259  
FXUS02 KWBC 040701  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
259 AM EDT MON APR 04 2022  
 
VALID 12Z THU APR 07 2022 - 12Z MON APR 11 2022  
   
..OVERVIEW
 
 
THE LARGE SCALE REGIME FROM LATE THIS WEEK INTO EARLY NEXT WEEK  
WILL REMAIN AMPLIFIED BUT PROGRESSION/EVOLUTION DURING THE PERIOD  
WILL ESSENTIALLY LEAD TO A FLIP OF THE UPPER LEVEL PATTERN, WITH  
AN INITIAL WESTERN RIDGE/EAST-CENTRAL U.S. TROUGH ULTIMATELY  
TRENDING TOWARD A WESTERN TROUGH/EASTERN RIDGE. PRECIPITATION  
WILL STEADILY DECREASE IN COVERAGE AND INTENSITY OVER THE EASTERN  
HALF OF THE COUNTRY WHILE CHILLY TEMPERATURES WILL PROGRESS FROM  
THE PLAINS THROUGH EAST LATE WEEK THROUGH THE WEEKEND. MEANWHILE  
THE WEST WILL SEE MUCH ABOVE NORMAL TEMPERATURES LATE THIS WEEK,  
WITH SOME DAILY RECORDS POSSIBLE OVER AND NEAR CALIFORNIA,  
FOLLOWED BY A COOLER TREND DURING THE WEEKEND INTO EARLY NEXT WEEK  
WHILE AREAS OF PRECIPITATION SPREAD ACROSS THE REGION. AS THIS  
OCCURS, ABOVE NORMAL TEMPERATURES WILL SHIFT INTO THE PLAINS AND  
EVENTUALLY PARTS OF THE EAST.  
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
BASED ON 12Z/18Z GUIDANCE, AN OPERATIONAL MODEL BLEND EARLY (WITH  
LEAST WEIGHT ON THE UKMET) FOLLOWED BY A MIX OF THE GFS/ECMWF/CMC  
AND 18Z GEFS/12Z ECMWF MEANS PROVIDED A GOOD DEPICTION OF  
CONSENSUS. CONTINUITY ADJUSTMENTS WERE AGAIN FAIRLY MODEST AND  
REPRESENTED TYPICAL RUN-TO-RUN DETAIL REFINEMENTS. THE OVERALL  
FORECAST OF THE DEEP EASTERN UPPER TROUGH AND ASSOCIATED SURFACE  
EVOLUTION IS FAIRLY CONSISTENT. THE MAJORITY CLUSTER MAINTAINS  
GOOD DEFINITION OF THE EMBEDDED UPPER LOW INTO DAY 4 FRIDAY,  
FOLLOWED BY SOLUTIONS SHOWING VARYING WAYS IN WHICH IT MAY  
WEAKEN/OPEN UP. LATEST UKMET RUNS HAVE BEEN THE FAST EXTREME  
WITH SHORTWAVE ENERGY ON THE EAST SIDE OF THE TROUGH AND THUS WITH  
THE MID-ATLANTIC THROUGH NEW ENGLAND COASTAL WAVE. THE  
ECMWF/ECMWF MEAN ARE A BIT ON THE SLOWER SIDE. AN INTERMEDIATE  
SOLUTION CONTINUES TO LOOK GOOD FOR DEPICTING THE SPECIFICS OF THE  
UPPER TROUGH AND SURFACE REFLECTION. FORECASTS OF THE UPPER  
TROUGH REACHING THE WEST HAVE BEEN MORE VARIED, DUE IN PART TO  
INVOLVEMENT OF SEPARATE SHORTWAVES. RECENT TRENDS HAVE BEEN  
TOWARD A SLIGHTLY BROADER TROUGH AS IT REACHES THE NORTHWEST EARLY  
IN THE WEEKEND (A LITTLE MORE TOWARD PRIOR GFS RUNS) BUT BY  
SUNDAY-MONDAY THE ENSEMBLE MEANS FROM THE PAST COUPLE DAYS HAVE  
BEEN STABLE IN DEPICTING STEADY AMPLIFICATION. RECENT GFS RUNS  
COULD BE OVERDONE WITH THE LEADING SHORTWAVE ENERGY PUSHING INTO  
THE CONSENSUS MEAN RIDGE CROSS SOUTHERN CANADA (TONED DOWN A BIT  
IN THE NEW 00Z RUN). OTHERWISE THE LATEST GFS/ECMWF/CMC RUNS  
COMPARE FAVORABLY TO EACH OTHER AND THE MEANS. AN EMBEDDED UPPER  
LOW MAY REACH THE NORTHWEST BY NEXT MONDAY.  
   
