198
FXUS01 KWBC 010741
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
341 AM EDT THU AUG 01 2024
VALID 12Z THU AUG 01 2024 - 12Z SAT AUG 03 2024
...DANGEROUS HEAT ENGULFS MUCH OF THE COUNTRY AS ONE HEATWAVE
CONTINUES FROM THE SOUTHERN PLAINS TO THE SOUTHEAST/MID-ATLANTIC
AND ANOTHER BEGINS IN THE WEST...
...SEVERE WEATHER AND FLASH FLOODING EXPECTED FOR PORTIONS OF THE
MIDWEST THURSDAY...
... LOCALLY HEAVY MONSOONAL SHOWER AND THUNDERSTORM CHANCES
CONTINUE FOR THE SOUTHWEST...
WIDESPREAD, DANGEROUS HEAT WILL UNFORTUNATELY BE THE MAIN WEATHER
STORY FOR MUCH OF THE COUNTRY THIS WEEK AS ONE HEATWAVE CONTINUES
FOR THE PLAINS, MIDDLE/LOWER MISSISSIPPI VALLEY, SOUTHEAST, AND
MID-ATLANTIC, AND ANOTHER HEATWAVE BEGINS OVER PORTIONS OF THE
WEST. A STRONG UPPER-LEVEL RIDGE WILL REMAIN IN PLACE OVER THE
SOUTHERN-TIER OF THE U.S. THE NEXT COUPLE DAYS, ALLOWING FOR HIGH
TEMPERATURES TO REACH INTO THE LOW 100S OVER PORTIONS OF THE
SOUTHERN PLAINS/HIGH PLAINS, THE UPPER 90S TO LOW 100S FOR THE
LOWER MISSISSIPPI VALLEY, AND THE UPPER 90S FOR THE SOUTHEAST INTO
THE SOUTHERN MID-ATLANTIC. HIGH HUMIDITY VALUES FOR AREAS EAST OF
THE HIGH PLAINS WILL BRING HEAT INDICES INTO THE 105 TO 110 DEGREE
RANGE, POTENTIALLY AS HIGH AS 115 FOR PARTS OF THE LOWER
MISSISSIPPI VALLEY, WITH MANY AREAS UNDER HEAT-RELATED ADVISORIES
OR WARNINGS. THE COMBINATION OF HOT TEMPERATURES/HIGH HEAT
INDICES, AS WELL AS VERY WARM MORNING LOWS ONLY DROPPING INTO THE
MID- TO UPPER 70S, WILL BE DANGEROUS TO ANYONE WITHOUT ACCESS TO
ADEQUATE AIR CONDITIONING. TEMPERATURES WARMING INTO THE UPPER
80S/LOW 90S WITH PERIODS OF HIGHER HUMIDITY WILL LEAD TO SOME
MUGGY, POTENTIALLY DANGEROUS CONDITIONS FOR PORTIONS OF NEW
ENGLAND AS WELL, PARTICULARLY ON FRIDAY. AN APPROACHING COLD FRONT
WILL BRING RELIEF TO NORTHERN PORTIONS OF THE SOUTHERN PLAINS AND
MIDDLE MISSISSIPPI VALLEY ON FRIDAY, WITH THE EXPECTATION THE HEAT
WAVE WILL BEGIN TO WANE FOR MOST LOCATIONS THROUGH THE WEEKEND.
IN THE WEST, AN UPPER-LEVEL RIDGE WILL ALSO BEGIN TO BUILD
NORTHWARD, SENDING HIGH TEMPERATURES ACROSS MUCH OF THE NORTHERN
TIER OF THE WEST 10-20 DEGREES ABOVE MID-SUMMER AVERAGES. FORECAST
HIGHS THURSDAY ARE INTO THE UPPER 90S/LOW 100S FOR THE INLAND
PACIFIC NORTHWEST/NORTHERN GREAT BASIN AND MID- TO UPPER 90S FOR
THE NORTHERN ROCKIES/HIGH PLAINS. TEMPERATURES WILL GET EVEN
HOTTER ON FRIDAY, WITH HIGHS INTO THE LOW TO MID-100S FOR MOST
LOCATIONS. MANY NEAR RECORD-TYING/BREAKING HIGHS ARE POSSIBLE.
SIMILAR TO AREAS FURTHER EAST, MANY HEAT-RELATED ADVISORIES AND
WARNINGS HAVE BEEN ISSUED AS THIS HEAT WILL ALSO REACH DANGEROUS
LEVELS FOR THE GENERAL PUBLIC. SMOKE FROM AREA WILDFIRES WILL ALSO
CONTINUE TO PLAGUE PARTS OF THE REGION, RESULTING IN HAZY
CONDITIONS AND POOR AIR QUALITY, AND THE RISK FOR MORE WILDFIRES
WILL INCREASE AS THE HOT, DRY CONDITIONS SETTLE IN.
AN UPPER-LEVEL LOW/ACCOMPANYING SURFACE FRONTAL SYSTEM TRAVERSING
THE NORTHERN SIDE OF THE RIDGE OVER THE SOUTHERN TIER OF THE U.S.
