971
FXUS01 KWBC 240754
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
353 AM EDT THU AUG 24 2023
VALID 12Z THU AUG 24 2023 - 12Z SAT AUG 26 2023
...DANGEROUS HEAT CONTINUES FROM THE MIDWEST TO GULF COAST, WITH
RELIEF FINALLY ON THE WAY FOR SOME BY THIS WEEKEND...
...SEVERE THUNDERSTORMS AND FLASH FLOODING POSSIBLE ACROSS THE
LOWER GREAT LAKES AND PARTS OF THE CENTRAL APPALACHIANS INTO
TONIGHT...
...SCATTERED FLASH FLOODING CONCERNS FORECAST FROM THE CENTRAL
GREAT BASIN TO THE CENTRAL HIGH PLAINS THROUGH FRIDAY...
YET ANOTHER DAY OF DANGEROUS AND OPPRESSIVE HEAT IS ANTICIPATED
THROUGHOUT A LARGE PORTION OF THE NATION SITUATED UNDERNEATH A
POTENT UPPER LEVEL RIDGE. RECORD-BREAKING HEAT WITH FORECAST HIGHS
INTO THE UPPER 90S AND LOW 100S WILL IMPACT A BROAD REGION BETWEEN
THE MIDWEST AND CENTRAL GULF COAST TODAY. WHEN FACTORING IN SULTRY
HUMIDITY LEVELS, HEAT INDICES COULD APPROACH 120 DEGREES. THIS
HEAT WAVE WILL POSE A GREATER HEALTH RISK THAN USUAL, AND BE
POTENTIALLY DEADLY, DUE TO MULTIPLE CONSECUTIVE DAYS OF EXTREME
HEAT, THE INTENSITY OF THE HEAT, AND LACK OF OVERNIGHT COOLING
ASSOCIATED WITH RECORD WARM OVERNIGHT LOWS. HEAT ALERTS (EXCESSIVE
HEAT WARNINGS/WATCHES AND ADVISORIES) CURRENTLY SPAN ACROSS 20
STATES AND INCLUDE JUST OVER 110 MILLION PEOPLE. RESIDENTS ARE
ADVISED TO FOLLOW PROPER HEAT SAFETY BY STAYING HYDRATED, AVOIDING
EXTENDING PERIODS OF TIME OUTDOORS, AND LOOKING OUT FOR VULNERABLE
FAMILY MEMBERS, FRIENDS, AND NEIGHBORS. THE GOOD NEWS FOR NORTHERN
REGIONS IMPACTED BY ONGOING SWELTERING CONDITIONS IS THAT A COLD
FRONT WILL BEGIN TO PUSH SOUTH TODAY AND BRING MUCH MORE
COMFORTABLE TEMPERATURES TO MUCH OF THE MIDWEST BY SATURDAY.
HOWEVER, SEARING HEAT WILL REMAIN THROUGHOUT THE SOUTH INTO THE
START OF THE WEEKEND.
ON THE NORTHEAST PERIPHERY OF THE AFOREMENTIONED UPPER RIDGE,
SHOWER AND THUNDERSTORM CHANCES EXIST FROM PARTS OF THE LOWER
GREAT LAKES TO THE UPPER OHIO VALLEY AND NORTHEAST. A SLOW-MOVING
WARM FRONT WILL PROVIDE A FOCUS FOR DEVELOPING THUNDERSTORMS.
THESE STORMS WILL BE ABLE TO TAKE ADVANTAGE OF ELEVATED
ATMOSPHERIC MOISTURE CONTENT TO CREATE INTENSE DOWNPOURS. AS A
RESULT, THE THREAT OF FLASH FLOODING EXISTS FROM NORTHEAST OHIO TO
MUCH OF PENNSYLVANIA AND SOUTHERN NEW YORK STATE. THUNDERSTORMS
MAY ALSO CONTAIN DAMAGING WINDS, LARGE HAIL, AND PERHAPS AND
TORNADO BETWEEN SOUTHERN MICHIGAN TO WESTERN PENNSYLVANIA. BY
FRIDAY, THE FRONTAL SYSTEM IS EXPECTED TO PUSH FARTHER SOUTH AND
EAST, SPREADING RAIN/THUNDERSTORM CHANCES TO NEW ENGLAND AND THE
MID-ATLANTIC.
FARTHER WEST, REMNANT TROPICAL MOISTURE FROM HAROLD ROUNDING THE
WESTERN EDGE OF THE CENTRAL U.S. UPPER RIDGE WILL CONTINUE TO LEAD
TO SCATTERED FLASH FLOODING POTENTIAL OVER THE CENTRAL GREAT BASIN
TODAY. IN PARTICULAR, SOUTHERN UTAH AND WESTERN COLORADO ARE
LOCATED WITHIN A SLIGHT RISK (LEVEL 2/4) OF EXCESSIVE RAINFALL.
THESE AREAS ARE SITUATED WITHIN OVERLAPPING VULNERABLE TERRAIN AND
BEST ATMOSPHERIC CONDITIONS CONDUCIVE FOR HEAVY RAINFALL. THE
FLASH FLOODING RISK IS EXPECTED TO SHIFT INTO THE CENTRAL ROCKIES
AND CENTRAL HIGH PLAINS BY FRIDAY AS THE AFOREMENTIONED LINGERING
TROPICAL MOISTURE INTERACTS WITH AN APPROACHING COLD FRONT. A FEW
INCHES OF RAIN WITHIN A SHORT PERIOD OF TIME COULD LEAD TO RAPID
RUNOFF AND FLOODING CONCERNS.
SNELL
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