907  
FXUS02 KWBC 280659  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
158 AM EST MON FEB 28 2022  
 
VALID 12Z THU MAR 03 2022 - 12Z MON MAR 07 2022  
   
..OVERVIEW
 
 
LATEST GUIDANCE CONTINUES TO SUGGEST THAT A STEADILY BUILDING  
EASTERN PACIFIC UPPER RIDGE FROM LATE THIS WEEK INTO EARLY NEXT  
WEEK WILL HELP TO ESTABLISH MEAN TROUGHING FROM CENTRAL CANADA  
THROUGH THE WESTERN U.S. THIS GENERAL PATTERN APPEARS LIKELY TO  
PERSIST BEYOND THE MEDIUM RANGE PERIOD. AHEAD OF THE DEVELOPING  
MEAN TROUGH, EASTWARD PROGRESSION OF AN INITIAL ROCKIES/HIGH  
PLAINS UPPER RIDGE WILL EVENTUALLY DISPLACE AN EASTERN NORTH  
AMERICAN MEAN TROUGH. BY EARLY NEXT WEEK A BROAD ZONE OF  
SOUTHWESTERLY FLOW SHOULD EXIST DOWNSTREAM FROM THE MEAN TROUGH  
AXIS. LEADING ENERGY MOVING INTO AND THROUGH THE WEST WILL SPREAD  
PRECIPITATION ACROSS THE REGION AND THEN BRING A BROAD AREA OF  
VARIOUS PRECIP TYPES TO THE CENTRAL U.S. AS ITS NORTHEASTWARD  
EJECTION SUPPORTS A PLAINS THROUGH UPPER GREAT LAKES SURFACE  
SYSTEM LATE FRIDAY THROUGH THE WEEKEND. THE TRAILING FRONT MAY  
BECOME A FOCUS FOR ENHANCED RAINFALL OVER PARTS OF THE  
EAST-CENTRAL U.S. LATE WEEKEND INTO EARLY NEXT WEEK. BELOW NORMAL  
TEMPERATURES WILL SPREAD OVER AN INCREASING PORTION OF THE  
WESTERN/CENTRAL U.S. WITH TIME WHILE ABOVE NORMAL TEMPERATURES  
BECOME MORE FOCUSED OVER THE EAST.  
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
FROM A MULTI-DAY MEAN PERSPECTIVE, GUIDANCE CONTINUES TO SHOW VERY  
GOOD AGREEMENT AND CONTINUITY FOR THE EXPECTED LARGE SCALE  
PATTERN. THE EMBEDDED DETAILS CONTINUE TO OFFER VARYING DEGREES  
OF UNCERTAINTY THOUGH. RECENT RUNS HAVE BEEN NUDGING A LITTLE  
SLOWER WITH THE LEADING SHORTWAVE ENTERING THE WEST LATE THIS WEEK  
BUT THE PAST COUPLE UKMET RUNS APPEAR SOMEWHAT EXTREME WITH THEIR  
SOUTHWESTWARD ELONGATION AS THE FEATURE NEARS THE COAST. MODELS  
CONTINUE TO SHOW DIFFERENT IDEAS FOR HOW THIS ENERGY WILL EVOLVE  
AS IT EJECTS THROUGH THE PLAINS DURING THE WEEKEND, WITH VARIOUS  
INFLUENCES FROM LOW-PREDICTABILITY SMALL-SCALE TRAILING IMPULSES  
DROPPING INTO THE MEAN TROUGH AS WELL AS POSSIBLY SOUTHERN  
CANADA/NORTHERN TIER U.S. ENERGY. AS A RESULT OPERATIONAL MODELS  
SHOW ABOUT A 20 MB SPREAD FOR SURFACE LOW PRESSURE BY THE TIME THE  
SYSTEM REACHES THE UPPER GREAT LAKES BY EARLY SUNDAY, WITH THE  
18Z/00Z GFS ON THE WEAK SIDE AND THE 12Z ECMWF DEEPEST. THE 00Z  
CMC HAS COME IN ALMOST AS STRONG AS THE 12Z ECMWF. A CURIOUS  
EVOLUTION ALOFT IN THE 00Z GFS KEEPS ITS WEAK SYSTEM STUCK OVER  
THE GREAT LAKES AN EXTRA DAY, VERSUS THE ENSEMBLE MEANS THAT  
MAINTAIN A REASONABLE NORTHEASTWARD PROGRESSION. ADDING TO THE  
INTRIGUE, THE NEW 00Z ECMWF TRENDS MUCH WEAKER AND EVEN REPLACES  
IT WITH ANOTHER SYSTEM BY MONDAY. BEHIND THE GREAT LAKES SYSTEM,  
CONFIDENCE IS FAIRLY LOW FOR SHORTWAVE DETAILS WITHIN THE WESTERN  
TROUGH (AS DEMONSTRATED IN CONSECUTIVE ECMWF RUNS) BUT THERE IS  
REASONABLE CONSENSUS THAT THE FRONT TRAILING FROM THE  
AFOREMENTIONED SYSTEM SHOULD BECOME ALIGNED WITH FLOW ALOFT BY  
EARLY NEXT WEEK.  
 
