583
FXUS01 KWBC 280744
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
343 AM EDT SUN JUL 28 2024
VALID 12Z SUN JUL 28 2024 - 12Z TUE JUL 30 2024
...FLASH FLOODING POSSIBLE IN THE OHIO/TENNESSEE VALLEYS SUNDAY,
SPREADING INTO THE CENTRAL/SOUTHERN APPALACHIANS BY MONDAY...
...SEVERE THUNDERSTORMS EXPECTED ACROSS PORTIONS OF THE
NORTHERN/CENTRAL PLAINS WITH FLASH FLOODING INTO THE UPPER MIDWEST
SUNDAY...
...COOLER THAN NORMAL FOR MUCH OF THE WEST WITH MONSOONAL
THUNDERSTORMS FOR PORTIONS OF THE SOUTHWEST...
A LINGERING FRONTAL BOUNDARY SNAKING THROUGH THE OHIO/TENNESSEE
VALLEYS DEEPER INTO THE SOUTHEAST AND OFF THE ATLANTIC COAST WILL
CONTINUE TO HELP TRIGGER SCATTERED SHOWERS AND THUNDERSTORMS OVER
THE NEXT COUPLE OF DAYS. AN UPPER-LEVEL WAVE PASSING OVER THE
OHIO/TENNESSEE VALLEYS WILL PROVIDE A FOCUS FOR MORE NUMEROUS
STORMS ON SUNDAY, POSSIBLY INTO THE CENTRAL/SOUTHERN APPALACHIANS
AS WELL, WITH VERY MOIST, SOUTHERLY GULF FLOW LEADING TO SOME
LOCALLY HEAVY DOWNPOURS. A SLIGHT RISK OF EXCESSIVE RAINFALL
(LEVEL 2/4) IS IN EFFECT FOR THE THREAT OF SOME SCATTERED
INSTANCES OF FLASH FLOODING, PARTICULARLY WHERE STORMS MAY HAVE
THE TENDENCY TO BACKBUILD/REPEAT OVER AREAS IN VICINITY OF THE
FRONTAL BOUNDARY. THEN, AS THE UPPER-LEVEL WAVE CONTINUES EAST ON
MONDAY, THE FOCUS FOR STORMS WILL SPREAD FURTHER INTO THE
CENTRAL/SOUTHERN APPALACHIANS, WITH ANOTHER SLIGHT RISK OF
EXCESSIVE RAINFALL IN EFFECT FOR ADDITIONAL INSTANCES OF FLASH
FLOODING. HIGH TEMPERATURES BROADLY ACROSS THE OHIO VALLEY INTO
THE SOUTHEAST AND ALONG THE GULF COAST WILL REMAIN AT OR A BIT
BELOW AVERAGE GIVEN WIDESPREAD CLOUDS AND STORMS, WITH HIGHS
GENERALLY IN THE MID-80S TO LOW 90S.
A FRONTAL SYSTEM PASSING SLOWLY THROUGH THE NORTHERN/CENTRAL
PLAINS AND THE UPPER MIDWEST WILL BRING STORM CHANCES TO THESE
REGIONS SUNDAY. PLENTIFUL MOISTURE, INSTABILITY, AND STRONG
UPPER-LEVEL FLOW OVERHEAD LEADING TO SUFFICIENT DEEP-LAYER SHEAR
IS EXPECTED TO RESULT IN SOME MORE INTENSE, ORGANIZED STORMS.
