602  
FXUS02 KWBC 190623  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
222 AM EDT TUE APR 19 2022  
 
VALID 12Z FRI APR 22 2022 - 12Z TUE APR 26 2022  
 
***THREAT OF WINTER STORM INCREASING FOR PORTIONS OF THE NORTHERN  
PLAINS THIS WEEKEND***  
   
..WEATHER PATTERN OVERVIEW
 
 
THE UPPER LEVEL PATTERN OVER THE CONTINENTAL U.S. BECOMES MORE  
AMPLIFIED BY THE END OF THE WEEK AND INTO THE WEEKEND AS A LARGE  
SYNOPTIC SCALE TROUGH FROM THE PACIFIC MOVES INLAND ACROSS THE  
INTERMOUNTAIN WEST, AND THIS WILL SPUR SURFACE CYCLOGENESIS ACROSS  
THE HIGH PLAINS BY FRIDAY NIGHT. THIS LOW WILL THEN TRACK ACROSS  
THE UPPER MIDWEST THROUGH EARLY SUNDAY, WITH A TRAILING FRONT  
ACROSS THE MISSISSIPPI RIVER VALLEY THAT WILL FUEL SHOWERS AND  
STORMS. MEANWHILE, A DOWNSTREAM RIDGE AXIS BUILDS ACROSS THE  
EASTERN U.S. AND RESULTS IN A CONSIDERABLE WARMING TREND FOR THE  
WEEKEND. ANOTHER PACIFIC TROUGH APPROACHES THE NORTHWESTERN U.S.  
BY THE BEGINNING OF NEXT WEEK.  
   
..MODEL GUIDANCE EVALUATION
 
 
THE 00Z MODEL GUIDANCE SUITE APPEARS TO HAVE ABOVE AVERAGE  
AGREEMENT ON THE MAIN SYNOPTIC SCALE FEATURES THROUGH EARLY  
SATURDAY, WITH JUST SOME MINOR DIFFERENCES IN THE TIMING OF THE  
UPPER TROUGH EVOLUTION OVER THE WESTERN STATES. THE GFS IS NOT AS  
PROGRESSIVE AS EARLIER RUNS WITH THE AXIS OF THE MAIN TROUGH AXIS  
ACROSS THE CENTRAL/NORTHERN PLAINS, ALTHOUGH THE CMC IS SLOWER IN  
LIFTING THE TROUGH/CLOSED LOW OUT OF THE REGION. BY EARLY NEXT  
WEEK, THE MODELS ARE IN GOOD AGREEMENT ON THE DEPICTION OF ANOTHER  
STORM SYSTEM OVER THE NORTHEAST PACIFIC OCEAN, BUT MODEL  
DIFFERENCES STILL EXIST WITH THE DEGREE OF UPPER LEVEL RIDGING  
AHEAD OF THAT FEATURE ACROSS THE INTERMOUNTAIN WEST. A NEARLY  
MULTI-DETERMINISTIC MODEL BLEND WAS INCORPORATED AS A STARTING  
POINT FOR FRIDAY AND SATURDAY, AND THEN MORE OF THE ECMWF/ECENS  
WAS USED GOING FORWARD INTO EARLY NEXT WEEK ALONG WITH SOME OF THE  
GFS AND GEFS MEAN.  
   
..SENSIBLE WEATHER/THREATS
 
 
THE THREAT OF A NOTEWORTHY WINTER STORM IS INCREASING WITH TIME  
FOR WESTERN NORTH DAKOTA AND PORTIONS OF EASTERN MONTANA FOR THE  
UPCOMING WEEKEND ON THE BACKSIDE OF THE INTENSIFYING SURFACE LOW,  
WHERE A WELL-DEFINED DEFORMATION ZONE WILL LIKELY EXIST. THIS  
WILL LIKELY BE COUPLED WITH STRONG NORTHERLY WINDS OWING TO THE  
TIGHT PRESSURE GRADIENT THAT WILL BE IN PLACE, AND THIS COULD  
RESULT IN BLIZZARD CONDITIONS FOR SOME AREAS IF THESE MODEL TRENDS  
CONTINUE. MODERATE TO HEAVY SNOW IS ALSO LIKELY FOR THE NORTHERN  
ROCKIES THROUGH EARLY SATURDAY, AND THIS WILL ALSO INCLUDE THE  
HIGHER TERRAIN OF NORTHERN UTAH AND CENTRAL COLORADO.  
 
HEAVY SHOWERS AND THUNDERSTORMS COULD ALSO MAKE WEATHER HEADLINES  
ON SUNDAY AND GOING INTO EARLY MONDAY ACROSS THE CENTRAL U.S. AS A  
DEEP SURGE OF GULF MOISTURE ADVECTS NORTHWARD AND INTERACTS WITH A  
SLOW MOVING SURFACE COLD FRONT WITH MULTIPLE SHORTWAVE  
PERTURBATIONS MOVING OVERHEAD. THIS WILL LIKELY BE IN THE FORM OF  
MULTIPLE MESOSCALE CONVECTIVE COMPLEXES WITH REPEATING ROUNDS OF  
CONVECTION, AND SOME STRONG TO SEVERE STORMS ARE ALSO POSSIBLE.  
 
IN TERMS OF TEMPERATURES, A MAJOR WARMING TREND IS FORECAST FOR  
MUCH OF THE EASTERN HALF OF THE NATION GOING INTO THE WEEKEND,  
ALONG WITH INCREASING HUMIDITY LEVELS, IN RESPONSE TO DEEP  
SOUTHERLY FLOW AHEAD OF THE CENTRAL U.S. STORM SYSTEM. ONE OF THE  
CAVEATS IN THE TEMPERATURE FORECAST WILL BE THE PRESENCE OF A BACK  
DOOR COLD FRONT/COLD AIR DAMMING FOR THE MID-ATLANTIC AND  
NORTHEAST U.S. THIS WEEKEND, WITH POTENTIALLY A BIG CONTRAST OVER  
A RELATIVELY SHORT DISTANCE NEAR THE FRONT. IT WILL LIKELY REMAIN  
UNCOMFORTABLY COLD FROM MONTANA TO NORTH DAKOTA AND NORTHERN  
MINNESOTA WITH NEAR-FREEZING HIGHS RUNNING 15 TO 25 DEGREES BELOW  
NORMAL.  
 
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, EXPERIMENTAL EXCESSIVE RAINFALL  
OUTLOOK, 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/#PAGE=ERO  
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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