820  
FXUS02 KWBC 030657  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
256 AM EDT SUN APR 03 2022  
 
VALID 12Z WED APR 06 2022 - 12Z SUN APR 10 2022  
   
..OVERVIEW
 
 
THE LOWER 48 WILL SEE AN AMPLIFIED UPPER PATTERN DURING THE  
PERIOD. DURING THE MID TO LATE WEEK TIME FRAME THE DOMINANT  
FEATURES WILL BE A DEEP EAST-CENTRAL U.S. TROUGH ANCHORED BY AN  
UPPER MIDWEST INTO GREAT LAKES LOW, AND A WESTERN U.S. RIDGE. THE  
UPPER LOW/TROUGH AND ASSOCIATED SURFACE EVOLUTION WILL PRODUCE A  
BROAD AREA OF PRECIPITATION ACROSS THE NORTHERN PLAINS AND EASTERN  
HALF OF THE COUNTRY (WITH SOME POCKETS OF LOCALLY HEAVY TOTALS  
POSSIBLE) WHILE THE WESTERN RIDGE WILL SUPPORT MUCH ABOVE NORMAL  
TEMPERATURES, INCLUDING POTENTIAL FOR SOME RECORD HIGHS/WARM LOWS  
OVER CALIFORNIA AND VICINITY. BY THE WEEKEND EXPECT A PACIFIC  
TROUGH TO MOVE INTO THE WEST, LEADING TO A COOLING TREND AND SOME  
PRECIPITATION, WHILE PROGRESSION OF THE EASTERN TROUGH TO EAST  
COAST SHOULD FAVOR DRIER WEATHER OVER THE EAST.  
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
A BLEND OF 12Z/18Z OPERATIONAL MODELS FOLLOWED BY A TRANSITION TO  
THE 18Z GFS/GEFS MEAN AND 12Z ECMWF PROVIDED A REASONABLE  
DEPICTION OF CONSENSUS IDEAS THROUGH THE PERIOD ALONG WITH FAIRLY  
GOOD CONTINUITY. THE ECMWF MEAN WAS COMPARABLE TO THE GEFS MEAN  
BUT WAS NOT AVAILABLE FOR INCLUDING IN THE BLEND DUE TO A LOCAL  
DATA ISSUE. FOR THE WAVE FORECAST TO BE OVER/NEAR THE  
MID-ATLANTIC EARLY WEDNESDAY, CONSENSUS THROUGH THE 18Z CYCLE WAS  
CONSISTENT WITH A NUMBER OF PREVIOUS RUNS BUT NEW 00Z RUNS  
ACTUALLY SEEM TO ENLARGE THE SPREAD. THE NEW UKMET/CMC ACTUALLY  
SHOW A TRACK INTO THE UPPER OHIO VALLEY BEFORE THE CMC DEVELOPS A  
SEPARATE WAVE THAT TRACKS OFFSHORE LIKE THE 12Z ECMWF AND FASTER  
GFS. UPSTREAM THE GUIDANCE HAD STABILIZED/CONVERGED FOR THE  
NORTHERN TIER UPPER LOW AND SURROUNDING TROUGH, PLUS THE TRIPLE  
POINT COASTAL WAVE, THOUGH BY LATE WEEK INTO THE WEEKEND SOME  
UNCERTAINTY DEVELOPS OVER WHETHER THE UPPER LOW MAY OPEN UP AND  
HOW MUCH SOUTHWESTWARD ELONGATION OF THE TROUGH MAY OCCUR. THE  
00Z UKMET IS QUICKEST TO OPEN UP THE LOW, ULTIMATELY LEADING TO A  
FAST PROGRESSION OF THE THURSDAY-FRIDAY COASTAL WAVE. GFS RUNS  
HAVE BEEN ON THE AMPLIFIED SIDE WITH THE SOUTHWESTERN PART OF THE  
TROUGH BUT THE NEW 00Z RUN HAS TONED DOWN THAT TRAIT SOMEWHAT.  
THE NEW 00Z ECMWF IS CONSISTENT WITH ITS PRIOR RUN. FOR THE UPPER  
TROUGH MOVING INTO THE WEST BY THE WEEKEND, THE CMC CONTINUES TO  
RUN ON THE FAST/DEEP SIDE OF THE SPREAD SO IT HAS NOT BEEN  
INCLUDED IN THE FORECAST BLEND. GFS RUNS HAVE BEEN A LITTLE  
INCONSISTENT WITH POTENTIAL FLOW SEPARATION. OVERALL THE 18Z RUN  
WAS CLOSEST TO THE SIMILAR AND CONSISTENT GEFS/ECMWF MEANS WHILE  
THE 00Z RUN HAS ADJUSTED FASTER AND FLATTER WITH ITS NORTHERN  
STREAM. DETAIL DIFFERENCES AMONG MODEL RUNS AND ENSEMBLE MEMBERS  
CONTINUE TO SUGGEST LOWER PREDICTABILITY FOR THIS OVERALL TROUGH  
VERSUS THE RIDGE/TROUGH CONFIGURATION FARTHER EAST.  
   
