297
FXUS02 KWBC 131900
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
200 PM EST THU FEB 13 2025
VALID 12Z SUN FEB 16 2025 - 12Z THU FEB 20 2025
...STRONG STORM TO BRING HEAVY SNOW TO THE NORTHEAST AND LOCALLY
HEAVY RAIN TO THE MID-ATLANTIC AND SOUTHEAST ON SUNDAY...
..OVERVIEW
A DEEP UPPER TROUGH LIFTING THROUGH THE EAST ON SUNDAY WILL
SUPPORT A STRENGTHENING SURFACE LOW THAT SHOULD TRACK FROM THE OHIO
VALLEY TO THE CANADIAN MARITIMES SUNDAY INTO MONDAY. THIS STORM IS
FORECAST TO BRING IMPACTFUL WINTER WEATHER AND STRONG WINDS TO NEW
ENGLAND AND LOCALLY HEAVY RAIN TO THE MID-ATLANTIC AND SOUTHEAST.
BEHIND THIS SYSTEM, AN ELONGATING UPPER TROUGH/LOW WILL LIKELY
LINGER ACROSS THE NORTHERN TIER OF THE NATION WHILE A FEW
SHORTWAVES/FRONTAL SYSTEMS MOVE INTO THE WEST. THESE SYSTEMS WILL
BRING ROUNDS OF LOW ELEVATION RAIN AND MOUNTAIN SNOW TO THE PACIFIC
NORTHWEST, NORTHERN CALIFORNIA, AND THE NORTHERN/CENTRAL ROCKIES
THROUGH THE PERIOD. PRECIPITATION IS EXPECTED TO SPREAD INTO THE
CENTRAL/SOUTHERN PLAINS EARLY NEXT WEEK AS A LOW PRESSURE SYSTEM
MOVES SOUTH ACROSS THE REGION TOWARDS THE GULF COAST, THEN
PRECIPITATION WILL EXPAND ACROSS THE SOUTH AND SOUTHEAST MID-NEXT
WEEK AS THE LOW SWINGS ALONG THE GULF COAST TO THE SOUTHEAST. SOME
WINTRY WEATHER IS EXPECTED ON THE NORTHERN SIDE OF THIS SYSTEM FROM
THE CENTRAL/SOUTHERN PLAINS THROUGH THE MID-MISSISSIPPI AND
TENNESSEE VALLEYS TO THE MID-ATLANTIC. MEANWHILE, ARCTIC HIGH
PRESSURE WILL EXPAND SOUTH AND EAST INTO THE CENTRAL AND EASTERN
U.S. THROUGH THE PERIOD, RESULTING IN MULTIPLE DAYS OF WELL BELOW
AVERAGE TEMPERATURES.
..GUIDANCE/PREDICTABILITY ASSESSMENT
MODELS CONTINUE TO SHOW GOOD AGREEMENT ON THE OVERALL PATTERN WITH
SOME DIFFERENCES IN THE DETAILS OF SPECIFIC SYSTEMS. SINCE
YESTERDAY, MODEL AGREEMENT HAS INCREASED AROUND THE POSITION,
TIMING, AND DEPTH OF THE TROUGHS OVER THE NORTHERN TIER AND IN THE
WEST LATE THIS WEEKEND INTO EARLY NEXT WEEK. THEREFORE, A GENERAL
BLEND OF THE 06Z GFS AND 00Z ECMWF/CMC/UKMET SEEMED TO PRODUCE A
GOOD STARTING POINT FOR WPCS AFTERNOON FORECAST. HEAVIEST WEIGHT
WAS PUT ON THE GFS AND ECMWF, WHICH SHOWED THE MOST SKILL ALTER IN
THE PERIOD WHEN MODEL SPREAD BECOMES MORE SIGNIFICANT. THE HIGHEST
UNCERTAINTY IN THE FORECAST IS ON DAY SEVEN/THURSDAY WHEN THE
EVOLUTION OF LOW PRESSURE OVER THE SOUTHEAST BECOMES LESS CLEAR.
THE GFS/ECMWF-AIFS ARE THE MOST PROGRESSIVE WITH THIS SYSTEM WHILE
THE ECMWF/CMC ARE QUITE A BIT SLOWER. FOR WPCS FORECAST, ENSEMBLE
MEANS FROM THE GEFS/ECENS WERE ADDED TO THE BLEND TO RESULT IN A
FORECAST FALLING IN THE MIDDLE OF THE FASTER AND SLOWER SOLUTIONS.
..WEATHER/HAZARDS HIGHLIGHTS
THE STRENGTHENING STORM LIFTING NORTHEASTWARD FROM THE UPPER OHIO
VALLEY ON SUNDAY WILL PUSH A QUICK-MOVING COLD FRONT EAST ACROSS
THE MID-ATLANTIC AND SOUTHEAST. LOCALLY HEAVY RAINFALL WILL BE
POSSIBLE AHEAD OF AND ALONG THE COLD FRONT, BUT THE THREAT OF FLASH
FLOODING WILL BE GREATLY REDUCED AS COMPARED TO SATURDAY. EVEN SO,
ANY ADDITIONAL RAINFALL IN THE MID-ATLANTIC AND APPALACHIANS COULD
CAUSE SOME FLOODING CONCERNS GIVEN THE SATURATED SOILS FROM
RAINFALL THE DAY BEFORE.
