661  
FXUS02 KWBC 071900  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
300 PM EDT MON APR 7 2025  
 
VALID 12Z THU APR 10 2025 - 12Z MON APR 14 2025  
 
   
..GENERAL OVERVIEW
 
 
THE LARGE UPPER TROUGH THAT WILL BE IN PLACE ACROSS THE NORTHEAST  
U.S. EARLY IN THE WEEK IS FORECAST TO LIFT OUT OF THE REGION BY  
THURSDAY. AN AMPLIFYING SHORTWAVE TROUGH ORIGINATING FROM SOUTH-  
CENTRAL CANADA IS EXPECTED TO AMPLIFY AS IT DROPS SOUTHEAST ACROSS  
THE OHIO VALLEY, TO SUPPORT A SURFACE LOW FROM THE MIDWEST TO THE  
MID-ATLANTIC COAST TO CLOSE OUT THE WORK WEEK AND EMERGING OFF THE  
COAST NEXT SATURDAY. MEANWHILE, AN UPPER LEVEL RIDGE BUILDS ACROSS  
THE INTERMOUNTAIN WEST AND ROCKIES THURSDAY INTO FRIDAY, AND THEN  
SHIFTS EASTWARD TO THE PLAINS BY NEXT WEEKEND. WITH THE RIDGE  
DEPARTING THE WEST, AN UPPER TROUGH APPROACHES FROM THE PACIFIC  
NORTHWEST AND SUPPORTS A COLD FRONT CROSSING THE INTERMOUNTAIN WEST  
TO THE CENTRAL/NORTHERN PLAINS THROUGH NEXT MONDAY.  
 
   
..GUIDANCE/PREDICTABILITY ASSESSMENT
 
 
THE LATEST MODELS AND ENSEMBLES REMAIN IN GOOD AGREEMENT AT LEAST  
THROUGH THE FIRST HALF OF THE PERIOD, SHOWING A DEPARTING EASTERN  
TROUGH ONLY TO BE REPLACED WITH AN AMPLIFYING SHORTWAVE ESTABLISHED  
OVER THE EAST BY SATURDAY. MODELS SUGGEST A BRIEF CLOSED LOW OVER  
THE EAST THIS WEEKEND AND THEN SOME INCREASED UNCERTAINTY IN TIMING  
AND PLACEMENT OF THE MAIN ENERGY AS IT EXITS THE NORTHEAST EARLY  
NEXT WEEK. THE NEXT TROUGH ENTERS THE NORTHWEST BY SATURDAY, AND  
THE PAST SEVERAL RUNS OF THE CMC HAS BEEN NOTABLY SLOWER WITH THIS.  
BY MONDAY, THE CMC HAS A CLOSED LOW STILL OVER THE INTERIOR WEST,  
WHILE THE GFS AND ECMWF (WITH SUPPORT FROM THE ENSEMBLE MEANS) IS  
WELL EAST INTO THE UPPER MIDWEST BY THAT POINT.  
 
THE WPC BLEND FOR TODAY UTILIZED A DETERMINISTIC MODEL BLEND FOR  
DAYS 3 AND 4, BRINGING IN THE ENSEMBLE MEANS IN PLACE OF THE CMC BY  
DAY 5. GRADUALLY INCREASED CONTRIBUTIONS OF THE ENSEMBLE MEANS FOR  
LATE PERIOD, BUT STILL MAINTAINED A 50/50 DETERMINISTIC (GFS AND  
ECMWF)/ENSEMBLE MEAN BLEND. THIS MAINTAINED GOOD AGREEMENT WITH THE  
PREVIOUS SHIFT AS WELL.  
 
