090  
FXUS01 KWBC 220709  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
308 AM EDT SAT JUL 22 2017  
 
VALID 12Z SAT JUL 22 2017 - 12Z MON JUL 24 2017  
 
...FLASH FLOODING AND SEVERE WEATHER WILL BE POSSIBLE OVER  
PORTIONS OF THE OHIO VALLEY AND MID-ATLANTIC STATES THIS WEEKEND...  
 
...ANOTHER DAY OF DANGEROUS HEAT IS EXPECTED FROM THE CENTRAL  
PLAINS AND MIDDLE MISSISSIPPI VALLEY TO THE MID-ATLANTIC COAST ON  
SATURDAY...  
 
...MONSOONAL MOISTURE WILL KEEP LOCALIZED FLASH FLOODING A THREAT  
FROM THE SOUTHWEST TO THE SOUTHERN AND CENTRAL ROCKIES OVER THE  
NEXT FEW DAYS...  
 
A WAVY FRONTAL BOUNDARY STRETCHING FROM THE CENTRAL PLAINS TO THE  
MID-ATLANTIC COAST EARLY SATURDAY WILL CONTINUE TO SERVE AS A  
FOCUS FOR SHOWERS AND THUNDERSTORMS WHILE IT GRADUALLY SINKS  
SOUTHEASTWARD THIS WEEKEND. AN ABUNDANCE OF MOISTURE AND  
INSTABILITY ALONG AND SOUTH OF THE BOUNDARY COULD LEAD TO HEAVY  
DOWNPOURS AND SEVERE WEATHER WITHIN DEVELOPING CONVECTION,  
ESPECIALLY FOR LOCATIONS ACROSS THE OHIO VALLEY AND NORTHERN  
MID-ATLANTIC STATES ON SATURDAY. STRONG TO SEVERE STORMS WILL  
ALSO BE POSSIBLE FARTHER NORTH OVER THE UPPER MISSISSIPPI VALLEY  
AND GREAT LAKES AS AMPLIFYING SHORTWAVE ENERGY PROGRESSES FROM THE  
NORTHERN PLAINS TO INTERIOR NEW ENGLAND THIS WEEKEND.  
 
HOT AND HUMID CONDITIONS WILL PERSIST FOR LOCATIONS SOUTH OF THE  
WAVY FRONTAL BOUNDARY STRETCHING FROM THE CENTRAL PLAINS TO THE  
MID-ATLANTIC COAST. WIDESPREAD EXCESSIVE HEAT WARNINGS AND HEAT  
ADVISORIES REMAIN IN EFFECT FOR MUCH OF THE CENTRAL TO SOUTHERN  
PLAINS, MIDDLE TO LOWER MISSISSIPPI VALLEY, AND SOUTHERN  
MID-ATLANTIC STATES, WHERE THE DANGEROUS COMBINATION OF HIGH  
TEMPERATURES AND DEW POINTS WILL LEAD TO TRIPLE DIGIT HEAT INDEX  
VALUES ON SATURDAY. LOCATIONS ACROSS KANSAS AND MISSOURI SHOULD  
BEGIN TO SEE RELIEF FROM THE HEAT AS THE WAVY FRONTAL BOUNDARY  
SINKS THROUGH THE REGION SATURDAY NIGHT, BUT ELSEWHERE, THE  
DANGEROUS HEAT WILL PERSIST INTO SUNDAY.  
 
WEAK IMPULSES OF ENERGY ALOFT COMBINED WITH MONSOONAL MOISTURE  
SHOULD HELP TRIGGER AND FUEL SCATTERED CONVECTION OVER THE  
SOUTHWEST AND SOUTHERN TO CENTRAL ROCKIES SATURDAY AND SUNDAY  
AFTERNOON AND EVENING. LOCALIZED FLASH FLOODING WILL BE POSSIBLE  
GIVEN THE ANOMALOUS MOISTURE IN PLACE ACROSS THE REGION.  
 
GERHARDT  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
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