694  
FXUS01 KWBC 212011  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
410 PM EDT SAT JUL 21 2018  
 
VALID 00Z SUN JUL 22 2018 - 00Z TUE JUL 24 2018  
 
...SLIGHT RISK OF SEVERE WEATHER AND FLASH FLOODING POSSIBLE  
ACROSS THE SOUTHEAST U.S....  
 
...EXCESSIVE RAIN AND FLASH FLOODING POSSIBLE ACROSS PORTIONS OF  
THE OHIO VALLEY THIS EVENING AND TONIGHT, AS WELL AS ALONG THE MID  
AND NORTHERN ATLANTIC COAST THROUGH SUNDAY...  
 
...SEVERE WEATHER POSSIBLE ACROSS THE NORTHERN HIGH PLAINS AND  
PORTIONS OF MINNESOTA THROUGH THE REST OF THE WEEKEND...  
 
...ABOVE NORMAL TEMPERATURES WILL CONTINUE ACROSS MUCH OF THE  
SOUTH-CENTRAL AND WESTERN UNITED STATES...  
 
THE FRONTAL SYSTEM THAT HAS BEEN IMPACTING THE MISSISSIPPI,  
TENNESSEE AND OHIO VALLEYS WILL CONTINUE TO PUSH SOUTHEASTWARD  
THROUGH THE REST OF THE WEEKEND. SHOWERS AND THUNDERSTORMS WILL  
CONTINUE ALONG THIS FRONT AIDED BY COPIOUS AMOUNTS OF MOISTURE AND  
INSTABILITY. THE STORM PREDICTION CENTER HAS INDICATED THAT SEVERE  
WEATHER WILL BE A CONCERN ESPECIALLY IN THE SOUTHEAST AND THE  
SOUTHERN APPALACHIANS THROUGH TONIGHT. THE THREAT FOR SEVERE  
WEATHER WILL THEN CONTINUE INTO SUNDAY ACROSS NORTHERN FLORIDA AND  
PORTIONS OF SOUTHERN MISSISSIPPI AND ALABAMA. THE LOW PRESSURE  
SYSTEM THAT IS DRIVING THIS ACTIVITY WILL REMAIN PARKED ACROSS THE  
OHIO VALLEY THROUGH MONDAY, LEADING TO THE CONTINUED CHANCE OF  
SHOWERS AND THUNDERSTORMS ACROSS MUCH OF THE EASTERN UNITED STATES  
(GENERALLY EAST OF THE MISSISSIPPI RIVER) DURING THIS TIME.  
 
MEANWHILE, A SURFACE LOW THAT HAS FORMED OFF THE COAST OF THE  
CAROLINAS WILL ALSO BE PUSHING NORTHWARD ALONG THE MID-ATLANTIC  
COAST AND TOWARDS THE NORTHEAST THROUGH TONIGHT. THIS SYSTEM WILL  
BE A FOCAL POINT FOR THUNDERSTORMS AND HEAVY RAINFALL,  
PARTICULARLY ALONG THE COASTAL REGIONS. THUS, THE WEATHER  
PREDICTION CENTER HAS ISSUED A SLIGHT RISK OF EXCESSIVE  
RAINFALL/FLASH FLOODING FOR COASTAL REGIONS OF THE MID-ATLANTIC  
THROUGH TONIGHT AND FOR COASTAL REGIONS OF THE NORTHEAST FOR  
SUNDAY.  
 
YET ANOTHER FRONTAL SYSTEM WILL SLIDE ACROSS THE NORTHERN HIGH  
PLAINS THROUGH SUNDAY, PRODUCING A LINE OF SHOWERS AND  
THUNDERSTORMS AS IT TRAVERSES EASTWARD. A SLIGHT RISK OF SEVERE  
WEATHER AND EXCESSIVE RAINFALL IS POSSIBLE, ESPECIALLY IN EASTERN  
MONTANA/WYOMING AND WESTERN PORTIONS OF THE DAKOTAS THROUGH  
TONIGHT. THE SLIGHT RISK OF SEVERE WEATHER THEN SHIFTS EASTWARD  
INTO THE EASTERN NORTHERN PLAINS AND PORTIONS OF MINNESOTA FOR  
SUNDAY. A MARGINAL RISK OF FLOODING WILL ALSO BE POSSIBLE FOR  
COLORADO WHERE SOME THUNDERSTORMS COULD PRODUCE FLASH FLOODING IN  
FAVORABLE TERRAIN.  
 
DANGEROUS HEAT REMAINS IN PLACE ACROSS THE SOUTHERN PLAINS, LOWER  
MISSISSIPPI VALLEY, AND MUCH OF THE SOUTHWEST AND WESTERN UNITED  
STATES. THIS HEAT IS EXPECTED TO REMAIN IN PLACE THROUGH AT LEAST  
MONDAY. EXCESSIVE HEAT WATCHES, WARNINGS AND HEAT ADVISORIES ARE  
IN PLACE ACROSS THESE REGIONS. HIGH TEMPERATURES WILL REACH WELL  
OVER THE CENTURY MARK ACROSS TEXAS AND OKLAHOMA THROUGH THIS  
WEEKEND--WITH AREAS NEAR THE DALLAS/FORT WORTH REGION REACHING UP  
TO 110 DEGREES! PORTIONS OF THE RED RIVER VALLEY COULD HAVE HEAT  
INDEX VALUES EVEN HOTTER, IN EXCESS OF 110 DEGREES. PORTIONS OF  
THE PACIFIC NORTHWEST WILL ALSO CONTINUE TO EXPERIENCE ABOVE  
NORMAL TEMPERATURES--ESPECIALLY BY THE END OF THE WEEKEND WHERE  
TEMPERATURES COULD REACH THE MID TO UPPER 90S AND EVEN REACH OVER  
100 IN SOME AREAS.  
 
WIX  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
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