597  
FXUS01 KWBC 180846  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
445 AM EDT TUE JUN 18 2024  
 
VALID 12Z TUE JUN 18 2024 - 12Z THU JUN 20 2024  
 
...SIGNIFICANT HEAVY RAIN/FLASH FLOODING THREAT WITH GUSTY WINDS  
WELL AHEAD OF POTENTIAL T.C. ONE EXPECTED TO IMPACT SOUTHERN TEXAS  
ON WEDNESDAY...  
 
...MORE ROUNDS OF HEAVY RAIN AND SEVERE THUNDERSTORMS EXPECTED FOR  
THE NORTHERN PLAINS AND UPPER MIDWEST TODAY BEFORE SHIFTING SOUTH  
INTO THE CENTRAL PLAINS ON WEDNESDAY...  
 
...A HEAT WAVE WILL PERSIST OVER THE GREAT LAKES, OHIO VALLEY AND  
THE NORTHEAST THROUGH MIDWEEK...  
 
...LATE-SEASON WET SNOW CONTINUES ACROSS THE HIGH-ELEVATIONS OF  
THE NORTHERN ROCKIES TODAY BEFORE TAPERING OFF EARLY ON  
WEDNESDAY...  
 
AN ACTIVE WEATHER PATTERN CONTINUES ACROSS THE U.S. MAINLAND.  
THIS WEATHER PATTERN THAT FEATURES SNOW, HEAT, HEAVY RAIN, SEVERE  
THUNDERSTORMS, STRONG WINDS, AND FIRE WEATHER IS NOW BRINGING  
POTENTIAL TROPICAL CYCLONE ONE IN THE MIDST. A LOW PRESSURE  
SYSTEM CURRENTLY INTENSIFYING ALONG A FRONTAL BOUNDARY IS  
FOSTERING ANOTHER ROUND OF HEAVY RAIN AND SEVERE THUNDERSTORMS  
ACROSS THE NORTHERN PLAINS INTO THE UPPER MIDWEST EARLY THIS  
MORNING. THE POTENT UPPER TROUGH AND THE ASSOCIATED DOME OF COLD  
AIR HAVE CONTINUED TO RESULT IN A ROUND OF LATE-SEASON WET SNOW  
ACROSS THE HIGHER-ELEVATIONS OF THE NORTHERN ROCKIES TOGETHER WITH  
RATHER STRONG WIND GUSTS. WITH LESS POTENT JET STREAM ENERGY  
BEHIND THIS SYSTEM, THE LOW PRESSURE SYSTEM WILL QUICKLY EJECT  
INTO SOUTHERN CANADA BY THIS EVENING, BRINGING THE INCLEMENT  
WEATHER ACROSS THE NORTHERN PLAINS TO AN END BY WEDNESDAY MORNING.  
HOWEVER, A SHARP FRONT TRAILING SOUTH AND SOUTHWEST FROM THE LOW  
CENTER WILL LIKELY TRIGGER AN AXIS OF HEAVY RAIN AND SEVERE  
THUNDERSTORMS FROM THE CENTRAL PLAINS TO THE UPPER MIDWEST BY  
TONIGHT INTO WEDNESDAY MORNING. FROM WEDNESDAY INTO THURSDAY  
MORNING, THE RAIN/STORMS SHOULD GRADUALLY BECOME MORE SCATTERED IN  
NATURE ACROSS THE CENTRAL PLAINS AS A COOL HIGH PRESSURE SYSTEM  
PASSES TO THE NORTH. THIS HIGH PRESSURE SYSTEM WILL ALSO PUSH THE  
WIDELY SCATTERED SHOWERS AND EMBEDDED THUNDERSTORMS FARTHER EAST  
INTO THE LOWER GREAT LAKES AND INTERIOR NEW ENGLAND THROUGH  
THURSDAY MORNING.  
 
