270  
FXUS02 KWBC 210650  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
149 AM EST MON FEB 21 2022  
 
VALID 12Z THU FEB 24 2022 - 12Z MON FEB 28 2022  
 
...HEAVY TO EXCESSIVE RAINFALL THREAT FROM THE MID-SOUTH TO THE  
MID-ATLANTIC THURSDAY ALONG WITH A SIGNIFICANT HEAVY SNOW/ICE  
THREAT FROM THE MID-MISSISSIPPI VALLEY NORTHEASTWARD TO THE  
NORTHEAST THURSDAY-FRIDAY...  
 
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
MODELS AND ENSEMBLES OFFER A SIMILAR MID-LARGER SCALE FLOW  
EVOLUTION IN A PATTERN WITH ABOVE NORMAL OVERALL PREDICTABILITY.  
AN 18 UTC GFS AND 12 UTC ECMWF/UKMET/CANADIAN COMPOSITE ALONG WITH  
THE 01 UTC NATIONAL BLEND OF MODELS SEEMS TO PROVIDE A GOOD  
FORECAST BASIS DAYS 3-5 (THURSDAY-SATURDAY). BLENDING OF THESE  
WELL CLUSTERED MODELS TENDS TO MITIGATE SMALLER SCALE SYSTEM  
VARIANCES CONSISTENT WITH PREDICTABILITY. NEWER 00 UTC GUIDANCE IS  
CONSISTENT. THE WPC PRODUCT SUITE INTO DAYS 6/7 WAS MAINLY DERIVED  
FROM THE ECMWF ENSEMBLE MEAN THAT MAINTAINS A SLIGHTLY MORE  
AMPLIFIED SOUTHEAST UPPER RIDGE THAT OFTEN LINGERS ON THE STRONGER  
SIDE OF THE FULL ENVELOPE OF SOLUTIONS IN THIS TYPE OF PATTERN.  
THIS PLAN MAINTAINS GREAT WPC PRODUCT CONTINUITY.  
   
..PATTERN OVERVIEW AND WEATHER HIGHLIGHTS/THREATS
 
 
A COLD PATTERN ENSUES THIS WEEK AS CANADIAN HIGH PRESSURE SETTLES  
ACROSS MUCH OF THE LOWER 48. UPPER LEVEL TROUGHS WILL DIG THROUGH  
THE WEST/SOUTHWEST, WITH EJECTING ENERGIES AND INDUCED FRONTAL  
WAVES PROGRESSING DOWNSTREAM OVERTOP A WARMING SOUTHEAST UPPER  
RIDGE. A MAIN UPPER TROUGH WILL EJECT OUT THROUGH THE  
SOUTH-CENTRAL PLAINS AND MID-SOUTH/OH VALLEY LATER THIS WEEK AS  
AMPLIFIED RIDGING BUILDS FROM THE EAST PACIFIC TO THE WEST COAST.  
THIS WILL FAVOR A HEAVY TO EXCESSIVE RAINFALL THREAT FROM THE  
MID-SOUTH TO THE MID-ATLANTIC THURSDAY, ALONG WITH A SIGNIFICANT  
HEAVY SNOW/ICE THREAT FROM THE COOLED MID-MISSISSIPPI VALLEY  
NORTHEASTWARD THROUGH OHIO VALLEY STATES TO THE NORTHEAST THURSDAY  
INTO FRIDAY. LATER, NORTHEAST PACIFIC UPPER TROUGH ENERGIES AND  
PRECIPITATION WILL SLOWLY WORK TOWARD THE PACIFIC NORTHWEST DAYS  
6/7 (SUN/NEXT MON). THIS OCCURS AS LEAD UPPER TROUGHING EJECTS OUT  
FROM THE WEST/SOUTHWEST TO ACROSS THE SOUTHERN U.S. TIER TO  
MODESTLY RENEW WAVES AND PRECIPITATION, ALBEIT WITH MORE UNCERTAIN  
PHASING WITH AN AMPLIFYING/COLD REINFORCING NORTHERN STREAM UPPER  
TROUGH THEN SET TO DIG INTO THE EAST-CENTRAL U.S..  
 
THE COLD HIGH PRESSURE SURGE WILL SPREAD MUCH BELOW TEMPERATURES  
ACROSS MUCH OF THE WESTERN AND CENTRAL U.S. BY MID-LATE WEEK TO  
INCLUDE WIDESPREAD RECORD COLD VALUES, ESPECIALLY FRIGID FROM THE  
NORTHERN HIGH PLAINS TO THE NORTHERN/CENTRAL PLAINS WHERE DAYTIME  
HIGHS AND OVERNIGHT LOWS COULD BE 30-40+ DEGREES BELOW NORMAL.  
THIS VERY COLD AIR WILL SPREAD, BUT GRADUALLY MODIFY LATER WEEK  
ACROSS THE MIDWEST/EAST. MEANWHILE, MUCH ABOVE NORMAL PRE-FRONTAL  
TEMPERATURES ARE EXPECTED ACROSS THE SOUTHEAST/EAST WITH SOME  
RECORD WARMTH LIKELY, ESPECIALLY OVERNIGHT MINS WITH UPPER LEVEL  
RIDGING AND ENHANCED PRE-FRONTAL MOISTURE INTO THE REGION.  
 
SCHICHTEL  
 
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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