191
FXUS01 KWBC 291750
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
149 PM EDT MON JUL 29 2024
VALID 00Z TUE JUL 30 2024 - 00Z THU AUG 01 2024
...FLASH FLOODING POSSIBLE IN THE OHIO/TENNESSEE VALLEYS AND
CENTRAL/SOUTHERN APPALACHIANS EARLY THIS WEEK...
...SCATTERED SEVERE THUNDERSTORMS AND HEAVY RAIN FORECAST ACROSS
PORTIONS OF THE NORTHERN PLAINS AND MIDWEST...
...DANGEROUS MID-SUMMER HEAT WAVE TO EXPAND ACROSS THE CENTRAL
U.S. AND SOUTHEAST...
BOUTS OF THUNDERSTORMS ARE EXPECTED TO CONTINUE OVER PORTIONS OF
THE OHIO/TENNESSEE VALLEYS AND SPREAD FURTHER INTO THE
CENTRAL/SOUTHERN APPALACHIANS TO START OFF THE WORK WEEK. AN
ACTIVE UPPER-LEVEL PATTERN FEATURING AT LEAST A COUPLE SHORTWAVES
AND AN APPROACHING SURFACE FRONTAL SYSTEM FROM THE WEST WILL HELP
TO FOCUS STORM DEVELOPMENT OVER THE OHIO/TENNESSEE VALLEYS AND
EVENTUALLY INTO THE SOUTHERN APPALACHIANS THROUGH TONIGHT.
PLENTIFUL MOISTURE IN PLACE WILL ALSO CONTINUE TO LEAD TO THE
THREAT OF HEAVIER RAIN RATES, WITH INCREASING STORM COVERAGE INTO
THE EVENING AND POTENTIAL BACK BUILDING/REPEATED ROUNDS OF STORMS
RAISING THE CHANCE FOR LOCALLY HEAVY RAINFALL TOTALS. AS SUCH, A
SLIGHT RISK OF EXCESSIVE RAINFALL (LEVEL 2/4) IS IN PLACE FOR THE
THREAT OF SOME SCATTERED FLASH FLOODING. IN ADDITION, SUFFICIENT
INSTABILITY/SHEAR WILL BE IN PLACE OVER THE OHIO VALLEY FOR A
COUPLE MORE INTENSE STORMS, AS WELL AS THE THREAT FOR A MORE
ORGANIZED STORM COMPLEX LATER THIS EVENING. THE STORM PREDICTION
CENTER HAS INCLUDED A SLIGHT RISK (LEVEL 2/5) FOR SEVERE WEATHER
AS WELL MAINLY FOR THE THREAT OF DAMAGING WINDS. A SIMILAR PATTERN
WILL BE IN PLACE ON TUESDAY, WITH THE FOCUS SHIFTING FURTHER INTO
THE SOUTHERN AND CENTRAL APPALACHIANS AS THE UPPER-LEVEL ENERGY
AND SURFACE FRONTAL SYSTEM MOVE EASTWARD. ANOTHER SLIGHT RISK OF
EXCESSIVE RAINFALL IS IN EFFECT HERE FOR ADDITIONAL INSTANCES OF
FLASH FLOODING. OUTSIDE OF THE FLASH FLOODING THREAT, SCATTERED
THUNDERSTORMS WITH MODERATE TO LOCALLY HEAVY RAINFALL ARE EXPECTED
MORE BROADLY OVER THE MIDWEST/SOUTHEAST MONDAY. RAIN CHANCES WILL
EXPAND OVER THE MID-ATLANTIC/NORTHEAST AS THE SYSTEM APPROACHES
FROM THE WEST ON TUESDAY. FORECAST HIGH TEMPERATURES ACROSS THE
EAST WILL VARY DEPENDING ON CLOUD/STORM COVERAGE, WITH MOSTLY
MID-80S TO LOW 90S EXPECTED.
SOME ADDITIONAL STORMS WILL BE POSSIBLE FURTHER WEST ALONG THE
FRONTAL BOUNDARY INTO THE UPPER MIDWEST AND NORTHERN PLAINS.
