078  
FXUS02 KWBC 092115  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
414 PM EST WED FEB 09 2022  
 
VALID 12Z SAT FEB 12 2022 - 12Z WED FEB 16 2022  
   
..WEATHER PATTERN OVERVIEW
 
 
GUIDANCE CONTINUES TO SHOW A SIGNIFICANT UPPER-LEVEL PATTERN  
CHANGE OVER THE COURSE OF THE PERIOD. THE WEST COAST  
RIDGE/EASTERN TROUGH CONFIGURATION THIS WEEKEND SHOULD TRANSITION  
TOWARD AN AMPLIFIED WESTERN TROUGH AND SOUTHWESTERLY MEAN FLOW  
FARTHER EAST, AS A SHORTWAVE TRAVERSING THE NORTH PACIFIC  
ULTIMATELY DROPS SOUTHEASTWARD DOWNSTREAM FROM A BUILDING PACIFIC  
RIDGE LIKELY TO REACH NEAR 140W LONGITUDE BY THE MIDDLE OF NEXT  
WEEK. WITHIN THE UPPER TROUGH CROSSING THE EAST, SOME DETAILS  
SEEM TO BE MORE UNCERTAIN THAN 24 HOURS AGO--AFFECTING SPECIFICS  
OF LOW PRESSURE EXPECTED TO DEVELOP OFF THE EAST COAST AROUND  
SUNDAY-SUNDAY NIGHT, ALONG WITH THE CORRESPONDING MOISTURE SHIELD.  
THERE ARE ALSO DETAIL QUESTIONS FOR THE TROUGH DIGGING INTO THE  
WEST DURING THE FIRST HALF OF NEXT WEEK, AFFECTING SPECIFICS OF  
ASSOCIATED PRECIPITATION AND THE LEADING WAVY COLD FRONT.  
PRECIPITATION SHOULD INCREASE OVER THE CENTRAL U.S. AROUND MIDWEEK  
AS LOW LEVEL FLOW FROM THE GULF BEGINS TO INTERACT WITH THIS  
FRONT.  
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
COMPARED TO EARLIER RUNS, SOME GUIDANCE HAS NOTICEABLY DIVERGED  
FOR THE EASTERN U.S./WESTERN ATLANTIC EVOLUTION AROUND  
SUNDAY-MONDAY. THERE IS STILL A RELATIVE MAJORITY THAT SHOWS  
OFFSHORE DEVELOPMENT IN RESPONSE TO ENERGY WITHIN THE UPPER TROUGH  
REMAINING OPEN. HOWEVER THE 00Z UKMET/12Z CMC HAVE A CLOSED UPPER  
LOW CROSSING THE GREAT LAKES REGION, DRAWING THE SURFACE LOW  
CLOSER TO THE EAST COAST AND SPREADING MUCH MORE PRECIPITATION  
ACROSS THE NORTHEAST. MEANWHILE SOME GFS RUNS HAVE BEEN SHARP  
ENOUGH WITH ENERGY FARTHER SOUTH TO EMPHASIZE THE CENTRAL-SOUTHERN  
APPALACHIANS INTO MID-ATLANTIC FOR PRECIPITATION WHILE KEEPING THE  
DEVELOPING LOW FAR ENOUGH OFFSHORE JUST TO BRUSH SOUTHERN/EASTERN  
NEW ENGLAND. RECENT ECMWF RUNS HAVE TENDED TO BE LIGHTER/MORE  
SUPPRESSED WITH ITS SNOW. THE 00Z UKMET/12Z CMC SCENARIO IS A  
RELATIVE MINORITY AMONG ENSEMBLES (BUT WITHIN THE ENVELOPE) THUS  
REQUIRING MINIMAL WEIGHT FOR A SINGLE DETERMINISTIC FORECAST, BUT  
TAKEN AS A WHOLE THERE IS SOMEWHAT MORE OF A SIGNAL FOR AT LEAST  
SOME SNOW OVER PARTS OF THE MID-ATLANTIC/NORTHEAST AS ENSEMBLE  
MEANS HAD BEEN HINTING.  
 