..WEATHER HIGHLIGHTS/THREATS
 
 
HEAVIEST RAINFALL WITH THE SYSTEM AFFECTING THE EASTERN HALF OF  
THE COUNTRY SHOULD BE THURSDAY INTO FRIDAY AND FOCUSED BY THE  
TRIPLE POINT WAVE LIFTING FROM THE MID-ATLANTIC INTO NEW ENGLAND.  
SPECIFICS WITHIN THIS AREA OF POTENTIALLY ENHANCED RAIN ARE STILL  
UNCERTAIN, WITH ADDITIONAL TIME NEEDED TO RESOLVE IMPORTANT  
DETAILS. SOME POCKETS OF LOCALLY MODERATE TO HEAVY RAINFALL COULD  
EXTEND ALONG THE TRAILING FRONT AS FAR SOUTH AS FLORIDA, AND THE  
STORM PREDICTION CENTER IS MONITORING SEVERE POTENTIAL OVER PARTS  
OF THE MID-ATLANTIC. CHECK SPC'S OUTLOOKS FOR THE LATEST  
INFORMATION ON SEVERE THREATS. PRECIPITATION IN THE VICINITY OF  
THE GREAT LAKES LOW SHOULD TREND LIGHTER AFTER MIDWEEK. HOWEVER  
COLD AIR ALOFT ASSOCIATED WITH THE UPPER TROUGH WILL LIKELY  
PROMOTE AREAS OF DIURNALLY ENHANCED SHOWERS FROM THE MIDWEST INTO  
THE NORTHERN HALF TO TWO-THIRDS OF THE EAST INTO FRIDAY-SATURDAY.  
SOME PRECIPITATION COULD BE IN THE FORM OF SNOW BETWEEN THE  
MIDWEST AND APPALACHIANS. THE UPPER TROUGH AMPLIFYING OVER THE  
WEST WILL GRADUALLY INCREASE THE COVERAGE OF MOSTLY LIGHT TO  
MODERATE RAIN AND HIGHER ELEVATION SNOW FROM LATE WEEK ONWARD.  
MOST OF THIS PRECIPITATION SHOULD BE OVER THE NORTHERN HALF OF THE  
REGION INTO EARLY MONDAY BUT MAY PUSH FARTHER SOUTH THEREAFTER.  
 
THE UPPER RIDGE OVER THE WEST LATE THIS WEEK WILL PRODUCE WELL  
ABOVE NORMAL TEMPERATURES ACROSS THE REGION. FORECASTS CONTINUE TO  
SHOW HIGHS REACHING 15-25F ABOVE NORMAL THURSDAY-FRIDAY FROM PARTS  
OF CALIFORNIA AND OREGON INTO THE GREAT BASIN ALONG WITH SOME  
DAILY RECORDS FOR HIGHS/WARM LOWS. THEN THE UPPER TROUGH ARRIVING  
FROM THE PACIFIC WILL BRING IN COOLER AIR, WITH THE NORTHWEST  
TRENDING BELOW NORMAL DURING THE WEEKEND AND MUCH OF THE WEST  
LIKELY TO SEE HIGHS 5-15F BELOW NORMAL BY NEXT MONDAY. MEANWHILE  
HIGHS OF 5-15F OR SLIGHTLY MORE BELOW NORMAL WILL PROGRESS FROM  
THE PLAINS/MISSISSIPPI VALLEY INTO THE EAST LATE WEEK INTO THE  
WEEKEND. A TRAILING WARMING TREND WILL BRING PLUS 10-20F  
ANOMALIES INTO THE PLAINS FOR THE WEEKEND AND PERSISTING OVER SOME  
AREAS INTO MONDAY WHILE EASTERN U.S. READINGS REBOUND CLOSER TO OR  
SLIGHTLY ABOVE NORMAL BY EARLY NEXT WEEK.  
 
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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