189  
FXUS01 KWBC 170721  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
320 AM EDT TUE SEP 17 2024  
 
VALID 12Z TUE SEP 17 2024 - 12Z THU SEP 19 2024  
 
...A COASTAL LOW WILL BRING A THREAT OF FLASH FLOODING TO THE  
MID-ATLANTIC TODAY...  
 
...A STRONG LOW PRESSURE SYSTEM WILL BRING UNSETTLED WEATHER TO  
THE ROCKIES AND PLAINS WITH SEVERE THUNDERSTORMS IN THE NORTHERN  
AND CENTRAL HIGH PLAINS...  
 
A COASTAL LOW, PREVIOUSLY LABELED AS POTENTIAL TROPICAL CYCLONE  
EIGHT, WILL CONTINUE TO SLOWLY MOVE NORTH ACROSS THE CAROLINAS  
TOWARDS THE MID-ATLANTIC OVER THE NEXT DAY OR SO. MOIST, ONSHORE  
FLOW WILL SUPPORT PERSISTENT SHOWERS AND THUNDERSTORMS ACROSS  
PORTIONS OF NORTH CAROLINA AND THE SOUTHERN MID-ATLANTIC TODAY,  
AND LOCALLY HEAVY RAINFALL COULD RESULT IN ISOLATED TO SCATTERED  
INSTANCES OF FLASH FLOODING. FLOOD WATCHES ARE IN EFFECT TODAY FOR  
PORTIONS OF SOUTHEASTERN VIRGINIA AND NORTH CAROLINA.  
PRECIPITATION COVERAGE AND INTENSITY SHOULD DECREASE ON WEDNESDAY,  
RESULTING IN A LOWER THREAT FOR FLASH FLOODING. COASTAL FLOODING  
WILL ALSO BE A CONCERN WITH A PROLONGED PERIOD OF ONSHORE WINDS  
ALONG THE MID-ATLANTIC COAST. BY THURSDAY, THIS SYSTEM WILL BEGIN  
TO SHIFT OFFSHORE INTO THE ATLANTIC AND HIGH PRESSURE WILL BUILD  
BEHIND IT.  
 
MEANWHILE, A STRONG LOW PRESSURE SYSTEM WILL MOVE ACROSS THE  
INTERMOUNTAIN WEST THIS MORNING AND IS EXPECTED TO EMERGE IN THE  
NORTHERN PLAINS, STRENGTHENING IN THE LEE OF THE ROCKIES LATER  
TODAY. STRONG, GUSTY WINDS AND WIDESPREAD SHOWERS AND  
THUNDERSTORMS ARE FORECAST WITH THIS SYSTEM IN THE VICINITY OF THE  
LOW PRESSURE CENTER AND ALONG AND AHEAD OF THE TRAILING COLD  
FRONT. SOME THUNDERSTORMS MAY BECOME SEVERE THIS AFTERNOON AND  
EVENING IN THE NORTHERN AND CENTRAL HIGH PLAINS, AND THE STORM  
PREDICTION CENTER HAS HIGHLIGHTED THIS AREA WITH A SLIGHT RISK OF  
SEVERE THUNDERSTORMS (LEVEL 2/5) WITH AN EMBEDDED ENHANCED RISK  
(LEVEL 3/5) OVER THE CENTRAL HIGH PLAINS. SEVERE STORM HAZARDS  
WILL INCLUDE DAMAGING WINDS AND ISOLATED LARGE HAIL.  
 
THE LOW PRESSURE CENTER OF THIS SYSTEM WILL BE NEARLY STATIONARY  
OVER MONTANA THROUGH WEDNESDAY AS IT'S FORWARD MOTION IS BLOCKED  
BY HIGH PRESSURE TO THE EAST. THIS WILL LIKELY RESULT IN HEAVY  
RAINFALL TOTALS THAT COULD CAUSE SCATTERED INSTANCES OF FLASH  
FLOODING IN PORTIONS OF MONTANA. THE TRAILING COLD FRONT WILL  
SLOWLY PUSH EAST ACROSS THE PLAINS ON WEDNESDAY AND THURSDAY,  
GRADUALLY LOSING STEAM, AND THE THREAT FOR SEVERE WEATHER WILL  
DECREASE.  
 
ANOTHER LOW PRESSURE SYSTEM WILL MOVE SOUTH ALONG THE WEST COAST  
WEDNESDAY AND THURSDAY, WHICH WILL BRING ANOTHER ROUND OF  
UNSETTLED WEATHER. PRECIPITATION WILL SPREAD FROM THE NORTHWEST TO  
THE GREAT BASIN AND SOUTHWEST BY THURSDAY, MAINLY FALLING AS RAIN,  
BUT SOME WINTRY PRECIPITATION WILL BE POSSIBLE IN THE HIGHER  
ELEVATIONS.  
 
INITIALLY, TEMPERATURES WILL BE WELL BELOW NORMAL IN THE WEST AND  
MID-ATLANTIC AND WELL ABOVE NORMAL IN THE CENTRAL U.S. AND  
NORTHEAST, BUT TEMPERATURE ANOMALIES WILL GRADUALLY MODERATE AS WE  
MOVE THROUGH THE REST OF THE WEEK.  
 
DOLAN  
 
GRAPHICS AVAILABLE AT  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  
 

 
 
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