224  
FXUS02 KWBC 070701  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
200 AM EST WED NOV 07 2018  
 
VALID 12Z SAT NOV 10 2018 - 12Z WED NOV 14 2018  
 
...GUIDANCE/PREDICTABILITY ASSESSMENT AND WEATHER  
HIGHLIGHTS/THREATS...  
 
RECENT GFS/ECMWF AND GEFS/ECMWF ENSEMBLE SOLUTIONS REMAIN FAIRLY  
WELL CLUSTERED OVERALL THROUGH MEDIUM RANGE TIME SCALES OVER MUCH  
OF THE NATION, BOLSTERING FORECAST CONFIDENCE. A COMPOSITE BLEND  
SOLUTION THAT MAINTAINS GOOD WPC CONTINUITY IS SUGGESTED.  
 
AMPLIFIED/DYNAMIC TROUGH PASSAGE ALOFT SATURDAY FROM THE  
EAST-CENTRAL TO NORTHEASTERN U.S. WILL SUPPORT LEAD SURFACE LOW  
AND FRONTAL SYSTEM PROGRESSION AND REDEVELOPMENT. EXITING  
PRECIPITATION OVER THE NORTHEAST WILL BE ENHANCED WITH TRIPLE  
POINT COASTAL LOW GENESIS. COOLED POST-SYSTEM TEMPS SUPPORTS  
WRAPBACK AND GREAT LAKE EFFECT SNOWS THAT SPREAD INTO THE INTERIOR  
NORTHERN MID-ATLANTIC AND NORTHEAST. SHOWERS WILL LINGER INTO NEXT  
WEEK DOWN OVER FLORIDA AND THE GULF COAST NEAR THE TRAILING  
STALLED FRONT.  
 
A STORM TRACK TO THE NORTHEAST PACIFIC/GULF OF ALASKA MAINTAINS AN  
AMPLIFIED DOWNSTREAM RIDGE POSITION ALONG/OFFSHORE WESTERN NORTH  
AMERICA INTO EARLY NEXT WEEK. DOWNSTREAM, A LEAD NORTHERN STREAM  
CLIPPER LOW TRACK AND FAVORABLE DYNAMICS WILL SQUEEZE OUT A SWATH  
OF SNOW IN COOLED AIR FROM THE NORTH-CENTRAL STATES THROUGH THE  
GREAT LAKES/NORTHEAST.  
 
SUBSEQUENT TROUGH RE-AMPLIFICATION ALOFT BACK OVER THE CENTRAL  
U.S. EARLY-MID NEXT WEEK MAY BE ENERGIZED BY PHASING NORTHERN AND  
SOUTHERN STREAM SHORTWAVE IMPULSES DIGGING TO THE LEE OF THE STILL  
AMPLIFIED BUT GRADUALLY EASTWARD SHIFTING UPSTREAM RIDGE. THERE IS  
A GROWING SIGNAL SUPPORTING AMPLE LEADING WAVE/FRONTAL GENESIS AND  
DEEP MOISTURE RETURN TO WOULD FUEL HEAVY RAIN/CONVECTION EXPANSION  
NORTHWARD ACROSS THE EAST-CENTRAL THEN EASTERN U.S. MOISTURE  
FEEDING BACK INTO A SHARPENING BAROCLINIC ZONE MEANWHILE PRESENTS  
AN ORGANIZED SNOW THREAT THROUGH THE APPALACHIANS/OHIO VALLEY,  
WITH AMPLE LAKE EFFECT ENHANCEMENT LEE OF THE GREAT LAKES AND FOR  
THE INTERIOR NORTHERN MID-ATLANTIC AND NORTHEAST WITH SYSTEM  
APPROACH. SIGNIFICANT EARLY SEASON SNOWS ARE POSSIBLE.  
 
WELL UPSTREAM, PACIFIC TROUGH ENERGY AND HEIGHT FALLS START TO  
WORK INTO THE NORTHWEST EARLY NEXT WEEK AS THE LEAD/AMPLIFIED  
RIDGE ALOFT GRADUALLY/FINALLY SHIFTS INLAND. THIS MAY SUPPORT AN  
INCREASED CHANCE FOR PRECIPITATION INCLUDING MODEST ELEVATION  
SNOWS.  
 
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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