571  
FXUS01 KWBC 200821  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
400 AM EDT THU JUN 20 2024  
 
VALID 12Z THU JUN 20 2024 - 12Z SAT JUN 22 2024  
 
...HEAVY RAIN/FLOODING THREATS AND GUSTY WINDS OVER SOUTH TEXAS  
GRADUALLY DECREASE TODAY AS TROPICAL STORM ALBERTO MAKES LANDFALL  
IN MEXICO AND DISSIPATES...  
 
...HEAVY RAIN AND FLASH FLOODING CONCERNS INCREASE ACROSS THE  
NORTHERN PLAINS TO THE UPPER MIDWEST LATER THURSDAY INTO FRIDAY AS  
SCATTERED THUNDERSTORMS COULD RESULT IN LOCALIZED FLOODING ISSUES  
FROM THE SOUTHERN HIGH PLAINS TO THE FOUR CORNERS...  
 
...A HEAT WAVE WILL PERSIST OVER THE GREAT LAKES, OHIO VALLEY, AND  
PORTIONS OF THE NORTHEAST INTO THE WEEKEND AS HEAT INTENSIFIES IN  
THE WESTERN U.S....  
 
TROPICAL STORM ALBERTO CENTERED OVER THE SOUTHWESTERN GULF OF  
MEXICO HAS BEGUN HEADING WEST TOWARD NORTHERN MEXICO EARLY THIS  
MORNING. ORGANIZED BANDS OF HEAVY RAIN EXTENDING NORTH FROM THE  
CENTER HAVE ALREADY BROUGHT CLOSE TO 10 INCHES OF RAIN LOCALLY  
NEAR THE MID-TEXAS COAST. AS THE HEAVY RAIN BANDS CONTINUE TO  
STEADILY MOVE WEST THROUGH THE RIO GRANDE VALLEY INTO NORTHERN  
MEXICO TODAY, THE HEAVY RAIN AND FLOODING THREATS WILL GRADUALLY  
DECREASE ACROSS SOUTH TEXAS. STRONG AND GUSTY WINDS WILL ALSO  
GRADUALLY WEAKEN WITH TIME. SOME OF THE TROPICAL MOISTURE FROM  
ALBERTO WILL BE DRAWN NORTHWARD AND ENERGIZE THE SCATTERED SHOWERS  
AND THUNDERSTORMS FROM THE SOUTHERN HIGH PLAINS TO THE FOUR  
CORNERS HEADING INTO THE WEEKEND. THESE SHOWERS/STORMS WILL BE  
MORE NUMEROUS DURING THE LATE AFTERNOON TO EARLY EVENING HOURS IN  
THESE AREAS.  
 
MEANWHILE, THE NATIONAL HURRICANE CENTER CONTINUES TO MONITOR THE  
POTENTIAL OF TROPICAL CYCLONE FORMATION OVER THE WESTERN ATLANTIC  
AS A TROPICAL WAVE MOVES WEST-NORTHWEST IN THE GENERAL DIRECTION  
OF NORTHEASTERN FLORIDA AND GEORGIA. SOME ENHANCED RAINFALL WITH  
GUSTY WINDS CAN BE EXPECTED TO REACH THESE AREAS THURSDAY NIGHT  
AND WILL LIKELY LINGER THROUGH MUCH OF FRIDAY.  
 
ACROSS THE NORTHERN TIER STATES, RELATIVELY LESS ACTIVE WEATHER IS  
EXPECTED TODAY AS A HIGH PRESSURE SYSTEM BRINGS COOLER AND MORE  
STABLE AIR FROM CANADA. HOWEVER, THE NEXT PIECE OF ENERGY EXITING  
THE CENTRAL ROCKIES WILL SET UP THE NEXT EPISODE OF HEAVY RAIN AND  
STRONG TO SEVERE STORMS ACROSS THE NORTHERN PLAINS TO THE UPPER  
MIDWEST BEGINNING TONIGHT. A COUPLE ROUNDS OF HEAVY RAIN FOCUSING  
JUST NORTH OF A NEARLY STATIONARY FRONT ACROSS THE REGION WILL  
RESULT IN SLIGHT TO MODERATE RISKS OF EXCESSIVE RAINFALL FROM  
EASTERN SOUTH DAKOTA, ACROSS SOUTHERN MINNESOTA INTO WESTERN  
WISCONSIN THROUGH SATURDAY MORNING. FARTHER EAST, SCATTERED  
THUNDERSTORMS ARE LIKELY ACROSS THE GREAT LAKES REGION AND THE  
NORTHEAST NEAR AND NORTH OF THE STATIONARY FRONT. MARGINAL TO  
SLIGHT RISKS OF SEVERE STORMS ARE DELINEATED EACH DAY FROM THE  
STORM PREDICTION CENTER (MAINLY FOR THE THREAT OF SEVERE WIND BUT  
WITH SOME LOW CHANCES FOR HAIL), AND MARGINAL RISKS OF EXCESSIVE  
RAINFALL ARE IN PLACE AS WELL.  
 
ALL THESE RAIN AND THUNDERSTORM AREAS ARE TAKING PLACE ALONG THE  
PERIPHERY OF AN UPPER RIDGE/HEAT DOME THAT EDGES FROM THE  
MID-ATLANTIC INTO THE MID-SOUTH OVER THE NEXT COUPLE OF DAYS AND  
SUSTAINS A HEAT WAVE ACROSS THE GREAT LAKES, NORTHEAST, AND  
MID-ATLANTIC. AFTERNOON HIGH TEMPERATURES AND WARM OVERNIGHT LOWS  
WILL CHALLENGE DAILY RECORDS AND EVEN SOME MONTHLY AND ALL-TIME  
RECORDS. HEAT INDEX READINGS ARE EXPECTED TO PEAK FROM 100 TO 105  
DEGREES IN MANY LOCATIONS. THOSE WITHOUT ACCESS TO RELIABLE AIR  
CONDITIONING ARE URGED TO FIND A WAY TO COOL DOWN. RECORD WARM  
OVERNIGHT TEMPERATURES WILL PREVENT NATURAL COOLING AND ALLOW THE  
HEAT DANGER TO BUILD OVER TIME INDOORS WITHOUT AIR CONDITIONING.  
TEMPERATURES MAY BE LOWER AND LESS HAZARDOUS CLOSER TO THE COAST  
IF/WHERE SEA BREEZES FORM. BY FRIDAY, CONDITIONS SHOULD IMPROVE  
OVER NEW ENGLAND AS COOLER AIR DIPS A BIT FARTHER SOUTH INTO THE  
AREA BEHIND A FRONT, BUT TEMPERATURES WELL INTO THE 90S AND HIGHER  
HEAT INDICES ARE FORECAST TO CONTINUE ACROSS THE OHIO VALLEY TO  
MID-ATLANTIC. MEANWHILE, COOLER THAN AVERAGE HIGHS ARE LIKELY INTO  
THE SOUTHERN HIGH PLAINS WITH THE CLOUDS AND RAIN FORECAST, BUT  
TEMPERATURES OVER THE WEST WILL GRADUALLY RISE ABOVE NORMAL  
THURSDAY AND FRIDAY. IN THE WESTERN U.S., IT APPEARS THAT THE  
HEAT WILL INCREASE BY SATURDAY AS TRIPLE-DIGIT HIGH TEMPERATURES  
ARE FORECAST FOR THE CENTRAL VALLEY OF CALIFORNIA AND THE GREAT  
BASIN.  
 
KONG/TATE  
 
GRAPHICS AVAILABLE AT  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
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