837
FXUS01 KWBC 310801
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
400 AM EDT WED JUL 31 2024
VALID 12Z WED JUL 31 2024 - 12Z FRI AUG 02 2024
...DANGEROUS HEATWAVE EXPANDS FROM THE PLAINS/MISSISSIPPI VALLEY
INTO THE SOUTHEAST AS ANOTHER HEATWAVE DEVELOPS OVER PORTIONS OF
THE WEST...
...SEVERE WEATHER AND FLASH FLOODING EXPECTED FOR THE
NORTHERN/CENTRAL PLAINS AND MIDWEST WEDNESDAY INTO THURSDAY...
...ANOTHER THREAT FOR FLASH FLOODING WEDNESDAY IN NORTHERN NEW
ENGLAND...
...MONSOONAL SHOWER AND THUNDERSTORM CHANCES CONTINUE FOR THE
SOUTHWEST...
WIDESPREAD, DANGEROUS HEAT WILL BE THE BIG STORY FOR MUCH OF THE
COUNTRY THIS WEEK AS ONE HEATWAVE EXPANDS FROM THE
PLAINS/MISSISSIPPI VALLEY INTO THE SOUTHEAST AND ANOTHER HEATWAVE
BEGINS OVER PORTIONS OF THE WEST. A STRONG UPPER-LEVEL HIGH WILL
REMAIN IN PLACE OVER THE SOUTHERN-TIER OF THE U.S., WITH FORECAST
HIGH TEMPERATURES WEDNESDAY AND THURSDAY ONCE AGAIN INTO THE LOW
TO MID-100S OVER MUCH OF THE CENTRAL PLAINS AND SOUTHERN HIGH
PLAINS AND MID- TO UPPER 90S FOR THE MIDDLE AND LOWER MISSISSIPPI
VALLEY. HIGH TEMPERATURES WILL ALSO BEGIN TO CLIMB INTO THE MID-
TO UPPER 90S OVER MUCH OF THE SOUTHEAST AND SOUTHERN MID-ATLANTIC.
HIGH HUMIDITY VALUES, ESPECIALLY FOR EASTERN PORTIONS OF THE
PLAINS INTO THE MISSISSIPPI VALLEY AND SOUTHEAST, WILL BRING HEAT
INDICES SOARING INTO THE 105-110 DEGREE RANGE FOR MANY, WITH SOME
LOCATIONS REACHING AS HIGH AS 115, AND MANY HEAT-RELATED WARNINGS
AND ADVISORIES ARE IN PLACE. THE COMBINATION OF HOT TEMPERATURES
TO THE WEST AND HIGH HEAT INDICES TO THE EAST, 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. AN APPROACHING COLD FRONT WILL BRING TEMPERATURES
AND HUMIDITY DOWN A BIT FROM THE MIDDLE MISSOURI VALLEY INTO THE
CENTRAL PLAINS THURSDAY. UNFORTUNATELY, AN UPPER-LEVEL RIDGE WILL
ALSO BEGIN TO BUILD NORTHWARD OVER THE WEST AS WELL. THIS WILL
QUICKLY CAUSE HIGH TEMPERATURES ACROSS MUCH OF THE NORTHERN TIER
OF THE WEST TO RISE FROM CLOSE TO AVERAGE ON WEDNESDAY TO 10-20
DEGREES ABOVE AVERAGE THURSDAY. FORECAST HIGHS WILL BE INTO THE
90S FOR THE PACIFIC NORTHWEST, NORTHERN ROCKIES, AND NORTHERN HIGH
PLAINS, WITH 100S OVER MUCH OF THE NORTHERN GREAT BASIN. SIMILAR
TO AREAS FURTHER EAST, MANY HEAT-RELATED WATCHES AND ADVISORIES
HAVE BEEN ISSUED AS THIS HEAT WILL BE DANGEROUS TO THOSE WITHOUT
ADEQUATE AIR CONDITIONING. SMOKE FROM AREA WILDFIRES WILL ALSO
CONTINUE TO PLAGUE PARTS OF THE REGION, RESULTING IN HAZY
CONDITIONS AND POOR AIR QUALITY.
AN UPPER-LEVEL WAVE/SURFACE FRONTAL SYSTEM ALONG THE NORTHERN SIDE
OF THE UPPER-LEVEL HIGH OVER THE NORTHERN/CENTRAL PLAINS WILL
CONTINUE EASTWARD INTO THE MIDWEST THURSDAY, BRINGING A THREAT FOR
SEVERE WEATHER AND FLASH FLOODING THE NEXT COUPLE OF DAYS.
