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FXUS01 KWBC 151928

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
328 PM EDT Tue Jun 15 2021

Valid 00Z Wed Jun 16 2021 - 00Z Fri Jun 18 2021

...Dangerous heat to continue across portions of the West and
Northern/Central Plains, with record-breaking temperatures and
fire danger in some areas...

...Rain and thunderstorms are forecast across Florida over the
next couple of days and could produce isolated flash flooding...

A strong upper-level ridge centered across the Four Corners region
will help sustain a substantial heat wave for the majority of the
western U.S. over the next several days, with the northern and
central U.S. also seeing periods of hot weather. Temperatures well
into the 110s to lower 120s are forecast for the Desert Southwest.
Meanwhile over Montana, high temperatures well into the 100s will
be as much as 30 degrees above average this afternoon and evening.
Dozens (possibly hundreds) of daily record high maximum and
minimum temperatures are likely to be set over the next few days
in California, the Intermountain West, Desert Southwest, Rockies,
and central/northern Plains. High temperatures across the lower
elevations of the Central Rockies region could even challenge
all-time records this afternoon and Wednesday at some locations.
By Thursday, the summer heat will push southward into the Central
Plains, as well as expanding west into the central valleys of
California. Widespread Excessive Heat Warnings and Heat Advisories
have been issued throughout eight states in the western U.S., from
southern California to northeast Montana. Residents enduring the
ongoing dangerous stretch of heat are advised to stay indoors and
seek air-conditioned buildings, stay hydrated, and take frequent
breaks if engaging in outdoor activities. Given the heat, dry
conditions, and gusty winds, fire danger is also a concern
throughout much of the West, with Critical Risks of fire weather
in place this evening across portions of the central Great Basin
and Northern Rockies.

The exception to the western heat will be the Pacific Northwest,
which can expect cooler than average temperatures as well as rain
chances tonight behind a cold front. Precipitation should decrease
in the Northwest on Wednesday, but winds are likely to strengthen
as a low pressure system intensifies in western Canada. The cold
front should drop temperatures closer to normal in Montana on
Wednesday, while also helping trigger some thunderstorms in the
Dakotas and Midwest before reaching the Great Lakes by Thursday.
Isolated storms could be strong to severe in these locations.

Scattered thunderstorms are likely across the Gulf Coast region
over the next couple of days. There is a Slight Risk for severe
weather (with gusty winds and hail the main threats) across the
coastal Carolinas into tonight. The Florida Peninsula in
particular should see good coverage of thunderstorms, with heavy
downpours potentially leading to isolated flash flooding.
Meanwhile, some showers and thunderstorms are possible in the
Northeast this evening as a couple of fronts move through the
region, which will also cause below normal and pleasant
temperatures through Thursday.


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