624
FXUS01 KWBC 210830
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
429 AM EDT TUE JUL 21 2026
VALID 12Z TUE JUL 21 2026 - 12Z THU JUL 23 2026
...STRONG FRONTAL SYSTEM TO PRODUCE WIDELY SCATTERED SEVERE
WEATHER AND FLASH FLOODING FROM THE MID-SOUTH INTO THE NORTHEAST...
..T.S. BERTHA TO BRING HEAVY RAIN THREATS ACROSS THE GULF COAST
...MONSOONAL THUNDERSTORMS TO CONTINUE OVER THE NEXT FEW DAYS FROM
THE SOUTHWEST INTO THE GREAT BASIN...
...HAZARDOUS HEAT BUILDS ACROSS THE SOUTHERN PLAINS AND
SOUTHEAST...
AN UNSEASONABLY DEEP LOW PRESSURE SYSTEM CONTINUES A STEADY
ADVANCE ACROSS THE UPPER GREAT LAKES THIS MORNING. OVER THE NEXT
48 HOURS, A WELL DEFINED COLD FRONT PROTRUDING FROM THIS LOW
CENTER IS EXPECTED TO PRESS SOUTHEASTWARD, WHICH WILL SET THE
STAGE FOR ACTIVE SEVERE WEATHER AND FLASH FLOODING FROM THE
MID-SOUTH INTO THE NORTHEAST AS A MOIST AND UNSTABLE AIRMASS POOLS
AHEAD OF THE FRONT. SEVERE WIND GUSTS AND FLASH FLOODING ARE
EXPECTED TO BE THE MAIN HAZARDS FROM ANY THUNDERSTORMS THIS
AFTERNOON, ALTHOUGH SEVERE HAIL AND A FEW TORNADOES ARE ALSO
POSSIBLE. BY TOMORROW, ANOTHER ROUND OF FLASH FLOODING AND SEVERE
WEATHER IS POSSIBLE OVER PORTIONS OF THE LOWER MID-ATLANTIC AS THE
FRONTAL BOUNDARY MIGRATES EASTWARD. MEANWHILE, ACROSS THE
NORTHEAST GULF, TROPICAL STORM BERTHA IS EXPECTED TO CONTINUE A
WESTWARD TRACK JUST SOUTH OF THE FLORIDA PANHANDLE TOWARDS
SOUTHEAST LOUISIANA. MUCH OF THE RAINFALL WITH THIS SYSTEM IS
STILL EXPECTED TO REMAIN SOUTH OF THE COASTLINE, ALTHOUGH THE
OUTER BANDS OF BERTHA COULD STILL SUPPORT ISOLATED TO SCATTERED
FLASH FLOODING OVER THE NEXT TWO DAYS. SEE THE LATEST NHC
ADVISORIES FOR ADDITIONAL AND UPDATED INFORMATION ON THIS STORM.
OVER THE SOUTHWEST, MONSOONAL MOISTURE CIRCULATING AROUND THE
WESTERN PERIPHERY OF THE RIDGE WILL CONTINUE TO SUPPORT SCATTERED
AFTERNOON AND EVENING THUNDERSTORMS ACROSS THE CENTRAL AND
SOUTHERN ROCKIES. STORM MOTIONS WILL GENERALLY REMAIN SLOW,
PRODUCING LOCALLY HEAVY RAINFALL, ESPECIALLY OVER HIGHER TERRAIN
THROUGH WEDNESDAY.
TEMPERATURE WISE, A SUBTROPICAL RIDGE WILL MAINTAIN ANOMALOUS HEAT
ACROSS THE SOUTHEAST AND SOUTHERN PLAINS WHERE 105-115 DEGREE HEAT
INDICES CAN BE EXPECTED. WITH THE ADDITION OF 75-80 DEGREE
OVERNIGHT LOWS, HEAT RELATED ILLNESSES WILL BE OF CONCERN OVER THE
NEXT FEW DAYS, ESPECIALLY FOR THOSE WITHOUT ADEQUATE COOLING OR
HYDRATION. FURTHER NORTH, BELOW NORMAL TEMPERATURES WILL BUILD
BEHIND THE COLD FRONT ACROSS THE UPPER MIDWEST, GREAT LAKES, AND
NORTHEAST.
ASHERMAN/OUDIT
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