853  
FXUS02 KWBC 040518  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
118 AM EDT SAT AUG 04 2018  
 
VALID 12Z TUE AUG 07 2018 - 12Z SAT AUG 11 2018  
   
..MORE HOT TEMPERATURES FOR THE WEST NEXT WEEK
 
 
   
..OVERVIEW AND GUIDANCE/UNCERTAINTY ASSESSMENT
 
 
THE UPPER HIGH IN THE WEST WILL ONLY BEGRUDGINGLY ABATE SOMEWHAT  
BY NEXT WEEKEND AS AN UPPER LOW SLOWLY MOVES INTO BRITISH  
COLUMBIA. THE EAST WILL SEE ANOTHER TROUGH SETTLE INTO THE REGION.  
THE MODELS/ENSEMBLES WERE MOSTLY ALIGNED IN THEIR FORECASTS THOUGH  
THE 12Z UKMET WAS SLOWER/DEEPER THAN MOST OF THE ENSEMBLES IN THE  
GREAT LAKES AROUND WEDNESDAY. A DETERMINISTIC BLEND WAS SUFFICIENT  
TO START THE PERIOD. BY NEXT FRI/SAT THE 12Z/18Z GFS RUNS WERE  
SLOWER TO BRING IN THE CLOSED LOW (WEAKENING TO AN OPEN WAVE) AND  
FARTHER SOUTH THAN THE ENSEMBLE MEANS AND 12Z ECMWF/CANADIAN, BUT  
WERE NOT THE MOST EXTREME SOLUTION OF THE MULTI-CENTER ENSEMBLE.  
NEVERTHELESS, TRENDED TOWARD THE ENSEMBLE MEANS AND ECMWF/CANADIAN  
FOR SOME DETAILS BY THE END OF THE PERIOD.  
 
   
..WEATHER HIGHLIGHTS/THREATS
 
 
WITH THE UPPER LOW LINGERING OFFSHORE, RIDGING WILL SUPPORT WELL  
ABOVE AVERAGE TEMPERATURES IN THE WEST/INTERIOR WEST. RANDOM  
RECORD HIGHS (INCLUDING MORE NUMEROUS RECORD WARM MINIMUMS) ARE  
AGAIN LIKELY FOR THE DESERT SOUTHWEST, GREAT BASIN, AND INTERIOR  
NORTHWEST (UNTIL HEIGHTS FALL AND THE FRONT PUSHES ASHORE).  
PRECIPITATION SHOULD BE CONFINED TO COASTAL WASHINGTON AND THEN ON  
THE EAST SIDE OF THE UPPER HIGH OVER NM/CO EASTWARD TO THE  
SOUTHERN PLAINS.  
 
UPPER TROUGH IN THE EAST RAISES THE CHANCE FOR PRECIPITATION THAT  
WILL FOCUS ALONG/AHEAD OF A SURFACE COLD FRONT. AS IT SETTLES INTO  
THE SOUTHEAST, THE TYPICAL WARM/HUMID AIRMASS WILL SUPPORT  
SCATTERED CONVECTION WITH LOCALLY HEAVY RAINFALL.  
 
FRACASSO/ROTH  
 
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  
 

 
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab HPC Page Main Text Page