MEANWHILE MOST MODELS AND MEANS HAVE COME INTO BETTER THAN AVERAGE  
AGREEMENT FOR THE UPPER TROUGH DIGGING INTO THE WEST, RELATIVE TO  
TYPICAL 5-7 DAY FORECASTS. THERE IS STILL SOME DEBATE OVER  
WHETHER AN EMBEDDED LOW MAY EXIST AS IT COMES ASHORE (NEW 12Z  
ECMWF ADDING TO THAT CLUSTER) AND THE 12Z UKMET IS A LITTLE  
SOUTHWEST OF MODELS THAT SHOW A LOW CENTER AT THAT TIME, BUT  
ULTIMATELY BY DAY 7 WEDNESDAY THE LATEST GFS/ECMWF/CMC RUNS ALL  
SHOW AN UPPER LOW REACHING THE SOUTHWEST/FOUR CORNERS REGION WHILE  
THE GEFS/ECENS/CMCENS MEANS ALL IMPLY SUCH A LOW WOULD EXIST AT A  
SIMILAR LOCATION.  
 
BETWEEN THESE TWO FEATURES, IN THE SATURDAY-MONDAY TIME FRAME  
MODELS HAVE BEEN DIVERSE AND INCONSISTENT WITH THE DETAILS OF A  
WEAK CLIPPER-TYPE WAVE THAT MAY DROP SOUTHEASTWARD BETWEEN THE  
PLAINS AND WEST OF THE APPALACHIANS BEFORE DISSIPATING. THESE  
ISSUES CORRESPOND TO VARYING DEPICTIONS OF SHORTWAVE ENERGY  
FORECAST TO FEED INTO THE MEAN TROUGH ALOFT CROSSING THE EAST.  
GUIDANCE BEHAVIOR UP TO THIS POINT AS WELL AS THE SMALL SCALE OF  
THE FEATURE YIELD LOW CONFIDENCE IN ANY PARTICULAR SOLUTION.  
 
THE EARLY-PERIOD OPERATIONAL MODEL BLEND OF 00Z/06Z GUIDANCE  
PLACED THE LEAST WEIGHT ON THE UKMET GIVEN ITS LOWER-PROBABILITY  
SOLUTION OVER THE EAST. FAVORABLE GUIDANCE COMPARISONS LED TO  
TRANSITIONING THE FORECAST BLEND TOWARD THE 06Z GFS/GEFS MEAN AND  
00Z ECMWF/ECMWF MEAN/CMC BY DAYS 6-7 TUESDAY-WEDNESDAY.  
   
..WEATHER HIGHLIGHTS/THREATS
 
 
BRISK WINDS AND COLDER AIR BEHIND THE SYSTEM TRACKING JUST NORTH  
OF MAINE ON SATURDAY SHOULD SUPPORT AN EPISODE OF LIGHT TO  
MODERATE LAKE EFFECT SNOW ACROSS PORTIONS OF MICHIGAN AND UPSTATE  
NEW YORK. EXPECT LOW PRESSURE TO FORM ALONG THE TRAILING FRONT  
NEAR THE EAST COAST BY SUNDAY, BUT WITH LOWER THAN DESIRED  
CONFIDENCE IN THE STRENGTH/TRACK OF THE SYSTEM AND  
COVERAGE/INTENSITY OF ASSOCIATED PRECIPITATION. RECENT TRENDS ARE  
AT LEAST SIGNALING POTENTIAL FOR SOME SNOW FROM THE  
CENTRAL-SOUTHERN APPALACHIANS INTO THE MID-ATLANTIC AND  
SOUTHERN/EASTERN NEW ENGLAND WITH RAIN POSSIBLE OVER PARTS OF THE  
SOUTHEAST/FLORIDA. HOWEVER THE CURRENT POSSIBILITIES FOR THE  
MID-ATLANTIC/NORTHEAST STILL RANGE BETWEEN MINIMAL AND SIGNIFICANT  
SNOWFALL. CONTINUE TO MONITOR FORECASTS OF THIS SYSTEM CLOSELY.  
EXPECT THE UPPER TROUGH/WAVY FRONT MOVING INTO THE WEST EARLY NEXT  
WEEK TO BRING AN EPISODE OF RAIN AND MOUNTAIN SNOW, WITH HIGHEST  
TOTALS LIKELY TO EXTEND FROM THE PACIFIC NORTHWEST INTO THE  
NORTHERN-CENTRAL ROCKIES. PRECIPITATION SHOULD INCREASE IN  
COVERAGE AND INTENSITY OVER THE CENTRAL/SOUTHERN PLAINS AND  
VICINITY BY NEXT WEDNESDAY OR SO AS THE SURFACE FRONT INTERACTS  
WITH A STRENGTHENING LOW LEVEL FLOW OF GULF MOISTURE. SOME SNOW  
MAY BE POSSIBLE FROM THE CENTRAL HIGH PLAINS NORTHEASTWARD.  
 
