Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
409 AM EDT Mon Jul 01 2024

Valid 12Z Mon Jul 01 2024 - 12Z Wed Jul 03 2024

...Dangerously hot conditions will continue across the southern Plains and
lower Mississippi Valley, while simmering heat builds throughout
California's Central Valley starting Tuesday...

...Heavy rain and flash flooding likely across parts of the Southeast
coastline today...

...Severe thunderstorm and heavy rain threat situated over northern Plains
and Midwest early this week...


July kicks off with anomalous and potentially dangerous heat impacting the
south-central U.S. and portions of the West Coast. As of this morning,
over 50 million residents are under heat-related watches, warnings, and
advisories. The upper-level pattern throughout the next few days
responsible for the summer heat consists of ridging just off the West
Coast and over the lower Mississippi Valley, while an upper trough
situates over the northern Rockies and northern Plains. For the central
U.S., high temperatures are forecast to soar into the upper 90s and low
100s across the southern Plains through midweek. 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 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 also be particularly
dangerous for those without effective cooling. High temperatures away from
the immediate coastline are forecast to reach into the 100-110F range,
which could break numerous daily records in the San Joaquin and Sacramento
valleys on Tuesday and Wednesday. Excessive Heat Warnings, Watches, and
Heat Advisories go into effect as early as Tuesday and span from southern
Oregon to the low desert of southeast California. 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 level of heat could
pose a danger to the entire population 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.

A cold front sliding down the East Coast today is forecast to slow its
southerly motion as it intersects the Southeast coastline, with developing
thunderstorms along the boundary. Some storms are expected to contain
intense rainfall rates and slow propagation, which creates the threat for
flash flooding. Parts of the South Carolina coastline, including the city
of Charleston, has been highlighted as having a Moderate Risk (level 3/4)
of Excessive Rainfall today. Areas most at risk for flooding are locations
with poor drainage, where heavy rainfall coincides with the afternoon high
tide, and in urbanized communities. Be sure to remain weather aware and
always remember to never drive through flooded roads.

Additionally, a storm system exiting the northern Rockies this morning is
anticipated to create some pre-Independence Day fireworks across the
northern Plains and Midwest through midweek as the threat of heavy rain
and severe weather slides eastward with time. Severe thunderstorm chances
are centered over Nebraska South Dakota today, with neighboring states
included in the potential for potent thunderstorms capable of containing
damaging wind gusts and sporadic hail. Of potentially greater concern
throughout the upper Mississippi Valley is the prospect for more heavy
rainfall over saturated soils and swollen rivers. As approaching frontal
boundaries provide a focus for several clusters of thunderstorms, areas of
intense rainfall rates are possible throughout the northern Plains and
upper Midwest today before sliding gradually eastward on Tuesday, but
still remaining centered over the Midwest. Probabilities for at least 1
inch of rain are high (70-90%) for much of Iowa, eastern Nebraska,
southern Minnesota, central/southern Wisconsin, and far northwest Illinois
through Tuesday. This next round of heavy rain could create instances of
flash flooding as well as exacerbate ongoing river flooding across areas
still recovering from last week's heavy rainfall.

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.
Regions most likely to be affected by scattered downpours include Arizona,
New Mexico, and southwestern Colorado, with burn scars and sensitive
terrain the most at risk for flash flooding.

Snell


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