Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
358 AM EDT Wed Jul 27 2022

Valid 12Z Wed Jul 27 2022 - 12Z Fri Jul 29 2022

...Moderate Risks of Excessive Rainfall are in place with areas of flash
flooding, potentially significant, across the Ohio Valley/Central
Appalachians through the end of the week...

...Monsoonal moisture to cause daily rounds of excessive rainfall and
flash flooding across portions of the Southwest and southern/central High
Plains with Slight to Moderate Risks of excessive rainfall...

...Heat wave to continue in the Pacific Northwest while staying
consistently hotter than normal along the Gulf Coast and into the
Southeast...

A seemingly endless supply of rich atmospheric moisture is going to create
a conveyor belt of heavy showers and thunderstorms that stretches from the
Desert Southwest to the Central Appalachians the second half of the week.
Along and east of the Mississippi River, the area most at risk for flash
flooding is from the Ozarks on east through the Ohio and Tennessee Valleys
and into the central Appalachians where a stationary front will stick
around through Thursday. The result is a nearly continuous feed of showers
and thunderstorms training over these regions for the next couple of days,
with the areas along and south of the Ohio River into the Tennessee Valley
and central Appalachians most susceptible to flash flooding. The Weather
Prediction Center (WPC) has issued a pair of Moderate Risks (threat level
3/4) for these specific regions both today and Thursday, where the
combination of increasingly saturated soils and training thunderstorms
containing Excessive Rainfall rates may not only lead to flash flooding,
but potentially significant areas of flash flooding. Even the Slight Risk
region (threat level 2/4) stretches as far west as the Middle Mississippi
Valley, where flash flooding is a concern the next couple of days as well.

Farther west, copious amounts of monsoonal moisture continues to be
responsible for widespread showers and thunderstorms, most of which are
capable of producing heavy downpours. Parts in the "Four Corners" region
of Arizona, New Mexico, Colorado, and Utah that are most at risk for flash
flooding are near burn scars, in slot canyons, urbanized locations, and
where soils are overly saturated after weeks of heavy rainfall. Meanwhile,
a nearby frontal boundary setting up near southeast Colorado will be at
the intersection of monsoonal moisture from the southwest and Gulf of
Mexico moisture from the southeast. Slow moving thunderstorms would favor
locally heavy rainfall amounts that, in turn, could lead to flash
flooding. As a result, WPC has a Moderate Risk for Excessive Rainfall out
for southeast Colorado on Thursday. The threat areas bleeds over into
southwest Kansas on Friday, where a Day 3 Moderate Risk for Excessive
Rainfall is out for a similar portion of the central High Plains.

Temperature-wise, a pair of upper level ridges in opposing corners of the
Lower 48 are responsible for searing heat in the Pacific Northwest and the
Southeast. The hottest daytime high temperature anomalies are forecast to
remain in the Pacific Northwest where triple digits will be common from
the Columbia Basin of eastern Washington on south into Oregon and far
northern California. Meanwhile, mid-upper 90s continue to be in the fold
each day in the Seattle and Portland metro areas. Expect record high
minimum and maximum temperatures to be tied and/or broken each day through
the remainder of the work-week. While daytime record highs will not be set
nearly as often in the Southeast, abnormally warm high minimum
temperatures will be quite common, giving residents from Texas to the
Carolinas little relief from the 90s-100s highs they will witness through
the rest of the week. In sharp contrast, considerably cooler than normal
temperatures look to engulf much of the northern and central Plains on
east into the Great Lakes and Midwest to close out the week. Some highs in
the central High Plains will see daytime highs as cool as 15 to 20 degrees
below normal. Farther east, the East Coast heats up into the upper 80s and
low 90s on Thursday before a cold front delivers another shot of
seasonally cooler temperatures to kickoff the the weekend.

Mullinax


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