MANY PARTS OF THE WEST WILL SEE WELL ABOVE NORMAL TEMPERATURES  
EXTEND THROUGH THE WEEKEND WITH SOME AREAS SEEING PLUS 10-20F  
ANOMALIES. BEST POTENTIAL FOR DAILY RECORDS WILL BE OVER  
CALIFORNIA SATURDAY-SUNDAY. THE UPPER TROUGH APPROACHING FROM THE  
PACIFIC WILL BEGIN A COOLING TREND OVER THE PACIFIC  
NORTHWEST/NORTHERN CALIFORNIA BY MONDAY WHILE THE GREAT BASIN AND  
SOUTHWEST REMAIN QUITE WARM. THEN EXPECT MODERATELY BELOW NORMAL  
HIGHS TO SPREAD ACROSS THE WEST/ROCKIES BY TUESDAY-WEDNESDAY.  
MEANWHILE THE PLAINS WILL SEE A WARMING TREND (UP TO PLUS 10-20F  
OR SO ANOMALIES) FROM THE WEEKEND INTO EARLY NEXT WEEK BEFORE THE  
WESTERN FRONT APPROACHES. AREAS NEAR THE EAST COAST WILL SEE A  
WARM DAY SATURDAY (PLUS 10F OR GREATER ANOMALIES) BEFORE PASSAGE  
OF A COLD FRONT, WITH TRAILING TEMPERATURES GENERALLY 10-20F BELOW  
NORMAL PROGRESSING FROM THE MISSISSIPPI VALLEY SATURDAY THROUGH  
THE EAST INTO EARLY NEXT WEEK. THE EAST WILL LIKELY REBOUND TO  
NEAR OR ABOVE NORMAL BY NEXT WEDNESDAY.  
 
RAUSCH  
 
HAZARDS:  
- HEAVY SNOW POSSIBLE ACROSS PORTIONS OF SOUTHEASTERN NEW ENGLAND,  
SUN, FEB 13.  
- HEAVY SNOW POSSIBLE ACROSS PORTIONS OF THE NORTHERN CASCADES AND  
NORTHERN ROCKIES, MON, FEB 14.  
- HEAVY RAIN POSSIBLE ACROSS PORTIONS OF THE SOUTHERN PLAINS TO  
THE MID-MISSISSIPPI VALLEY, AND INTO THE MIDWEST, WED, FEB 16.  
- MUCH BELOW NORMAL TEMPERATURES ACROSS THE UPPER MIDWEST INTO THE  
UPPER GREAT LAKES, SAT, FEB 12.  
- MUCH BELOW NORMAL TEMPERATURES ACROSS THE LOWER GREAT LAKES AND  
NORTHERN NEW ENGLAND, SUN-TUE, FEB 13-FEB 15.  
 
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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