850  
FXUS02 KWBC 040642  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
241 AM EDT WED JUL 04 2018  
 
VALID 12Z SAT JUL 07 2018 - 12Z WED JUL 11 2018  
   
..OVERVIEW
 
 
AN UPPER HIGH WILL CONTINUE TO DOMINATE THE LOWER 48 THIS COMING  
WEEKEND INTO THE MIDDLE OF NEXT WEEK. TROUGHS IN THE NORTHWEST AND  
NORTHEAST WILL FLATTEN WITH TIME AS A MORE ZONAL FLOW TAKES SHAPE  
ALONG THE US/CANADIAN BORDER AS HEIGHTS BECOME ABOVE AVERAGE FROM  
COAST TO COAST. A FRONT IN THE EAST WILL SINK INTO THE SOUTHEAST  
THIS WEEKEND AND DISSIPATE NEXT WEEK AS A WESTERN FRONT TILTS  
ACROSS THE UPPER MIDWEST/GREAT LAKES AND EVENTUALLY MOVES INTO THE  
NORTHEAST.  
   
..WEATHER THREATS/HIGHLIGHTS
 
 
TEMPERATURES WILL BE NEAR OR BELOW AVERAGE IN MUCH OF THE EAST  
THIS WEEKEND BUT TREND BACK TO ABOVE AVERAGE BY THE MIDDLE OF NEXT  
WEEK. THE DEEP SOUTH WILL LIE SOUTH OF THE UPPER HIGH AND SUBJECT  
TO EASTERLY MID-LEVEL SHORTWAVES THAT, COUPLED WITH THE SURFACE  
FRONT, WILL MAINTAIN A DAILY CHANCE OF SHOWERS/STORMS AND COOLER  
THAN AVERAGE MAX TEMPERATURES. THE WEST WILL SEE NEAR TO ABOVE  
AVERAGE TEMPERATURES, ESPECIALLY SATURDAY IN SOUTHERN CALIFORNIA  
WITH 90S LIKELY TO THE COAST AND 100S INLAND WHICH SHOULD  
TIE/BREAK DAILY RECORDS.  
 
MOISTURE IS FORECAST TO GRADUALLY INCREASE INTO THE SOUTHWEST OUT  
OF MEXICO, FIRST INTO NEW MEXICO AND THEN INTO ARIZONA. THIS WILL  
KEEP DAYTIME TEMPERATURES NEAR OR A COUPLE DEGREES BELOW AVERAGE.  
   
..GUIDANCE EVALUATION/PREFERENCES
 
 
MODELS/ENSEMBLES REMAINED IN VERY GOOD AGREEMENT AND A CONSENSUS  
BLEND WAS USED THROUGH THE PERIOD. THE 12Z ECMWF MAY BE TOO  
AGGRESSIVE IN ITS FORECAST OF A FORMING UPPER LOW IN THE NORTHEAST  
NEXT WEDNESDAY AS THE CONSENSUS LIED OFFSHORE IN A WEAKER STATE.  
 
FRACASSO  
 
WPC MEDIUM RANGE FORECASTS OF 500 MB HEIGHTS, SURFACE SYSTEMS,  
WEATHER GRIDS, QUANTITATIVE PRECIPITATION, AND WINTER WEATHER  
OUTLOOK PROBABILITIES 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  
 

 
 
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