697
FXUS01 KWBC 201731
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
130 PM EDT THU JUL 20 2023
VALID 00Z FRI JUL 21 2023 - 00Z SUN JUL 23 2023
...THE HIGHEST RISK OF FLASH FLOODING/SEVERE STORMS SHOULD PERSIST
INTO THURSDAY NIGHT IN AND NEAR THE COLORADO/KANSAS BORDER...
...LENGTHY & DANGEROUS HEAT WAVE TO CONTINUE ACROSS THE SOUTHERN
TIER & IN THE WEST...
...COOLER AND MORE COMFORTABLE AIR-MASS TO ENGULF THE GREAT PLAINS
AND MIDWEST...
A STRONG COLD FRONT PRESSING SOUTH AND EAST THROUGH THE NATION'S
HEARTLAND WILL COLLIDE WITH AN EXCEPTIONALLY HOT AND MUGGY
AIR-MASS TO PRODUCE WIDESPREAD THUNDERSTORMS INTO THURSDAY NIGHT.
THE REGION MOST AT-RISK FOR FLASH FLOODING (MODERATE RISK) AND
SEVERE STORMS (ENHANCED RISK) IS THE CENTRAL HIGH PLAINS. ROBUST
THUNDERSTORM ACTIVITY COULD PRODUCE ANY COMBINATION OF FLASH
FLOODING, DAMAGING WINDS, LARGE HAIL, AND TORNADOES THERE. THE
SEVERE WEATHER AND FLASH FLOOD THREAT (SLIGHT RISK) IS ALSO
PRESENT FOR MANY LOCATIONS FARTHER EAST, WHICH WOULD EXTEND INTO
THE EVENING HOURS ON THURSDAY. SEE THE LATEST WPC AND SPC
OUTLOOKS FOR MORE DETAILS. BY FRIDAY THE COLD FRONT CONTINUES TO
ADVANCE FARTHER SOUTH AND EAST, PLACING THE BEST THREAT FOR FLASH
FLOODING AND STRONG-TO-SEVERE STORMS OVER THE SOUTHERN HIGH
PLAINS, MID-SOUTH. AND NORTHEAST. BY SATURDAY MORNING, MUCH OF THE
MID-SOUTH AND NORTHEAST WILL TREND DRIER AS THE COLD FRONT EXITS
OFF THE EAST COAST. HOWEVER, THE FRONT BECOMES STATIONARY OVER THE
GULF COAST STATES, SETTING UP A STORMY SATURDAY IN THE SOUTH.
FOR THE REMAINDER OF THE WORK-WEEK, MUCH OF THE SOUTHERN TIER
(SOUTH OF THE ADVANCING FRONT) AND WESTERN THIRD OF THE U.S. WILL
REMAIN MIRED IN THIS PROLONGED AND DANGEROUS HEAT WAVE. RECORD
BREAKING DAYTIME HIGHS AND WARM MORNING LOWS WILL BE COMMON FROM
THE DESERT SOUTHWEST AND SOUTH TEXAS ALL THE WAY EAST TO FLORIDA.
THE FORECAST CALLS FOR DAYTIME HIGHS TO SOAR INTO THE TRIPLE
DIGITS IN THE DESERT SOUTHWEST AND SOUTHERN PLAINS, WHILE THE GULF
COAST AND MID-SOUTH CAN EXPECT DAYTIME HIGHS IN THE UPPER 90S THAT
COINCIDE WITH OPPRESSIVELY HIGH DEW POINTS THROUGH FRIDAY,
RESULTING IN SWELTERING HEAT INDICES AS HIGH AS 120 DEGREES IN
SOME SPOTS. MEANWHILE, DAILY LOW TEMPERATURES REMAIN QUITE WARM
WITH BREAKING RECORD WARM DAILY MINIMUMS EXPECTED, WHICH WILL
LIMIT RELIEF FROM THE HEAT OVERNIGHT. FLORIDA WILL ALSO CONTEND
WITH STIFLING HEAT AHEAD OF THE FRONT, WHERE LIGHTER THAN AVERAGE
WINDS HAVE LED TO ABOVE AVERAGE SEA SURFACE TEMPERATURES DUE TO A
WEAKER THAN AVERAGE BERMUDA HIGH. PLEASE VISIT HEAT.GOV, AS WELL
AS THE KEY MESSAGES ISSUED BY THE WEATHER PREDICTION CENTER AND
CLIMATE PREDICTION CENTER FOR MORE INFORMATION ON IMPACTS FROM THE
HEAT WAVE.
BEHIND THE COLD FRONT, COOLER AND DRIER AIR SWEEPS IN. BY FRIDAY,
PARTS OF THE CENTRAL PLAINS COULD SEE DAYTIME HIGHS THAT ARE AS
LOW AS 15-20 DEGREES BELOW NORMAL. THE EAST WILL SEE MILDER AIR
ARRIVE BY SATURDAY, INCLUDING IN THE MID-ATLANTIC AND NORTHEAST
WHERE DAYTIME HIGHS LOOK TO BE SEVERAL DEGREES BELOW NORMAL AND
HUMIDITY LEVELS THAT ARE MORE REFRESHING FOR MID-LATE JULY.
ROTH/MULLINAX
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