394  
FXUS01 KWBC 200758  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
357 AM EDT FRI JUL 20 2018  
 
VALID 12Z FRI JUL 20 2018 - 12Z SUN JUL 22 2018  
 
...A MODERATE RISK OF SEVERE THUNDERSTORMS IS POSSIBLE ACROSS THE  
TENNESSEE AND OHIO VALLEYS....  
 
...HEAVY RAIN EXPECTED TO IMPACT THE OHIO VALLEY AND ALONG THE  
EAST COAST...  
 
...ABOVE NORMAL TEMPERATURES TO CONTINUE ACROSS THE SOUTHERN  
PLAINS ALONG WITH THE PACIFIC NORTHWEST...  
 
A FRONTAL SYSTEM MOVING OUT OF THE MISSISSIPPI VALLEY WILL SLOWLY  
MOVE ACROSS THE TENNESSEE AND OHIO VALLEYS. COPIOUS AMOUNTS OF  
MOISTURE WILL POOL ALONG THE FRONT ALONG WITH UNSTABLE AIR. THIS  
WILL LEAD TO MORE ROUNDS OF SEVERE WEATHER--PARTICULARLY FROM  
NORTHWEST TENNESSEE INTO SOUTHERN INDIANA WHERE THE STORM  
PREDICTION CENTER HAS ISSUED A MODERATE RISK. THUNDERSTORMS WILL  
SPAN FROM THE UPPER GREAT LAKES TO THE WESTERN PORTIONS OF THE  
SOUTHEAST--WITH FLASH FLOODING A CONCERN ACROSS THESE REGIONS. BY  
SATURDAY, THE SYSTEM BEGINS TO PUSH EASTWARD TOWARD THE NORTHEAST  
AND MID-ATLANTIC; PRECIPITATION WILL INCREASE ACROSS THE LOWER  
GREAT LAKES SOUTHWARD INTO GEORGIA AND ALABAMA. THERE IS A SLIGHT  
RISK OF SEVERE WEATHER POSSIBLE ALONG THE SOUTHERN APPALACHIANS.  
 
A DEVELOPING LOW OFF THE CAROLINA COAST WILL SLOWLY MOVE NORTHWARD  
ALONG THE MID-ATLANTIC AND INTO THE NORTHEAST. INITIALLY, THE  
HEAVY RAINFALL WILL CONCENTRATE ACROSS THE COASTAL PORTIONS OF  
NORTH AND SOUTH CAROLINA TODAY WHERE A SLIGHT RISK OF FLASH  
FLOODING WILL BE A CONCERN. AS THE LOW MOVES TOWARD THE NEW  
ENGLAND COASTLINE BY LATE SATURDAY NIGHT/EARLY SUNDAY MORNING,  
HEAVY RAINFALL WILL IMPACT THIS REGION WHERE THERE IS ALSO A  
SLIGHT RISK OF FLASH FLOODING.  
 
DANGEROUS HEAT REMAINS IN PLACE ACROSS THE SOUTHERN PLAINS, LOWER  
MISSISSIPPI VALLEY AND INTO THE SOUTHEAST/TENNESSEE VALLEY OVER  
THE NEXT FEW DAYS WHERE EXCESSIVE HEAT WARNINGS AND HEAT  
ADVISORIES ARE IN PLACE. HIGH TEMPERATURES WILL REACH WELL OVER  
THE CENTURY MARK WILL OCCUR ACROSS TEXAS AND OKLAHOMA THROUGH THIS  
WEEKEND. 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. ELSEWHERE,  
MONSOONAL MOISTURE WILL FIRE OFF THUNDERSTORMS ACROSS THE DESERT  
SOUTHWEST--WHERE FLASH FLOODING COULD OCCUR IN FAVORED TERRAIN,  
DESERT REGIONS, AND URBAN CORRIDORS. A MARGINAL RISK OF FLASH  
FLOODING IS POSSIBLE THROUGH SUNDAY.  
 
REINHART  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
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