386
FXUS01 KWBC 271953
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
350 PM EDT TUE AUG 27 2024
VALID 00Z WED AUG 28 2024 - 00Z FRI AUG 30 2024
...RECORD HEAT ON TAP FOR THE OHIO VALLEY, TENNESSEE VALLEY,
SOUTHERN APPALACHIANS AND MID-ATLANTIC, BUT RELIEF ON THE WAY...
...ACTIVE THUNDERSTORMS, HEAVY RAINS, FLASH FLOODING AND SEVERE
WEATHER POSSIBLE OVER LARGE PORTIONS OF THE NORTH CENTRAL TO EAST
CENTRAL U.S...
...FIRE WEATHER THREAT FOR PORTIONS OF THE NORTHWEST/NORTHERN
ROCKIES, ALONG WITH EARLY SEASON HIGH ELEVATION SNOW...
MUCH ABOVE AVERAGE TEMPERATURES WILL CONTINUE OVER THE NEXT FEW
DAYS ACROSS A LARGE PORTION OF THE NATION FROM THE CENTRAL TO
SOUTHERN PLAINS, EAST INTO THE MISSISSIPPI VALLEY, OHIO VALLEY,
SOUTHEAST AND MID-ATLANTIC. ACROSS MUCH OF THESE AREAS, HIGH
TEMPERATURES ARE FORECAST TO BE FROM 10 TO 15 DEGREES ABOVE
AVERAGE. THIS WILL RESULT IN THE POTENTIAL FOR RECORD HIGH
TEMPERATURES ACROSS MUCH OF THE OHIO AND TENNESSEE VALLEYS INTO
THE SOUTHERN APPALACHIANS AND MID-ATLANTIC ON WEDNESDAY AND ACROSS
THE OHIO AND TENNESSEE VALLEYS AND SOUTHERN APPALACHIANS ON
THURSDAY. THE COMBINATION OF THE MUCH ABOVE AVERAGE TEMPERATURES
AND CONTINUED HIGH LEVELS OF HUMIDITY WILL PRODUCE MAXIMUM HEAT
INDICES ON WEDNESDAY AND THURSDAY IN THE 105 TO 110+ DEGREES F
RANGE ACROSS THESE AREAS, PRODUCING MAJOR TO EXTREME HEAT RISKS
THROUGH THE OHIO/TENNESSEE VALLEYS INTO THE MID-ATLANTIC.
EXCESSIVE HEAT WARNING AND HEAT ADVISORIES ARE CURRENTLY IN EFFECT
ACROSS MUCH OF THESE AREAS, AFFECTING OVER 77 MILLION PEOPLE.
SOME RELIEF IS IN STORE FOR PORTIONS OF THE U.S. ON WEDNESDAY THAT
HAVE HAD VERY HOT TEMPERATURES THE PAST FEW DAYS. A COLD FRONT
WILL BE PRESSING SOUTH OUT OF THE UPPER GREAT LAKES INTO THE
MID-WEST TONIGHT, BRINGING RELIEF TO THE VERY HOT RECENT
TEMPERATURES FOR SOUTHERN MICHIGAN INTO CENTRAL TO SOUTHERN
WISCONSIN, NORTHERN TO CENTRAL ILLINOIS, EASTERN IOWA INTO
NORTHEAST MISSOURI. THIS FRONT WILL CONTINUE TO PRESS
SOUTHEASTWARD WEDNESDAY NIGHT BRINGING RELIEF BY THURSDAY TO THE
HEATWAVE FOR THE MID-ATLANTIC REGION INTO THE UPPER OHIO VALLEY.
THE TREND OF SHRINKING AREAL EXTENT OF MAJOR TO EXTREME HEAT RISKS
WILL ACCELERATE BY THE BEGINNING OF THE HOLIDAY WEEKEND ACROSS
LARGE PORTIONS OF THE NATION.
THE FRONTAL BOUNDARY SINKING SOUTHEASTWARD FROM THE UPPER
MISSISSIPPI VALLEY/UPPER GREAT LAKES REGION AND A SECOND STRONG
FRONT MOVING FROM THE NORTHERN ROCKIES/NORTH HIGH PLAINS TONIGHT
INTO THE NORTHERN TO CENTRAL PLAINS/UPPER MISSISSIPPI VALLEY
REGION WEDNESDAY INTO THURSDAY WILL BE THE FOCUS FOR AREAS OF
ACTIVE THUNDERSTORMS. WITH MOISTURE VALUES EXPECTED TO BE MUCH
ABOVE AVERAGE ALONG AND AHEAD OF EACH OF THESE FRONTS, LOCALLY
HEAVY RAIN AND ISOLATED FLASH FLOODING IS POSSIBLE FROM THE GREAT
LAKES INTO THE OHIO VALLEY LATE THIS AFTERNOON INTO EARLY
WEDNESDAY, AND ACROSS THE OHIO VALLEY INTO THE MID-ATLANTIC, AND
PORTIONS OF THE NORTHERN PLAINS INTO THE UPPER MISSISSIPPI VALLEY
LATE WEDNESDAY INTO THURSDAY. IN ADDITION TO THE HEAVY RAIN/FLASH
FLOOD THREATS, THESE THUNDERSTORMS MAY ALSO PRODUCE SEVERE WEATHER
ACROSS THESE AREAS, WITH LARGE HAIL AND HIGH WINDS THE GREATEST
THREAT, WITH A LESSER THREAT FOR TORNADOES.
THE STRONG FRONT PUSHING EAST FORM THE NORTHWEST LATE THIS
AFTERNOON WILL PRODUCE STRONG GUSTY WINDS IN ITS WAKE OVER THE
NORTHERN GREAT BASIN INTO THE NORTHERN ROCKIES. THESE WINDY
CONDITIONS, COMBINED WITH LOW RELATIVE HUMIDITIES WILL PRODUCE
FIRE WEATHER THREATS INTO WEDNESDAY , WITH RED FLAG WARNINGS IN
EFFECT ACROSS THESE AREAS. THE COLD TEMPERATURES IN THE WAKE OF
THIS STRONG FRONT WILL ALSO SUPPORT SNOWFALL POTENTIAL ABOVE 5000
FEET IN THE NORTHERN ROCKIES OF MONTANA WHERE SNOWFALL AMOUNTS OF
3 TO 6 INCHES ARE POSSIBLE ON WEDNESDAY.
ORAVEC
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