067  
FXUS02 KWBC 160701  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
200 AM EST WED JAN 16 2019  
 
VALID 12Z SAT JAN 19 2019 - 12Z WED JAN 23 2019  
   
..MAJOR CENTRAL TO NORTHEASTERN U.S. ARCTIC BLAST/WINTER STORM
 
 
   
..GUIDANCE EVALUATION/PREFERENCES
 
 
THE WPC MEDIUM RANGE PRODUCT SUITE WAS PRIMARILY DERIVED FROM A  
BLEND OF WELL CLUSTERED GUIDANCE FROM THE 12 UTC ECMWF/ECENS AND  
THE 18 UTC GEFS. RECENT GFS RUNS ARE NOW OVERALL A BIT MORE  
PROGRESSIVE WITH SYSTEMS, ALBEIT WITH LESS ENSEMBLE SUPPORT.  
DESPITE TIMING VARIANCE, THERE REMAINS A STRONG SIGNAL FOR THE  
UPCOMING MAJOR CENTRAL TO NORTHEASTERN U.S. ARCTIC BLAST/WINTER  
STORM.  
   
..WEATHER HIGHLIGHTS/HAZARDS
 
 
FRIGID ARCTIC AIR SPILLS ACROSS THE CENTRAL THEN EASTERN U.S. AS  
THE NORTHERN STREAM AMPLIFIES AROUND A HUDSON BAY UPPER VORTEX.  
UNDERNEATH, AMPLIFIED SOUTHERN STREAM MID-UPPER LEVEL TROUGH  
APPROACH/HEIGHT FALLS AND FAVORABLE COUPLED UPPER JET SUPPORT WILL  
SPAWN LEAD CYCLOGENESIS FROM THE SOUTH-CENTRAL TO EASTERN U.S.  
OVER MLK JR. WEEKEND. DEEPENING GULF OF MEXICO THEN ATLANTIC  
MOISTURE WILL ADVECT INLAND IN ADVANCE AND AROUND THE DEVELOPING  
STORM AND OVERRUN A SHARP ARCTIC FRONT. HEAVY SNOW WILL SPREAD  
FROM PORTIONS OF THE CENTRAL PLAINS THROUGH THE MIDWEST/OHIO  
VALLEY, APPALACHIANS AND MID-ATLANTIC/NORTHEAST ALONG WITH SOME  
THREAT OF BLIZZARD CONDITIONS IN THE TIGHT PRESSURE GRADIENT  
BETWEEN A MAIN SURFACE LOW AND A STRONG ARCTIC HIGH. MEANWHILE,  
HEAVY WARM-SECTOR RAINS/STRONG CONVECTION MOVE THROUGH THE  
SOUTH/SOUTHEAST/MID-ATLANTIC AND A TRANSITION ZONE BETWEEN SNOW  
AND RAIN IS LIKELY TO INCLUDE SIGNIFICANT SLEET AND FREEZING RAIN.  
PLEASE CONSULT WPC DAY 4-7 QPF AND WINTER WEATHER OUTLOOK FOR A  
PROBABILISTIC ASSESSMENT OF THE SIGNIFICANT WINTER WEATHER THREAT.  
 
UPSTREAM, PACIFIC STORM SYSTEMS WILL RELOAD WITH NEW FOCUS AS A  
HEAVY PRECIPITATION THREAT INTO THE PACIFIC NORTHWEST. WINTERY  
WEATHER SPREADS/MODERATES INLAND ACROSS THE NORTH-CENTRAL GREAT  
BASIN/ROCKIES LATER IN THE HOLIDAY WEEKEND THEN ACROSS THE CENTRAL  
U.S. EARLY-MID NEXT WEEK. THERE IS A SIGNAL FOR INCREASED  
MID-UPPER LEVEL TROUGH AMPLITUDE/SEPARATION OVER THE S-CENTRAL  
U.S., BUT THERE IS MORE UNCERTAINTY WITH THE SPECIFICS OF THIS  
FLOW AND ASSOCIATED SURFACE SYSTEM RESPONSE. HOWEVER, MOST  
GUIDANCE SUPPORTS AN INCREASING LEAD GULF MOISTURE INFLOW AND  
PRECIPITATION PATTERN WITH ADDITIONAL POTENTIAL FOR WINTERY  
WEATHER ON THE COOLED NORTHERN PERIPHERY HEADING INTO TUE/WED.  
 
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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