129  
FXUS02 KWBC 070601  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
100 AM EST FRI DEC 07 2018  
 
VALID 12Z MON DEC 10 2018 - 12Z FRI DEC 14 2018  
   
..PATTERN/WEATHER HIGHLIGHTS AND HAZARDS
 
 
LINGERING PRECIPITATION INCLUDING A SWATH OF SNOW OVER A COOLED  
SOUTHERN MID-ATLANTIC IS EXPECTED WITH A DEPARTING LOW PRESSURE  
SYSTEM TO REDEVELOP OFFSHORE THE CAROLINAS MONDAY AS A MARITIME  
GALE HAZARD BEING FOLLOWED BY OPC. IN THE WAKE OF THE LOW AND  
SUPPORTING/DOUBLE BARRELLED TROUGH ALOFT, COOL TEMPERATURE  
REINFORCING/DRY HIGH PRESSURE SURGES WILL DIG THROUGH THE CENTRAL  
AND EASTERN U.S. INTO EARLY-MID NEXT WEEK.  
 
OUT WEST, PRECIPITATION WILL PERIODICALLY INCREASE EARLY-MID NEXT  
WEEK AND HEADING INTO NEXT WEEKEND AS HEIGHTS FALL WITH A  
SUCCESSION OF APPROACHING SHORTWAVES/FRONTAL SYSTEMS. HIGHER  
TERRAIN OF WESTERN OREGON/WASHINGTON HAVE POTENTIAL FOR HEAVIEST  
PRECIPITATION AMOUNTS (RAIN AND MOUNTAIN SNOW) AS SHOTS OF DYNAMIC  
SNOWS DRIVE INLAND INTO FAVORED NORTH-CENTRAL GREAT BASIN/ROCKIES  
TERRAIN. SOME OF THIS ENERGY WILL PROGRESS EASTWARD OVER THE  
NORTH-CENTRAL THROUGH NORTHEASTERN US TO SUPPORT MODEST NORTHERN  
STREAM SNOWS. POTENTIAL FOR SUBSTANTIAL ENERGY INFUSION INTO AN  
EMERGING SOUTHERN STREAM LATER NEXT WEEK MEANWHILE OFFERS  
POTENTIAL FOR DEEPER SYSTEM GENESIS AND THE THREAT FOR MORE  
WIDESPREAD AND GULF OF MEXICO MOISTURE FUELED HEAVY PRECIPITATION  
OVER THE SOUTH-CENTRAL U.S. INCLUDING A THREAT OF SNOW/ICE ON THE  
COLDER NORTHERN PERIPHERY OF AN EXPANDING/INTENSIFYING  
PRECIPITATION SHIELD. SYSTEM EFFECTS/HAZARDS SPREAD INTO THE EAST  
HEADING INTO NEXT WEEKEND.  
   
..GUIDANCE EVALUATION/PREFERENCES
 
 
THE WPC MEDIUM RANGE PRODUCT SUITE WAS PRIMARILY DERIVED FROM A  
BLEND OF THE LATEST GEFS/ECMWF ENSEMBLE MEANS. RECENT  
DETERMINISTIC RUNS GFS/ECMWF HAVE BEEN OFFERED WELL LESS THAN  
STELLAR RUN TO RUN CONSISTENCY. THE ENSEMBLE MEANS HAVE VARIED A  
BIT MORE THAN NORMAL, BUT HAVE BEEN MUCH MORE CONSISTENT WITH THE  
ABOVE MENTIONED SYSTEMS, BUT AMPLE FORECAST SPREAD/UNCERTAINTY  
REMAINS. LATEST GFS/ECMWF RUNS OVERALL TREND BETTER IN LINE WITH  
THE ENSEMBLE MEANS IN THE NORTHERN AND EMERGING SOUTHERN STREAM AS  
WELL WITH HOLDING MORE SUBTROPICAL TROUGHING OFF BAJA IN LUE OF  
MORE PROGRESSIVE INFUSION INTO THE U.S. SOUTHERN TIER FLOW.  
 
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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