626  
FXUS02 KWBC 260659  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
259 AM EDT SUN MAR 26 2023  
 
VALID 12Z WED MAR 29 2023 - 12Z SUN APR 2 2023  
   
..SYNOPTIC OVERVIEW
 
 
THE WEATHER PATTERN MID NEXT WEEK WILL BE FEATURED WITH STRONG LOW  
PRESSURE SYSTEM OVER CALIFORNIA THAT MOVES INLAND ACROSS THE  
INTERMOUNTAIN WEST THURSDAY, AND THEN EMERGES OVER THE PLAINS AND  
MIDWEST BY FRIDAY AND INTO NEXT WEEKEND. THIS WILL LIKELY RESULT  
IN AN INCREASE OF SHOWERS AND THUNDERSTORMS ACROSS MUCH OF THE  
PLAINS AND MIDWEST STATES. THIS TROUGH OVER THE WESTERN U.S. WILL  
SERVE TO AMPLIFY THE DOWNSTREAM UPPER RIDGE OVER THE SOUTH-CENTRAL  
U.S. AND THE GULF COAST REGION FOR THE END OF THE WEEK. BY  
SATURDAY, A SECOND TROUGH WILL BECOME ESTABLISHED OVER THE PACIFIC  
NORTHWEST AS A SHORTWAVE DROPS SOUTH FROM THE GULF OF ALASKA. THE  
CLOSED UPPER LOW OVER THE HUDSON BAY REGION WILL REMAINED NEARLY  
ANCHORED IN PLACE, AND THERE WILL BE SOME SHORTWAVES PIVOTING  
AROUND THE SOUTHERN PERIPHERY OF THIS LOW ACROSS THE NORTH-CENTRAL  
U.S. THROUGH THE END OF THE WEEK.  
 
   
..MODEL GUIDANCE/PREDICTABILITY ASSESSMENT
 
 
THE 00Z MODEL GUIDANCE SUITE IS IN DECENT SYNOPTIC SCALE AGREEMENT  
THROUGH THURSDAY NIGHT, AND A GENERAL MODEL BLEND SUFFICES FOR  
THIS TIME PERIOD. THERE HAS BEEN A TREND FOR A MORE OFFSHORE AND  
WEAKER SOLUTION WITH THE DEVELOPING LOW OFF THE EAST COAST  
WEDNESDAY COMPARED TO THE 12Z GUIDANCE, AND THIS WOULD KEEP NEARLY  
ALL OF ITS PRECIPITATION AWAY FROM NEW ENGLAND. LOOKING AHEAD TO  
THE END OF THE WEEK, THE 00Z GFS DEVELOPS A CLOSED LOW BY FRIDAY  
NIGHT ACROSS THE CENTRAL PLAINS AND A LITTLE FASTER THAN THE  
ECMWF/CMC, BUT NOT QUITE AS FAST AS THE GEFS MEAN, WHICH HAS  
CONSISTENTLY BEEN MORE PROGRESSIVE OVER THE PAST FEW DAYS WITH  
THIS TROUGH. BY NEXT SUNDAY, THE GFS IS STRONGER WITH THE NEXT  
TROUGH DEVELOPING OVER THE PACIFIC NORTHWEST. TAKING THESE  
FACTORS INTO ACCOUNT, THE FORECAST FOR FRIDAY-SUNDAY WAS PRIMARILY  
DERIVED FROM A CMC/ECMWF/GFS BLEND WHILE GRADUALLY INCREASING USE  
OF THE ECENS AND SOME OF THE GEFS MEAN.  
 
   
..WEATHER/HAZARDS HIGHLIGHTS
 
 
THE STORM SYSTEM AFFECTING CALIFORNIA EARLY NEXT WEEK WILL LIKELY  
BE ABATING IN INTENSITY BY WEDNESDAY WITH LINGERING MODERATE TO  
LOCALLY HEAVY RAINFALL, WITH PERHAPS HALF AN INCH TO ONE INCH OF  
ADDITIONAL RAINFALL THROUGH WEDNESDAY EVENING BEFORE THINGS BEGIN  
TO DRY OUT. MODERATE TO HEAVY SNOW IS ALSO LIKELY FOR THE HIGHER  
TERRAIN OF THE SIERRA AND SOUTHERN CALIFORNIA MOUNTAINS, WHERE 6  
TO 12 INCHES OF ACCUMULATION IS LIKELY ON WEDNESDAY. SINCE MOST  
OF THE SIGNIFICANT RAINFALL SHOULD OCCUR PRIOR TO 12Z WEDNESDAY,  
THERE ARE NO AREAS ON THE DAY 4 EXCESSIVE RAINFALL OUTLOOK,  
ALTHOUGH THIS COULD CHANGE GOING INTO THE SHORT RANGE PERIOD IF  
THIS STORM SYSTEM SLOWS DOWN IN FUTURE MODEL RUNS.  
 
ON WEDNESDAY, A SURFACE LOW IS LIKELY TO DEVELOP OVER THE OFFSHORE  
WATERS OF THE WESTERN ATLANTIC, AND WITH THIS FORECAST CYCLE, IT  
APPEARS MOST OF THE PRECIPITATION SHOULD REMAIN OFFSHORE AND NOT  
AFFECT THE NORTHEAST STATES, SO A MORE OPTIMISTIC FORECAST FOR  
THIS REGION. BY THE END OF THE WEEK, SHOWERS AND STORMS ARE  
EXPECTED TO INCREASE AHEAD OF A DEVELOPING STORM SYSTEM ACROSS THE  
PLAINS AND MIDWEST. SOME OF THESE STORMS COULD BE SEVERE ON  
THURSDAY ACROSS PORTIONS OF THE SOUTHERN PLAINS, AND WINDY  
CONDITIONS ARE LIKELY TO DEVELOP ACROSS MUCH OF THE PLAINS IN  
GENERAL.  
 
TEMPERATURES ARE EXPECTED TO BE WELL BELOW LATE MARCH AVERAGES  
ACROSS MUCH OF THE NORTHERN INTERMOUNTAIN WEST, THE ROCKIES, AND  
THE DAKOTAS FOR THE WEDNESDAY TO FRIDAY TIME PERIOD, WITH HIGHS  
RUNNING 10 TO 20+ DEGREES BELOW AVERAGE IN MANY CASES. THE  
COLDEST CONDITIONS WILL RESIDE ACROSS NORTH DAKOTA WHERE SOME  
MORNING LOWS NEAR OR EVEN SLIGHTLY BELOW ZERO WILL BE POSSIBLE  
EARLY ON WEDNESDAY. MEANWHILE, THE PRESENCE OF THE GULF COAST  
UPPER RIDGE WILL TEND TO FAVOR TEMPERATURES RUNNING UP TO 15  
DEGREES ABOVE AVERAGE FROM TEXAS TO THE SOUTHEAST U.S. AND FLORIDA  
FOR THE END OF THE WEEK, WITH THE GREATEST ANOMALIES FOR OVERNIGHT  
LOWS WITH INCREASED CLOUDS AND WINDS.  
 
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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