629  
FXUS01 KWBC 300801  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
400 AM EDT SAT JUN 30 2018  
 
VALID 12Z SAT JUN 30 2018 - 12Z MON JUL 02 2018  
 
...SEVERE WEATHER AND FLASH FLOODING POSSIBLE FOR PARTS OF THE  
PLAINS TO THE MIDWEST...  
 
...WIDESPREAD AND DANGEROUS HEAT WAVE TO CONTINUE THROUGH THE  
WEEKEND FOR MUCH OF THE EASTERN HALF OF THE COUNTRY...  
 
A COLD FRONT MOVING SLOWLY EASTWARD AND A SURFACE LOW LIFTING  
THROUGH THE UPPER MIDWEST/GREAT LAKES ON SATURDAY WILL REMAIN A  
FOCUS FOR POTENTIALLY STRONG TO SEVERE CONVECTION AND HEAVY TO  
EXCESSIVE RAINFALL. THE STORM PREDICTION CENTER HAS HIGHLIGHTED  
PORTIONS OF THE EASTERN CENTRAL PLAINS TO THE UPPER MIDWEST WITHIN  
A SLIGHT TO ENHANCED RISK FOR SEVERE WEATHER TODAY, WITH SLIGHT  
RISKS ALSO ACROSS PORTIONS OF THE CENTRAL HIGH PLAINS AND THE  
NORTHEAST. THE PRIMARY THREATS WITH THESE STORMS WILL BE WIND AND  
LARGE HAIL, BUT A FEW TORNADOES CANNOT BE RULED OUT. GIVEN  
SIGNIFICANT MOISTURE POOLING ALONG THE MAIN BOUNDARY, THESE STORMS  
WILL ALSO BE CAPABLE OF HEAVY TO EXCESSIVE RAINFALL AND FLASH  
FLOODING, AND WPC HAS PLACED ROUGHLY THE SAME REGION (FROM EASTERN  
NEBRASKA TO WESTERN WISCONSIN WITHIN A SLIGHT TO MODERATE RISK ON  
THE DAY 1 OUTLOOK. BY SUNDAY, THIS SYSTEM BECOMES A BIT MORE  
PROGRESSIVE AS THE SURFACE LOW RACES NORTHWARD THROUGH THE UPPER  
GREAT LAKES, WHICH SHOULD LIMIT THE OVERALL FLASH FLOOD THREAT,  
BUT SEVERE WEATHER WILL REMAIN A POSSIBILITY ALONG THE COLD FRONT.  
REFER TO THE PRODUCTS ISSUED BY THE STORM PREDICTION CENTER AND  
WPC FOR ADDITIONAL DETAILS REGARDING THE SEVERE WEATHER AND FLASH  
FLOODING THREATS.  
 
THE OTHER BIG WEATHER STORY THIS WEEKEND IS THE MAJOR ONGOING HEAT  
WAVE AFFECTING MUCH OF THE EASTERN TWO-THIRDS OF THE COUNTRY THIS  
WEEKEND, AND EXTENDING INTO THE UPCOMING HOLIDAY WEEK. AFTERNOON  
HIGH TEMPERATURES COULD BE AS MUCH AS 10 TO 20 DEGREES ABOVE  
NORMAL AND COMBINED WITH HIGH HUMIDITY VALUES, WILL LEAD TO  
DANGEROUS HEAT INDICES APPROACHING OR EXCEEDING 100 DEGREES FOR  
MANY PLACES. DAYTIME MAXIMUM AND OVERNIGHT HIGH-MINIMUM  
TEMPERATURE RECORDS ARE IN JEOPARDY AND WIDESPREAD EXCESSIVE HEAT  
WARNINGS/WATCHES AND HEAT ADVISORIES ARE IN EFFECT FROM THE  
CENTRAL PLAINS TO THE OHIO VALLEY AND PARTS OF THE NORTHEAST.  
 
ELSEWHERE, HOT, DRY, AND WINDY CONDITIONS WILL CONTINUE SATURDAY  
FOR PARTS OF THE FOUR CORNERS REGION, AS WELL AS NORTH-CENTRAL  
CALIFORNIA, LEADING TO AN ELEVATED FIRE WEATHER RISK. RED FLAG  
WARNINGS REMAIN IN EFFECT FOR SOME LOCATIONS IN UTAH AND  
CALIFORNIA. ACROSS THE SOUTHEASTERN U.S., A WEAK SURFACE WAVE WILL  
KEEP SHOWERS AND THUNDERSTORMS IN THE FORECAST, WITH HEAVY  
RAINFALL POSSIBLE.  
 
SANTORELLI  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
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