729  
FXUS01 KWBC 201945  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
344 PM EDT SAT JUL 20 2024  
 
VALID 00Z SUN JUL 21 2024 - 00Z TUE JUL 23 2024  
 
...A BREAK IN THE HEAT CONTINUES FOR MUCH OF THE HEARTLAND BUT  
DANGEROUS HEAT WILL BUILD ACROSS THE INTERIOR PACIFIC NORTHWEST  
THIS WEEKEND AND INTO NEXT WEEK...  
 
...SCATTERED THUNDERSTORMS CONTINUE ACROSS THE SOUTH AND SOUTHEAST  
AS MONSOONAL THUNDERSTORMS LINGER ACROSS THE FOUR CORNERS REGION...  
 
...SCATTERED THUNDERSTORMS OVER THE CENTRAL PLAINS TODAY WILL  
GRADUALLY SHIFT INTO THE SOUTHERN PLAINS BY MONDAY WHILE A COLD  
FRONT WILL BRING NEW ROUNDS OF THUNDERSTORMS ACROSS THE NORTHERN  
TIER STATES...  
 
AN COOLER THAN NORMAL AIR-MASS THAT HAS SETTLED IN THROUGHOUT MUCH  
OF THE HEARTLAND WILL STICK AROUND NOT ONLY FOR THE REMAINDER OF  
THE WEEKEND BUT INTO THE FIRST HALF OF THE UPCOMING WEEK. AFTER  
SEEING SOME PARTS OF THE LOWER MISSOURI RIVER VALLEY REGISTERING  
DAYTIME HIGHS ONLY IN THE 70S, A COLD FRONT WILL CONTINUE TO  
ADVANCE SOUTH TONIGHT THROUGH THE SOUTHERN PLAINS. BY SUNDAY,  
DAYTIME HIGHS IN THE 70S AND 80S (AS LOW AS 15 TO 20 DEGREES BELOW  
NORMAL IN THE SOUTHERN HIGH PLAINS) WILL BE COMMON FROM CENTRAL  
NEW MEXICO TO AS FAR EAST AS THE MIDDLE MISSISSIPPI RIVER VALLEY.  
MEANWHILE, A STALLED FRONTAL BOUNDARY OVER THE MID-SOUTH IS  
RESPONSIBLE FOR DAILY ROUNDS OF SHOWERS AND STORMS. THE EXPANSIVE  
CLOUD COVER THROUGHOUT THE SOUTH WILL KEEP DAYTIME HIGHS CAPPED  
GENERALLY IN THE MID-UPPER 80S, WHICH IS SEVERAL DEGREES BELOW  
NORMAL (LONE EXCEPTION IS FLORIDA AND SOUTH TEXAS WHERE HIGHS WILL  
BE IN THE 90S ON SUNDAY). THE FOOTPRINT OF UNUSUALLY COOL  
TEMPERATURES FOR LATE JULY WILL PERSIST IN THE SOUTHERN AND  
CENTRAL PLAINS THROUGH MONDAY.  
 
WHILE COOLER THAN NORMAL TEMPERATURES ENVELOPE MUCH OF THE  
HEARTLAND, DANGEROUS HEAT WILL BE A MAINSTAY IN THE WEST THROUGH  
EARLY NEXT WEEK. THE EXPERIMENTAL HEATRISK PRODUCT DEPICTS MAJOR  
TO EXTREME HEAT RISKS FROM PARTS OF THE LOWER COLORADO RIVER  
VALLEY AND MOJAVE DESERT TO AS FAR NORTH AS THE SNAKE RIVER PLAIN  
AND COLUMBIA RIVER BASIN. SOME DAILY RECORD HIGHS AND WARM MINIMUM  
TEMPS ARE LIKELY TO BE BROKEN IN THESE AREAS WITH THE INTERIOR  
NORTHWEST MOST LIKELY TO WITNESS THE BULK OF THE RECORD HEAT.  
MAJOR HEATRISK LEVELS RETURN TO CALIFORNIA'S GREAT VALLEY BY  
MONDAY AND LOOK TO EXPAND THROUGHOUT THE CENTER OF THE GOLDEN  
STATE BY TUESDAY. OVERALL, THESE AREAS CAN EXPECT HIGHS IN THE 90S  
TO 100S WITH LITTLE RELIEF OVERNIGHT THANKS TO LOWS IN THE 60S AND  
70S. THOSE IN AFFECTED AREAS SHOULD STAY HYDRATED, LIMIT OUTDOOR  
ACTIVITIES, AND USE FANS WHEN AIR CONDITIONING IS NOT AVAILABLE.  
 
THIS STAGNANT WEATHER PATTERN WILL MAKE FOR A STORMY SOUTHERN TIER  
OF THE U.S. INTO NEXT WEEK. AN ELONGATED FRONTAL BOUNDARY WILL  
SPARK NUMEROUS SHOWERS AND STORMS FROM THE SOUTHERN ROCKIES AND  
PLAINS TO THE SOUTHEAST AND MID-ATLANTIC THROUGH MONDAY. TODAY,  
SPC DOES HAVE A COUPLE MARGINAL RISK AREAS(THREAT LEVEL 1/5) IN  
THE SOUTHEAST AND IN BOTH THE SOUTHERN AND CENTRAL HIGH PLAINS.  
HOWEVER, AN UNUSUALLY HIGH CONCENTRATION OF MOISTURE ALOFT IS  
SUPPORTING A RATHER WIDE AREA FOR EXCESSIVE RAINFALL POTENTIAL.  
WPC HAS ISSUED A COUPLE SLIGHT RISKS (THREAT LEVEL 2/4) FOR PARTS  
OF THE SOUTHERN MID-ATLANTIC AND IN BOTH CENTRAL NEW MEXICO AND  
SOUTHEAST ARIZONA. A MARGINAL RISK (THREAT LEVEL 1/4) FOR  
EXCESSIVE RAINFALL INCLUDE MUCH OF THE FOUR CORNERS REGION, THE  
CENTRAL PLAINS, AND THE SOUTHEAST. THIS WILL BE A COMMON THEME FOR  
BOTH SUNDAY AND MONDAY WITH SLIGHT RISKS POSTED IN PARTS OF THE  
SOUTHWEST ON SUNDAY AND IN BOTH THE SOUTHERN ROCKIES AND SOUTHERN  
PLAINS. THE MARGINAL RISK AREAS EACH DAY ARE EXPANSIVE,  
ENCOMPASSING MUCH OF THE SOUTHERN U.S. AND PORTIONS OF THE  
SOUTHERN MID-ATLANTIC. LASTLY, A FRONTAL SYSTEM WILL TRIGGER  
SCATTERED SHOWERS AND STORMS ACROSS PARTS OF THE MIDWEST THIS  
AFTERNOON AND SUNDAY. HIT-OR-MISS SHOWERS AND STORMS WILL REMAIN  
IN THE FORECAST ACROSS THE MIDWEST AND GREAT LAKES EARLY NEXT  
WEEK.  
 
MULLINAX  
 
GRAPHICS AVAILABLE AT  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  
 
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