003  
FXUS02 KWBC 141847  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
245 PM EDT MON MAR 14 2022  
 
VALID 12Z THU MAR 17 2022 - 12Z MON MAR 21 2022  
 
1830 UTC UPDATE...  
 
NO MAJOR CHANGES TO THE FORECAST THINKING FROM THE OVERNIGHT SHIFT  
FOLLOWING THE 00Z/06Z MODEL RUNS. THE LAST FEW RUNS OF THE GFS  
(INCLUDING THE MOST RECENT 12Z RUN FROM TODAY) CONTINUES TO BE  
STRONGER WITH SOUTHERN STREAM ENERGY THROUGH THE PLAINS/MIDWEST  
LATE THIS WEEK, RESULTING IN A MORE WRAPPED, DEEPER, AND FARTHER  
NORTH SURFACE LOW PLACEMENT. AGAIN, TODAYS UPDATE TO THE WPC  
FORECAST LEANED MORE TOWARDS THE BETTER CLUSTERED ECMWF, CMC, AND  
UKMET SOLUTIONS FOR THIS SYSTEM. ELSEWHERE, AN ECMWF/GFS BLEND  
WITH THE ENSEMBLE MEANS SEEMS TO CONTINUE TO SERVE WELL WITH THE  
NEXT TROUGH/CLOSED LOW IN THE SOUTHWEST EARLY NEXT WEEK AMIDST  
GOOD LARGE SCALE AGREEMENT BUT PLENTY OF DETAIL UNCERTAINTIES  
STILL TO BE WORKED OUT. SEE PREVIOUS DISCUSSION BELOW FOR  
ADDITIONAL INFORMATION CONCERNING THE MEDIUM RANGE PERIOD FORECAST  
AND ASSOCIATED WEATHER/HAZARD THREATS.  
 
SANTORELLI  
   
..PREVIOUS DISCUSSION ISSUED AT 0628 UTC
 
 
   
..OVERVIEW
 
 
A FAST, PROGRESSIVE FLOW PATTERN WITH INCREASING AMPLITUDE IS  
EXPECTED TO EVOLVE OVER THE CONUS THROUGHOUT THE FORECAST PERIOD.  
THE INITIAL SYSTEM OVER THE SOUTHEAST THURSDAY WILL QUICKLY DEPART  
TO THE NORTHEAST OFFSHORE WHILE ANOTHER STORM SYSTEM BREWS OVER  
THE SOUTHERN PLAINS THURSDAY/FRIDAY BEFORE LIFTING INTO THE GREAT  
LAKES BY NEXT WEEKEND. BY LATE IN THE WEEKEND TO EARLY NEXT WEEK,  
A MUCH STRONGER AND AMPLIFIED TROUGH WILL PROGRESS THROUGH THE  
WESTERN U.S., REACHING THE PLAINS BY EARLY NEXT WEEK. THIS COULD  
BRING WIDESPREAD, BENEFICIAL RAINS TO THE WESTERN U.S. AND EVOLVE  
INTO A STRONG STORM SYSTEM JUST BEYOND THE FORECAST PERIOD. NO  
SIGNIFICANT COLD AIR OUTBREAKS ARE ANTICIPATED AND TEMPERATURES  
WILL GENERALLY OSCILLATE BETWEEN NEAR NORMAL AND MUCH ABOVE NORMAL  
AHEAD OF THE VARIOUS WAVES OF LOW PRESSURE.  
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
WHILE LARGE SCALE FEATURES IN THE LATEST DETERMINISTIC AND  
ENSEMBLE GUIDANCE SHOW AVERAGE TO ABOVE AVERAGE PREDICTABILITY AND  
AGREEMENT, THERE ARE SOME NOTABLE SURFACE DIFFERENCES THAT HAVE  
IMPACTS ON TIMING AND SENSIBLE WEATHER. INITIALLY, THE FIRST AREA  
OF MODEL DIFFERENCES LIES WITH THE NEUTRALLY TITLED SHORTWAVE  
TROUGH COMING THROUGH THE PLAINS LATE IN THE WEEK. THE ASSOCIATED  
SURFACE LOW HAS SIGNIFICANT LATITUDINAL DIFFERENCES WITH THE GFS  
BEING A FAST, PROGRESSIVE AND NORTHERN OUTLIER COMPARED TO THE  
SLOWER ECMWF/UKMET/CMC. THIS IS LARGELY DRIVEN BY ITS DEEPER,  
STRONGER 500 MB TROUGH THAT TAKES ON A SLIGHT NEGATIVE TILT AS IT  
SWINGS THROUGH THE MIDWEST. FOR NOW, THE WPC BLEND FAVORED THE  
SLOWER, NON-GFS SOLUTION BUT DID INCLUDE SOME OF IT TO MAINTAIN  
CONTINUITY. BEYOND THAT SYSTEM, THE FLOW PATTERN TAKES ON MORE  
AMPLITUDE WITH THE WESTERN U.S. LIKELY TO SEE A DIGGING TROUGH  
THAT EVENTUALLY CLOSES OFF AROUND THE FOUR CORNERS REGION BY THE  
END OF THE PERIOD. WHILE THERE ARE SOME TIMING DIFFERENCE, BOTH  
THE ECMWF/GFS AND ECENS/GEFS MEANS SHOW FAIRLY GOOD AGREEMENT IN  
THIS SETUP. AS THE ENERGY REACHES THE PLAINS, STRONG CYCLOGENESIS  
IS POSSIBLE. OVERALL, THE WPC BLEND INCORPORATED THE 12Z ECMWF/CMC  
AND 18Z GFS FOR DAYS 3-5 THEN INCLUDED MORE OF THE ECENS/GEFS FOR  
DAYS 6-7 GIVEN THE TYPICAL MODEL SPREAD.  
 
   
..WEATHER HIGHLIGHTS/THREATS
 
 
THE SLOW-MOVING GULF TO SOUTHEAST COASTAL SYSTEM WILL BRING  
WIDESPREAD LIGHT TO MODERATE RAINFALL TO THE COASTAL REGIONS  
THURSDAY BEFORE THE SYSTEM MOVES WELL OFFSHORE INTO FRIDAY. THE  
NEXT SYSTEM MOVING THROUGH THE PLAINS COULD BRING SOME MODERATE TO  
LOCALLY HEAVY RAINFALL AS WELL AS POTENTIAL WINTER WEATHER ON THE  
NORTHWEST/COLD SIDE, THOUGH THE AFOREMENTIONED MODEL DIFFERENCES  
AND MARGINALLY SUPPORTIVE THERMAL PROFILES FOR WINTER WEATHER WILL  
KEEP THE LATEST WINTER WEATHER OUTLOOK FOR DAY 5 GENERALLY VERY  
LOW. FINALLY, THE ACTIVE/UNSETTLED WEATHER GREETING THE WESTERN  
U.S. TOWARD THE END OF THE PERIOD WILL BE MOSTLY BENEFICIAL AND  
WELCOMED PRECIPITATION. TEMPERATURES LOOK TO BE MOSTLY NEAR TO  
ABOVE NORMAL, AHEAD OF THE VARIOUS WAVES OF LOW PRESSURE. SOME  
DIPS TO BELOW NORMAL READINGS ARE POSSIBLE ACROSS THE WEST AND  
INTERIOR WEST AS THE NEXT LARGE SCALE WEATHER SYSTEM MOVES THROUGH  
THANKS TO CLOUDS AND PRECIPITATION.  
 
TAYLOR  
 
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  
 
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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