864  
FXUS01 KWBC 111941  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
340 PM EDT FRI MAY 11 2018  
 
VALID 00Z SAT MAY 12 2018 - 00Z MON MAY 14 2018  
 
...SEVERE THUNDERSTORMS WILL BE POSSIBLE ON SATURDAY ACROSS  
PORTIONS OF THE UPPER MIDWEST, UPPER OHIO VALLEY AND NORTHERN  
MID-ATLANTIC STATES...  
 
...CRITICAL FIRE DANGER EXISTS ACROSS THE SOUTHWEST AND SOUTHERN  
ROCKIES...  
 
...RAIN AND LATE SEASON MOUNTAIN SNOW EXPECTED ACROSS THE  
INTERMOUNTAIN WEST AND NORTHERN TO CENTRAL ROCKIES...  
 
OVER THE NEXT FEW DAYS, A WAVY AND QUASI-STATIONARY FRONT WILL  
REMAIN IN PLACE STRETCHING FROM THE CENTRAL HIGH PLAINS EAST ALL  
THE WAY TO THE MID-ATLANTIC STATES. MEANWHILE, ALONG THIS FRONT  
THERE WILL BE MULTIPLE WAVES OF LOW PRESSURE TENDING TO ADVANCE  
EAST ALONG IT. THESE WAVES OF LOW PRESSURE COUPLED WITH WARM,  
MOIST AIR LIFTING NORTH FROM THE GULF OF MEXICO AND OVERRUNNING  
THE FRONT WILL FOSTER AN EXPANSIVE AREA OF SHOWERS AND  
THUNDERSTORMS. THE ACTIVITY WILL COVER A LARGE AREA INCLUDING MUCH  
THE CENTRAL PLAINS, MIDWEST AND AREAS EAST ACROSS THE LOWER GREAT  
LAKES, MID-ATLANTIC AND SOUTHERN NEW ENGLAND.  
 
IN FACT, THERE WILL BE A CONCERN ON SATURDAY FOR SEVERE  
THUNDERSTORMS FROM THE UPPER MIDWEST EAST ACROSS THE UPPER OHIO  
VALLEY AND THROUGH THE NORTHERN MID-ATLANTIC REGION. THE GREATEST  
RISK AT THIS TIME APPEARS TO BE FOCUSED ON EASTERN OHIO AND  
NORTHERN WEST VIRGINIA EAST ACROSS PENNSYLVANIA, NORTHERN MARYLAND  
AND NEW JERSEY WHICH IS WHERE THE STORM PREDICTION CENTER HAS  
HIGHLIGHTED AN ENHANCED RISK OF SEVERE WEATHER.  
 
IN ADDITION TO THE SEVERE WEATHER THREAT, HEAVY RAINFALL WILL ALSO  
BE A CONCERN GOING THROUGH THE WEEKEND ALONG AND GENERALLY NORTH  
OF THIS FRONTAL ZONE. SOME OF THE HEAVIEST TOTALS THIS WEEKEND ARE  
EXPECTED TO BE OVER THE LOWER GREAT LAKES, UPPER OHIO VALLEY AND  
THE NORTHERN MID-ATLANTIC REGION WHERE AS MUCH AS 1 TO 2 INCHES OF  
RAIN POSSIBLE. SOME LOCALIZED FLOODING CONCERNS WILL BE POSSIBLE  
AS A RESULT.  
 
MUCH OF THE NORTHERN TIER STATES WILL BE COOLER THROUGH THE  
WEEKEND, AS HIGH PRESSURE WILL STRADDLE THIS REGION FROM WEST TO  
EAST. MEANWHILE, ACROSS THE SOUTH, THE TEMPERATURES WILL BE NEAR  
OR ABOVE NORMAL. AN EXCEPTION WILL BE OVER FLORIDA WHERE AN AREA  
OF DISTURBED WEATHER ASSOCIATED WITH AN UPPER LOW SHOULD BRING  
PLENTY OF CLOUDS AND A THREAT OF LOCALLY HEAVY RAINFALL. THE  
HEAVIEST RAINS SHOULD BE ALONG THE EAST COAST OF FLORIDA WHERE  
LOCALLY 2 TO 3 INCHES OF RAIN CAN BE EXPECTED FROM LATE SATURDAY  
THROUGH SUNDAY. THIS WILL CERTAINLY KEEP TEMPERATURES RELATIVELY  
COOLER AS WELL.  
 
LOCALLY HOT, DRY AND WINDY CONDITIONS WILL PREVAIL ACROSS MUCH OF  
THE SOUTHWEST U.S. AND TOWARD THE SOUTHERN ROCKIES WHICH WILL  
MAINTAIN A CRITICAL FIRE WEATHER THREAT. MANY OF THESE AREAS ARE  
IN AN EXTREME TO EXCEPTIONAL DROUGHT, AND UNFORTUNATELY MOST OF  
THIS REGION IS NOT EXPECTED TO SEE ANY RAIN THROUGH THE WEEKEND.  
 
RAIN AND LATE SEASON MOUNTAIN SNOW THOUGH IS EXPECTED FARTHER  
NORTH ACROSS THE WEST WITH A LARGE SCALE UPPER TROUGH AMPLIFYING  
AND CLOSING OFF OVER THE INTERMOUNTAIN WEST. THE HEAVIEST RAIN AND  
SNOWFALL TOTALS SHOULD BE OVER THE NORTHERN AND CENTRAL ROCKIES,  
WHERE MOIST EASTERLY FLOW INTO THE TERRAIN WILL ENHANCE  
PRECIPITATION FOR THE FAVORED UPSLOPE REGIONS.  
 
ORRISON  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
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