   
..WEATHER/HAZARDS HIGHLIGHTS
 
 
THE LOW PRESSURE SYSTEM CROSSING THE OHIO VALLEY AND THEN REACHING  
THE EAST COAST TO CLOSE OUT THE WEEK WILL BE THE NEXT EVENT TO  
MONITOR, WITH WIDESPREAD SHOWERS EXPECTED FROM THE DEEP SOUTH TO  
THE GREAT LAKES ON THURSDAY. EVEN THOUGH FORECAST RAINFALL TOTALS  
ARE NOT EXPECTED TO BE HEAVY, THE GROUND WILL LIKELY STILL BE QUITE  
SATURATED FOR MANY OF THOSE AREAS AFFECTED BY THE PROLIFIC RECENT  
RAINFALL, SO THAT IS SOMETHING THAT WILL CONTINUE TO BE MONITORED,  
BUT FOR NOW NO RISK AREAS APPEAR WARRANTED FOR THE DAY 4/THURSDAY  
EXCESSIVE RAINFALL OUTLOOK. COLDER HIGH PRESSURE HELD OVER THE  
NORTHEAST INTERIOR IN ADVANCE OF THE SYSTEM MAY ALLOW FOR SOME  
TERRAIN FOCUSING SNOW CHANCES. A DEEPENING COASTAL LOW NEAR THE  
MID- ATLANTIC COAST ON FRIDAY AND INTO EARLY SATURDAY SHOULD BRING  
HIGHER RAIN CHANCES AND BREEZY CONDITIONS FROM VIRGINIA TO NEW  
ENGLAND INTO NEXT WEEKEND. A MARGINAL RISK AREA CONTINUES FOR DAY  
5/FRIDAY FROM NJ/PA NORTHWARD TO SOUTHERN NEW ENGLAND WITH MORE OF  
AN ENHANCED QPF SIGNAL IN THE DETERMINISTIC GUIDANCE, WITH PERHAPS  
1-2 INCHES OF RAINFALL.  
 
ELSEWHERE ACROSS THE COUNTRY, PERIODS OF MODERATE RAIN AND  
MOUNTAIN SNOW RETURN TO WESTERN WASHINGTON AND OREGON COURTESY OF  
ONSHORE FLOW AND A SHORTWAVE PASSAGE THURSDAY, BUT THIS DOES NOT  
LOOK LIKE A MAJOR EVENT AT THIS TIME. LIGHT SNOW THEN REACHES THE  
HIGHER ELEVATIONS OF THE NORTHERN ROCKIES BY NEXT WEEKEND AS THE  
MOISTURE MOVES INLAND. DRY CONDITIONS ARE FORECAST FROM THE  
SOUTHWESTERN U.S. TO THE CENTRAL/SOUTHERN PLAINS DURING THE ENTIRE  
FORECAST PERIOD.  
 
IN TERMS OF TEMPERATURES, A MODERATING TREND COMMENCES BY THE END  
OF THE WEEK ACROSS THE EASTERN U.S. AS THE UPPER TROUGH LIFTS OUT  
OF NEW ENGLAND. LOOKING AHEAD TO NEXT WEEKEND, LOWS SHOULD BE NEAR  
AVERAGE WHILE DAYTIME HIGHS REMAIN SLIGHTLY BELOW AVERAGE WITH  
INCREASED CLOUD COVER. MEANWHILE, A WARM PATTERN IS EXPECTED FOR  
THE WESTERN U.S. THROUGH THE END OF THE WEEK WITH BOTH DAYTIME  
HIGHS AND OVERNIGHT LOWS ABOUT 10-20 DEGREES ABOVE AVERAGE, WITH  
THE GREATEST ANOMALIES OVER THE GREAT BASIN ON FRIDAY. THESE MILDER  
CONDITIONS THEN REACH THE CENTRAL AND NORTHERN PLAINS BY NEXT  
WEEKEND AS THE RIDGE SHIFTS EASTWARD.  
 
SANTORELLI/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 FORECAST (QPF), EXCESSIVE RAINFALL  
OUTLOOK (ERO), WINTER WEATHER OUTLOOK (WWO) PROBABILITIES, HEAT  
INDICES, AND KEY MESSAGES CAN BE ACCESSED FROM:  
 
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  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/#PAGE=OVW  
 

 
 
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