060  
FXUS02 KWBC 160700  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
159 AM EST WED FEB 16 2022  
 
VALID 12Z SAT FEB 19 2022 - 12Z WED FEB 23 2022  
   
..OVERVIEW
 
 
THE MEDIUM RANGE PERIOD WILL BEGIN SATURDAY WITH GENERALLY QUIET  
WEATHER, BESIDES A CLIPPER SYSTEM BRINGING SNOW TO THE GREAT LAKES  
REGION. THEN AS NEXT WEEK BEGINS, TROUGHING IS FORECAST TO DEVELOP  
IN THE WEST AND SLOWLY TRACK EASTWARD ALONG WITH A STRONG FRONTAL  
SYSTEM. PRECIPITATION CHANCES SHOULD INCREASE IN THE WEST WITH  
THIS PATTERN AND SPREAD INTO THE CENTRAL U.S. ONCE AGAIN BY NEXT  
MONDAY THROUGH WEDNESDAY, WITH THE POSSIBILITY OF NORTHERN TIER  
SNOW AND SOUTHERN U.S. RAIN.  
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
RECENT MODEL GUIDANCE SHOWS GOOD AGREEMENT OVERALL WITH THE LARGE  
SCALE PATTERN EVEN THROUGH THE MIDDLE OF NEXT WEEK, WITH SOME  
TYPICAL DIFFERENCES IN THE SMALLER SCALE DETAILS. TO START THE  
PERIOD, THE SURFACE LOW/CLIPPER OVER THE GREAT LAKES AND  
UPPER-LEVEL ENERGY SUPPORTING IT HAVE GOOD CONSENSUS AMONG 12/18Z  
MODELS. A LESS CERTAIN FEATURE DURING THIS TIMEFRAME IS A COMPACT  
SHORTWAVE TRACKING INTO THE WEST AHEAD OF THE MAIN LARGER SCALE  
TROUGH. OVERALL RECENT MODELS HAVE TRENDED STRONGER WITH THIS  
INITIAL ENERGY, WITH INCREASING CONSENSUS FOR A CLOSED LOW LIKELY  
CENTERED JUST WEST OF CALIFORNIA ON SATURDAY. THE GFS WAS THE  
SLOWEST MODEL TO COME TO THIS CONCLUSION (THE 12Z HAD ITS LOW  
DISPLACED EAST AND THE 18Z RUN SHOWED AN OPEN TROUGH), BUT THE 00Z  
GFS DOES SHOW A CLOSED LOW IN LINE WITH OTHER GUIDANCE. THOUGH  
THERE IS BETTER AGREEMENT NOW, CONSIDERING THE SMALL SCALE OF THE  
LOW ROUNDING THE PACIFIC RIDGE, ADDITIONAL SHIFTS IN THE FORECAST  
ARE POSSIBLE.  
 
THEN THERE IS GOOD AGREEMENT FOR ENERGY TO SPILL INTO THE WEST AND  
DEVELOP TROUGHING AS NEXT WEEK BEGINS, WHILE MUCH OF THE CENTRAL  
AND EASTERN U.S. SHIFTS TO ZONAL FLOW AND THEN RIDGING. 12/18Z GFS  
RUNS REMAIN AMONG THE STRONGEST, SPECIFICALLY WITH CLOSING OFF A  
LOW WITHIN THE TROUGH EVEN BY EARLY SUNDAY SINKING INTO THE  
PACIFIC NORTHWEST, WHILE THE 12Z CMC WAS SLIGHTLY EAST WITH ITS  
TROUGH AXIS BY AROUND TUESDAY COMPARED TO CONSENSUS. THE PHASING  
DIFFERENCES WITH POTENTIAL STREAM SEPARATION ARE CAUSING MINOR  
MODEL DIFFERENCES THAT COULD CONTINUE TO BE AN ISSUE WITH THE  
EVOLUTION OF THE TROUGHING. THE ECMWF HAS BEEN MORE CONSISTENT AND  
FAVORED AMONG THE DETERMINISTIC GUIDANCE, THOUGH BOTH THE 12Z AND  
NEW 00Z RUNS MAY BE A BIT SLOW WITH LINGERING ENERGY ACROSS THE  
WEST BY WEDNESDAY. DESPITE THESE MODEL DIFFERENCES, THE THEME OF  
TROUGHING DEVELOPING IN THE WEST FOR THE FIRST HALF OF THE WEEK  
SLOWLY SHIFTING EASTWARD AS WELL AS SENDING NORTHERN STREAM ENERGY  
ACROSS THE NORTH-CENTRAL U.S. BY MIDWEEK IS CONSISTENT.  
 