..WEATHER HIGHLIGHTS/THREATS
 
 
THE DEEP-LAYER LOW TRACKING OVER THE UPPER MIDWEST INTO GREAT  
LAKES, ALONG WITH A LEADING TRIPLE POINT WAVE THAT MAY BECOME THE  
PRIMARY SYSTEM BY THE END OF THE WEEK--PLUS THE TRAILING COLD  
FRONT--SHOULD SUPPORT MULTIPLE AREAS OF ENHANCED PRECIPITATION  
MID-LATE WEEK. SPECIFICS FOR HEAVIEST TOTALS ARE STILL FAIRLY  
UNCERTAIN THOUGH. ONE AREA OF FOCUS MAY BE FOR SOME COMBINATION  
OF RAIN AND/OR SNOW OVER OR A LITTLE WEST/SOUTH OF LAKE SUPERIOR,  
JUST NORTH OF THE PARENT LOW'S TRACK. MEANWHILE THE WAVE EXPECTED  
TO TRACK FROM THE MID-ATLANTIC NORTHEASTWARD MAY PRODUCE SOME  
LOCALLY MODERATE TO HEAVY RAINFALL. FAR INTERIOR SECTIONS OF NEW  
ENGLAND MAY SEE SOME WINTRY WEATHER ON THE LEADING SIDE OF THE  
MOISTURE. MORE LOCALIZED POCKETS OF ENHANCED RAINFALL ARE  
POSSIBLE FARTHER SOUTH ALONG THE TRAILING COLD FRONT. THE STORM  
PREDICTION CENTER IS MONITORING POTENTIAL FOR SEVERE THREATS  
ACROSS THE SOUTHERN TIER. CHECK THEIR LATEST OUTLOOKS FOR MORE  
INFORMATION. EXPECT LINGERING SHOWERY PRECIPITATION, POSSIBLY  
INCLUDING SOME SNOW FROM THE MIDWEST INTO THE APPALACHIANS, UNDER  
THE COLD UPPER TROUGH INTO SATURDAY. THE UPPER TROUGH PUSHING  
INTO THE WEST BY THE WEEKEND SHOULD BRING MOSTLY LIGHT TO MODERATE  
RAIN AND HIGH ELEVATION SNOW INTO THE NORTHWEST STARTING FRIDAY OR  
SATURDAY.  
 
THE UPPER RIDGE BUILDING INTO THE WEST WILL SPREAD A BROAD AREA OF  
WELL ABOVE NORMAL TEMPERATURES ACROSS THE REGION MID-LATE WEEK.  
HIGHEST TEMPERATURES WILL LIKELY BE ON THURSDAY-FRIDAY WHEN PARTS  
OF CALIFORNIA AND OREGON INTO THE GREAT BASIN COULD SEE READINGS  
15-25F ABOVE NORMAL. SOME DAILY RECORDS FOR HIGHS/WARM LOWS WILL  
BE POSSIBLE. THE UPPER TROUGH ARRIVING FROM THE PACIFIC WILL  
BRING A RAPID COOLING TREND DURING THE WEEKEND, WITH MUCH OF THE  
WEST SEEING NEAR TO BELOW NORMAL HIGHS BY SUNDAY. FARTHER EAST,  
HIGHS GENERALLY 5-15F OR SO BELOW NORMAL WILL PROGRESS FROM THE  
NORTHERN PLAINS/NORTHERN-CENTRAL ROCKIES INTO THE EAST DURING  
WEDNESDAY-SATURDAY UNDER THE DEEP UPPER TROUGH. EXPECT  
TEMPERATURES TO MODERATE NOTICEABLY BY NEXT SUNDAY. FLOW AHEAD OF  
THE UPPER TROUGH WILL BRING A COUPLE DAYS OF ABOVE NORMAL READINGS  
(ESPECIALLY FOR MORNING LOWS) TO THE EAST AROUND  
WEDNESDAY-THURSDAY.  
 
RAUSCH  
 
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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