268  
FXUS02 KWBC 170655  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
254 AM EDT SUN APR 17 2022  
 
VALID 12Z WED APR 20 2022 - 12Z SUN APR 24 2022  
   
..WEATHER PATTERN OVERVIEW
 
 
THE DEPARTURE OF THE STRONG LOW PRESSURE SYSTEM FROM NEW ENGLAND  
WILL LEAVE A SURFACE HIGH IN ITS WAKE ACROSS THE EASTERN U.S. ON  
WEDNESDAY. AT THE SAME TIME, AN ORGANIZING STORM SYSTEM JUST  
NORTH OF THE CANADIAN BORDER WILL BRING A COLD FRONT EASTWARD  
ACROSS THE NORTH-CENTRAL U.S. WITH A WEAKENING LOW FARTHER SOUTH  
ACROSS THE CENTRAL PLAINS. ATTENTION THEN TURNS TO THE WESTERN  
U.S. BY FRIDAY AS AN AMPLIFIED UPPER LEVEL TROUGH BECOMES  
ESTABLISHED OVER THE INTERMOUNTAIN WEST, AND THIS WILL SUPPORT THE  
DEVELOPMENT OF A POTENTIALLY STRONG SURFACE LOW OVER THE  
CENTRAL/NORTHERN PLAINS IN TIME FOR THE WEEKEND.  
   
..MODEL GUIDANCE EVALUATION
 
 
THE 00Z MODEL GUIDANCE SUITE APPEARS TO HAVE ABOVE AVERAGE  
AGREEMENT ON THE MAIN SYNOPTIC SCALE FEATURES THROUGH THURSDAY  
NIGHT, WITH JUST SOME MINOR DIFFERENCES IN COLD FRONT TIMING  
ACROSS THE GREAT LAKES AND MIDWEST. BY FRIDAY, THE 18/00Z RUNS OF  
THE GFS BECOME MORE PROGRESSIVE WITH THE AXIS OF THE MAIN TROUGH  
AXIS ACROSS THE WESTERN U.S., AND THIS DIFFERENCE IS EVEN MORE  
APPARENT GOING INTO SATURDAY ACROSS THE HIGH PLAINS. MEANWHILE,  
THE 00Z CMC AND ECMWF ARE IN CLOSE AGREEMENT AND DEPICT A CLOSED  
LOW EVOLVING OVER THE DESERT SOUTHWEST BY FRIDAY NIGHT, AND THIS  
ALSO HAS SUPPORT FROM THE 00Z UKMET. THE EARLIER 12Z RUN OF THE  
CMC WAS MUCH SLOWER AND ON THE EDGE OF THE ENSEMBLE SPREAD. THIS  
TREND CONTINUES THROUGH THE WEEKEND, AND THE MODEL PREFERENCE FOR  
THE LATER HALF OF THE FORECAST PERIOD IS FOR A CMC/ECMWF/ECENS  
BLEND AS A STARTING POINT.  
   
..SENSIBLE WEATHER/THREATS
 
 
IN THE PRECIPITATION DEPARTMENT, THE WEST COAST REGION IS EXPECTED  
TO REMAIN ACTIVE WITH A STRONG COLD FRONT AND ONSHORE FLOW  
DIRECTED INLAND ACROSS THE MOUNTAINOUS TERRAIN OF CENTRAL AND  
NORTHERN CALIFORNIA. THIS LATE SEASON EVENT WILL DELIVER HIGHLY  
BENEFICIAL PRECIPITATION TO DROUGHT-STRICKEN AREAS OF CALIFORNIA,  
WITH THE POTENTIAL FOR UP TO THREE INCHES OF RAIN IN SOME AREAS  
NEXT WEEK, AND 1-3 FEET OF SNOW FOR THE SIERRA. ELSEWHERE ACROSS  
THE CONTINENTAL U.S., IMPROVING WEATHER CAN BE EXPECTED FOR THE  
NORTHEAST AS THE STRONG STORM SYSTEM MOVES OUT OF THE REGION.  
ANOTHER ROUND OF ORGANIZED SHOWERS AND STORMS IS EXPECTED TO  
DEVELOP ACROSS THE CENTRAL U.S. AND EXTENDING NORTHWARD TO THE  
GREAT LAKES BY MID-LATE WEEK AS GULF MOISTURE IS ADVECTED  
NORTHWARD AHEAD OF THE ORGANIZING STORM SYSTEM OVER THE CENTRAL  
PLAINS. ADDITIONAL MODERATE TO HEAVY SNOW IS ALSO EXPECTED FOR  
PORTIONS OF THE NORTHERN ROCKIES FOR FRIDAY AND INTO THE WEEKEND,  
WITH SOME SNOW POTENTIALLY AFFECTING WESTERN PORTIONS OF THE  
DAKOTAS BY NEXT WEEKEND.  
 
TEMPERATURES ARE EXPECTED TO REMAIN RATHER CHILLY FROM THE  
NORTHERN PLAINS TO THE GREAT LAKES AND APPALACHIANS THROUGH ABOUT  
WEDNESDAY, AND THESE BELOW AVERAGE READINGS MAY PERSIST EVEN  
LONGER ACROSS NORTH DAKOTA AND NORTHERN MINNESOTA GOING THROUGH  
THE END OF THE WEEK. ON THE CONTRARY, WARM CONDITIONS ARE  
CURRENTLY EXPECTED ACROSS MUCH OF THE INTERIOR WESTERN U.S. FOR  
THE MAJORITY OF THE FORECAST PERIOD AHEAD OF THE UPPER TROUGH,  
WITH WELL ABOVE NORMAL READINGS PROBABLE ACROSS THE WESTERN HIGH  
PLAINS BY THE END OF THE WEEK AND INTO TEXAS. TEMPERATURES SHOULD  
ALSO MODERATE FOR THE EASTERN U.S. BY THURSDAY AS THE SURFACE HIGH  
MOVES OFF THE COAST AND WARMER SOUTHERLY FLOW COMMENCES.  
 
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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