Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
355 PM EDT Sun Jun 30 2024

Valid 00Z Mon Jul 01 2024 - 00Z 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...

...Severe thunderstorm and heavy rain threat for the East Coast today; a
Moderate Risk for Excessive Rainfall has been posted for portions of the
Southeast coast for Monday...

...Showers and thunderstorms for the Four Corners/Southwest over the next
few days; active weather pattern to produce some pre-Independence Day
fireworks in the Northern Plains and Midwest...

As the calendar prepares to flip over to July tomorrow, sweltering summer
heat will be one of the top stories in the days leading up to Independence
Day. To start the week, strong upper level high pressure over the South
will be responsible for heat indices that range between 105-110F (locally
up to 115F) through Tuesday from the Southern Plains on east to the Lower
Mississippi Valley. Much of these regions have Excessive Heat Warnings and
Heat Advisories that are in place through at least Monday. Meanwhile,
California and Desert Southwest will gradually heat up as another
impressive upper level ridge of high pressure builds in over the northeast
Pacific on Tuesday. Daily record highs may be challenged in parts of
central California and heat indices in the Golden State's Great Valley may
approach 105F. This approaching heat dome along the West Coast will likely
be a fixture for Californians and eventually for more residents along the
West Coast by Independence Day. On the flip side, following an
oppressively hot Sunday in the Northeast, the strong cold front
responsible for today's widespread shower and thunderstorm activity will
usher in a more refreshing air-mass tonight. High pressure over the Great
Lakes tomorrow is set to lock in pleasant weather across the northeastern
U.S. through Tuesday. The other regions likely to experience cooler than
normal temperatures the first couple days of July are the Northern Rockies
and northern Great Plains as northwesterly flow keeps any excessive heat
at bay in the short term.

In terms of active weather, the evening will remain quite busy along and
east of I-95 this evening from southern New England on south to the
Mid-Atlantic states. The severe threat will conclude for interior parts of
the Northeast this afternoon as the cold front races south and east. Some
thunderstorms could be severe this evening, particularly from North
Carolina to as far north as Maine where the Storm Prediction Center has a
Slight Risk (threat level 2/5) in place. The area most at risk for severe
weather is from the Delaware Valley to southern New England where SPC has
issued an Enhanced Risk (threat level 3/5). There is also an opportunity
for these storms to pose a flash flood threat along the East Coast as
evident in a lengthy Marginal Risk area (threat level 1/4) that stretches
from southern New England all the way to South Florida. By Monday, the
front cold front will end up in the Southeast where a surplus of rich
atmospheric moisture and ample instability will favor not only
strong-to-severe thunderstorms capable of producing torrential downpours,
but training lines of thunderstorms in some cases. WPC has issued a
Moderate Risk (threat level 3/4) for portions of the Southeast coast that
include cities such as Savannah, GA and Charleston, SC. Localized rainfall
totals in these areas could surpass 6 inches where the heaviest
thunderstorms occur. Elsewhere, anomalous moisture content in the Four
Corners region will provide scattered thunderstorms in the Southern
Rockies with more than enough moisture to produce Excessive Rainfall
rates. WPC has a pair of Slight Risks (threat level 2/4); one in southern
Arizona and another in parts of the Central Rockies. By Monday and
Tuesday, the moisture content is not as impressive, but given the presence
of lingering monsoonal moisture and some soils in the region growing more
sensitive, a Marginal Risk for Excessive Rainfall is present for both days
across parts of the Four Corners region.

Farther north, a potent upper level trough traversing the Northern Rockies
will be the catalyst for numerous showers and thunderstorms this afternoon
and evening. SPC does have a Slight Risk across much of southern Montana
today with a Marginal Risk (threat level 1/5) that extends as far south as
the Denver metro area and as far east as the western Dakotas. By Monday, a
strengthening area of low pressure in the northern Great Plains will be
the focus for more severe weather and Excessive Rainfall. Both WPC and SPC
have Slight Risks in place across a large section of the North Central
U.S.. SPC's Slight Risk encompasses more of the northern Great Plains,
while WPC's Slight Risk for Excessive Rainfall includes more of the Upper
Midwest where soils remain overly saturated and river/stream flooding is
still ongoing. The storm system continues to track east on Tuesday with
the Midwest and Central Plains forecast to see the brunt of the severe
weather and heavy rainfall. Both WPC and SPC have hoisted Slight Risks for
Excessive Rainfall and severe weather for portions of these regions on
Tuesday. With additional heavy rainfall in parts of the Midwest, it is
possible this rainfall will either renew or exacerbate the ongoing
river/stream flooding in parts of the Upper Mississippi Valley through
mid-week.

Mullinax


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