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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