300  
FXUS01 KWBC 241914  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
313 PM EDT TUE JUL 24 2018  
 
VALID 00Z WED JUL 25 2018 - 00Z FRI JUL 27 2018  
 
...ADDITIONAL HEAVY RAINS WILL CONTINUE TO RAISE FLOODING CONCERNS  
ACROSS PORTIONS OF THE MID-ATLANTIC AND NORTHEAST THROUGH  
WEDNESDAY...  
 
...STRONG TO SEVERE THUNDERSTORMS POSSIBLE FOR PORTIONS OF THE  
NORTHERN AND CENTRAL PLAINS TO THE UPPER MIDWEST...  
 
...DANGEROUS HEAT TO CONTINUE ACROSS THE SOUTHWEST AND PORTIONS OF  
THE WEST COAST...  
 
...RISK OF HEAVY RAINFALL LEADING TO FLASH FLOODING FOR THE  
CENTRAL/SOUTHERN ROCKIES AND CENTRAL HIGH PLAINS...  
 
MOIST SOUTHERLY WINDS AHEAD OF A BROAD AREA OF LOW PRESSURE IN THE  
SOUTHEAST WILL CONTINUE TO SUPPORT PERIODS OF SHOWERS AND  
THUNDERSTORMS ACROSS PORTIONS OF THE MID-ATLANTIC AND THE  
NORTHEAST INTO WEDNESDAY. THESE STORMS WILL HAVE THE POTENTIAL TO  
PRODUCE ADDITIONAL HEAVY ACCUMULATIONS, RAISING FURTHER FLOODING  
CONCERNS. GIVEN THE RECENT HEAVY RAINS AND SATURATED SOIL  
CONDITIONS, FLASH FLOODING REMAINS A CONCERN, WITH WPC INDICATING  
A MODERATE RISK FOR EXCESSIVE RAINFALL FROM EASTERN NORTH CAROLINA  
NORTHWARD INTO CENTRAL PENNSYLVANIA AND THE SOUTHERN TIER REGION  
OF NEW YORK TUESDAY EVENING INTO EARLY WEDNESDAY.  
 
ON WEDNESDAY INTO EARLY THURSDAY, AS THE LOW OVER THE SOUTHEAST IS  
EXPECTED TO WEAKEN AND LIFT OUT TO THE NORTH AHEAD OF AN  
APPROACHING FRONTAL SYSTEM, THE GREATER POTENTIAL FOR HEAVY RAIN  
IS EXPECTED TO SHIFT FURTHER TO THE NORTHEAST, WITH WPC INDICATING  
A MODERATE RISK FOR EXCESSIVE RAINFALL FROM PORTIONS EASTERN  
PENNSYLVANIA AND NORTHERN NEW JERSEY INTO PARTS OF UPSTATE NEW  
YORK. BY LATE THURSDAY, THE HEAVY RAINFALL THREAT IS EXPECTED TO  
WANE AS THE DEEPER MOISTURE SHIFTS EAST OUT OVER THE ATLANTIC.  
 
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP NEAR AN  
ORGANIZING AREA OF LOW PRESSURE MOVING EAST FROM EASTERN MONTANA  
INTO THE DAKOTAS TUESDAY EVENING INTO THE OVERNIGHT HOURS. THIS  
LOW IS EXPECTED TO MOVE INTO THE UPPER MIDWEST ON WEDNESDAY, WITH  
A WELL-DEFINED TRAILING COLD FRONT DROPPING INTO THE MID  
MISSISSIPPI VALLEY AND CENTRAL PLAINS. SPC IS HIGHLIGHTING THE  
POTENTIAL FOR STORMS DEVELOPING NEAR AND ALONG THE FRONT TO BECOME  
SEVERE, WITH A SLIGHT RISK FOR SEVERE THUNDERSTORMS EXTENDING FROM  
THE CENTRAL PLAINS INTO FAR SOUTHERN MINNESOTA ON WEDNESDAY. IN  
ADDITION TO SHOWERS AND STORMS, THIS SYSTEM WILL USHER IN COOLER  
TEMPERATURES TO REGION, WITH SEASONAL TO BELOW-NORMAL TEMPERATURES  
EXTENDING SOUTH FROM THE NORTHERN PLAINS AND UPPER MIDWEST ON  
WEDNESDAY INTO THE CENTRAL PLAINS AND MID MISSISSIPPI VALLEY ON  
THURSDAY.  
 
SHOWERS AND THUNDERSTORMS ARE POSSIBLE BOTH TUESDAY AND WEDNESDAY  
ACROSS PORTIONS OF THE CENTRAL AND SOUTHERN ROCKIES INTO THE  
ADJACENT PLAINS. THESE STORMS MAY CAUSE FLASH FLOODING CONCERNS,  
ESPECIALLY OVER RECENT BURN SCAR AREAS.  
 
WHILE PORTIONS OF THE CENTRAL U.S. CONTINUE TO MODERATE, DANGEROUS  
HEAT WILL REMAIN AN ISSUE ACROSS PARTS OF THE WESTERN U.S. WITH  
TEMPERATURES EXPECTED TO REMAIN WELL ABOVE THEIR SEASONAL  
AVERAGES, EXCESSIVE HEAT WARNINGS REMAIN IN EFFECT THROUGH  
THURSDAY FROM SOUTHERN ARIZONA WESTWARD INTO SOUTHERN NEVADA AND  
SOUTHERN CALIFORNIA. HEAT ADVISORIES ARE IN EFFECT FURTHER TO THE  
NORTH THROUGH IN THE INTERIOR VALLEYS OF CENTRAL AND NORTHERN  
CALIFORNIA INTO WESTERN OREGON.  
 
PEREIRA  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
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