517
FXUS01 KWBC 260514
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
112 AM EDT WED AUG 26 2026
VALID 12Z WED AUG 26 2026 - 12Z FRI AUG 28 2026
...DANGEROUS RECORD-BREAKING HEAT CONTINUES ACROSS THE
SOUTH-CENTRAL U.S. INTO THE SOUTHWEST THIS WEEK...
...HEAVY RAINFALL AND SEVERE THUNDERSTORMS ACROSS THE MIDWEST,
LOWER MISSISSIPPI VALLEY, AND GREAT LAKES/OHIO VALLEY ON
WEDNESDAY...
...FLASH FLOODING THREAT ACROSS THE SOUTHEAST AND LOWER
MISSISSIPPI VALLEY INTO THE NORTHEAST ON THURSDAY...
A STRONG UPPER-LEVEL RIDGE WILL REMAIN ANCHORED ACROSS THE
SOUTHWEST INTO THE SOUTH-CENTRAL U.S. INTO LATE WEEK, BRINGING
DAYTIME HIGHS IN THE UPPER 90S TO LOW 100S, WITH ISOLATED AREAS
REACHING BETWEEN 100-115 DEGREES IN THE SOUTHWEST AND SOUTHERN
PLAINS. RECORD-BREAKING OVERNIGHT TEMPERATURES WILL LIMIT RECOVERY
FROM THE HEAT, WHICH MAY RESULT IN HEAT-RELATED ILLNESSES FOR
THOSE WITHOUT ADEQUATE COOLING AND HYDRATION. THEREFORE,
WIDESPREAD MAJOR TO EXTREME HEATRISK WILL CONTINUE ACROSS PORTIONS
OF TEXAS INTO THE SOUTHWEST THROUGH THURSDAY. SEE THE LATEST KEY
MESSAGES LINKED AT THE BOTTOM OF THE DISCUSSION FOR MORE
INFORMATION.
A PROGRESSIVE UPPER-LEVEL TROUGH WILL MOVE EASTWARD ACROSS THE
MIDWEST INTO THE GREAT LAKES TOWARD THE NORTHEAST. ORGANIZED
CONVECTION WILL DEVELOP ALONG THE FRONTAL BOUNDARY EXTENDING FROM
CENTRAL/SOUTHERN PLAINS AND MIDWEST INTO THE OHIO VALLEY AND
EVENTUALLY THE NORTHEAST, AS MOISTURE AND INSTABILITY INCREASES.
THE STRONGEST STORMS WILL HAVE THE POTENTIAL TO PRODUCE LIGHTNING,
LARGE HAIL, DAMAGING WINDS, AND EXCESSIVE RAINFALL/FLASH FLOODING
THROUGH WEDNESDAY, ESPECIALLY ACROSS THE MID-MISSISSIPPI VALLEY
INTO THE GREAT LAKES/OHIO VALLEY. FURTHERMORE, AS A SLOW-MOVING
FRONTAL BOUNDARY ACROSS THE SOUTHEAST AND LOWER MISSISSIPPI VALLEY
WEAKENS, THE COLD FRONT FROM THE PRIMARY FRONTAL SYSTEM WILL MOVE
SOUTHEASTWARD BY LATE WEDNESDAY. DEEP GULF MOISTURE WILL CONTINUE
TO POOL ALONG THE BOUNDARY, WHICH WILL MAINTAIN A CORRIDOR
FAVORABLE FOR HEAVY RAINFALL AND SEVERE THUNDERSTORMS FROM LOWER
MISSISSIPPI VALLEY INTO PORTIONS OF THE SOUTHEAST. ON THURSDAY,
THE SEVERE THUNDERSTORM SHIFTS TO THE NORTHEAST AND OHIO VALLEY,
WHILE THE HEAVY RAINFALL/FLASH FLOODING THREAT ENCOMPASSES
PORTIONS OF THE NORTHEAST, MID-ATLANTIC, AND SOUTHEAST AS THE
FRONTAL BOUNDARY MOVES EASTWARD.
MEANWHILE, CONTINUED MONSOONAL MOISTURE TRANSPORT AROUND THE
WESTERN PERIPHERY OF THE RIDGE WILL SUPPORT DAILY THUNDERSTORMS
ACROSS THE PORTIONS OF THE SOUTHWEST, GREAT BASIN, ROCKIES, AND
CENTRAL/SOUTHERN PLAINS. THE COMBINATION OF HIGH MOISTURE AND
INSTABILITY MAY LEAD TO ORGANIZED SLOW-MOVING STORMS, WHICH WILL
CONTINUE TO FAVOR ISOLATED FLASH FLOODING ACROSS MUCH OF THE FOUR
CORNERS INTO THE CENTRAL/SOUTHERN HIGH PLAINS AND ROCKIES THROUGH
THURSDAY. ADDITIONALLY, SOME OF ORGANIZED CONVECTION MAY PRODUCE
STRONG WINDS, LARGE HAIL, AND LIGHTNING ACROSS THE
CENTRAL/SOUTHERN HIGH PLAINS.
OUDIT
GRAPHICS AVAILABLE AT
HTTPS://WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP
EXTREME HEAT KEY MESSAGES AVAILABLE AT:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/KEY_MESSAGES/LATESTKEYMESSAGE_1.PNG
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