374
FXUS02 KWBC 301941
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
341 PM EDT SAT MAR 30 2024
VALID 12Z TUE APR 02 2024 - 12Z SAT APR 06 2024
...HEAVY RAIN THREAT FROM PENNSYLVANIA TO NEW JERSEY ALONG WITH
STRONG TO POSSIBLY SEVERE THUNDERSTORMS DOWN THE SPINE OF THE
APPALACHIANS ON TUESDAY...
...NEW ENGLAND COASTAL STORM WITH MARITIME HAZARDS/HIGH
WIND/COASTAL FLOODING ALONG WITH INCREASING HEAVY SNOW THREAT
WEDNESDAY-THURSDAY...
..WIDESPREAD PRECIPITATION/COOLING FOR THE WEST MID-LATE WEEK
...PATTERN OVERVIEW, GUIDANCE/PREDICTABILITY ASSESSMENT, AND
WEATHER/HAZARDS HIGHLIGHTS...
THE MEDIUM-RANGE PERIOD WILL BEGIN WITH A LOW PRESSURE SYSTEM
DEVELOPING FROM ACROSS THE MID-MISSISSIPPI TO THE OHIO VALLEY.
MODEL GUIDANCE CONTINUES WITH THE ONGOING TREND OF SLOWING DOWN THE
UPPER TROUGH THAT IS FORECAST TO LIFT NORTHEASTWARD ACROSS THE
CENTRAL PLAINS. THIS TREND HAS HELPED STRENGTHEN A LOW PRESSURE
WAVE FARTHER BACK OVER THE MID-MISSISSIPPI VALLEY ON TUESDAY WHILE
KEEPING ANOTHER WAVE FARTHER DOWNSTREAM NEAR THE UPPER OHIO VALLEY.
THE BEST DYNAMICS WILL LIKELY SUPPORT HEAVY RAIN FROM PENNSYLVANIA
TO NEW JERSEY ON TUESDAY WHILE AN AXIS OF MODERATE TO HEAVY RAIN
EXTENDS SOUTHWESTWARD DOWN THE SPINE OF THE APPALACHIANS WELL AHEAD
OF A COLD FRONT WHERE MINOR ADJUSTMENTS TO THE MARGINAL EXCESSIVE
RAINFALL RISK AREA WAS NECESSARY. SOME STRONG TO POSSIBLY SEVERE
THUNDERSTORMS ARE EXPECTED TO ACCOMPANY THIS AXIS OF ENHANCED
RAINFALL.
WEDNESDAY WILL LIKELY FEATURE CYCLOGENESIS OVER THE EASTERN U.S.,
WITH NEW ENGLAND LIKELY BEING IMPACTED BY A SIGNIFICANT
NOR'EASTER BY THURSDAY. THERE ARE TWO IMPORTANT CONTRIBUTORS TO
THE CYCLOGENESIS. AN UPPER TROUGH ASSOCIATED WITH A SURGE OF COLD
AIR FROM CENTRAL CANADA IS FORECAST TO DIVE TOWARD THE UPPER GREAT
LAKES ON TUESDAY. GIVEN THE ONGOING SLOWING TREND OF THE UPPER
TROUGH LIFTING ACROSS THE CENTRAL PLAINS, MODELS ARE TRENDING
TOWARD HAVING A DOUBLE-BARREL INSTEAD OF A CONSOLIDATED LOW
PRESSURE SYSTEM TO MOVE ACROSS THE NORTHEAST WEDNESDAY-THURSDAY.
THE SLOWER LIFTING OF THE TROUGH OVER THE CENTRAL PLAINS WILL ALSO
HELP TO LINGER A STRONGER LOW BACK ACROSS THE GREAT LAKES WHILE
KEEPING THE COLD AIR IN PLACE OVER NEW ENGLAND. AS A RESULT, THE
CHANCE OF HEAVY SNOW, INSTEAD OF HEAVY RAIN, HAS CONTINUED TO
INCREASE FROM CENTRAL NEW ENGLAND THROUGH ALL OF MAINE ON THURSDAY.
THERE IS ALSO INCREASING MODEL SUPPORT FOR A RAPIDLY INTENSIFYING
COASTAL LOW TO TAKE OVER AS THE MAIN LOW AND IMPACT NEW ENGLAND
WITH HIGH WINDS, COASTAL FLOODING AND MARINE HAZARDS FROM LATE
WEDNESDAY TO THURSDAY. SNOW COULD BE THE PRIMARY PRECIPITATION
TYPE ALTHOUGH FREEZING RAIN AND SLEET ARE STILL POSSIBLE NEAR THE
COAST.
MEANWHILE AND SIGNIFICANTLY ON THE COLDER NORTHERN SIDE OF STORM
SYSTEM, THERE WILL BE A SIGNIFICANT THREAT FOR LAKE-EFFECT SNOW
BANDS AND SNOW SQUALLS OUT FROM THE GREAT LAKES AND THROUGH THE
INTERIOR NORTHEAST TUESDAY TO THURSDAY AS DEPICTED BY ENHANCED WPC
WINTER WEATHER OUTLOOK PROBABILITIES.
TOWARD THE END OF NEXT WEEK, MODELS SHOW EXCELLENT AGREEMENT ON A
HIGHLY-AMPLIFIED UPPER PATTERN ACROSS THE U.S. WITH A RIDGE
BUILDING OVER THE CENTRAL U.S. AS THE DEEP LOW SLOWLY PULLS OUT OF
THE NORTHEAST AND THE NEXT UPPER TROUGH DIGS JUST OFF THE WEST
COAST. THIS 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.
KONG/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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