WINTRY WEATHER IS EXPECTED ON THE NORTHERN SIDE OF THIS SYSTEM AS
THE LOW TRACKS JUST SOUTH OF NEW ENGLAND. A SWATH OF HEAVY SNOW
WILL BE POSSIBLE FROM THE EASTERN GREAT LAKES THROUGH THE
NORTHEAST, AND A TRANSITION ZONE OF WINTRY MIXED PRECIPITATION WILL
EXIST BETWEEN THE SNOW ZONE AND RAIN TO THE SOUTH. PRECIPITATION
SHOULD TAPER OFF ACROSS THE EAST SUNDAY NIGHT THROUGH MONDAY AS THE
SYSTEM MOVES OFFSHORE INTO THE ATLANTIC, BUT SOME LINGERING LAKE
EFFECT SNOW IS POSSIBLE IN THE GREAT LAKES. THE TIGHT PRESSURE
GRADIENT AROUND THIS SYSTEM MAY RESULT IN A PERIOD OF STRONG, GUSTY
WINDS ACROSS THE APPALACHIANS AND THE NORTHEAST EARLY NEXT WEEK.
IN THE WEST, A PACIFIC SYSTEM WILL LIKELY CONTINUE TO PRODUCE RAIN
AND MOUNTAIN SNOW OVER THE PACIFIC NORTHWEST ON SUNDAY.
PRECIPITATION AMOUNTS/RATES ARE STILL FORECAST TO STAY BELOW THE
CRITERIA FOR AN EXCESSIVE RAINFALL OUTLOOK AREA, BUT LIGHT TO
MODERATE PRECIPITATION WILL BE POSSIBLE. PRECIPITATION WILL PUSH
EAST/SOUTHEAST THROUGH THE ROCKIES EARLY NEXT WEEK WHILE TAPERING
OFF IN THE PACIFIC NORTHWEST. THEN, ANOTHER SYSTEM SHOULD BRING
PRECIPITATION BACK TO THE NORTHWEST TUESDAY INTO WEDNESDAY WITH
ANOTHER ROUND OF LIGHT TO MODERATE TOTALS.
ENERGY FROM THE LEADING PACIFIC SYSTEM SHOULD EMERGE EAST OF THE
ROCKIES BY MONDAY/TUESDAY AND LOW PRESSURE AND PRECIPITATION WILL
DEVELOP ACROSS THE CENTRAL/SOUTHERN PLAINS. THIS AREA OF LOW
PRESSURE WILL SINK SOUTH TOWARDS THE GULF COAST, THEN SWING EAST
TOWARDS THE SOUTHEAST WEDNESDAY/THURSDAY. HEAVY RAIN WILL BE
POSSIBLE ACROSS THE SOUTH AND SOUTHEAST, AND WINTRY WEATHER WILL BE
POSSIBLE ON THE NORTHERN SIDE OF THE SYSTEM FROM THE PLAINS
THROUGH THE MID-MISSISSIPPI/TENNESSEE VALLEYS TO THE MID-ATLANTIC.
TEMPERATURE-WISE, WELL BELOW NORMAL TEMPERATURES WILL LIKELY
PREVAIL THROUGH THE PERIOD OVER MUCH OF THE CENTRAL U.S., WITH
SURGES REACHING INTO THE SOUTHERN PLAINS ON SUNDAY AND AGAIN NEXT
WEDNESDAY-THURSDAY. RECENT COLDER TRENDS IN GUIDANCE SUGGEST SOME
LOCATIONS COULD BE AT LEAST 30 DEGREES BELOW NORMAL (ESPECIALLY FOR
HIGHS) WITH AN INCREASING SIGNAL FOR SOME DAILY RECORD LOWS/COLD
HIGHS BY AROUND MIDWEEK. THE EAST WILL ALSO SEE SIGNIFICANTLY
COLDER TEMPERATURES AFTER A VERY BRIEF EPISODE OF WARMTH ALONG THE
EAST COAST AHEAD OF THE SUNDAY SYSTEM'S COLD FRONT. COLDEST
ANOMALIES OF 10-25 DEGREES BELOW AVERAGE OVER THE EAST SHOULD
EXTEND OVER THE GREAT LAKES/OHIO VALLEY INTO THE MID-
ATLANTIC/SOUTHERN NEW ENGLAND. EXPECT TEMPERATURES IN THE WEST TO
REMAIN FAIRLY CLOSE TO NORMAL, WITH THE NORTHWEST TENDING TO BE
SLIGHTLY BELOW AND SOUTHERN AREAS A LITTLE ABOVE.
DOLAN/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 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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