PLENTIFUL MOISTURE AT THE SURFACE, STRONG TO EXTREME INSTABILITY,
AND ACCOMPANYING STRONG FLOW ALOFT WILL HELP LEAD TO SOME MORE
INTENSE THUNDERSTORMS. FIRST, ON WEDNESDAY, THE STORM PREDICTION
CENTER HAS OUTLINED AN ENHANCED RISK OF SEVERE WEATHER (LEVEL 3/5)
OVER THE MIDDLE MISSOURI VALLEY, WITH A BROADER SLIGHT RISK WEST
INTO PORTIONS OF THE PLAINS AND SOUTHEAST INTO MIDDLE
MISSISSIPPI/OHIO VALLEYS AND SOUTHERN APPALACHIANS. SOME INITIAL
ISOLATED THUNDERSTORMS OVER THE PLAINS MAY PRODUCE VERY LARGE HAIL
AND SOME SIGNIFICANT WIND GUSTS IN THE LATE AFTERNOON. THEN, INTO
THE EVENING HOURS, STORMS ARE EXPECTED TO EXPAND IN COVERAGE AND
DEVELOP INTO AN ORGANIZED CONVECTIVE SYSTEM OVER THE MIDDLE
MISSOURI VALLEY, WITH AN ACCOMPANYING THREAT FOR MORE WIDESPREAD
SIGNIFICANT WIND GUSTS. ADDITIONAL STORMS ARE EXPECTED ALONG A
WARM FRONT SOUTHEAST INTO THE MIDDLE MISSISSIPPI/OHIO VALLEYS AND
SOUTHERN APPALACHIANS, POTENTIALLY ORGANIZING INTO ANOTHER
CONVECTIVE SYSTEM HERE AS WELL, POSING A THREAT FOR SOME DAMAGING
WIND GUSTS. THE EXPANDING COVERAGE OF STORMS INTO THE EVENING
HOURS, AS WELL AS THE PLENTIFUL MOISTURE AND STRONGER STORMS
CAPABLE OF PRODUCING INTENSE DOWNPOURS, WILL BRING THE CHANCE OF
SOME HEAVIER RAINFALL TOTALS. A SLIGHT RISK OF EXCESSIVE RAINFALL
(LEVEL 2/4) COVERS THE SAME REGION FOR THE THREAT OF SOME
SCATTERED INSTANCES OF FLASH FLOODING. A SIMILAR PATTERN WILL BE
IN PLACE THURSDAY AS THE SYSTEM SHIFTS EAST INTO THE MIDWEST, WITH
THE THREAT FOCUSING ON PORTIONS OF THE GREAT LAKES AND OHIO VALLEY
IN VICINITY OF A LIFTING WARM FRONT AND AHEAD OF THE APPROACHING
COLD FRONT. SCATTERED THUNDERSTORMS ARE FORECAST TO INCREASE IN
COVERAGE DURING THE EVENING, ORGANIZING INTO YET ANOTHER
CONVECTIVE SYSTEM, LIKELY MOVING SOUTHEASTWARD FROM NORTHEASTERN
ILLINOIS INTO CENTRAL INDIANA AND NORTHERN KENTUCKY/SOUTHWESTERN
OHIO. ANOTHER SLIGHT RISK OF SEVERE WEATHER IS IN PLACE MAINLY FOR
THE THREAT OF DAMAGING WINDS, WITH A SLIGHT RISK OF EXCESSIVE
RAINFALL FOR SOME ADDITIONAL INSTANCES OF FLASH FLOODING.
SHOWERS AND THUNDERSTORMS ARE EXPECTED AHEAD OF ANOTHER
UPPER-LEVEL WAVE/COLD FRONT APPROACHING THE NORTHEAST ON
WEDNESDAY. HIGH MOISTURE LINGERING OVER THE REGION MAY LEAD TO
SOME LOCALLY HEAVY DOWNPOURS, WITH A HEIGHTENED THREAT OF FLASH
FLOODING OVER PORTIONS OF NORTHERN NEW ENGLAND GIVEN THE VERY WET
ANTECEDENT CONDITIONS FOLLOWING HISTORIC AMOUNTS OF RAINFALL ON
TUESDAY. ANOTHER SLIGHT RISK OF EXCESSIVE RAINFALL AS WELL AS
FLOOD WATCHES ARE IN PLACE FOR THE REGION. THE FRONT WILL
WEAKEN/PUSH EASTWARD ON THURSDAY WITH SOME LINGERING SHOWER
CHANCES, MOST LIKELY OVER MAINE. HIGH TEMPERATURES WILL ALSO RISE
INTO THE UPPER 80S TO LOW 90S FOLLOWING THE DEPARTURE OF THE
SYSTEM, WITH HUMIDITY PRODUCING SOME MUGGY CONDITIONS. SHOWERS AND
STORMS ARE ALSO EXPECTED FURTHER SOUTH OVER PORTIONS OF THE
SOUTHEAST/FLORIDA ON WEDNESDAY WITH SOME MODERATE TO LOCALLY HEAVY
RAINFALL POSSIBLE, WITH SOME LOWER STORM CHANCES LINGERING INTO
THURSDAY.
DAILY MONSOONAL SHOWER AND THUNDERSTORM CHANCES WILL REMAIN OVER
PORTIONS OF THE SOUTHWEST WITH SOME HEAVY DOWNPOURS POSSIBLE AND
AN ISOLATED THREAT FOR FLASH FLOODING. A PASSING UPPER-LEVEL
SHORTWAVE WILL LEAD TO GREATER COVERAGE OF THUNDERSTORMS OVER
SOUTH-CENTRAL ARIZONA ON WEDNESDAY, WITH A SLIGHT RISK OF
EXCESSIVE RAINFALL IN PLACE FOR A LOCALLY HIGHER THREAT FOR SOME
FLASH FLOODING. FORECAST HIGH TEMPERATURES MORE BROADLY IN THE
REGION WILL REMAIN CLOSER TO AVERAGE THE NEXT COUPLE OF DAYS
COMPARED TO NORTHERN AREAS OF THE WEST, WITH HIGHS IN THE 60S AND
70S FOR COASTAL CALIFORNIA, 80S AND 90S FOR THE FOUR CORNERS
REGION AND HIGHER TERRAIN OF THE SOUTHWEST, THE 90S TO LOW 100S
FOR INTERIOR CALIFORNIA INTO THE CENTRAL GREAT BASIN, AND MID- TO
UPPER 100S FOR THE DESERT SOUTHWEST.
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