509
FXUS01 KWBC 030748
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
347 AM EDT THU AUG 03 2023
VALID 12Z THU AUG 03 2023 - 12Z SAT AUG 05 2023
...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER PARTS OF THE
OHIO/TENNESSEE/MIDDLE MISSISSIPPI VALLEYS, SOUTHEAST AND SOUTHERN
APPALACHIANS, ALONG WITH TWO AREAS OVER THE NORTHERN/CENTRAL
PLAINS INTO THE GREAT BASIN...
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
THE CENTRAL HIGH PLAINS...
...EXCESSIVE HEAT WARNINGS AND ADVISORIES FROM PARTS OF
CENTRAL/SOUTHERN PLAINS AND THE MIDDLE/LOWER MISSISSIPPI
VALLEY/CENTRAL GULF COAST...
A WAVE OF LOW PRESSURE OVER THE CENTRAL PLAINS WILL MOVE EASTWARD
INTO THE OHIO/TENNESSEE VALLEYS BY FRIDAY. TROPICAL MOISTURE,
UPPER-LEVEL ENERGY, AND A NEARBY FRONT WILL CREATE SHOWERS AND
THUNDERSTORMS WITH HEAVY RAIN OVER PARTS OF THE
OHIO/TENNESSEE/MIDDLE MISSISSIPPI VALLEYS, SOUTHEAST AND SOUTHERN
APPALACHIANS. THEREFORE, THE WPC HAS ISSUED A SLIGHT RISK OF
EXCESSIVE RAINFALL OVER PARTS OF THE OHIO/TENNESSEE/MIDDLE
MISSISSIPPI VALLEYS, SOUTHEAST AND SOUTHERN APPALACHIANS THROUGH
FRIDAY MORNING. THE ASSOCIATED HEAVY RAIN WILL CREATE MAINLY
LOCALIZED AREAS OF FLASH FLOODING, WITH URBAN AREAS, ROADS, AND
SMALL STREAMS THE MOST VULNERABLE.
ADDITIONALLY, THE SYSTEM WILL PRODUCE SHOWERS AND SEVERE
THUNDERSTORMS OVER PARTS OF TENNESSEE, ALABAMA, AND NORTHWESTERN
GEORGIA. THEREFORE, THE SPC HAS ISSUED A SLIGHT RISK OF SEVERE
THUNDERSTORMS OVER PARTS OF THE TENNESSEE VALLEY, SOUTHEAST, AND
SOUTHERN APPALACHIANS THROUGH FRIDAY MORNING. THE HAZARDS
ASSOCIATED WITH THESE THUNDERSTORMS ARE FREQUENT LIGHTNING, SEVERE
THUNDERSTORM WIND GUSTS, HAIL, AND A FEW TORNADOES.
MEANWHILE, UPPER-LEVEL ENERGY AND A STEADY MOISTURE SUPPLY WILL
PRODUCE SHOWERS AND SEVERE THUNDERSTORMS OVER PARTS OF COLORADO,
NORTHWESTERN KANSAS, AND SOUTHWESTERN NEBRASKA. THEREFORE, THE SPC
HAS ISSUED AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER THE
CENTRAL HIGH PLAINS THROUGH FRIDAY MORNING. THE HAZARDS ASSOCIATED
WITH THESE THUNDERSTORMS ARE FREQUENT LIGHTNING, SEVERE
THUNDERSTORM WIND GUSTS, HAIL, AND A MINIMAL THREAT OF TORNADOES.
HOWEVER, THERE IS AN INCREASED THREAT OF SEVERE THUNDERSTORM WIND
GUSTS OF 65 KNOTS OR GREATER OVER THE REGION.
MOREOVER, THE SHOWERS AND THUNDERSTORMS WILL CREATE HEAVY RAIN
OVER IDAHO, UTAH, WYOMING, AND SOUTH DAKOTA, AS WELL AS AN AREA
OVER PARTS OF EASTERN COLORADO, SOUTHERN NEBRASKA, AND NORTHERN
KANSAS. THEREFORE, THROUGH FRIDAY MORNING, THE WPC HAS ISSUED A
SLIGHT RISK OF EXCESSIVE RAINFALL OVER PARTS OF THE NORTHERN
INTERMOUNTAIN REGION, GREAT BASIN, NORTHERN/CENTRAL PLAINS, AND
NORTHERN ROCKIES, INCLUDING A SECOND AREA OVER PARTS OF THE
CENTRAL HIGH/CENTRAL PLAINS. THE ASSOCIATED HEAVY RAIN WILL CREATE
MAINLY LOCALIZED AREAS OF FLASH FLOODING, WITH URBAN AREAS, ROADS,
AND SMALL STREAMS THE MOST VULNERABLE.
ALSO, ON THURSDAY, A WEAK FRONT MOVING SOUTHEASTWARD OUT OF
CENTRAL CANADA WILL TRIGGER SHOWERS AND SEVERE THUNDERSTORMS OVER
PARTS OF NORTH-CENTRAL NEW YORK STATE LATE IN THE DAY. THEREFORE,
THE SPC HAS ISSUED A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER
PARTS OF NORTH-CENTRAL NEW YORK STATE THROUGH FRIDAY MORNING. THE
HAZARDS ASSOCIATED WITH THESE THUNDERSTORMS ARE FREQUENT
LIGHTNING, SEVERE THUNDERSTORM WIND GUSTS, HAIL, AND A FEW
TORNADOES.
