613
FXUS01 KWBC 020757
PMDSPD

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
356 AM EDT Tue Jul 02 2024

Valid 12Z Tue Jul 02 2024 - 12Z Thu Jul 04 2024

...Dangerously hot conditions to impact much of the southern
Plains, lower Mississippi Valley, and western U.S. this week...

...Severe thunderstorms and flash flooding possible over portions
of the Midwest through midweek...

...Unsettled weather with localized flash flooding chances
continue across the Southeast and southern Rockies...


Over 60 million residents are currently under heat-related
watches, warnings, and advisories this morning as early-July heat
swelters much of the south-central and western United States. The
weather pattern responsible for the potentially record-breaking
heat includes upper-level ridging just off the West Coast and and
a separate upper ridge over the south-central U.S. today before
sliding to the east by midweek. For the southern Plains, high
temperatures are forecast to soar into the upper 90s and low 100s.
When combined with elevated humidity levels, heat indices are
forecast to rise into the 110s across the lower Mississippi Valley
and Gulf Coast. Excessive Heat Warnings and Heat Advisories
currently span from Kansas/Missouri to the Gulf Coast States.
After enjoying a refreshing start to the workweek, the Midwest and
East Coast can expect a gradual return to muggy summer warmth by
Wednesday as surface high pressure reorients itself off the East
Coast and ushers in southerly flow. Extreme heat building
throughout the West Coast and more specifically interior
California this week will be particularly dangerous for those
without effective cooling. High temperatures away from the
immediate coastline are forecast to reach into the 105-115F range,
which could break numerous daily records in the San Joaquin and
Sacramento Valleys. Heat begins to build northward on Independence
Day as highs into the 90s reach Oregon and interior Washington.
Excessive Heat Warnings, Watches, and Heat Advisories go into
effect today for some and stretch from southwest Washington to the
Desert Southwest. The duration of this heat wave is concerning as
the current forecast keeps scorching conditions in place through
at least the end of the week. This magnitude and duration of heat
could pose a danger to the public if proper heat safety is not
followed. This includes staying hydrated, out of direct sunlight,
and in properly air-conditioned buildings. Additionally, it is
very important to check on vulnerable friends, family, and
neighbors to confirm their safety.

Active and stormy weather associated with a few storm systems
progressing from the northern Rockies to the Midwest this week
will create fireworks of their own this holiday week. Initially, a
cold front swinging from the upper Midwest to the Great Lakes by
early Wednesday is forecast to spark numerous thunderstorms from
northeast Kansas to central Wisconsin. Some storms could turn
severe and produce damaging wind gusts, a few tornadoes, and large
hail from northeast Kansas to southern Iowa. This area is
highlighted by the Storm Prediction Center as having an Enhanced
Risk (level 3/5) of severe weather. Thunderstorms are also
expected to contain intense rainfall rates as elevated levels of
atmospheric moisture content remain in place. Flood Watches have
been issued for much of Iowa, with the threat of scattered flash
floods also encompassing much of the Midwest today. For areas
experiencing swollen rivers from prior rainfall, any additional
heavy rain could exacerbate flooding concerns. By Wednesday, a
cold front is forecast to stretch from the lower Great Lakes to
the central/southern Plains and provide a focus for additional
potent thunderstorms across the mid-Mississippi Valley. Once again
thunderstorms are expected to produce the potential for damaging
wind gusts and flash flooding. A separate area of potentially
organized convection may impact the central High Plains, where a
greater threat for large hail and tornadoes exists. The Fourth of
July will feature the aforementioned frontal boundary lingering
over the Ohio Valley and lifting as a warm front over the central
Plains as an area of low pressure ejects off the High Plains. This
will lead to shower and thunderstorm chances from the northern
Plains and Midwest to the Ohio Valley and Mid-Atlantic, with the
highest chances for severe weather extending from eastern Kansas
to central/southern Missouri.

Continued sufficient moisture content over the Southwest and
southern Rockies will also aid in the development of daily showers
and thunderstorms capable of producing localized instances of
flash flooding through midweek. Regions most likely to be affected
by scattered downpours include southeast Arizona and New Mexico,
with burn scars and sensitive terrain the most at risk for flash
flooding. Meanwhile, a dying stationary front entering the
Southeast from the western Atlantic will also aid in daily widely
scattered thunderstorms across the Gulf Coast, Florida, and the
Southeast coastline/southern Georgia.

Snell


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