955  
FXUS02 KWBC 081913  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
212 PM EST SAT JAN 08 2022  
 
VALID 12Z TUE JAN 11 2022 - 12Z SAT JAN 15 2022  
   
..OVERVIEW
 
 
MODEL GUIDANCE INDICATES THAT GENERAL RIDGING WILL PREVAIL OVER  
THE WESTERN U.S. AS BROAD TROUGHING TENDS TO EJECT DISTURBANCES  
EASTWARD ACROSS THE NORTHERN TIERS AS WELL AS THE DEEP SOUTH UNDER  
A SPLIT FLOW PATTERN. MEANWHILE, A CLOSED UPPER LOW LINGERING  
JUST OFF THE SOUTHWEST WILL LIKELY PLAY A ROLE IN BRINGING GULF  
MOISTURE INTO THE SOUTH LATE NEXT WEEK. HEAVY PRECIPITATION WILL  
EDGE CLOSER TOWARD THE PACIFIC NORTHWEST TUE/WED BUT WITH THE  
HEAVIEST ACTIVITIES LIKELY OVER VANCOUVER ISLAND.  
   
..GUIDANCE/PREDICTABILITY ASSESSMENT
 
 
OVERALL, MODELS SHOW REASONABLY GOOD AGREEMENT IN PREDICTING THE  
PATTERN EVOLUTION ACROSS THE U.S. FOR THE MEDIUM-RANGE PERIOD,  
WITH EXPECTED LARGE SPREAD TOWARD THE END OF NEXT WEEK. THE MAIN  
ISSUES ARE WITH REGARD TO HOW THE LINGERING UPPER LOW OFF THE  
SOUTHWEST SHOULD BE HANDLED, AS WELL AS THE SPEED AND AMPLITUDE OF  
THE NEXT PACIFIC TROUGH/UPPER LOW SHOULD APPROACH THE WEST COAST  
DURING THE LATTER HALF OF NEXT WEEK. FARTHER EAST, THERE IS  
UNCERTAINTY WITH REGARD TO THE SPEED OF THE NORTHERN STREAM  
DISTURBANCES AS WELL AS HOW MUCH THEY PHASE WITH THE SOUTHERN  
STREAM ENERGY. IT APPEARS THAT THE LATEST ENSEMBLE MEANS FAVOR  
MORE PHASING OF THE TWO STREAMS WITH A COUPLE OF LOW PRESSURE  
SYSTEM TRACKING THROUGH THE NORTHERN TIER STATES AND THE DEEP  
SOUTH BY NEXT WEEKEND.  
 
A MULTI-MODEL/ENSEMBLE BLEND WAS USED TO COMPOSE THIS MORNING'S  
WPC MEDIUM-RANGE FORECASTS. THE 06Z GFS WAS NOTED TO DIVE TOO  
MUCH SHORTWAVE ENERGY ACROSS THE MIDWEST TOWARD THE SOUTHEAST NEXT  
THU-FRI. IT WAS ALSO TOO SLOW BRINGING IN THE UPPER LOW ACROSS  
THE SOUTHWEST LATE NEXT WEEK COMPARED WITH THE REST OF THE  
GUIDANCE. THE 00Z AND 12Z GFS WERE MORE AGREEABLE IN THIS REGARD.  
THE 00Z CMC WAS TOO AGGRESSIVE IN TRACKING A FRONTAL WAVE  
NEAR/NORTH OF THE GREAT LAKES BY DAY 5 IN CONTRADICTION WITH ITS  
ENSEMBLE MEAN. THE ECMWF REMAINS QUITE REASONABLE WITH ITS  
ENSEMBLE MEANS THROUGH DAY 7. THEREFORE, LITTLE TO NONE OF THE  
06Z GFS AND 00Z CMC WERE INCLUDED IN THE BLEND BEYOND DAY 5, WITH  
THE REMAINING PORTION FROM THE 00Z ECMWF/00Z EC MEAN, THE 06Z  
GEFS, AND THE 00Z CMC MEAN.  
   
..WEATHER HIGHLIGHTS
 
 
THE PACIFIC NORTHWEST SHOULD SEE HEAVY PRECIPITATION EDGING CLOSER  
AHEAD OF A WARM FRONT TUE/WED. HIGHER TOTALS ARE EXPECTED OVER  
TYPICAL UPSLOPE AREAS OF THE OLYMPICS AND CASCADES BUT THE  
HEAVIEST ACTIVITIES WILL LIKELY BE NORTH OF THE BORDER OVER  
VANCOUVER ISLAND. IN CONTRAST, DRY CONDITIONS WITH A CONTINUED  
WARMING TREND WILL LIKELY ENGULF MUCH OF THE CENTRAL AND NORTHERN  
PLAINS. A LARGE SURFACE HIGH WILL ALSO MAINTAIN DRY CONDITIONS  
OVER THE INTERMOUNTAIN WEST. MEANWHILE, A CLOSED UPPER LOW  
LINGERING JUST OFF THE SOUTHWEST WILL LIKELY MOVE INLAND AND PLAY  
A ROLE IN BRINGING GULF MOISTURE INTO THE SOUTH LATE NEXT WEEK.  
IT APPEARS THAT A SWATH OF WINTRY PRECIPITATION WILL TRACK ACROSS  
THE GREAT LAKES TOWARD NEW ENGLAND BY THE WEEKEND IN ASSOCIATION  
WITH THE NORTHERN STREAM SYSTEM. MEANWHILE, THE RAIN IN THE SOUTH  
SHOULD THEN SPREAD TOWARD THE EASTERN U.S. WHERE THE SPLIT FLOW  
TENDS TO PHASE NEXT WEEKEND.  
 
COLD AIR WILL BE IN PLACE OVER THE UPPER MIDWEST AND INTO THE  
NORTHEAST ON TUESDAY, WITH HIGH TEMPERATURES 10-30F BELOW AVERAGE  
FOR ONE OF THE COLDEST DAYS OF THE SEASON THUS FAR. THEN THE  
CENTRAL U.S. WILL SEE A PRONOUNCED WARMING TREND NEXT WEEK WITH  
EXPANDING COVERAGE OF MAX/MIN TEMPERATURES 10-20F ABOVE NORMAL  
TUESDAY ONWARD. SOME LOCATIONS IN THE NORTHERN TWO-THIRDS OF THE  
PLAINS MAY SEE EVEN WARMER READINGS MID-LATE WEEK. ACROSS THE WEST  
EXPECT TO SEE DAYTIME HIGHS WITHIN 10F ON EITHER SIDE OF NORMAL  
THROUGH THE PERIOD, WHILE ABOVE NORMAL LOWS SHOULD BECOME MORE  
PREVALENT WITH TIME. BY THE END OF THE WEEK TEMPERATURES ARE  
CURRENTLY FORECAST TO MODERATE CLOSE TO NORMAL.  
 
KONG  
 
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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