375  
FXUS02 KWBC 050645  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
244 AM EDT THU JUL 05 2018  
 
VALID 12Z SUN JUL 08 2018 - 12Z THU JUL 12 2018  
   
..WEATHER THREATS/HIGHLIGHTS.
 
 
AN UPPER HIGH WILL CONTINUE TO DOMINATE THE LOWER 48 NEXT WEEK.  
TROUGHS OVER THE NORTHWEST AND NORTHEAST FLATTEN WITH TIME AS A  
MORE ZONAL FLOW TAKES SHAPE ALONG THE US/CANADIAN BORDER. HEIGHTS  
WILL BECOME ABOVE AVERAGE COAST TO COAST WHICH SUPPORTS NEAR TO  
ABOVE AVERAGE TEMPERATURES OVER MOST AREAS OUTSIDE THE SOUTHERN  
TIER. A MODERATING FRONT IN THE EAST WILL DISSIPATE NEXT WEEK AS  
WESTERN NORTH AMERICAN FRONTS SHIFT DOWNSTREAM ACROSS THE NORTHERN  
PLAINS, UPPER MIDWEST/GREAT LAKES AND NORTHEAST ALONG WITH  
THUNDERSTORM FOCUS AND LOCAL SEVERE STORM THREAT AS PER SPC. THE  
SOUTHWEST WILL SEE ENHANCED MONSOONAL MOISTURE AROUND THE UPPER  
HIGH REALIZED AS PRECIPITATION INITIALLY OVER THE HIGHER TERRAIN  
AND THEN INTO SOME OF THE LOWER DESERTS.  
 
   
..GUIDANCE EVALUATION/PREFERENCES
 
 
MODELS AND ENSEMBLES REMAIN IN GOOD AGREEMENT OVERALL, BUT WITH A  
NOTICEABLE EXCEPTION OVER THE PACIFIC NORTHWEST. THE GEFS AND  
ECMWF ENSEMBLES HAVE TRENDED AWAY FROM EACH OTHER IN THEIR 12Z  
RUNS EARLY IN THE WEEK WITH AN APPROACHING TROUGH JUST AHEAD OF  
THE REMNANTS OF FORMER TROPICAL SYSTEM PRAPIROON. WITH SUCH A  
LARGE DISPARITY AND SUDDEN CHANGE, OPTED TO TAKE A MIDDLE GROUND  
NEAR THE 12Z EWCMF (WITH THE 18Z GFS MUCH SLOWER AND CLOSED OFF)  
AND SOMEWHAT LIKE THE 12Z GFS. OVER THE REST OF THE LOWER 48, THE  
UPPER HIGH MAY ATTEMPT TO PUSH EASTWARD AGAIN NEXT TUE-THU BUT THE  
ENSEMBLES DIFFER ON HOW MUCH TROUGHING TO ALLOW THROUGH THE  
NORTHEAST. AGAIN SPLIT THE DIFFERENCE GIVEN THE UPSTREAM  
UNCERTAINTY.  
 
FRACASSO  
 
WPC MEDIUM RANGE 500 MB HEIGHTS, SURFACE SYSTEMS, WEATHER GRIDS,  
QUANTITATIVE PRECIPITATION, WINTER WEATHER OUTLOOK PROBABILITIES  
AND HEAT INDEXES ARE FOUND AT:  
 
HTTP://WWW.WPC.NCEP.NOAA.GOV/MEDR/5DAYFCST500_WBG.GIF  
HTTP://WWW.WPC.NCEP.NOAA.GOV/MEDR/5DAYFCST_WBG_CONUS.GIF  
HTTP://WWW.WPC.NCEP.NOAA.GOV/5KM_GRIDS/5KM_GRIDSBODY.HTML  
HTTP://WWW.WPC.NCEP.NOAA.GOV/QPF/DAY4-7.SHTML  
HTTP://WWW.WPC.NCEP.NOAA.GOV/WWD/PWPF_D47/PWPF_MEDR.PHP?DAY=4  
HTTP://WWW.WPC.NCEP.NOAA.GOV/HEAT_INDEX.SHTML  
 

 
 
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