818  
FXUS02 KWBC 150700  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
200 AM EST SAT JAN 15 2022  
 
VALID 12Z TUE JAN 18 2022 - 12Z SAT JAN 22 2022  
   
..PATTERN OVERVIEW
 
 
GUIDANCE OVERALL AGREES THAT A MEAN UPPER RIDGE WILL AMPLIFY OFF  
THE WEST COAST MID-LATER NEXT WEEK. DOWNSTREAM, THIS SHOULD FORCE  
AN INCREASINGLY DOMINANT SERIES OF NORTHERN STREAM IMPULSES DIG  
DOWN FROM CANADA TO CARVE OUT A LARGE AND CENTRAL U.S. CENTERED  
MEAN UPPER TROUGH.  
   
..GUIDANCE/PREDICTABILITY ASSESSMENT
 
 
THE WPC FORECAST SUITE WAS MAINLY DERIVED FROM A COMPOSITE BLEND  
OF REASONABLY WELL CLUSTERED SOLUTIONS FROM THE 18 UTC GFS AND 12  
UTC ECMWF/UKMET/CANADIAN DAYS 3-5 (TUE-THU) ALONG WITH THE 01 UTC  
NBM IN A PATTERN WITH SEEMINGLY ABOVE NORMAL PREDICTABILITY. WPC  
PRODUCT CONTINUITY IS WELL MAINTAINED. FORECAST SPREAD AND MODEL  
RUN TO RUN CONSISTENCY BECOME A BIT LESS MANAGEABLE INTO DAYS 6/7  
(FRI-NEXT SATURDAY). PREFER A COMPOSITE OF THE LARGER SCALE  
COMPATIBLE 18 UTC GEFS MEAN AND 12 UTC NAEFS/ECMWF ENSEMBLE MEANS  
TO MAINTAIN MAX WPC PRODUCT CONTINUITY BEYOND LESS PREDICTABLE  
SMALLER SCALE EMBEDDED SYSTEM DETAIL. OVERALL, THE RESULTANT  
SOLUTION SEEMS REASONABLE AND A SIMILAR PATTERN  
AMPLIFICATION/EVOLUTION IS DEPICTED WITH COMPOSITE OF NEWER 12 UTC  
MODEL AND ENSEMBLE RUNS.  
 
   
..WEATHER HIGHLIGHTS/HAZARDS
 
 
A SIGNIFICANT WINTER STORM IS SLATED TO EXIT STILL WINDY NEW  
ENGLAND TO THE CANADIAN MARITIMES BY TUESDAY AS ANOTHER ORGANIZED  
LOW PRESSURE SYSTEM DIGS INTO THE NORTH-CENTRAL U.S. LOW  
DEVELOPMENT AND SUBSEQUENT TRACK ROUGHLY EASTWARD ALONG THE  
U.S./CANADIAN BORDER INTO WED/THU WILL BRING SOME SNOW TO THE  
UPPER MIDWEST, GREAT LAKES THEN NORTHERN NEW ENGLAND, WITH LOCALLY  
HIGHER TOTALS EXPECTED NEAR TYPICAL LAKE ENHANCEMENT AREAS AS COLD  
HIGH PRESSURE SWEEPS DOWN ACROSS THE CENTRAL AND EASTERN U.S. IN  
THE WAKE OF THE LOW. GUIDANCE VARIES WITH POTENTIAL FOCUS, BUT  
SUSPECT THE WAVY TRAILING COLD FRONT ON THE LEADING EDGE OF THIS  
ARCTIC BLAST WILL GAIN AT LEAST MODEST MOISTURE FROM THE GULF OF  
MEXICO TO FUEL AN EMERGING AREA OF PRECIPITATION OVER THE  
SOUTHEAST THAT OFFERS SOME LATER NEXT WEEK POTENTIAL FOR  
OVERRUNNING SNOW/ICE ON THE NORTHERN PERIPHERY OF ACTIVITY. THE  
CANADIAN AND SOME ENSEMBLE MEMBERS ARE MORE ROBUST WITH  
FRONTAL/COASTAL WAVE AMPLITUDE AND PRECIPITATION EXTENT ACROSS THE  
REGION AND OVER THE EAST COAST AT THESE LONGER TIME PERIODS. THE  
MAIN UPPER TROUGH POSITION IS FAR ENOUGH WEST TO NOT DISCOUNT THIS  
POSSIBILITY.  
 
MEANWHILE, THE WEST COULD SEE SOME LIGHT PRECIPITATION THROUGH THE  
PERIOD, PARTICULARLY OVER THE PACIFIC NORTHWEST AND INTO THE  
NORTHERN ROCKIES AS WEAKENING SYSTEMS CROSS THE REGION, WITH  
MAINLY DRY CONDITIONS ELSEWHERE.  
 
SCHICHTEL  
 
ADDITIONAL 3-7 DAY HAZARD INFORMATION CAN BE FOUND ON THE WPC  
MEDIUM RANGE HAZARDS OUTLOOK CHART AT:  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP  
 
WPC MEDIUM RANGE 500MB HEIGHTS, SURFACE SYSTEMS, WEATHER GRIDS,  
QUANTITATIVE PRECIPITATION, WINTER WEATHER OUTLOOK PROBABILITIES  
AND HEAT INDICES ARE 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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