EMBEDDED UPPER-LEVEL ENERGY WILL HELP TO TRIGGER ONE ROUND OF
STORMS OVER THE NORTHERN PLAINS TODAY. STRONGER UPPER-LEVEL FLOW
WILL LEAD TO MORE DEEP-LAYER SHEAR HERE THAN FURTHER EAST, WITH
ANOTHER SLIGHT RISK OF SEVERE WEATHER FOR THE THREAT OF SOME VERY
LARGE HAIL AS WELL AS SIGNIFICANT DAMAGING WINDS IF STORMS
CONSOLIDATE/GROW UPSCALE INTO AN ORGANIZED SYSTEM LATER IN THE
EVENING. ANOTHER ROUND OF SEVERE WEATHER IS POSSIBLE DOWNSTREAM
OVER THE UPPER MIDWEST TUESDAY AS YET ANOTHER UPPER-LEVEL IMPULSE
HELPS TO TRIGGER STORMS ALONG THE FRONTAL BOUNDARY. VERY HIGH
MOISTURE WILL LEAD TO STRONG TO EXTREME INSTABILITY, WITH A SLIGHT
RISK IN PLACE FOR THE CHANCE OF MORE DAMAGING WINDS.
OUTSIDE OF THE SEVERE WEATHER THREAT, HEAT WILL BECOME THE BIG
STORY MORE BROADLY OVER THE CENTRAL U.S. OVER THE NEXT FEW DAYS AS
AN UPPER-LEVEL HIGH STRENGTHENS/EXPANDS OVER THE REGION. FORECAST
HIGH TEMPERATURES MONDAY AND TUESDAY ARE EXPECTED TO SOAR INTO THE
TRIPLE DIGITS OVER THE CENTRAL PLAINS, WITH UPPER-90S TO LOW 100S
TO THE WEST OVER MUCH OF THE HIGH PLAINS, AND MID- TO UPPER 90S
FOR THE MIDDLE AND LOWER MISSISSIPPI VALLEY. HIGH HUMIDITY VALUES
OVER THE MISSISSIPPI VALLEY AND EASTERN PORTIONS OF THE PLAINS
WILL LEAD TO HEAT INDICES IN THE 105-110 DEGREE RANGE, POTENTIALLY
AS HIGH AS 115 FOR SOME LOCATIONS, WITH WIDESPREAD HEAT-RELATED
WARNINGS/ADVISORIES IN PLACE. WARM MORNING LOWS ONLY DROPPING INTO
THE MID- TO UPPER 70S WILL PROVIDE LITTLE RELIEF FROM THE HEAT
OVERNIGHT. THIS COMBINATION OF HOTTER TEMPERATURES TO THE WEST,
HIGHER HEAT INDICES TO THE EAST, AND THE MULTI-DAY DURATION OF
THIS HEAT WAVE WILL INCREASE THE DANGER NOT ONLY TO MORE SENSITIVE
GROUPS, BUT ALSO THE GENERAL PUBLIC, PARTICULARLY THOSE WITHOUT
ADEQUATE AIR CONDITIONING.
A STAGNANT TROUGHING PATTERN OVER THE WEST WILL KEEP TEMPERATURES
MOSTLY BELOW AVERAGE ACROSS THE REGION, ESPECIALLY OVER PORTIONS
OF THE PACIFIC NORTHWEST AND NORTHERN GREAT BASIN/ROCKIES.
FORECAST HIGHS MONDAY-TUESDAY RANGE BETWEEN THE 60S AND 70S ALONG
THE PACIFIC COAST, THE 70S AND 80S IN THE PACIFIC NORTHWEST AND
NORTHERN GREAT BASIN/ROCKIES, THE 80S AND 90S FOR INTERIOR
CALIFORNIA AND THE CENTRAL GREAT BASIN/FOUR CORNERS REGION, AND
100S IN THE DESERT SOUTHWEST. A COLD FRONT PASSING THROUGH THE
PACIFIC NORTHWEST WILL BRING SOME RAIN CHANCES ON MONDAY,
SPREADING INTO THE NORTHERN ROCKIES TUESDAY. SMOKE FROM AREA
WILDFIRES WILL ALSO CONTINUE TO PLAGUE PARTS OF THE WEST,
PARTICULARLY OVER PORTIONS OF THE NORTHERN GREAT BASIN, RESULTING
IN POOR AIR QUALITY AND AREAS OF REDUCED VISIBILITY.
PUTNAM/SNELL
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