Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
400 AM EDT Tue Jun 21 2022

Valid 12Z Tue Jun 21 2022 - 12Z Thu Jun 23 2022

...Monsoonal moisture will support widespread showers and thunderstorms
across parts of the Southwest and southern Rockies, posing a risk for
flash flooding...

...Severe thunderstorms expected across the Midwest today, while the
severe weather and flash flood threats head east for the northern
Mid-Atlantic on Wednesday...

...Stifling heat and humidity across the Plains and Midwest to expand east
and include the Southeast by mid-week...

An upper level pattern conducive for channeling moisture-rich monsoonal
flow will bring about additional rounds of heavy showers and thunderstorms
to parts of the Southwest. Moisture streaming over New Mexico and Arizona
the next couple days has origins that reach as far south as tropical East
Pacific. This combined with classic monsoonal flow aloft will result in a
plume of rich atmospheric moisture atop the Southwest through mid-week.
The combination of heavy rainfall atop overly saturated soils throughout
New Mexico has resulted in the issuance of a Slight Risk for Excessive
Rainfall both Tuesday and Wednesday due to the elevated flash flood threat
in parts of the state. The threat of flash flooding spans from the
US/Mexico border to southern Colorado where a broad Marginal Risk for
Excessive Rainfall is also in place. Monsoonal flow is forecast to linger
into Thursday as well with much of eastern Arizona, western New Mexico,
and southern Colorado still at risk of flash flooding into the second half
of the week.

Elsewhere, a cold front swinging through the Midwest and Central Plains
today will spawn heavy showers and thunderstorms from the northern Great
Lakes to the central High Plains. A pair of Marginal Risks, both for
Excessive Rainfall and severe weather, have been issued for portions of
these regions today. Meanwhile, along a warm front draped atop the
Northeast, heavy thunderstorms could produce Excessive Rainfall rates,
leading to the issuance of a Marginal Risk for possible flash flooding
later today. As the front races east on Wednesday, it will trigger
additional areas of severe storms from the Ohio Valley to the northern
Mid-Atlantic. In addition, rich moisture content and sufficient
instability aloft provides a favorable environment for Excessive Rainfall
rates in the northern Mid-Atlantic. In response to this setup, a pair of
Slight Risks have been hoisted for parts of the northern Mid-Atlantic for
Wednesday. Farther west, along the trailing end of the cold front, strong
thunderstorms are possible in the central Plains on Wednesday along and
north of the front with a Marginal Risk for Excessive Rainfall issued for
much of Kansas.

Temperature-wise, another day of sizzling summer heat is on tap up and
down the Mississippi Valley, through the Southern Plains, and on east into
the Great Lakes and Deep South. The hottest temperature anomalies today
reside in the Great Lakes where daytime highs look to range between 15-25
degrees above normal. Record warm minimum temps as well as record high
temps are expected to be broken from the Upper Mississippi Valley to the
Great Lakes. By Wednesday, while the heat in the Great Lakes backs off to
an extent (while still remaining above normal), the core of the most
anomalous heat will shift to the Southeast where daytime high temps are
forecast to reach triple digits. This will result in some instances of
record breaking heat in the Southeast. Both Tuesday and Wednesday also
feature increasingly hot conditions in northern California where upper
level ridging is expected to build in aloft. In contrast, unusually cooler
conditions will transpire over New Mexico and other parts of the Southwest
due to extensive cloud cover from ongoing monsoonal shower and
thunderstorm activity. The Northeast will remain socked in under on shore
flow thanks to an upper low off the Northeast coast. This creates a sharp
gradient in the temperature forecast throughout the region as much of New
England and the immediate Mid-Atlantic coast struggle to get above 80,
while neighbors farther south and west see temps rise as high as the low
90s by Wednesday.

Mullinax

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