427  
FXUS02 KWBC 300715  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
315 AM EDT SAT MAR 30 2024  
 
VALID 12Z TUE APR 02 2024 - 12Z SAT APR 06 2024  
   
..HEAVY RAIN/SEVERE WEATHER THREAT TO THE EASTERN U.S. MIDWEEK
 
 
...NEW ENGLAND COASTAL STORM WITH MARITIME HAZARDS/HIGH WIND/COASTAL  
FLOODING AND INTERIOR NORTHEAST HEAVY SNOW THREAT TUESDAY-THURSDAY...   
..WIDESPREAD PRECIPITATION/COOLING FOR THE WEST MID-LATER WEEK
 
 
   
..GUIDANCE/PREDICTABILITY ASSESSMENT
 
 
MODEL GUIDANCE HAS BECOME INCREASINGLY BETTER CLUSTERED THROUGH  
MEDIUM RANGE TIME SCALES, BOLSTERING FORECAST CONFIDENCE IN AT  
LEAST THE MID-LATER SCALE SYSTEM DEVELOPMENTS AND EVOLUTIONS. A  
FAVORED MODEL COMPOSITE SEEMS TO MITIGATE SMALLER SCALE EMBEDDED  
SYSTEM VARIANCE TO PROVIDE A REASONABLE FORECAST BASIS WITH DETAIL  
CONSISTENT WITH AN ANOMOLOUS AND STORMY EARLY SPRING PATTERN WITH  
SEEMINGLY ABOVE NORMAL PREDICTABILITY. WPC PRODUCT CONTINUITY IS  
WELL MAINTAINED AND SUPPORTED BY MULTI-MODEL ENSEMBLES.  
   
..PATTERN OVERVIEW AND WEATHER/HAZARDS HIGHLIGHTS
 
 
 
MOISTURE AND INSTABILITY REMAIN ANOMALOUSLY HIGH INTO TUESDAY AS A  
ORGANIZED MAIN LOW/FRONTAL SYSTEM TRACKS INTO THE EAST UNDER  
FAVORABLE UPPER SUPPORT. THE HEAVIEST RAINFALL WILL WORK OUT FROM  
THE TENNESSEE VALLEY/OHIO VALLEYS AND THROUGH THE APPALACHIANS AND  
NORTH-CENTRAL MID-ATLANTIC WHERE A WPC MARGINAL RISK EXCESSIVE  
RAINFALL OUTLOOK (ERO) MARGINAL RISK THREAT AREA REMAINS IN PLACE.  
THE STORM PREDICTION CENTER IS MONITORING SEVERE POTENTIAL IN THE  
WARM SECTOR. UNCERTAINTY WITH CONVECTIVE LOCAL FOCUS HAS PRECLUDED  
ISSUANCE OF A SLIGHT RISK ERO AREA AT THIS TIME DESPITE MOIST MID-  
ATLANTIC SOILS AND SOME HEAVIER MODEL QPF SIGNALS TO MONITOR.  
 
THIS SYSTEM WILL TRANSITION TO A DEEP/SLOW MOVING COASTAL STORM  
JUST OFF NEW ENGLAND WEDNESDAY AND THURSDAY. THIS SETUPS A  
PROTRACTED PERIOD WITH ENHANCED WRAP-BACK ATLANTIC MOISTURE INFLOW  
INTO NEW ENGLAND TO FUEL COOLED HEAVY RAINFALL, WITH FOCUS AND  
DURATION MAXIMIZED OVER EASTERN NEW ENGLAND WET SOILS WHERE A DAY  
5/WEDNESDAY SLIGHT RISK ERO HAS BEEN INTRODUCED TO INCLUDE RUNOFF  
SUSCEPTIBLE METRO AREAS FROM PROVIDENCE AND BOSTON TO PORTLAND.  
 
MEANWHILE AND SIGNIFICANTLY ON THE COLDER NORTHERN SIDE OF STORM  
SYSTEM, THERE WILL BE A SIGNIFICANT THREAT FOR BLOWING WINDS AND  
HEAVY SNOWS OUT FROM THE GREAT LAKES AND THROUGH THE INTERIOR  
NORTHEAST TUESDAY TO THURSDAY AS DEPICTED BY ENHANCED WPC WINTER  
WEATHER OUTLOOK PROBABILITIES.  
 
WELL UPSTREAM, A STRONGLY AMPLIFYING UPPER TROUGH/CLOSED LOW AND  
LEADING AND WAVY COLD FRONT/SECONDARY CANADIAN COLD SURGE DIGGING  
INTO THE WEST SHOULD ACT TO COOL TEMPERATURES AND SPREAD ENHANCED  
PRECIPITATION AND WINDY/UNSETTLED FLOW TO INCLUDE COASTAL RAINS  
DOWN THROUGH CALIFORNIA ALONG WITH A PROLONGED PERIOD WITH INTERIOR  
AND TERRAIN/MOUNTAIN SNOWS INCREASINGLY INLAND ACROSS MUCH OF THE  
WEST MIDWEEK INTO NEXT WEEKEND. DEPICTED AREAS OF PRECIPITATION ARE  
CURRENTLY ON THE MODEST TO MODERATE SIDE GIVEN TRACK/MOISTURE, BUT  
AMPLE UPPER SUPPORT AND FAVORED TERRAIN LIFT MAY LEAD TO LOCALLY  
HEAVIER FOCUS AND ACTIVITY TO MONITOR. THE WPC WINTER WEATHER  
OUTLOOK SHOWS THE GREATEST SNOW PROBABILITIES OVER NORTHWEST TO  
NORTHERN INTERMOUNTAIN/ROCKIES TERRAIN/MOUNTAINS.  
 
SCHICHTEL  
 
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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