546  
FXUS01 KWBC 230603  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
202 AM EDT WED SEP 23 2026  
 
VALID 12Z WED SEP 23 2026 - 12Z FRI SEP 25 2026  
 
...SIGNIFICANT HEAVY RAINFALL/FLOODING THREAT ACROSS NEW MEXICO  
AND THE SOUTHERN HIGH PLAINS THROUGH THURSDAY...  
 
...HEAVY RAINFALL/FLOODING THREAT ACROSS PORTIONS OF THE  
OHIO/TENNESSEE VALLEY, MID-ATLANTIC, AND PORTIONS OF THE SOUTHEAST  
THROUGH WEDNESDAY...  
 
THE WELL-DEFINED SHORTWAVE ENERGY WILL CONTINUE TO LIFT NORTHWARD  
INTO NEW MEXICO, WHILE STRENGTHENING UPPER-LEVEL FORCING  
OVERSPREADS ACROSS PARTS OF THE FOUR CORNERS AND SOUTHERN/CENTRAL  
PLAINS. THE COMBINATION OF DEEP MOISTURE, INSTABILITY AND  
UPPER-LEVEL FORCING, WIDESPREAD SHOWERS AND THUNDERSTORMS MAY  
PRODUCE HIGH-RAINFALL RATES THAT MAY LEAD TO FLASH FLOODING,  
ESPECIALLY ACROSS SENSITIVE TERRAIN, BURNS SCARS, AND URBAN AREAS.  
THEREFORE, WPC CONTINUES TO HIGHLIGHT A MODERATE RISK (AT LEAST  
40% CHANCE) OF EXCESSIVE RAINFALL ACROSS PORTIONS OF NEW MEXICO, A  
SLIGHT RISK (AT LEAST 15% CHANCE) EXPANDING INTO WEST TEXAS,  
ARIZONA, AND COLORADO, AND A MARGINAL RISK (AT LEAST 5% CHANCE)  
ACROSS PORTIONS OF THE FOUR CORNERS INTO CENTRAL PLAINS. FURTHER  
NORTH, A SLOW-MOVING BOUNDARY AND THE ASSOCIATED MOISTURE PLUME  
WILL PROGRESS NORTHEASTWARD FROM THE SOUTHERN HIGH PLAINS INTO THE  
NORTHERN PLAINS/UPPER MIDWEST BY LATE WEDNESDAY INTO THURSDAY,  
BRINGING SHOWERS AND THUNDERSTORMS ALONG THE BOUNDARY.  
 
ALTHOUGH FORCING WILL BECOME LESS CONCENTRATED ON THURSDAY OVER  
THE SOUTHWEST, THE SHORTWAVE ENERGY WILL CONTINUE TO LIFT FURTHER  
NORTHWARD INTO CENTRAL U.S. AND INTERACT WITH THE REMAINING  
MOISTURE, LEADING TO ADDITIONAL SHOWERS AND THUNDERSTORMS OVER THE  
SOUTHWEST INTO THE CENTRAL PLAINS. REPEATED CONVECTION/TRAINING  
WILL BRING ANOTHER DAY OF FLOODING CONCERNS, PARTICULARLY OVER  
AREAS WITH SATURATED SOILS FROM PRECEDING RAINFALL. THEREFORE, A  
SLIGHT RISK OF EXCESSIVE RAINFALL CONTINUES OVER PORTIONS OF THE  
SOUTHWEST, WHILE A MARGINAL RISK EXPANDS INTO THE CENTRAL/SOUTHERN  
PLAINS.  
 
THE UPPER-LEVEL TROUGH OVER THE GREAT LAKES WILL CONTINUE TO SHIFT  
EASTWARD AND THE SLOW-MOVING FRONTAL BOUNDARY CONTINUES TO PUSH  
SOUTHWARD ACROSS THE MID-ATLANTIC INTO THE SOUTHEAST, WHILE THE  
SURFACE TROUGHS CONTINUE TO MAINTAIN A MOIST AND UNSTABLE  
ENVIRONMENT THROUGH WEDNESDAY. ADDITIONALLY, A COASTAL LOW  
OFFSHORE WILL BRING ONSHORE FLOW AND LOW-LEVEL MOISTURE,  
SUPPORTING PERIODS OF SHOWERS AND THUNDERSTORMS FROM PORTIONS OF  
THE OHIO/TENNESSEE VALLEY, MID-ATLANTIC, AND SOUTHEAST. SUFFICIENT  
WARM MOISTURE AND SLOW-MOVING STORMS MAY LEAD TO FLASH FLOODING  
CONCERNS ACROSS PORTIONS OF THE OHIO/TENNESSEE VALLEY INTO THE  
MID-ATLANTIC AND SOUTHEAST. FURTHERMORE, LOCALIZED INSTABILITY MAY  
DEVELOP ALONG THE SURFACE TROUGH, LEADING TO SEVERE THUNDERSTORM  
CONCERNS ACROSS PORTIONS OF THE TENNESSEE VALLEY. FURTHER SOUTH, A  
MOIST AND UNSTABLE AIRMASS WILL PERSIST ACROSS SOUTHERN FLORIDA  
LEADING TO SHOWERS AND THUNDERSTORMS THAT MAY PRODUCE HEAVY  
DOWNPOURS, LEADING TO FLOODING CONCERNS THROUGH WEDNESDAY.  
 
OTHERWISE, A STRONG SURFACE HIGH WILL BRING WILL BRING COLDER THAN  
AVERAGE TEMPERATURES ACROSS THE NORTHERN/CENTRAL PLAINS,  
NORTHEAST, AND MID-ATLANTIC, WITH HIGHS GENERALLY IN THE 60S.  
ACROSS THE PACIFIC NORTHWEST AND NORTHERN ROCKIES, ABOVE NORMAL  
TEMPERATURES WILL BEGIN TO COOL AS SHOWERS DEVELOP BY LATE WEEK.  
 
OUDIT  
 
GRAPHICS AVAILABLE AT  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  
 

 
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab HPC Page Main Text Page