704  
FXUS02 KWBC 041559  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
1058 AM EST SUN NOV 04 2018  
 
VALID 12Z WED NOV 07 2018 - 12Z SUN NOV 11 2018  
   
..OVERVIEW
 
 
BROAD CYCLONIC FLOW ALOFT WILL REMAIN ANCHORED OVER MOST OF THE  
LOWER 48 THIS WEEK INTO THE WEEKEND AS EMBEDDED SYSTEMS PASS  
THROUGH THE LARGE SCALE MEAN TROUGH. AN ORGANIZING SOUTHERN PLAINS  
SYSTEM WILL DROP OUT OF THE INTERMOUNTAIN WEST AND LIFT INTO THE  
GREAT LAKES FRIDAY WITH SOME WINTRY WEATHER ON ITS NORTH SIDE.  
COOLER THAN AVERAGE TEMPERATURES ARE FAVORED FOR MOST OF THE LOWER  
48 EXCEPT THE WEST/EAST COASTS AND ALONG THE GULF COAST WED/THU  
(BEFORE A COLD FRONT MOVES THROUGH).  
 
   
..GUIDANCE/PREDICTABILITY ASSESSMENT AND PREFERENCES
 
 
MAIN STORM OF INTEREST WILL BE THE MIDWEST CYCLONE FRIDAY WHERE  
THE MODELS/ENSEMBLE VARY ON TIMING/STRENGTH OF THE LOW/FRONT AS  
WELL AS THE INFLUENCE OF A STALLED FRONT ALONG THE COAST. THE GFS  
RUNS REMAINED A BIT QUICKER THAN THE ENSEMBLE MEANS, WHICH WERE  
QUICKER THAN THE 00Z ECMWF AND UKMET (SLOWEST). THOUGH THE SYSTEM  
MAY HAVE REASON TO MODESTLY DEEPEN AND TRACK SLOWER NORTHEASTWARD,  
LEAD SYSTEM IN THE SHORT RANGE HAS TRENDED QUICKER IN THE BROAD  
FLOW AS INDIVIDUAL SHORTWAVES MAY HAVE A HARDER TIME TRYING TO  
SLOW THE ENTIRE PATTERN. THUS, OPTED TO STAY NEAR THE MIDDLE OF  
THE GUIDANCE VIA THE ENSEMBLE MEANS FOR NOW. ONCE THE LOW LIFTS  
INTO CANADA AND THE FRONT CLEARS THE EAST COAST (AND INTO SOUTHERN  
FLORIDA), HIGH PRESSURE WILL SLIDE INTO THE EAST WITH PERHAPS  
ANOTHER NORTHERN STREAM SYSTEM DROPPING THROUGH THE HIGH PLAINS.  
06Z GFS AND 00Z PARALLEL GFS (FV3-GFS) WERE REASONABLE  
DETERMINISTIC WEIGHTS WITH THE ENSEMBLE MEANS BY NEXT WEEKEND AS  
THE 00Z ECMWF APPEARED MUCH TOO STRONG OVER THE NORTHEASTERN  
PACIFIC WITH AN INCOMING LOW INTO WESTERN CANADA SAT/SUN.  
 
   
..WEATHER HIGHLIGHTS/THREATS
 
 
GENERALLY LIGHT BUT OCCASIONAL MODEST RAIN/SNOW IN THE WEST TIED  
TO THE INCOMING SHORTWAVE AND SURFACE COLD FRONT (SOUTH) AND  
STATIONARY FRONT (NORTH) WILL EXIT THE ROCKIES ONTO THE PLAINS  
WHERE ENE FLOW AROUND A SURFACE HIGH TO THE NORTH MAY SUPPORT A  
SWATH OF LIGHT SNOW THROUGH THE CENTRAL PLAINS (EASTERN CO ACROSS  
NE/KS NORTHEASTWARD). TO THE SOUTH, GULF MOISTURE WILL SUPPORT  
MODEST RAINFALL (POTENTIALLY LOCALLY HEAVY VIA EMBEDDED  
CONVECTION) FROM THE LOWER MISSISSIPPI VALLEY EASTWARD INTO THE  
SOUTHEAST AS THE FRONT PROGRESSES EASTWARD. AS THE FRONT CLEARS  
THE EAST COAST, LAKE-EFFECT SNOW IS LIKELY (POTENTIALLY SEVERAL  
INCHES) WITH COLD TEMPERATURES ALOFT ATOP MILD LAKE TEMPERATURES  
(NEAR OR UNDER FREEZING OVER LAND) AND GENERALLY NW FLOW.  
TEMPERATURES WILL BE MOST ANOMALOUSLY COOL AROUND THE UPPER  
MIDWEST/GREAT LAKES (5-20F BELOW AVERAGE) AS WELL AS TEXAS BEHIND  
THE COLD FRONT. THIS MAY BE NEAR RECORD COLD MAXIMUM TEMPERATURES  
FOR SOME LOCATIONS IN THE MIDWEST.  
 
FRACASSO  
 
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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