM EDT Tue Aug 09 2022

Valid 00Z Wed Aug 10 2022 - 00Z Fri Aug 12 2022

...Hot weather to continue from the Northwest into the Plains, some relief
by Wednesday for the Northeast...

...Heavy Rain and Flash Flooding threat from the Ohio Valley into the
Central Appalachians...

...Monsoonal Showers to continue from the Southwest, portions of
California and into the Great Basin...

A key weather story over the Lower 48 today remains the prolific heat over
the Interior Northwest and I-95 corridor in the Northeast, with modest
relief from the record high temperatures anticipated this week. Over the
Northwest, the heat streak is forecast to moderate some over the next
several days, although notable above average temperatures will linger over
the Interior Northwest before spilling into the Plains by midweek. This
will translate to daily high temperatures to the mid-upper 90's over parts
of the Interior Northwest and east across the Plains. Heat advisories and
Excessive Heat Warnings are in effect across eastern Washington, Oregon
and northern Idaho through the afternoon. Moreover, the warm weather and
gusty winds will support an Elevated fire weather risk tomorrow across
portions of the Interior Northwest, per the Storm Prediction Center.
Meanwhile, cooler temperatures will begin to filter into the Great Lakes
and Northeast today and continue through Wednesday as a slow moving cold
front meanders south across the Interior Northeast into the Upper
Mississippi Valley. Much of the East will have another day of the heat
before temperatures start to moderate to around average, before a
secondary cold front in Canada brings a reinforcing shot of cool air into
the region by the end of the work week.

Temperatures aside, showers and thunderstorms developing ahead of and
along the slow moving lead cold front will bring a threat of heavy
rainfall and flash flooding from the Mississippi Valley to the Central
Appalachians; these locations have been very wet the last few weeks, so it
would not take much rain to cause flash flooding. As such, WPC maintains a
Slight Risk (level 2/4) of Excessive Rainfall across the Mississippi
Valley into the Central Appalachians through Thursday. The Western half of
the CONUS remains wet, too. A stagnant area of upper high pressure will
build across the Rockies, in turn pushing deep layered moisture northward.
This above average moisture will help trigger widespread scattered
monsoonal showers and thunderstorms across these areas over the next few
days.  Isolated flash flooding is possible across these areas, especially
over burn scars, slot canyons, dry river beds or urban areas.

The Southeast quarter of the Lower 48 will also hold in a stagnant, wet
pattern. The frontal boundary pressing into the Ohio Valley and Northeast
will not make much headway south through this week, keeping the Southeast
in the warm sector through Thursday. As such, expect widespread showers
and thunderstorms in the region, where portions of the Lower Mississippi
Valley and Central Gulf Coast have the best chances for heavy rains.  The
clouds and rain across this area will also keep high temperatures over the
next few days slightly below average.

Asherman/Campbell

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