949  
FXUS02 KWBC 250547  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
146 AM EDT WED JUL 25 2018  
 
VALID 12Z SAT JUL 28 2018 - 12Z WED AUG 01 2018  
   
..HEAT WAVE LINGERS OVER THE WEST
 
 
...HEAVY RAINFALL THREAT TO SPREAD FROM THE CENTRAL PLAINS TO  
MID-SOUTH THEN THE SOUTHEAST/EAST...  
   
..GUIDANCE/UNCERTAINTY ASSESSMENT AND WEATHER THREATS
 
 
WEEKEND MID-UPPER LEVEL TROUGHING LIFTS OVER THE NORTHEAST WITH  
SCATTERED CONVECTION, BUT HEAVY ACTIVITY TRAILS SOUTHWARD OFF THE  
EAST COAST INTO FLORIDA. MEANWHILE, A SOUTHWEST/WEST MID-UPPER  
LEVEL RIDGE OFFERS MORE ABOVE NORMAL SUMMER HEAT INTO NEXT WEEK.  
ACTIVE IMPULSES LINGER IN SOUTHWEST/SRN ROCKIES MONSOONAL FLOW AND  
OVERTOP THE RIDGE. THESE DIG INTO THE CENTRAL U.S. IN FAVORABLE  
UPPER DIFFLUENCE TO INTERACT WITH SURFACE BOUNDARIES, INSTABILITY,  
AND FAVORABLE LOW LEVEL MOISTURE INFLOW/CONVERGENCE. WEEKEND  
MID-UPPER LEVEL TROUGH AMPLIFICATION OVER THE N-CENTRAL U.S. WILL  
DIG THROUGH THE MS VALLEY EARLY NEXT WEEK AND INDUCE FRONTAL LOWS  
AND GRADUAL SYSTEM PROGRESSIONS DOWNSTREAM OVER THE E-CENTRAL U.S.  
EXPECT MULTIPLE EPISODES OF HEAVY CONVECTION FROM THE CENTRAL  
ROCKIES/PLAINS THROUGH THE MID-LOWER MS/MID-SOUTH THIS WEEKEND  
WHOSE THREAT SPREADS OVER THE E-CENTRAL TO SOUTHEAST/ERN U.S.  
EARLY-MID NEXT WEEK. HEAVY RAINFALL WITH REPEAT CELLS OFFER A  
WIDESPREAD EXCESSIVE RAINFALL THREAT FUELED BY AN INCREASINGLY  
DEEP LAYERED MOISTURE INFLOW PATTERN TO ALIGN ROUGHLY PARALLEL TO  
THE MAIN FRONT AS STORMS CHANNEL BETWEEN THE SLOW TO TRANSLATE  
UPSTREAM TROUGH ALOFT AND A DOWNSTREAM WESTERN ATLANTIC RIDGE.  
 
THE WPC MEDIUM RANGE PRODUCT SUITE WAS MAINLY DERIVED FROM A  
COMPOSITE BLEND OF BEST CLUSTERED GUIDANCE FROM THE 12 UTC ECMWF  
AND 12 UTC GEFS/NAEFS/ECMWF ENSEMBLES IN A PATTERN WITH ABOVE  
NORMAL PREDICTABILITY.  
 
SCHICHTEL  
 
WPC MEDIUM RANGE 500 MB HEIGHTS, SURFACE SYSTEMS, WEATHER GRIDS,  
QUANTITATIVE PRECIPITATION, WINTER WEATHER OUTLOOK PROBABILITIES  
AND HEAT INDEXES ARE FOUND AT:  
 
HTTPS://WWW.WPC.NCEP.NOAA.GOV/MEDR/5DAYFCST500_WBG.GIF  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/MEDR/5DAYFCST_WBG_CONUS.GIF  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/5KM_GRIDS/5KM_GRIDSBODY.HTML  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/QPF/DAY4-7.SHTML  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/WWD/PWPF_D47/PWPF_MEDR.PHP?DAY=4  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/HEAT_INDEX.SHTML  
 

 
 
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