THE THREAT OF SEVERE THUNDERSTORMS CONTINUES ON FRIDAY OVER PARTS
OF THE NORTHEAST. THEREFORE, THE SPC HAS ISSUED A SLIGHT RISK OF
SEVERE THUNDERSTORMS OVER PARTS OF THE NORTHEAST FROM FRIDAY INTO
SATURDAY MORNING. THE HAZARDS ASSOCIATED WITH THESE THUNDERSTORMS
ARE FREQUENT LIGHTNING, SEVERE THUNDERSTORM WIND GUSTS, HAIL, AND
A MINIMAL THREAT OF TORNADOES.
FURTHERMORE, THE SHOWERS AND THUNDERSTORMS WILL CREATE HEAVY RAIN
OVER PARTS OF NEW ENGLAND. THEREFORE, THE WPC HAS ISSUED A SLIGHT
RISK OF EXCESSIVE RAINFALL OVER PARTS OF NEW ENGLAND FROM FRIDAY
INTO SATURDAY MORNING. THE ASSOCIATED HEAVY RAIN WILL CREATE
MAINLY LOCALIZED AREAS OF FLASH FLOODING, WITH URBAN AREAS, ROADS,
AND SMALL STREAMS THE MOST VULNERABLE.
ON FRIDAY, UPPER-LEVEL ENERGY AND A STEADY SUPPLY OF MOISTURE WILL
PRODUCE SHOWERS AND THUNDERSTORMS WITH HEAVY RAIN OVER PARTS OF
SOUTHEASTERN MONTANA, NORTHEASTERN WYOMING, SOUTHWESTERN NORTH
DAKOTA, AND THE WESTERN HALF OF SOUTH DAKOTA. THEREFORE, THE WPC
HAS ISSUED A SLIGHT RISK OF EXCESSIVE RAINFALL OVER PARTS OF THE
NORTHERN HIGH/NORTHERN PLAINS FROM FRIDAY THROUGH SATURDAY
MORNING. THE ASSOCIATED HEAVY RAIN WILL CREATE MAINLY LOCALIZED
AREAS OF FLASH FLOODING, WITH URBAN AREAS, ROADS, AND SMALL
STREAMS THE MOST VULNERABLE. ADDITIONALLY, SHOWERS AND MODERATE TO
STRONG THUNDERSTORMS WILL DEVELOP OVER PARTS OF THE CENTRAL
PLAINS, MIDDLE/LOWER MISSISSIPPI VALLEY, AND THE SOUTHEAST ON
FRIDAY.
FURTHERMORE, AN UPPER-LEVEL HIGH OVER THE SOUTHERN PLAINS/LOWER
MISSISSIPPI VALLEY WILL CREATE OPPRESSIVE DAYTIME HEAT, LIMITED
OVERNIGHT COOLING, WHICH WILL ALSO CONTRIBUTE TO THE EFFECTS OF
HEAT, PROMPTING EXCESSIVE HEAT WARNINGS AND HEAT ADVISORIES OVER
PORTIONS OF THE CENTRAL/SOUTHERN PLAINS AND THE MIDDLE/LOWER
MISSISSIPPI VALLEY/CENTRAL GULF COAST. FURTHER, A SECOND REGION OF
EXCESSIVE HEAT WARNINGS AND HEAT ADVISORIES ARE OVER PARTS OF
SOUTHEASTERN CALIFORNIA AND SOUTHWEST.
IN ADDITION, AN EXPANSIVE HEAT WAVE WILL CONTINUE TO AFFECT MUCH
OF THE COUNTRY S SOUTHERN TIER THROUGH THE WEEKEND. THE HEAT WILL
BE MOST PERSISTENT IN THE SOUTH-CENTRAL U.S., WHERE IT MAY LAST
THROUGH THE END OF NEXT WEEK WITH NO RELIEF. THE COMBINATION OF
HEAT AND HUMIDITY IN THE GULF COAST REGION WILL RESULT IN
EXTREMELY DANGEROUS PEAK HEAT INDEX VALUES WELL IN EXCESS OF 110 F
FROM THE WEEKEND INTO EARLY NEXT WEEK. THE OPPRESSIVE DAYTIME
HEAT, LIMITED OVERNIGHT COOLING, AND WIDESPREAD RECORD-WARM
NIGHTTIME LOWS WILL POSE A SIGNIFICANT HEALTH RISK TO ANYONE
WITHOUT EFFECTIVE COOLING AND ADEQUATE HYDRATION.
FURTHERMORE, THE MOST PERSISTENTLY ELEVATED HEAT INDICES ARE
LIKELY TO BE IN SOUTH AND SOUTHEAST TEXAS AND SOUTHERN LOUISIANA.
A FEW LOCATIONS COULD SEE A HEAT INDEX APPROACHING OR EXCEEDING
120 F.
MOREOVER, DANGEROUS HEAT IS ALSO LIKELY TO RETURN TO THE
SOUTHWEST, PARTICULARLY THIS WEEKEND. THE HEAT MAY AFFECT THE
CENTRAL VALLEY OF CALIFORNIA.
ZIEGENFELDER
GRAPHICS AVAILABLE AT
HTTPS://WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP
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