885  
FXUS02 KWBC 041856  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
155 PM EST TUE JAN 04 2022  
 
VALID 12Z FRI JAN 07 2022 - 12Z TUE JAN 11 2022  
   
..GENERAL PATTERN OVERVIEW
 
 
THE UPPER LEVEL PATTERN OVER THE CONTINENTAL U.S. THROUGH THE  
BEGINNING OF NEXT WEEK SHOULD REMAIN FAIRLY AMPLIFIED BUT ALSO  
PROGRESSIVE. A STRONG SHORTWAVE TROUGH AND ASSOCIATED NOR'EASTER  
WILL EXIT THE EAST COAST FRIDAY, AND THIS SHOULD GIVE WAY TO A  
CANADIAN SURFACE HIGH AND COLD WEATHER SETTLING ACROSS THE  
EAST-CENTRAL U.S. IN THE WAKE OF THE STRONG COLD FRONT. INLAND  
PROGRESSION OF AN EARLY FRIDAY PACIFIC NORTHWEST SYSTEM WILL BRING  
A DRIER TREND TO THAT REGION AS UPPER RIDGING BUILDS OVER THE WEST  
BY SUNDAY-MONDAY. MEANWHILE BY THE WEEKEND THE FLOW AHEAD OF  
PLAINS LOW PRESSURE AND A TRAILING COLD FRONT WILL SUPPORT AN  
EXPANDING AREA OF RAIN FROM THE GULF COAST INTO AT LEAST THE  
TENNESSEE VALLEY. ALSO ANOTHER SURGE OF ARCTIC AIR WILL REACH THE  
NORTH-CENTRAL U.S. BEHIND THE SYSTEM.  
   
..GUIDANCE/PREDICTABILITY ASSESSMENT
 
 
THERE WAS REASONABLY GOOD AGREEMENT FOR SIGNIFICANT FEATURES IN  
THE 00Z-06Z MODELS/ENSEMBLES. THE LARGE SCALE OF THE EASTERN  
TROUGH BY EARLY NEXT WEEK SUGGESTS BETTER THAN AVERAGE  
PREDICTABILITY WHILE THERE IS SOME UNCERTAINTY WITH SHORTWAVES  
THAT MAY TRY TO MOVE INTO/AROUND THE UPPER RIDGE BUILDING INTO THE  
WEST. DETAILS BECOME SOMEWHAT AMBIGUOUS OVER AND NEAR THE  
SOUTHWESTERN U.S. BY THE FIRST HALF OF NEXT WEEK AS SOLUTIONS  
DIVERGE FOR WHAT BECOMES OF SMALLER-SCALE ENERGY IN THE  
SOUTHERNMOST PART OF THE UPPER TROUGH CROSSING THE WEST DURING THE  
WEEKEND AS WELL AS ANOTHER FEATURE THAT APPROACHES FROM THE  
PACIFIC. A BLEND OF THE LATEST OPERATIONAL MODELS REPRESENTED  
CONSENSUS IDEAS FROM FRIDAY INTO SUNDAY AND INCORPORATING SOME  
WEIGHT OF THE 06Z GEFS/00Z ECMWF MEANS ALONG WITH THE 06Z GFS AND  
00Z ECMWF/CMC REFLECTED THE CONTINUED LARGE SCALE AGREEMENT WHILE  
ACCOUNTING FOR THE UNCERTAINTY NEAR THE SOUTHWEST NEXT WEEK. THE  
RESULTING FORECAST YIELDED GOOD CONTINUITY.  
 
GUIDANCE IS FINALLY BETTER CLUSTERED FOR THE DEEPENING STORM THAT  
TRACKS FROM OFF THE NEW ENGLAND COAST INTO THE CANADIAN MARITIMES  
LATE THIS WEEK. TODAY'S GFS RUNS ARE STRONGER VERSUS A NUMBER OF  
PRIOR RUNS WHILE THE CONSISTENTLY STRONG ECMWF HAS NUDGED ITS  
TRACK A BIT TO THE EAST OVER THE PAST COUPLE DAYS. NEW GUIDANCE  
STILL SHOWS VARIOUS IDEAS FOR THE WEAK SHORTWAVE ENERGY THAT MAY  
LINGER OVER THE SOUTHWEST BY LATE WEEKEND/EARLY NEXT WEEK WITH THE  
GFS STILL WEAKEST/MOST PROGRESSIVE AND 00Z ECMWF THE MOST  
CONCENTRATED. THE 00Z ECMWF'S HANDLING OF THAT FEATURE LIKELY  
PLAYS A ROLE IN ITS GREATER DEFLECTION OF APPROACHING PACIFIC  
ENERGY VERSUS WHAT MOST OTHER MODELS AND MEANS SHOW. 12Z ECMWF  
TRENDS ARE FAVORABLE COMPARED TO OTHER GUIDANCE.  
   
