521  
FXUS02 KWBC 270701  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
200 AM EST THU JAN 27 2022  
 
VALID 12Z SUN JAN 30 2022 - 12Z THU FEB 03 2022  
   
..COASTAL WINTER STORM TO TRACK AWAY FROM NEW ENGLAND ON SUNDAY
 
 
   
..OVERVIEW
 
 
BY THE START OF THE MEDIUM RANGE PERIOD EARLY SUNDAY, THE DEEP  
SYSTEM TRACKING JUST OFF THE EAST COAST LATE THIS WEEK INTO THE  
WEEKEND SHOULD REACH A POSITION EAST OR NORTHEAST OF MAINE, STILL  
SUPPORTING SOME STRONG WINDS EVEN IF PRECIPITATION TAPERS OFF.  
THIS STORM WILL CONTINUE MOVING RAPIDLY AWAY FROM NEW ENGLAND  
DURING THE DAY SUNDAY. FOR INFORMATION ON THE STORM'S EFFECTS  
BEFORE EARLY SUNDAY CONSULT THE WPC WEBSITE FOR UPDATED KEY  
MESSAGES AND CHECK YOUR LOCAL FORECAST AT WEATHER.GOV. THROUGH THE  
REST OF THE PERIOD THE DOMINANT THEME WILL BE A SIGNIFICANT  
PATTERN CHANGE AS AN UPPER TROUGH STRONGLY AMPLIFIES FROM THE  
NORTHEASTERN PACIFIC INTO THE WESTERN/CENTRAL U.S. WHILE A STRONG  
RIDGE BUILDS AND THEN PERSISTS OVER THE EASTERN PACIFIC WHILE  
ANOTHER RIDGE CROSSING THE EAST COAST TUESDAY SETTLES OVER THE  
WESTERN ATLANTIC THEREAFTER. THIS EVOLUTION WILL INITIALLY SPREAD  
PRECIPITATION ACROSS THE WEST AND THEN LIKELY PRODUCE SIGNIFICANT  
PRECIPITATION FARTHER EASTWARD AS A LEADING WAVY FRONT INTERACTS  
WITH A STRONG FLOW OF GULF MOISTURE. AHEAD OF THE TROUGH, A  
SOUTHERN STREAM SHORTWAVE/UPPER LOW MAY GENERATE SOME ENHANCED  
RAINFALL ALONG/NORTH OF THE GULF COAST.  
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
AN OPERATIONAL MODEL BLEND EARLY IN THE PERIOD FOLLOWED BY A  
TRANSITION TOWARD SLIGHTLY LESS THAN HALF TOTAL WEIGHT OF 18Z  
GEFS/12Z ECMWF MEANS CONTINUED TO PROVIDE A GOOD REPRESENTATION OF  
CONSENSUS IDEAS WITH MAINLY JUST TYPICAL RUN-TO-RUN DETAIL CHANGES  
VERSUS PREVIOUS CYCLE. FOR THE STORM PRODUCING LINGERING EFFECTS  
OVER NEW ENGLAND, THERE ARE STILL MEANINGFUL DIFFERENCES IN THE  
SHORT RANGE DUE IN PART TO FINE-SCALE ISSUES WITH THE SUPPORTING  
UPPER LOW SO THERE IS STILL A FAIR AMOUNT OF UNCERTAINTY OVER THE  
EXACT LOCATION/STRUCTURE OF THE STORM AS OF EARLY SUNDAY. OVERALL  
THE LATEST GFS/GEFS MEAN ARE ON THE FASTER SIDE AND THE 12Z  
ECMWF/ECMWF MEAN ARE SLOWEST, CONFORMING TO LONG-HISTORICAL  
TENDENCIES. MEANWHILE GUIDANCE CONTINUES TO CONSOLIDATE FOR THE  
HANDLING OF THE SOUTHERN STREAM SHORTWAVE/UPPER LOW EMERGING FROM  
THE SOUTHWEST, WITH THE 00Z UKMET STRAYING FASTER THAN MOST OTHER  
SOLUTIONS. THIS FEATURE SHOULD RAPIDLY SHEAR OUT BEYOND THE  
PLAINS. FARTHER WEST, THERE ARE STILL DIFFERENCES IN HOW SOME  
ENERGY PULLS OFF FROM THE SOUTHWESTERN PART OF THE SHORTWAVE  
APPROACHING THE WEST COAST SUNDAY BUT NOW WITH LESS PRONOUNCED  
SPREAD THAN IN THE PAST COUPLE CYCLES. AS THE LARGER SCALE UPPER  
TROUGH DIGS INTO THE WESTERN/CENTRAL U.S. TUESDAY-THURSDAY, THE  
ENSEMBLE MEANS AND A MULTI-RUN AVERAGE OF OPERATIONAL RUNS SUGGEST  
ABOVE AVERAGE PREDICTABILITY FOR THE LARGE-SCALE FEATURE WHILE  
INDIVIDUAL MEMBERS/MODEL RUNS SHOW EMBEDDED DETAIL UNCERTAINTIES.  
EXAMPLES OF THE LATTER INCLUDE TO WHAT DEGREE FLOW MAY SEPARATE  
NEAR THE FOUR CORNERS REGION AROUND WEDNESDAY AND THE CHARACTER OF  
UPSTREAM ENERGY DROPPING INTO THE MEAN TROUGH BY THURSDAY. THE 18Z  
GFS/12Z ECMWF/12Z CMC PROVIDED THE MOST APPEALING OPERATIONAL  
COMPONENTS FOR THIS TROUGH TO GO ALONG WITH THE ENSEMBLE MEAN  
INPUT. THE NEW 00Z CMC HAS COME IN LAGGING CONSENSUS A BIT  
RELATIVE TO THE BETTER FITTING 12Z RUNS FROM THE PAST COUPLE DAYS,  
THOUGH THE NEW 00Z ECMWF HAS SLOWED A BIT AS WELL.  
   
