867  
FXUS02 KWBC 190701  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
200 AM EST SAT FEB 19 2022  
 
VALID 12Z TUE FEB 22 2022 - 12Z SAT FEB 26 2022  
 
...HEAVY TO EXCESSIVE RAIN THREAT FROM THE LOWER  
MISSISSIPPI/TENNESSEE VALLEY TO THE MID-ATLANTIC TUESDAY-FRIDAY...  
 
...HEAVY SNOW/ICE THREATS FROM THE UPPER MIDWEST TO MAINE TUESDAY  
AND SOUTHERN PLAINS TO NORTHEAST WEDNESDAY-SATURDAY...  
 
   
..PATTERN OVERVIEW
 
 
A VERY ACTIVE WEATHER PATTERN IS EXPECTED TO DEVELOP BY EARLY NEXT  
WEEK OVER OUR FINE NATION AS AN UPPER LEVEL TROUGH DIGS ACROSS THE  
WESTERN U.S. WITH EJECTING ENERGIES AND INDUCED FRONTAL WAVES  
PROGRESSING DOWNSTREAM. THE UPPER TROUGH SHOULD SHIFT EASTWARD  
INTO THE CENTRAL PLAINS AND MIDWEST BY LATER NEXT WEEK AS  
AMPLIFIED RIDGING BUILDS OVER THE EAST PACIFIC AND WEST COAST.  
THIS AMPLIFIED PATTERN RESULTS IN A RENEWED HEAVY RAIN AND  
FLOODING THREAT FROM ROUGHLY THE LOWER MISSISSIPPI/TENNESSEE  
VALLEY TO THE MID-ATLANTIC THROUGH MOST OF NEXT WEEK. THERE IS  
ALSO A DOUBLE DOSE OF WINTER STORM POTENTIAL WITH A LEADING SWATH  
FROM THE UPPER MIDWEST TO MAINE TUESDAY, THEN BROADLY FROM THE  
SOUTHERN PLAINS TO THE NORTHEAST WEDNESDAY INTO SATURDAY.  
 
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
THE LATEST MODELS AND ENSEMBLES CONTINUE AN ONGOING RECENT TREND  
TO OFFER QUITE SIMILAR MID-LARGER SCALE FLOW EVOLUTIONS IN A  
MEDIUM RANGE PATTERN WITH OVERALL ABOVE NORMAL PREDICTABILITY. A  
COMPOSITE OF GENERALLY WELL CLUSTERED GUIDANCE FROM THE  
GFS/ECMWF/UKMET/CANADIAN ALONG WITH THE NATIONAL BLEND OF MODELS  
(NBM) SEEMINGLY PROVIDES A GOOD FORECAST BASIS FOR DAYS 3-5  
(TUESDAY-THURSDAY). THIS SOLUTION IS WELL SUPPORTED BY GEFS/ECMWF  
ENSEMBLES. THE WPC PRODUCT SUITE WAS THEN MAINLY DERIVED FROM THE  
GEFS/ECMWF ENSEMBLE MEANS AND NBM INTO DAYS 6/7 IN A PERIOD WITH  
GRADULALY GROWING MODEL FORECAST SPREAD. THIS BROAD STRATEGY TENDS  
TO MITIGATE LINGERING SMALLER SCALE SYSTEM VARIANCES WHILE  
MAINTAINING GOOD WPC PRODUCT CONTINUITY.  
 
   
..WEATHER HIGHLIGHTS/THREATS
 
 
MODERATE TO HEAVY MOUNTAIN SNOWS ARE LIKELY TO FOCUS EARLY TO MID  
NEXT WEEK ACROSS THE COOLING WEST/ROCKIES AS POTENT UPPER TROUGH  
ENERGIES DIG INTO THE WEST AS ENHANCED BY POST-FRONTAL UPSLOPE  
FETCH. THE WAVY FRONT ON THE LEADING EDGE OF A COLD SURGE SET TO  
DIG INTO THE CENTRAL U.S. EARLY-MID NEXT WEEK WILL HAVE UPPER  
SUPPORT TO FAVOR A SWATH OF HEAVY SNOW FROM THE UPPER MIDWEST TO  
MAINE TUESDAY WITH SOME ICE ACCUMULATIONS POSSIBLE ALONG THE  
SOUTHERN EDGE. MEANWHILE, AMPLE UPPER ENERGIES WORKING DOWNSTREAM  
FROM THE WEST NEXT WEEK WILL ALSO ACT TO INDUCE WAVES ALONG A LEAD  
FRONT AND TAP DEEPENING MOISTURE FROM THE GULF OF MEXICO. THIS IS  
EXPECTED TO FUEL A HEAVY RAIN AND EXPERIMENTAL "SLIGHT" ERO FLOOD  
THREAT FROM THE LOWER MISSISSIPPI/TENNESSEE VALLEYS TO THE  
MID-ATLANTIC STARTING EARLY NEXT WEEK ALONG WITH POTENTIAL FOR  
PERIODIC RE-DEVELOPMENT AND TRAINING ALONG THE WAVY/SLOWED  
TRAILING FRONT THROUGH LATER NEXT WEEK. A MAIN SECOND WAVE  
EVOLUTION MAY ALSO SUPPORT THE SPREAD OF A HEAVY SNOW/ICE THREAT  
FROM PARTS OF THE SOUTHERN PLAINS AND MID-MISSISSIPPI/OHIO VALLEYS  
AND INTO A COLD AIR DAMMED NORTHERN MID-ATLANTIC AND NORTHEAST  
WEDNESDAY INTO SATURDAY. GIVEN LINGERING DETAIL UNCERTAINTIES IN  
THE GUIDANCE, CONFIDENCE ON EXACT SNOW/ICE AMOUNTS AND LOCATIONS  
REMAINS LESS CERTAIN AT THESE LONGER LEAD TIMES, BUT THE POTENTIAL  
IS THERE IN THIS FAVORABLE PATTERN.  
 
ARCTIC HIGH PRESSURE SURGING SOUTHWARD INTO THE CENTRAL U.S.  
DURING THE FIRST HALF OF NEXT WEEK WILL SUPPORT MUCH BELOW  
TEMPERATURES FROM THE NORTHWEST INTO MUCH OF THE CENTRAL U.S. AS  
FAR SOUTH AS TEXAS. ESPECIALLY FROM THE NORTHERN HIGH PLAINS TO  
THE NORTHERN/CENTRAL PLAINS, DAYTIME HIGHS AND OVERNIGHT LOWS  
COULD BE 30-40 BELOW NORMAL, WHICH COULD APPROACH TO EXCEED RECORD  
LOW MINS AND MAX VALUES. DAYTIME HIGHS ACROSS THE NORTHERN PART OF  
THIS REGION COULD STRUGGLE TO GET ABOVE 0F TUESDAY. THIS VERY COLD  
AIR WILL SPREAD, BUT GRADUALLY MODIFY LATER NEXT WEEK ACROSS THE  
MIDWEST/EAST. MEANWHILE, MUCH ABOVE NORMAL PRE-FRONTAL  
TEMPERATURES ARE EXPECTED ACROSS THE SOUTHEAST/EAST EARLY IN THE  
PERIOD (WITH SOME RECORDS POSSIBLE, ESPECIALLY OVERNIGHT MINS)  
WITH UPPER LEVEL RIDGING OVER 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  
 

 
 

 
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab HPC Page Main Text Page