IN STARK CONTRAST TO THE COOL, WINDY, RAINY AND EVEN SNOWY WEATHER  
IN THE WEST, A HEAT WAVE WILL SETTLE AND PERSIST ACROSS THE GREAT  
LAKES, OHIO VALLEY AND THE NORTHEAST THROUGH THE NEXT FEW DAYS.  
FORECAST HIGHS TODAY AND WEDNESDAY WILL REACH INTO THE MID- TO  
UPPER 90S, EVEN THE CENTURY MARK WEDNESDAY AND THURSDAY AFTERNOON  
AT THE HOTTEST LOCATIONS IN INTERIOR NORTHERN NEW ENGLAND.  
WIDESPREAD, NUMEROUS RECORD-TYING/BREAKING HIGH TEMPERATURES ARE  
POSSIBLE. ADDITIONALLY, MORNING LOWS WILL REMAIN IN ABOUT THE  
MID-70S, AT RECORD-TYING/BREAKING LEVELS, PROVIDING LITTLE RELIEF  
FROM THE HEAT OVERNIGHT. THE EARLY ARRIVAL OF THIS MAGNITUDE OF  
HEAT, THE DURATION, ABUNDANT SUNSHINE, AND LACK OF RELIEF  
OVERNIGHT WILL INCREASE THE DANGER OF THIS HEATWAVE BEYOND WHAT  
THE EXACT TEMPERATURE VALUES WOULD SUGGEST. THIS IS ESPECIALLY  
TRUE FOR THOSE WITHOUT ADEQUATE AIR CONDITIONING, WHICH BECOMES  
MORE OF A CONCERN FOR LOCATIONS FURTHER NORTH THAT ARE NOT AS  
ACCUSTOMED TO PERIODS OF PERSISTENT HEAT.  
 
ANOTHER BIG WEATHER STORY OVER THE NEXT COUPLE OF DAYS WILL BE IN  
THE GULF OF MEXICO WHERE THE NATIONAL HURRICANE CENTER HAS ALREADY  
INITIATED ADVISORIES ON POTENTIAL TROPICAL CYCLONE ONE. AN  
ELONGATED UPPER TROUGH DIGGING INTO THE SOUTHERN PLAINS AND  
NORTHEASTERN MEXICO HAS ALREADY DRAWN A PLUME OF TROPICAL MOISTURE  
NORTHWARD INTO THE CENTRAL GULF COAST REGION. THIS UPPER TROUGH  
WILL BE INSTRUMENTAL IN DRAWING THE TROPICAL MOISTURE WELL NORTH  
OF THE CENTER OF PTC ONE INTO SOUTHERN TEXAS MAINLY ON WEDNESDAY  
AS PTC ONE TRACKS WEST TOWARD NORTHERN MEXICO. AN AXIS OF VERY  
HEAVY RAIN MAY DEVELOP JUST INLAND OF THE TEXAS COASTLINE BEHIND A  
COASTAL FRONT WITH DYNAMIC SUPPORT FROM THE ELONGATED UPPER  
TROUGH. THIS PATTERN COULD RESULT IN LOCALLY HEAVY RAINFALL IN  
EXCESS OF 10 INCHES NEAR OR JUST INLAND OF THE LOWER TO MIDDLE  
TEXAS COAST WHICH WOULD RESULT IN SIGNIFICANT FLASH FLOODING. THE  
HEAVY RAIN IS FORECAST TO PUSH FARTHER INLAND ACROSS THE RIO  
GRANDE VALLEY EARLY ON THURSDAY. IN ADDITION TO THE HEAVY  
RAINFALL, SOME COASTAL FLOODING ALONG WITH TROPICAL-STORM-FORCE  
WINDS CAN BE EXPECTED UP THE TEXAS COAST ON WEDNESDAY. SEE THE  
LATEST ADVISORY FROM THE NATIONAL HURRICANE CENTER FOR ADDITIONAL  
DETAILED UPDATES. MEANWHILE, FIRE DANGER ACROSS THE FOUR CORNERS  
REGION SHOULD GRADUALLY EASE OVER THE NEXT FEW DAYS WITH THE  
ARRIVAL OF SLIGHTLY COOLER AIR FOLLOWED BY THE ARRIVAL OF MOISTURE  
FROM THE NORTHERN EDGE OF POTENTIAL TROPICAL CYCLONE ONE.  
 
KONG/PUTNAM  
 
GRAPHICS AVAILABLE AT  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  
 

 
 
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