THE WPC FORECAST UTILIZED A MULTI-MODEL DETERMINISTIC BLEND OF THE  
12/18Z GUIDANCE FOR THE EARLY PART OF THE PERIOD, SLIGHTLY  
FAVORING THE ECMWF AND CMC. PHASED IN SOME GEFS AND ECMWF ENSEMBLE  
MEAN GUIDANCE FOR THE LATTER PART OF THE PERIOD, ENDING UP WITH  
ABOUT HALF DETERMINISTIC MODELS AND HALF MEANS BY DAY 7,  
MITIGATING THE INDIVIDUAL MODEL ECCENTRICITIES. THE MAIN  
DIFFERENCE FROM THE PREVIOUS WPC FORECAST WAS A CONTINUED TREND  
NORTHWARD WITH THE AXIS OF HEAVIEST QPF ACROSS THE MID-SOUTH  
MONDAY-WEDNESDAY OF NEXT WEEK.  
   
..WEATHER HIGHLIGHTS/THREATS
 
 
LINGERING SNOW IS FORECAST ON SATURDAY ACROSS THE GREAT LAKES  
REGION WITH THE CLIPPER SYSTEM, WITH GENERALLY LIGHT TO PERHAPS  
LOCALLY MODERATE AMOUNTS. MAINLY DRY CONDITIONS ARE EXPECTED  
ELSEWHERE ON SATURDAY OTHER THAN A FEW SHOWERS POSSIBLE IN  
FLORIDA, EXCEPT THAT PRECIPITATION WILL BE INCREASING IN THE  
PACIFIC NORTHWEST AND NORTHERN ROCKIES WITH THE UPPER TROUGH  
COMING IN. COASTAL AND VALLEY RAIN AND MOUNTAIN SNOW ARE LIKELY  
OVER THE PACIFIC NORTHWEST SPREADING INTO CALIFORNIA, THE GREAT  
BASIN, AND THE ROCKIES THROUGH THE EARLY PART OF NEXT WEEK. SNOW  
COULD ALSO SPREAD FARTHER EAST INTO THE NORTHERN HIGH PLAINS  
SUNDAY AND INTO THE REST OF THE NORTHERN TIER STATES AS THE FIRST  
HALF OF THE WEEK PROGRESSES. THE CONFIDENCE IN THE AXIS OF  
HEAVIEST SNOW AND SNOWFALL AMOUNTS REMAINS SOMEWHAT LOW. FARTHER  
SOUTH, MOIST INFLOW IS FORECAST TO RETURN TO THE SOUTH-CENTRAL AND  
SOUTHEASTERN U.S., INCREASING CHANCES FOR RAINFALL THAT COULD  
BECOME HEAVY OVER THE MID-SOUTH IN PARTICULAR BY MONDAY AND  
TUESDAY.  
 
TEMPERATURES OVER THE WEEKEND ARE EXPECTED TO BE ABOVE NORMAL FOR  
PARTS OF THE WEST INTO THE PLAINS, WITH THE LARGEST ANOMALIES OF  
HIGHS 20+ DEGREES ABOVE AVERAGE OVER SOUTH DAKOTA AND NEBRASKA.  
MEANWHILE, COOLER TO NEAR AVERAGE TEMPERATURES OVER THE EASTERN  
THIRD OF THE COUNTRY SATURDAY WILL WARM SUNDAY. AS THE PATTERN  
AMPLIFIES, THE SOUTH-CENTRAL U.S. TO THE EAST COAST WILL FURTHER  
WARM THROUGH THE FIRST HALF OF NEXT WEEK, WITH WIDESPREAD HIGHS  
10-20F AND LOWS 20-30F ABOVE NORMAL. MEANWHILE, A COLD ARCTIC HIGH  
IS FORECAST TO SHIFT INTO THE NORTH-CENTRAL U.S., LEADING TO WELL  
BELOW AVERAGE TEMPERATURES INITIALLY ACROSS THE NORTHERN HIGH  
PLAINS AND SPREADING SOUTHWARD THROUGH MIDWEEK. TEMPERATURES IN  
SOME PLACES COULD BE 30 OR MORE DEGREES BELOW NORMAL, AND HIGHS IN  
THE SINGLE DIGITS ARE EXPECTED FOR MONTANA AND THE DAKOTAS MONDAY  
AND TUESDAY.  
 
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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