WILL BRING ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS TO THE
MIDWEST THURSDAY. HIGH SURFACE MOISTURE LEADING TO VERY STRONG
INSTABILITY WILL SUPPORT INTENSE THUNDERSTORM DEVELOPMENT THROUGH
THE AFTERNOON ACROSS THE WARM SECTOR AHEAD OF AN APPROACHING COLD
FRONT, WITH LINGERING OUTFLOW BOUNDARIES FROM OVERNIGHT CONVECTION
HELPING TO TRIGGER INDIVIDUAL AND CLUSTERS OF STORMS. SUFFICIENT
SHEAR WITH THE PASSING UPPER-LEVEL WAVE WILL LEAD TO THE THREAT OF
SEVERE WEATHER, WITH A SLIGHT RISK (LEVEL 2/5) FROM THE STORM
PREDICTION CENTER COVERING ILLINOIS, INDIANA, KENTUCKY, AND
SOUTHWESTERN OHIO, MAINLY FOR THE THREAT OF SOME DAMAGING WINDS.
THE THREAT FOR SOME INTENSE DOWNPOURS GIVEN THE HIGH
MOISTURE/STRONG STORMS, AND POTENTIAL FOR SOME MORE WIDESPREAD,
ORGANIZED CLUSTERS OF STORMS, WILL LEAD TO SOME HEAVIER RAINFALL
TOTALS AND THE RISK FOR FLASH FLOODING. MANY OF THESE LOCATIONS
HAVE SEEN RECENT HEAVY RAINFALL GIVEN REPEATED ROUNDS OF ORGANIZED
STORMS PASSING THROUGH, LEADING TO WETTER ANTECEDENT CONDITIONS
MORE SENSITIVE TO ANY ADDITIONAL RAINFALL. A SLIGHT RISK OF
EXCESSIVE RAINFALL (LEVEL 2/4) COVERS MUCH OF SAME REGION FROM
NORTHEASTERN ILLINOIS SOUTHEAST THROUGH INDIANA/WESTERN OHIO AND
INTO EASTERN KENTUCKY. SOME SLOW MOVING STORMS PRODUCING HEAVY
RAINFALL UNDER THE PASSING UPPER-LOW MAY ALSO LEAD TO SOME FLASH
FLOODING, WITH THE SLIGHT RISK EXTENDING NORTHWEST INTO SOUTHERN
WISCONSIN. SOME MORE ISOLATED STORMS WILL BE POSSIBLE FURTHER EAST
INTO THE APPALACHIANS AND MID-ATLANTIC THURSDAY. ADDITIONAL STORMS
WILL BE POSSIBLE ACROSS THE REGION FRIDAY AS THE SYSTEM SHIFTS
EASTWARD, WITH A GREATER CHANCE OF STORMS SPREADING INTO THE
APPALACHIANS AND THE MID-ATLANTIC. SOME ISOLATED SEVERE STORMS AND
INSTANCES OF FLASH FLOODING WILL BE POSSIBLE. A LINGERING
UPPER-LEVEL WEAKNESS WILL LEAD TO SCATTERED SHOWERS AND
THUNDERSTORMS OVER FLORIDA AND PORTIONS OF THE SOUTHEAST THURSDAY,
WITH MODERATE TO LOCALLY HEAVY RAINFALL POSSIBLE, ESPECIALLY OVER
THE FLORIDA PENINSULA. MORE WIDELY SCATTERED STORMS WILL REMAIN
POSSIBLE FRIDAY.
PERSISTENT MONSOONAL CONDITIONS OVER THE SOUTHWEST WILL CONTINUE
TO BRING DAILY SHOWER AND THUNDERSTORM CHANCES. SUFFICIENT
MOISTURE ACROSS THE REGION WILL LEAD TO THE THREAT FOR SOME
LOCALLY HEAVY DOWNPOURS AND AN ISOLATED FLASH FLOODING,
PARTICULARLY OVER TERRAIN SENSITIVE AREAS SUCH AS BURN SCARS. A
LINGERING FRONTAL BOUNDARY WILL LEAD TO SOME STORMS OVER PORTIONS
OF THE SOUTHERN HIGH PLAINS AS WELL ON THURSDAY, AND A SUBTLE
UPPER-LEVEL WAVE ALONG THE EDGE OF THE UPPER-RIDGING WILL BRING
STORM CHANCES NORTHWESTWARD INTO PORTIONS OF CALIFORNIA FRIDAY,
PARTICULARLY IN VICINITY OF THE SIERRA NEVADA. SIMILAR TO AREAS
FURTHER NORTH, FORECAST HIGH TEMPERATURES MORE BROADLY IN THE
REGION WILL BE TRENDING HOTTER AND ABOVE AVERAGE, WITH 90S AND LOW
100S FOR MOST LOCATIONS OUTSIDE OF THE CALIFORNIA COAST, AND
MID-100S TO LOW 110S FOR THE DESERT SOUTHWEST.
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