..HAZARDS/SENSIBLE WEATHER HIGHLIGHTS
 
 
AFTER AN ACTIVE PERIOD OF WEATHER DURING THE SHORT RANGE PERIOD  
ACROSS THE PACIFIC NORTHWEST, SOME LINGERING RAIN AND MOUNTAIN  
SNOW IS STILL LIKELY FROM NORTHERN CALIFORNIA TO WESTERN  
WASHINGTON, AND SNOW FOR THE NORTHERN ROCKIES, ON FRIDAY. A  
DRYING TREND SHOULD COMMENCE IN TIME FOR THE WEEKEND ACROSS MUCH  
OF THE WEST AS HIGH PRESSURE BUILDS BACK INTO THE REGION.  
MEANWHILE, AN INTENSIFYING NOR'EASTER OFF THE NEW ENGLAND COAST ON  
FRIDAY MAY PRODUCE SOME SNOW OVER EASTERN/NORTHERN NEW ENGLAND IN  
PARTICULAR (AMOUNTS VERY SENSITIVE TO EXACT TRACK) ALONG WITH  
LINGERING SNOW SHOWERS OVER THE REST OF THE NORTHEAST. NEW  
ENGLAND MAY SEE A BRIEF PERIOD OF BRISK TO STRONG WINDS BEHIND  
THIS SYSTEM. GULF MOISTURE AHEAD OF A PLAINS COLD FRONT SHOULD  
SPREAD RAIN AND THUNDERSTORMS FROM THE LOWER MISSISSIPPI VALLEY  
INTO THE TENNESSEE VALLEY/SOUTHERN APPALACHIANS THIS WEEKEND WITH  
LESSER AMOUNTS OF RAIN EXTENDING FARTHER NORTH. SOME LOCALLY  
MODERATE TO HEAVY ACTIVITY IS POSSIBLE BUT CONFIDENCE IN SPECIFICS  
IS FAIRLY LOW AT THIS TIME. AREAS FROM THE UPPER GREAT LAKES INTO  
THE NORTHEAST COULD SEE WINTRY WEATHER, EITHER EXCLUSIVELY OR  
BEFORE A CHANGEOVER TO RAIN. PARTS OF THE GREAT LAKES MAY SEE  
LAKE EFFECT SNOW BEHIND THE PASSING FRONT.  
 
TEMPERATURES WILL BE QUITE COLD ACROSS THE CENTRAL/NORTHERN PLAINS  
TO THE UPPER MIDWEST ON FRIDAY WITH A LARGE SURFACE HIGH OF ARCTIC  
ORIGIN GOVERNING THE WEATHER PATTERN FOR THIS REGION. LOWS MAY BE  
20-30F BELOW NORMAL WHILE HIGHS 15-20F OR SO BELOW NORMAL MAY  
EXTEND AS FAR SOUTHEAST AS THE TENNESSEE VALLEY AND SOUTHERN  
APPALACHIANS. EXPECT SOME MODERATION OF THE SEVERE COLD OVER THE  
PLAINS/MIDWEST ON SATURDAY AHEAD OF THE NEXT ARCTIC SURGE THAT  
REACHES INTO THE NORTHERN TIER STATES BY SUNDAY-MONDAY. THE  
SECOND SURGE MAY NOT BE QUITE AS INTENSE AS ITS PREDECESSOR BUT  
TEMPERATURES COULD STILL BE 15-25F BELOW NORMAL OVER SOME AREAS.  
FROM FRIDAY INTO SUNDAY ABOVE NORMAL TEMPERATURES WILL PROGRESS  
FROM THE SOUTHERN PLAINS INTO THE DEEP SOUTH WITH GREATEST  
ANOMALIES OF PLUS 20-25F POSSIBLE AT SOME LOCATIONS FOR HIGHS ON  
SATURDAY AND MORNING LOWS ON SUNDAY. SEASONABLY COLD CONDITIONS  
ARE LIKELY WEST OF THE CONTINENTAL DIVIDE WITH READINGS GENERALLY  
WITHIN 10 DEGREES OF CLIMATOLOGICAL AVERAGES, THOUGH LOCALLY A  
LITTLE MORE THAN THAT ON THE WARM SIDE OF NORMAL FOR LOWS ON  
FRIDAY-SATURDAY.  
 
RAUSCH/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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