126  
FXUS02 KWBC 020654  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
153 AM EST SUN JAN 2 2022  
 
VALID 12Z WED JAN 5 2022 - 12Z SUN JAN 9 2022  
 
...ADDITIONAL ROUNDS OF HEAVY COASTAL RAIN AND MOUNTAIN SNOW FOR  
THE NORTHWESTERN STATES...  
...FRIGID AIR MASS FOR THE NORTH-CENTRAL U.S. AND POTENTIAL SNOW  
FOR INLAND PORTIONS OF THE EAST COAST REGION LATE IN THE WEEK...  
 
   
..GENERAL PATTERN OVERVIEW
 
 
THE UPPER LEVEL FLOW PATTERN OVER THE NATION WILL BE RATHER  
AMPLIFIED THROUGH THE END OF THE WEEK WITH A LARGE SCALE TROUGH  
OVER THE EAST-CENTRAL U.S. AND A BROAD RIDGE OVER THE WEST COAST,  
BEFORE TRANSITIONING TO A MORE QUASI-ZONAL FLOW BY NEXT WEEKEND.  
TWO WELL DEFINED LOW PRESSURE SYSTEMS ARE EXPECTED TO AFFECT THE  
GREAT LAKES REGION AND ALSO THE EAST COAST, AND A THIRD SYSTEM IS  
POSSIBLE BY NEXT WEEKEND ACROSS THE PLAINS AND MIDWEST. AN ARCTIC  
AIR MASS WILL SETTLE SOUTHWARD ACROSS MUCH OF THE NORTH-CENTRAL  
U.S. IN THE WAKE OF THE STRONG COLD FRONT.  
   
..GUIDANCE ASSESSMENT AND UNCERTAINTY
 
 
THE 00Z MODEL GUIDANCE SUITE IS IN EXCELLENT SYNOPTIC SCALE  
AGREEMENT THROUGH THE MAJORITY OF THE FORECAST PERIOD WITH SOME  
MESOSCALE TIMING AND AMPLITUDE DIFFERENCES WITH THE INDIVIDUAL  
SHORTWAVE PASSAGES. THESE MINOR DIFFERENCES ARE ALL WITHIN THE  
ENSEMBLE SPREAD FOR THE MOST PART. BY FRIDAY WITH THE EAST COAST  
SYSTEM, THE 00Z GFS IS SLIGHTLY FARTHER OFFSHORE WITH THE TRACK OF  
THE LOW AND THUS WOULD BE LESS IMPACTFUL IN TERMS OF RAIN/SNOW  
ACROSS THE NORTHEAST. THE CMC BECOMES FASTER WITH THE SHORTWAVE  
CROSSING THE PLAINS BY SATURDAY AND ALSO MORE AMPLIFIED ACROSS THE  
SOUTHEAST, WHEREAS THE ECMWF/GFS SUGGEST A FLATTER MID-UPPER FLOW  
PATTERN HERE.  
 
THE WPC FORECAST WAS BASED PRIMARILY ON A MULTI-DETERMINISTIC  
MODEL BLEND THROUGH THURSDAY, AND THEN GFS/ECMWF/SOME CMC ALONG  
WITH GRADUALLY INCREASING USE OF THE ECENS AND GEFS MEANS THROUGH  
NEXT WEEKEND.  
   
..SENSIBLE WEATHER
 
 
THE GREAT LAKES STORM SYSTEM IS EXPECTED TO PRODUCE WIDESPREAD  
LIGHT TO MODERATE SNOW ACROSS MICHIGAN AND WISCONSIN THROUGH EARLY  
THURSDAY, WITH SOME LAKE ENHANCEMENT TO THE SNOW LIKELY AS THE LOW  
PULLS AWAY. WINDS MAY BE STRONG ENOUGH IN SOME PLACES TO PRODUCE  
BLIZZARD CONDITIONS. FOR THE SYSTEM NEAR THE EAST COAST, THERE  
HAS BEEN A SLIGHTLY SOUTHEASTWARD TREND IN THE AXIS OF QPF, AND  
SNOW IS LIKELY FOR INLAND PORTIONS OF THE MID-ATLANTIC AND  
NORTHEAST AND GUSTY WINDS NEAR THE COAST. HEAVY COASTAL RAIN AND  
HEAVY MOUNTAIN SNOW WILL CONTINUE TO MAKE WEATHER HEADLINES ACROSS  
PORTIONS OF THE PACIFIC NORTHWEST, AND ALSO ACROSS THE NORTHERN  
ROCKIES.  
 
TEMPERATURES ARE EXPECTED TO BE FRIGID ACROSS THE CENTRAL/NORTHERN  
PLAINS TO THE UPPER MIDWEST THROUGH THE END OF THE WEEK WITH A  
LARGE SURFACE HIGH OF ARCTIC ORIGIN GOVERNING THE WEATHER PATTERN  
FOR THIS REGION. HIGHS IN THE DOUBLE DIGITS BELOW ZERO ARE ONCE  
AGAIN LIKELY FOR PORTIONS OF EASTERN MONTANA AND INTO NORTH  
DAKOTA, AND HIGHS IN THE TEENS SETTLING AS FAR SOUTH AS SOUTHERN  
KANSAS ON THURSDAY. SOME ABATEMENT IN THE SEVERE COLD MAY COME TO  
PASS ACROSS THIS REGION AHEAD OF THE NEXT ARCTIC SURGE NEXT  
SUNDAY. ELSEWHERE, SEASONABLY COLD CONDITIONS ARE EXPECTED WEST  
OF THE CONTINENTAL DIVIDE WITH READINGS GENERALLY WITHIN 10  
DEGREES OF CLIMATOLOGICAL AVERAGES, AND COLD NEXT WEEKEND ALONG  
THE EAST COAST WITH HIGHS ABOUT 10 DEGREES BELOW NORMAL.  
 
HAMRICK  
 
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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