DURING THE FIRST HALF OF THE PERIOD THE 18Z GFS, 12Z CMC, AND PAST  
TWO ECMWF RUNS THROUGH 12Z/27 PROVIDED THE BEST CLUSTER OF  
GUIDANCE WITH GENERAL ENSEMBLE MEAN SUPPORT. THEN THE FORECAST  
TRENDED TO AN EVEN MODEL/ENSEMBLE MEAN WEIGHT BY DAY 7 MONDAY  
GIVEN THE INCREASING DETAIL UNCERTAINTIES. THIS APPROACH YIELDED  
AN INTERMEDIATE SOLUTION FOR THE SYSTEM TRACKING THROUGH THE UPPER  
GREAT LAKES.  
   
..WEATHER HIGHLIGHTS/THREATS
 
 
THE SYSTEM MOVING INTO THE WEST LATE THIS WEEK WILL SPREAD A BROAD  
AREA OF MOSTLY LIGHT TO MODERATE (THOUGH PERHAPS LOCALLY HEAVIER)  
RAIN AND HIGH ELEVATION SNOW ACROSS THE REGION. SOME SCATTERED  
PRECIPITATION MAY PERSIST OVER THE WEST THROUGH THE REST OF THE  
PERIOD DEPENDING ON SHORTWAVE DETAILS. TOWARD THE END OF THE WEEK  
THROUGH THE WEEKEND PRECIPITATION SHOULD BECOME MORE WIDESPREAD  
ACROSS THE CENTRAL U.S. AS LOW PRESSURE TRACKS FROM THE CENTRAL  
PLAINS THROUGH THE UPPER GREAT LAKES. THE BEST POTENTIAL FOR  
WINTRY PRECIPITATION TYPES CONTINUES TO EXTEND FROM THE NORTHERN  
HALF OF THE HIGH PLAINS INTO THE UPPER GREAT LAKES AND EVENTUALLY  
NEW ENGLAND. HIGHEST PROBABILITY OF SIGNIFICANT SNOWFALL  
CURRENTLY EXISTS OVER THE UPPER MIDWEST, JUST TO THE NORTHWEST OF  
THE SURFACE LOW TRACK. THERE IS STILL CONSIDERABLE UNCERTAINTY  
OVER THE STRENGTH OF THE SYSTEM SO CONFIDENCE IN THE  
PRECIPITATION/WIND SPECIFICS IS FAIRLY LOW. RAINFALL OF VARYING  
INTENSITY WILL BE POSSIBLE OVER THE REST OF THE  
CENTRAL/EAST-CENTRAL U.S. AHEAD OF THE TRAILING COLD FRONT.  
GUIDANCE IS SIGNALING THE POTENTIAL FOR HEAVIER RAINFALL WITHIN AN  
AREA FROM THE SOUTHERN PLAINS INTO THE OHIO/TENNESSEE VALLEYS BY  
SATURDAY NIGHT/SUNDAY INTO MONDAY, AS THE FRONT DECELERATES WHILE  
IT BECOMES MORE ALIGNED WITH FLOW ALOFT AND INTERACTS WITH LOW  
LEVEL GULF MOISTURE. THE NORTHERN FRINGE OF THIS LATE-PERIOD  
MOISTURE SHIELD COULD CONTAIN SOME WINTRY WEATHER.  
 
LATE THIS WEEK EXPECT ABOVE NORMAL TEMPERATURES FROM THE  
CENTRAL/SOUTHERN PLAINS THROUGH THE SOUTHEAST, AND INCLUDING BACK  
TO THE GREAT BASIN/SOUTHWEST ON THURSDAY. HIGHEST ANOMALIES  
SHOULD BE IN THE PLUS 15-25F RANGE OVER THE CENTRAL PLAINS. ON  
THE OTHER HAND THE NORTHERN TIER MAY SEE READINGS UP TO 10-20F  
BELOW NORMAL. COLDER AIR OVERSPREADING THE WEST STARTING LATE  
THIS WEEK WILL CONTINUE TO EXPAND INTO THE PLAINS DURING THE  
WEEKEND INTO EARLY NEXT WEEK, YIELDING A BROAD AREA OF  
TEMPERATURES 5-15F BELOW NORMAL BY NEXT MONDAY. MEANWHILE THE  
EASTERN U.S. WILL SEE INCREASING COVERAGE OF WARMER TEMPERATURES  
SATURDAY-MONDAY, GENERALLY PLUS 10-20F ANOMALIES FOR HIGHS AND UP  
TO PLUS 20-25F ANOMALIES FOR MORNING LOWS. TEMPERATURES MAY  
CHALLENGE RECORD HIGHS OVER THE SOUTHEAST.  
 
RAUSCH  
 
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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