Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
416 AM EDT Mon Jul 04 2022

Valid 12Z Mon Jul 04 2022 - 12Z Wed Jul 06 2022

...Excessive rainfall and severe thunderstorms forecast across the
Northern Tier of the U.S. for the Fourth of July Holiday...

...Showers and thunderstorms likely into the work week from the Northern
High Plains to the East Coast ...

...Cool temperatures continue for the West while hot Summer conditions
persist for the Midwest and Plains...

A wet and stormy Fourth of July Holiday is expected for parts of the
Northern Tier of the U.S. as thunderstorms develop along multiple
quasi-stationary frontal boundaries from the Northern High Plains to the
Midwest/Great Lakes Region. The heaviest rain is forecast for portions of
eastern Iowa, southern Wisconsin, and northern Illinois with areal average
totals in the 1-2" range. There is a Slight Risk of excessive rainfall
(level 2/4) for the area as the higher rain totals and potentially heavy
rain rates greater than 1" per hour may lead to a few instances of
flooding. In addition, instances of severe weather are possible where
stronger winds aloft along a coincident upper-level ridge over the frontal
boundaries leads to higher shear and more organized storms. The Storm
Prediction Center (SPC) has issued a Slight Risk of severe thunderstorms
(level 2/5) overlapping the excessive rainfall threat across the
Midwest/Great Lakes for the risk of large hail and damaging winds. There
is also a Slight Risk further west over portions of eastern Montana and
the western Dakotas for a similar chance of large hail and damaging winds.
While not expected to be as intense, showers and thunderstorms are also
forecast for the Holiday across portions of the Pacific Northwest, the
Central/Southern Rockies and adjacent High Plains, and the Southeast.

A low pressure system will move across the Great Lakes to the East Coast
on Tuesday with trailing frontal boundaries remaining across the Midwest,
Plains, and into the Northern High Plains, leading to more showers and
thunderstorms to start the work week. The heavy rainfall threat will shift
into the Upper Ohio Valley and Central Appalachians as organized
thunderstorms moving across the area feed off high moisture and may
produce over an inch of rain, with a Slight Risk of excessive rainfall in
effect. Meanwhile, the SPC has outlined a large Slight Risk of severe
weather from the Mid-Atlantic west to the Northern High Plains as ample
moisture and instability along the frontal boundary and sufficient shear
once again lead to organized thunderstorms. Both organized thunderstorm
complexes and individual supercells may occur leading to scattered
instances of large hail and damaging winds.

South of the unsettled weather across the North, hot summer weather will
persist across the Midwest and Plains under the upper-level ridge. Highs
in the upper 90s to low 100s are forecast both Monday and Tuesday across
the area. Widespread Heat Advisories are in effect for the Missouri Valley
southeast to the Middle Mississippi Valley and Mid-South as the
combination of high temperatures and high humidity push heat indices
closer to an uncomfortable 105-110 degrees. Morning lows will remain in
the mid-70s to near 80 providing little relief from the heat overnight. On
the other hand, temperatures will remain quite cool for the Summer to the
west of the ridge for portions of the Great Basin, Pacific Northwest, and
California. Highs in the 60s and 70s are forecast for the Pacific
Northwest and California coast for the Holiday, with the cooler weather
continuing into Tuesday along the coast. While not quite as cool, highs in
the low to mid-80s forecast for portions of the western Great Basin are
still around 10-15 degrees cooler than normal for this time of year.
Despite the moderate temperatures, the SPC has highlighted the threat for
Critical Fire Weather for portions of eastern Nevada and western Utah as
humidity remains low and windy conditions persist across the area.   

Putnam

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