INITIALLY ISOLATED STORMS/SUPERCELLS OVER PORTIONS OF SOUTH
DAKOTA, CENTRAL NEBRASKA, AND NORTHWESTERN KANSAS MAY PRODUCE SOME
LARGE HAIL AND DAMAGING WINDS. EVENTUAL UPSCALE GROWTH INTO AN
ORGANIZED CONVECTIVE SYSTEM SUNDAY EVENING MAY BRING A DAMAGING
WIND THREAT DOWNSTREAM INTO SOUTHWESTERN MINNESOTA AND
NORTHWESTERN IOWA. THE STORM PREDICTION CENTER HAS HIGHLIGHTED
THESE AREAS WITH A SLIGHT RISK (LEVEL 2/5) OF SEVERE WEATHER. THE
EXPANDING COVERAGE OF STORMS HEADING EASTWARD, AS WELL AS
PLENTIFUL MOISTURE TO LEAD TO HEAVY RAINFALL RATES, WILL ALSO
BRING THE THREAT OF FLASH FLOODING INTO IOWA. ADDITIONAL STORMS
WILL CONTINUE AHEAD OF THE FRONT OVER MINNESOTA THROUGH EARLY
MORNING SUNDAY, WITH ANOTHER ROUND OF STORMS EXPECTED SUNDAY
NIGHT. REPEATED STORMS BRINGING HEAVY RAINFALL ON TOP OF ALREADY
WET ANTECEDENT CONDITIONS WILL LEAD TO THE RISK OF SOME SCATTERED
FLASH FLOODING HERE AS WELL. A SLIGHT RISK OF EXCESSIVE RAINFALL
EXTENDS FROM PORTIONS OF MINNESOTA SOUTHWARD INTO IOWA TO COVER
THESE THREATS. THE SYSTEM WILL CONTINUE INTO THE GREAT LAKES
REGION MONDAY, BRINGING SHOWERS AND STORMS WITH MODERATE TO
LOCALLY HEAVY RAINFALL. HIGH TEMPERATURES AHEAD OF THE FRONT WILL
BE RATHER HOT, RUNNING 10-15 DEGREES ABOVE AVERAGE FOR SOME
LOCATIONS, WITH 80S TO NEAR 90 IN THE UPPER MIDWEST AND 90S TO LOW
100S SOUTHWESTWARD INTO THE CENTRAL PLAINS AND SOUTHERN HIGH
PLAINS. A FEW NEAR RECORD-TYING/BREAKING HIGHS WILL BE POSSIBLE IN
THE SOUTHERN HIGH PLAINS MONDAY.
AN UPPER-TROUGH OVER THE WEST WILL KEEP TEMPERATURES BELOW AVERAGE
FOR MOST OF THE REGION. FORECAST HIGHS SUNDAY-MONDAY RANGE BETWEEN
THE 60S AND 70S ALONG THE PACIFIC COAST; 70S AND 80S IN THE
PACIFIC NORTHWEST; 80S AND 90S IN THE GREAT BASIN, FOUR CORNERS
REGION, AND INTERIOR CALIFORNIA; AND THE 100S INTO THE DESERT
SOUTHWEST. SOME MONSOONAL STORMS WILL CONTINUE OVER PARTS OF THE
SOUTHWEST, PARTICULARLY SOUTHEASTERN ARIZONA/SOUTHWESTERN NEW
MEXICO, WITH AN ISOLATED THREAT OF FLASH FLOODING. A STORM SYSTEM
APPROACHING THE PACIFIC NORTHWEST WILL BRING SOME SHOWER CHANCES
HERE AS WELL. SMOKE FROM WILDFIRES WILL ALSO CONTINUE TO PLAGUE
PARTS OF THE WEST, PARTICULARLY OVER THE NORTHERN GREAT
BASIN/ROCKIES, RESULTING IN POOR AIR QUALITY AND AREAS OF REDUCED
VISIBILITY. ELSEWHERE, CONDITIONS WILL BE TRENDING HOTTER ACROSS
MOST OF THE NORTHEAST, WITH 80S AND LOW 90S FORECAST. A COASTAL
LOW APPROACHING SOUTHERN NEW ENGLAND IS LOOKING MORE LIKELY TO
BRING COOLER TEMPERATURES AND SOME RAIN CHANCES OVER THE NEXT
COUPLE OF DAYS.
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