527  
FXUS02 KWBC 231810  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
109 PM EST WED FEB 23 2022  
 
VALID 12Z SAT FEB 26 2022 - 12Z WED MAR 2 2022  
 
18Z UPDATE: THE 12Z MODEL GUIDANCE SUITE IS IN GOOD AGREEMENT ON  
THE OVERALL SYNOPTIC SCALE PATTERN ON SATURDAY. HOWEVER,  
NOTEWORTHY SHORTWAVE AND TIMING DIFFERENCES BECOME APPARENT AS  
EARLY AS SUNDAY, WITH THE 12Z ECMWF MORE AMPLIFIED WITH THE  
SOUTHERN STREAM TROUGH CROSSING THE SOUTHERN PLAINS AND DEEP SOUTH  
THROUGH MONDAY NIGHT, AND THE CMC STRONGER WITH THE PACIFIC TROUGH  
REACHING THE WEST COAST AND MOVING INLAND ACROSS THE INTERMOUNTAIN  
WEST. MAJOR TIMING DIFFERENCES ARE APPARENT ACROSS CENTRAL CANADA  
WITH THE NEXT NORTHERN STREAM SHORTWAVE DROPPING SOUTHWARD, WITH  
THE GFS MUCH MUCH PROGRESSIVE THAN THE ECMWF, WHILST THE CMC IS  
LESS PRONOUNCED WITH THIS SAME SHORTWAVE. THE MODELS ARE ALSO  
STRUGGLING WITH HOW THAT SHORTWAVE FROM CANADA POTENTIALLY  
INTERACTS WITH THE PACIFIC TROUGH EXITING THE ROCKIES, AND THIS  
LEADS TO A MORE UNCERTAIN FORECAST FROM THE UPPER MIDWEST TO THE  
NORTHEAST THROUGH THE EARLY TO MIDDLE OF NEXT WEEK.  
 
AT THE TIME OF THE FRONTS/PRESSURES PREPARATION, THE BLEND WAS  
WEIGHTED MORE HEAVILY TOWARDS THE GFS/CMC/UKMET/GEFS MEAN SINCE  
THERE WAS BETTER ENSEMBLE CLUSTERING FOR A STRONGER TROUGH ACROSS  
THE EASTERN U.S. EARLY NEXT WEEK, WHEREAS THE 00Z ECMWF WAS MORE  
ZONAL AND DID NOT HAVE AS MUCH ENSEMBLE SUPPORT. GIVEN THE  
INCREASING UNCERTAINTY BY TUESDAY-WEDNESDAY, THE FORECAST WAS  
HEDGED MORE ON THE GEFS/ECENS ALONG WITH SOME OF THE CMC/GFS AND  
PREVIOUS WPC CONTINUITY. /HAMRICK  
-------------------------------  
   
..PATTERN OVERVIEW
 
 
OVERALL COLD AND DRIER CONDITIONS ARE SLATED FOR MUCH OF THE LOWER  
48 STATES THIS WEEKEND INTO EARLY NEXT WEEK TO BE FOLLOWED BY  
BROAD MODERATION OF TEMPERATURES SPREADING FROM THE WEST TO THE  
EAST EARLY TO MID NEXT WEEK.  
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
THE WPC MEDIUM RANGE PRODUCT SUITE WAS PRIMARILY DERIVED FROM THE  
18 UTC GEFS MEAN AND THE 01 UTC NATIONAL BLEND OF MODELS. DESPITE  
REASONABLY SIMILAR LARGER SCALE PATTERN EVOLUTION, EMPHASIS ON ANY  
INDIVIDUAL MODEL DOES NOT SEEM PRUDENT GIVEN RECENT RUN TO RUN  
CONTINUITY ISSUES AND VARIANCE WITH EMBEDDED WEATHER FEATURES.  
WHILE SOUTHERN STREAM DIFFERENCES ACTUALLY SEEM A BIT LESS  
PRONOUNCED THAN YESTERDAY, THE LAST FEW ECMWF AND ECMWF ENSEMBLE  
MEAN RUNS TRENDED MUCH FLATTER OVER THE CENTRAL TO EASTERN U.S.  
WITH NORTHERN STREAM UPPER TROUGHING THIS WEEKEND INTO EARLY NEXT  
WEEK DESPITE AMPLIFIED UPSTREAM RIDGING OVER WESTERN NORTH  
AMERICA. WHILE EMBEDDED SYSTEM WAVELENGTH SPACING COULD SUPPORT  
THIS TREND AROUND A HUDSON BAY VORTEX POSITION, INSTEAD HAVE  
LEANED THE WPC SOLUTION TO A MORE AMPLIFIED AND COLDER 18 UTC GEFS  
MEAN OR PROBABLY THE SLIGHTLY LESS AMPLIFIED 00 UTC GEFS MEAN.  
THIS PLAN BEST MAINTAINS WPC PRODUCT CONTINUITY.  
   
..WEATHER HIGHLIGHTS/THREATS
 
 
COLD HIGH PRESSURE WILL SETTLE ACROSS MUCH OF THE COUNTRY BY THIS  
WEEKEND INTO NEXT WEEK. THE WEATHER PATTERN WILL ALSO FAVOR DRIER  
CONDITIONS. AN EXCEPTION MAY BE ACROSS THE SOUTH-CENTRAL TO  
SOUTHEASTERN U.S. WHERE PRECIPITATION COULD RETURN THIS WEEKEND.  
THIS WILL BE MAINLY IN THE FORM OF LIGHT TO MODERATE COLD RAINS,  
BUT WITH SOME SNOW/ICE THREAT ON THE NORTHERN PERIPHERY OF THE  
SWATH OF PRECIPITATION. IN ADDITION, MODEST PRECIPITATION IS  
EXPECTED TO DEVELOP FOR THE PACIFIC NORTHWEST/NORTHERN CA THIS  
WEEKEND WITH SLOW APPROACH OF NORTHEAST PACIFIC SYSTEMS.  
PRECIPITATION TOTALS ARE FORECAST TO INCREASE OVER THE PACIFIC  
NORTHWEST/NORTHERN CA AND GRADUALLY SPREAD ACROSS THE NORTHWESTERN  
STATES EARLY-MID NEXT WEEK, INCLUDING TERRAIN ENHANCED SNOWS.  
 
SCHICHTEL/HAMRICK  
 
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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