781
FXUS01 KWBC 230555
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
154 AM EDT THU JUL 23 2026
VALID 12Z THU JUL 23 2026 - 12Z SAT JUL 25 2026
...TROPICAL STORM BERTHA MAY LEAD TO ISOLATED FLASH FLOODING,
TROPICAL STORM CONDITIONS, AND COASTAL FLOODING ALONG THE GULF
COAST AND INTO SOUTHERN TEXAS...
...RISK OF FLASH FLOODING EXPECTED ACROSS PORTIONS OF THE SOUTHERN
MID-ATLANTIC/CAROLINAS, TENNESSEE VALLEY, AND THE SOUTHEAST
THROUGH FRIDAY...
...MONSOONAL THUNDERSTORMS CONTINUE OVER THE SOUTHWEST, GREAT
BASIN AND PARTS OF THE PLAINS...
...HAZARDOUS HEAT CONTINUES OVER PARTS OF THE SOUTHERN TIER;
BUILDS OVER THE GREAT BASIN AND NORTHERN PLAINS FRIDAY...
TROPICAL STORM BERTHA WILL CONTINUE TO TRACK ALONG THE NORTHERN
GULF COAST ON THURSDAY, BRINGING SHOWERS ALONG THE GULF COAST NEAR
LOUISIANA AND TEXAS. AREAS ALONG THE GULF COAST HAVE ISSUES A
TROPICAL STORM WARNING FOR THEIR COASTAL WATERS
NEAR LOUISIANA AND UPPER TEXAS GULF COAST THROUGH LATE THURSDAY.
BY FRIDAY, DEEP TROPICAL MOISTURE FROM T.S. BERTHA COMBINED WITH
EMBEDDED UPPER-LEVEL DISTURBANCES AND QUASI-STATIONARY FRONT WILL
SUPPORT ANOTHER ROUND OF SLOW-MOVING THUNDERSTORMS CAPABLE OF
PRODUCING LOCALLY EXCESSIVE RAINFALL AND COASTAL FLOODING ALONG
SOUTHERN TEXAS.
A FRONTAL PASSAGE WILL DROP INTO THE TENNESSEE VALLEY/SOUTHEAST
AND EXTEND INTO THE MID-ATLANTIC ON THURSDAY AND BECOME
QUASI-STATIONARY. THE SLOW MOVING FRONT WILL POOL WARM TROPICAL
MOISTURE ALONG THE BOUNDARY, FAVORING WIDESPREAD SHOWERS AND
THUNDERSTORMS. THE COMBINATION OF UNSTABLE AIRMASS AND SUFFICIENT
MID-LEVEL MOISTURE MAY LEAD TO HIGH RAIN RATES AND REPEATED ROUNDS
OF CONVECTION, WHICH CAN BRING AN INCREASED RISK FOR FLASH
FLOODING ACROSS PORTIONS OF SOUTHERN MID-ATLANTIC, THE CAROLINAS,
AND THE SOUTHEAST. THE FRONTAL BOUNDARY WILL ALSO EXTEND INTO
PARTS OF THE CENTRAL PLAINS, BRINGING CHANCES FOR SHOWERS AND
THUNDERSTORMS. THE SHORTWAVE DISTURBANCES WILL ALSO SUPPORT
MULTIPLE ROUND OF THE CONVECTION, WHICH MAY LEAD TO FLASH FLOODING
AND A CHANCE FOR SEVERE THUNDERSTORMS ACROSS THE CENTRAL/SOUTHERN
PLAINS. ON FRIDAY, THE EXCESSIVE RAINFALL THREAT CONTINUES AS THE
FRONTAL BOUNDARY STALLS AND INSTABILITY INCREASES, LEADING TO
ANOTHER ROUND OF HEAVY RAINFALL ACROSS THE SOUTHEAST.
ACROSS THE WESTERN U.S. PERSISTENT SOUTHERLY FLOW ALONG THE
WESTERN FLANK OF THE UPPER-LEVEL RIDGE CENTERED OVER THE ROCKIES,
WILL CONTINUE TO TRANSPORT DEEP MONSOONAL MOISTURE NORTHWARDS INTO
PARTS OF THE GREAT BASIN AND SOUTHWEST ON THURSDAY. DAYTIME
HEATING COMBINED WITH TERRAIN-INDUCED LIFT, WILL AID IN SHOWERS
AND THUNDERSTORM DEVELOPMENT, WHICH WILL BRING A RISK FOR
SCATTERED FLASH FLOODING. ON FRIDAY, THE RISK EXPANDS INTO THE
CENTRAL PLAINS/MID-MISSISSIPPI VALLEY AS THE MOISTURE INTERACTS
WITH THE FRONTAL BOUNDARY AND SHORTWAVE TROUGHS, LEADING TO
ORGANIZED THUNDERSTORMS ACROSS THE AREA. ADDITIONALLY, OVER INTO
THE NORTHERN TIER, A SHORTWAVE TROUGH WILL BRING A CHANCE FOR
SEVERE THUNDERSTORMS ACROSS THE DAKOTAS INTO PARTS OF MINNESOTA ON
FRIDAY.
HAZARDOUS HEAT CONTINUES THIS WEEK OVER THE SOUTHERN TIER OF THE
U.S. BEFORE BEGINNING TO EXPAND NORTHWARD THROUGH THE GREAT BASIN
AS WELL AS ACROSS THE NORTHERN AND THEN CENTRAL PLAINS FRIDAY INTO
THE WEEKEND. FORECAST HIGHS RANGE IN THE MID-90S TO MID-100S WITH
HEAT INDICES EXCEEDING 105-115 DEGREES FOR SOME LOCATIONS. RECORD
WARM OVERNIGHT LOWS IN THE 75 TO 80 DEGREE RANGE WILL PROVIDE
LITTLE RELIEF FROM TH HEAT OVERNIGHT. WIDESPREAD MAJOR TO LOCALLY
EXTREME HEATRISK (LEVELS 3 AND 4/4) IS EXPECTED WHICH INDICATES A
LEVEL OF HEAT DANGEROUS TO ANYONE WITHOUT ADEQUATE COOLING OR
HYDRATION. CONTINUE TO MONITOR WPC'S KEY MESSAGES FOR MORE DETAILS
AND UPDATES ON THE HEAT. OVER THE PACIFIC NORTHWEST, COOLER
TEMPERATURES RETURN AS A COLD FRONT MOVES INTO THE AREA, BRINGING
BELOW AVERAGE TEMPERATURES BY THE WEEKEND. IN ADDITION, THE
MIDWEST TO MID-ATLANTIC/NORTHEAST WILL SEE BELOW AVERAGE
TEMPERATURES FOLLOWING A COLD FRONT PASSAGE, WITH HIGHS IN THE 70S
TO LOW 80S THROUGH FRIDAY.
OUDIT/PUTNAM
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