Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
350 AM EDT Wed Jul 03 2024

Valid 12Z Wed Jul 03 2024 - 12Z Fri Jul 05 2024

...Dangerous heatwave to impact much of the West, while oppressive heat
and humidity also swelter areas from the Southern Plains to the
Mid-Atlantic...

...Flash flooding and severe thunderstorms possible over the next few days
across portions of the Plains, Midwest, and Ohio Valley...


Record-breaking and dangerous heat is forecast to make this Fourth of July
week a scorcher across much of the West and from the southern Plains to
the Mid-Atlantic. Over 110 million residents are currently under
heat-related watches, warnings, and advisories throughout 21 states as of
early this morning. An upper-level high situated just off the West Coast
today is forecast to strengthen and reorient directly over the western
U.S. by the end of the week. This pattern will support well above average
temperatures over California today before heat spreads further along the
West Coast by the end of the week. High temperatures are forecast to reach
into the 105-115F range throughout interior California away from the
immediate coastline, as well as into much of the Desert Southwest.
Afternoon temperatures will also begin to increase across much of Oregon
and Washington by Thursday and Friday, with widespread highs soaring into
the 90s. Dozens of record highs are possible, expressing the rarity of
this early-July heatwave. The duration of this heat is also concerning as
scorching above average temperatures are forecast to linger into next
week. Heat impacts can compound over time, therefore it is important to
remain weather aware and follow the advice of local officials. This level
of heat throughout the Sacramento and San Joaquin valleys of California
could pose a risk to anyone if proper heat safety is not followed. This
includes staying hydrated, out of direct sunlight, and in buildings with
sufficient air-conditioning. It is also very important to check on the
safety of vulnerable friends, family, and neighbors.

Oppressive heat and humidity will also be found throughout the southern
Plains and lower Mississippi Valley into the Independence Day holiday
while also expanding eastward to the Mid-Atlantic for the end of the week.
High temperatures rising into the upper 90s and low 100s are expected,
with heat indices soaring into the 110s across the lower Mississippi
Valley. Warm overnight conditions in the upper 70s and low 80s will offer
little relief, leading to a dangerous situation for those without access
to adequate cooling. A cold front entering the southern Plains is
anticipated to offer cooler and below average temperatures to Oklahoma and
much of northern/western Texas by Friday.

An active and stormy weather pattern over the central U.S. is expected to
create chances for severe thunderstorms and heavy rainfall, which could
impact holiday gatherings this week. A developing area of low pressure
over the central High Plains today forecast to progress into the upper
Midwest by Thursday along with a lingering frontal boundary stretching
from the lower Great Lakes to the central Plains are anticipated to be the
triggers for some meteorological fireworks. For today, the best chances
for scattered flash flooding due to thunderstorms capable of producing
intense rainfall rates is forecast between eastern Kansas and the Ohio
Valley along the aforementioned frontal boundary. Instances of severe
weather (mainly associated with damaging wind gusts) are also possible,
with chances for severe storms also located in parts of the
northern/central High Plains closer to the developing low pressure system.
By Independence Day, thunderstorm chances span from the southern
Plains/Rockies to the middle/upper Mississippi Valley and also eastward to
the Ohio Valley and Mid-Atlantic. However, the greatest threat for strong
thunderstorms turning severe resides over parts of eastern Kansas,
northeast Oklahoma, and southern/central Missouri. Damaging wind gusts and
frequent lightning are the most likely weather hazard associated with
these Fourth of July storms, with isolated strong storms also possible
into the Midwest, Ohio Valley, and Mid-Atlantic. Flash flooding will
remain a concern throughout the upper Midwest as well due to yet another
round of thunderstorms overlapping areas dealing with ongoing river
flooding and saturated soils. Portions of southern Minnesota, eastern
South Dakota, western Wisconsin, and northern Iowa currently have the
highest probabilities (70-90%) for at least 1 inch of rain on Thursday.
Residents and visitors located within areas expecting severe weather
and/or heavy rainfall this week are advised to remain weather aware, have
multiple ways to receive warnings, and never drive across flooded
roadways.

Snell


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