..WEATHER HIGHLIGHTS/THREATS
 
 
EXPECT STRONG WINDS OVER NEW ENGLAND AT THE START OF SUNDAY TO  
MODERATE OVER THE COURSE OF THE DAY AS STRONG LOW PRESSURE TRACKS  
RAPIDLY AWAY FROM THE REGION. OTHERWISE THE EFFECTS OF THIS STORM  
WILL BE IN THE SHORT RANGE. SEE THE WPC WEBSITE FOR LATEST KEY  
MESSAGES ON THE SYSTEM AND ADDITIONAL INFORMATION IN THE  
PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION, PLUS CHECK YOUR  
LOCAL FORECAST AT WEATHER.GOV.  
 
THE UPPER TROUGH/LOW REACHING THE SOUTHWEST BY EARLY SUNDAY SHOULD  
PRODUCE LITTLE IF ANY PRECIPITATION OVER THAT REGION. HOWEVER AS  
THE FEATURE CONTINUES EASTWARD, THERE WILL BE SOME POTENTIAL FOR  
LOCALLY MODERATE TO HEAVY RAINFALL FROM EASTERN TEXAS ACROSS PARTS  
OF THE GULF COAST REGION DURING THE FIRST HALF OF THE WEEK. BEST  
POTENTIAL AT THIS TIME APPEARS TO BE OVER EASTERN TEXAS WITH LOWER  
CONFIDENCE IN DETAILS FARTHER EAST. SOME ASPECTS OF THIS EVENT MAY  
HINGE ON SMALL-SCALE DETAILS NOT EASILY RESOLVED VERY FAR IN  
ADVANCE. THE NORTHEASTERN PACIFIC UPPER TROUGH DIGGING INTO THE  
WEST SUNDAY-TUESDAY WILL SPREAD MODERATE AMOUNTS OF RAIN AND  
MOUNTAIN SNOW FROM THE PACIFIC NORTHWEST EASTWARD AND  
SOUTHEASTWARD INTO MUCH OF THE ROCKIES. HIGHEST TOTALS ARE LIKELY  
TO BE IN THE PACIFIC NORTHWEST BUT SHOULD NOT BE TOO EXTREME. IN  
GENERAL THE FORECAST REMAINS ON TRACK FOR A SIGNIFICANT INCREASE  
OF COVERAGE AND INTENSITY OF PRECIPITATION OVER THE EAST-CENTRAL  
U.S. BY WEDNESDAY-THURSDAY AS THE UPPER TROUGH EMERGES FROM THE  
ROCKIES AND THE LEADING WAVY FRONT INTERACTS WITH A STRONG LOW  
LEVEL FEED OF GULF MOISTURE. AT THIS TIME THE BEST POTENTIAL FOR  
HEAVIEST RAINFALL EXTENDS ACROSS THE LOWER HALF OF THE MISSISSIPPI  
VALLEY INTO PARTS OF THE OHIO/TENNESSEE VALLEYS. WINTRY WEATHER  
WILL BE POSSIBLE ON THE NORTHWEST SIDE OF THE MOISTURE SHIELD,  
WITH AT LEAST SOME POTENTIAL FOR MEANINGFUL SNOW FROM THE  
CENTRAL/SOUTH-CENTRAL PLAINS NORTHEASTWARD THROUGH THE GREAT  
LAKES. WHILE CONFIDENCE IN A HEAVY RAIN AREA APPEARS BETTER THAN  
AVERAGE, DETAILS IN THE COLDER AIR MAY BE MORE DEPENDENT ON  
LOWER-CONFIDENCE DETAILS OF EJECTING SHORTWAVE ENERGY AND FRONTAL  
WAVES.  
 
COLD CONDITIONS NEAR THE EAST COAST WILL EXTEND THROUGH SUNDAY  
WITH MANY AREAS 10-20F BELOW NORMAL. SUBFREEZING LOWS SHOULD  
EXTEND INTO PORTIONS OF FLORIDA AND PARTS OF THE FLORIDA PENINSULA  
MAY CHALLENGE DAILY RECORDS FOR BOTH MORNING LOWS AND DAYTIME  
HIGHS. MUCH OF THE PLAINS WILL SEE ABOVE NORMAL TEMPERATURES  
SUNDAY INTO THE FIRST PART OF NEXT WORK WEEK, WITH SOME  
NORTHERN/CENTRAL AREAS POSSIBLY SEEING PLUS 20F OR GREATER  
ANOMALIES ON ONE OR TWO DAYS. THIS WARM AIR WILL PROGRESS INTO THE  
EASTERN HALF OF THE COUNTRY TUESDAY-THURSDAY, BRINGING A BROAD  
AREA OF TEMPERATURES 10-20F ABOVE NORMAL AND PERHAPS GREATER  
ANOMALIES FOR LOWS OVER THE NORTHEAST BY THURSDAY. ALSO DURING  
TUESDAY-THURSDAY MUCH OF THE WEST AND THEN INTO THE PLAINS WILL  
SEE AN EPISODE OF CHILLY TEMPERATURES WITH THE ROCKIES AND PLAINS  
SEEING THE BEST POTENTIAL FOR READINGS 10-20F BELOW NORMAL.  
 
RAUSCH/TATE  
 
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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