778  
FXUS01 KWBC 182011  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
410 PM EDT WED JUL 18 2018  
 
VALID 00Z THU JUL 19 2018 - 00Z SAT JUL 21 2018  
 
...HEAVY RAIN AND SEVERE THUNDERSTORMS POSSIBLE ACROSS THE  
NORTH-CENTRAL UNITED STATES THROUGH THE END OF THE WORK WEEK...  
 
...SHOWERS AND THUNDERSTORMS WILL CONTINUE ACROSS THE SOUTHEAST  
THROUGH THE END OF THE WORK WEEK...  
 
...EXCESSIVE HEAT WILL CONTINUE TO POSE CONCERN ACROSS MUCH OF THE  
WESTERN AND SOUTH-CENTRAL UNITED STATES...  
 
A LOW PRESSURE SYSTEM CURRENTLY OVER THE CENTRAL PLAINS WILL  
CONTINUE TO DEEPEN AS IT SHIFTS EAST-NORTHEASTWARD THROUGH THE  
NORTHERN PLAINS AND TOWARDS THE UPPER MISSISSIPPI VALLEY BY THE  
END OF THE WORK WEEK. AS THIS LOW DEEPENS, A STRONG PULL OF WARM,  
MOIST AIR FROM THE GULF OF MEXICO WILL RESULT IN THE DEVELOPMENT  
OF A FAIRLY STRONG WARM FRONT, AND THEN EVENTUALLY A COLD FRONT AS  
A COLDER AIR GETS PULLED IN FROM CANADA. THIS SYSTEM WILL ALSO BE  
THE EPICENTER FOR SHOWER AND THUNDERSTORM DEVELOPMENT ACROSS THIS  
REGION. THE STORM PREDICTION CENTER HAS OUTLINED AN ENHANCED RISK  
FOR SEVERE THUNDERSTORM DEVELOPMENT ACROSS PORTIONS OF THE CENTRAL  
AND NORTHERN PLAINS FOR THIS AFTERNOON THROUGH TONIGHT. A MARGINAL  
AND SLIGHT RISK HAVE ALSO BEEN OUTLINED ACROSS PORTIONS OF THE MID  
MISSISSIPPI VALLEY FOR THURSDAY, SHIFTING EASTWARD INTO THE OHIO  
VALLEY FOR FRIDAY AHEAD OF THE DEVELOPING COLD FRONT. EXCESSIVE  
RAINFALL AND FLASH FLOODING WILL BE POSSIBLE WITH THESE STORMS AS  
WELL. THE WEATHER PREDICTION CENTER HAS ALSO OUTLINED PORTIONS OF  
THE NORTHERN MISSOURI RIVER BASIN AS BEING IN A MARGINAL TO SLIGHT  
RISK OF EXCESSIVE RAINFALL THIS AFTERNOON AND TONIGHT. PORTIONS OF  
THE UPPER MISSISSIPPI RIVER VALLEY HAVE A MARGINAL TO SLIGHT  
CHANCE OF EXCESSIVE RAINFALL ON THURSDAY.  
 
MEANWHILE, THE ONGOING QUASI-STATIONARY FRONT EXTENDING FROM THE  
SOUTHERN MID-ATLANTIC INTO PARTS OF THE SOUTHERN PLAINS WILL  
SLOWLY DISSIPATE OVER THE SOUTHERN PLAINS/LOWER MISSISSIPPI VALLEY  
BY THURSDAY NIGHT, WHILE THE BOUNDARY OVER THE SOUTHEAST REMAINS  
BUT STALLS. THIS FRONT WILL BE THE EPICENTER FOR SHOWER AND  
THUNDERSTORM DEVELOPMENT ACROSS THE SOUTHEAST AND SOUTHERN  
MID-ATLANTIC COAST THROUGH THE END OF THE WORK WEEK. THE WEATHER  
PREDICTION CENTER HAS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS  
PORTIONS OF THESE AREAS THROUGH THE END OF THE WEEK.  
 
IN ADDITION TO THE THUNDERSTORM AND EXCESSIVE RAINFALL CONCERNS,  
HEAT IS ALSO IMPACTING MANY STATES ACROSS THE U.S. A STRONG PULL  
OF WARM AIR INTO THE CENTRAL PORTION OF THE UNITED STATES IS  
CURRENTLY LEADING TO WELL ABOVE NORMAL TEMPERATURES IN ADDITION TO  
HIGH HUMIDITY VALUES. THIS WILL ONLY INCREASE AS THE ABOVE  
MENTIONED LOW PRESSURE SYSTEM CONTINUES TO GAIN STRENGTH. LARGE  
PORTIONS OF THE SOUTHERN PLAINS, LOWER MISSISSIPPI VALLEY, AS WELL  
AS SOME LOCATIONS IN NEBRASKA AND MISSOURI ARE UNDER HEAT  
ADVISORIES AND WARNINGS THROUGH THE END OF THE WORK WEEK AS A  
RESULT. FURTHERMORE, MUCH OF THE WESTERN UNITED STATES IS ALSO  
FEELING THE EFFECTS OF EXCESSIVE HEAT. EXCESSIVE HEAT WATCHES,  
ADVISORIES, AND WARNINGS ARE ALL IN EFFECT ACROSS CALIFORNIA,  
PORTIONS OF THE EXTREME SOUTHEAST, AND THE CENTRAL GREAT BASIN.  
WIND IS AIDING TO THE PROBLEM FARTHER NORTH, WITH RED FLAG  
WARNINGS POSTED ACROSS PORTIONS OF THE NORTHWEST AND INTO THE  
NORTHERN ROCKIES.  
 
WIX  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
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