114  
FXUS02 KWBC 142044  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
344 PM EST FRI JAN 14 2022  
 
VALID 12Z MON JAN 17 2022 - 12Z FRI JAN 21 2022  
   
..MAJOR WINTER STORM TO IMPACT THE NORTHEAST THROUGH MONDAY
 
 
   
..OVERVIEW
 
 
A POTENT CLOSED LOW MOVING THROUGH THE MID-ATLANTIC AS THE PERIOD  
STARTS MONDAY WILL CONTINUE TO SPREAD HEAVY SNOW INTO PARTS OF THE  
NORTHEAST. BEHIND THIS, GENERAL TROUGHINESS WILL CONTINUE ACROSS  
THE GREAT LAKES NEXT WEEK AS THE NEXT AMPLIFIED SHORTWAVE DROPS  
THROUGH THE PLAINS AND INTO THE EAST NEXT THURSDAY AND FRIDAY. OUT  
WEST, A CLOSED LOW OFF THE SOUTHERN CALIFORNIA COAST WILL WEAKEN  
AS IT SLIDES EAST, WITH WEAK SHORTWAVES PERIODICALLY ACTING TO  
BREAK DOWN RIDGING SITUATED OVER THE NORTHWEST BEFORE A STRONGER  
SHORTWAVE TRIES TO MOVE IN LATE IN THE WEEK.  
   
..GUIDANCE/PREDICTABILITY ASSESSMENT
 
 
MODELS AND ENSEMBLES HAVE COME INTO CLOSER AGREEMENT REGARDING THE  
ONGOING MAJOR WINTER STORM AS THE PERIOD STARTS MOVING INTO THE  
NORTHEAST. THIS LENDS TO INCREASED CONFIDENCE IN THE SPECIFICS,  
THOUGH SOME UNCERTAINTY STILL LINGERS. MOST IF NOT ALL OF THE  
GUIDANCE NOW SHOWS THE LOW INLAND OVER THE MID-ATLANTIC MONDAY  
MORNING (NEAR PHILADELPHIA), ALTHOUGH THE UKMET IS STILL DISPLACED  
A LITTLE SOUTH AND THE GEFS MEAN REMAINS A BIT FARTHER EAST  
SHOWING THE LOW RIGHT ALONG THE COAST. OF COURSE, EVEN MINOR  
CHANGES IN THE LOW TRACK CAN HAVE BIGGER EFFECTS ON WINTER PRECIP  
AND TYPE ACROSS ESPECIALLY EASTERN PORTIONS OF THE MID-ATLANTIC  
AND THE NORTHEAST.  
 
ELSEWHERE, THERE'S FAIRLY GOOD AGREEMENT ON GENERAL AND REINFORCED  
TROUGHING ACROSS THE GREAT LAKES NEXT WEEK, WITH SOME MINOR  
DIFFERENCES IN THE DETAILS. A STRONGER SHORTWAVE LOOKS TO DROP  
THROUGH THE PLAINS MID TO LATE NEXT WEEK AND EVENTUALLY INTO THE  
EAST. SOME RECENT MODEL RUNS (MOSTLY THE CMC) INDICATE ANOTHER  
POTENTIAL LOW PRESSURE AREA NEAR THE EAST COAST, BUT UNCERTAINTY  
IN THE STRENGTH OF THIS SYSTEM IS HIGHLY UNCERTAIN AT THIS TIME.  
OUT WEST, THE GREATEST DIFFERENCES BEGIN TO POP UP NEXT  
THURSDAY-FRIDAY WITH THE HANDLING OF PACIFIC SYSTEM ENERGY INTO AN  
UPPER RIDGE OFF/OVER THE WEST COAST. THE 06Z GFS IS MORE ERNEST  
WITH A SHORTWAVE THROUGH THE EAST PACIFIC AND EVEN SHOWS A CLOSED  
LOW OFF THE PACIFIC NORTHWEST COAST NEXT FRIDAY. MEANWHILE, THE  
CMC AND ECMWF ARE BOTH WEAKER AND MORE DEFLECTS THE ENERGY OVER  
THE RIDGE. THE ENSEMBLE MEANS TEND TO FAVOR A SOLUTION CLOSER TO  
THE ECMWF AND CMC.  
 
THE WPC FORECAST FOR TODAY USED A COMPOSITE BLEND OF THE  
DETERMINISTIC MODELS DAYS 3-5, WITH INCREASING ENSEMBLE MEANS  
THEREAFTER TO ACCOUNT FOR DETAIL DIFFERENCES ACROSS THE EAST LATE  
PERIOD AND THE ENERGY OFF/OVER THE NORTHWEST. THIS PROVIDED A  
CONSISTENT FORECAST WITH OVERNIGHT WPC CONTINUITY.  
 
   
..WEATHER HIGHLIGHTS/HAZARDS
 
 
A MAJOR WINTER LOW DEVELOPING OVER THE WEEKEND SEEMS SET TO LIFT  
FROM THE NORTHERN MID-ATLANTIC/LOWER GREAT LAKES THROUGH THE  
NORTHEAST ON MONDAY. THIS WILL PRESENT A CONTINUING FULL ARRAY OF  
WEATHER HAZARDS AND THREATS. HEAVY WRAPPING SNOWS WILL SPREAD IN  
EARNEST ALONG/ON THE BACKSIDE OF THE DEEPENING LOW AND WEST OF THE  
I-95 CORRIDOR INTO INTERIOR AREAS. FOR LOCATIONS CLOSER TO THE  
COAST, PRECIPITATION MAY START OUT AS SOME BRIEF SNOW, WITH A  
CHANGEOVER TO SLEET AND RAIN AS WARMER AIR FILTERS IN FROM THE  
EAST. GUSTY WINDS SURROUNDING THE SURFACE LOW MAY CREATE HIGH  
WAVES OFF THE COAST LEADING TO POSSIBLE COASTAL FLOOD CONCERNS  
ALONG THE NORTHEAST COASTLINE.  
 
AFTER THE MAIN LOW EXITS THE NORTHEAST BY TUESDAY, ANOTHER LOW  
PRESSURE SYSTEM IS FORECAST TO TRACK OVER THE NORTH-CENTRAL U.S.  
IN RESPONSE TO A MID-UPPER SHORTWAVE AND BRING SOME SNOW TO THE  
UPPER MIDWEST AND GREAT LAKES THEN NORTHERN NEW ENGLAND, WITH  
POSSIBLY HIGHER TOTALS NEAR TYPICAL LAKE ENHANCEMENT AREAS. THE  
WEST COULD SEE SOME LIGHT PRECIPITATION DURING THE PERIOD,  
PARTICULARLY OVER THE PACIFIC NORTHWEST AND INTO THE NORTHERN  
ROCKIES, WITH MAINLY DRY CONDITIONS ELSEWHERE. RAIN MAY DEVELOP  
ACROSS THE LOWER MISSISSIPPI VALLEY AND SOUTHEAST FOR MID-LATER  
NEXT WEEK WITH MODEST RETURN GULF FLOW WITH INDUCED WAVE PASSAGES.  
 
FOR TEMPERATURES, THE EAST SHOULD MODERATE BACK TOWARDS NORMAL  
AFTER MONDAY'S STORM WITH COLDER TEMPERATURES MOVING BACK IN BY  
THE END OF THE WEEK. THE CENTRAL U.S. WILL START MILD AND ABOVE  
NORMAL EARLY IN THE WEEK, THOUGH AS STRONG CANADIAN HIGH PRESSURE  
SINKS SOUTHWARD, WILL QUICKLY TREND BELOW TO WELL BELOW NORMAL  
WEDNESDAY AND THURSDAY. DAYTIME HIGHS COULD BE NEAR OR BELOW ZERO  
ACROSS PARTS OF THE NORTHERN PLAINS AND NORTHERN MISSISSIPPI  
VALLEY. WEST OF THE ROCKIES SHOULD BE MOSTLY NEAR OR SLIGHTLY  
ABOVE NORMAL INFLUENCED BY THE UPPER LEVEL RIDGE.  
 
SANTORELLI/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  
 
HAZARDS:  
- HEAVY PRECIPITATION ACROSS PORTIONS OF THE NORTHEAST, MON, JAN  
17.  
- HEAVY SNOW ACROSS PORTIONS OF THE NORTHEAST AND THE GREAT LAKES,  
MON, JAN 17.  
- HEAVY SNOW ACROSS PORTIONS OF THE NORTHEAST AND THE GREAT LAKES,  
WED-THU, JAN 19-JAN 20.  
- FLOODING OCCURRING OR IMMINENT ACROSS PORTIONS OF THE LOWER  
MISSISSIPPI VALLEY, THE PACIFIC NORTHWEST, AND THE OHIO VALLEY.  
- HIGH WINDS ACROSS PORTIONS OF THE NORTHEAST, MON, JAN 17.  
- MUCH BELOW NORMAL TEMPERATURES ACROSS PORTIONS OF THE CENTRAL  
PLAINS, THE NORTHERN PLAINS, THE MIDDLE MISSISSIPPI VALLEY, THE  
UPPER MISSISSIPPI VALLEY, THE GREAT LAKES, AND THE OHIO VALLEY,  
WED-SAT, JAN 19-JAN 20.  
- HIGH SIGNIFICANT WAVE HEIGHTS FOR COASTAL PORTIONS OF THE  
MID-ATLANTIC AND THE NORTHEAST, MON, JAN 17.  
- HEAVY PRECIPITATION ACROSS PORTIONS OF THE ALASKA PANHANDLE AND  
MAINLAND ALASKA, FRI, JAN 21.  
- HIGH WINDS ACROSS PORTIONS OF THE ALASKA PANHANDLE AND MAINLAND  
ALASKA, FRI, JAN 21.  
 
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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