034
FXUS02 KWBC 041859
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
159 PM EST TUE FEB 4 2025
VALID 12Z FRI FEB 07 2025 - 12Z TUE FEB 11 2025
...POTENTIALLY HEAVY SNOW AND ICE ACROSS THE NORTHERN MID-ATLANTIC
AND NORTHEAST THIS WEEKEND...
..OVERVIEW
QUASI-ZONAL FLOW WITH EMBEDDED SHORTWAVES ACROSS THE LOWER 48 LATE
WEEK WILL TRANSITION TO A PATTERN WITH A POSITIVELY TILTED MEAN
TROUGH SETTING UP ACROSS THE INTERIOR WEST THIS WEEKEND INTO EARLY
NEXT WEEK, JUST DOWNSTREAM OF A HIGHLY AMPLIFIED PACIFIC THROUGH
AND ALASKA UPPER RIDGE. PRECIPITATION IS LIKELY TO SPREAD THROUGH
THE WEST FRIDAY BEFORE FINALLY TRENDING DRIER OVER THE WEEKEND.
FARTHER EAST, SNOW ACROSS THE NORTH-CENTRAL U.S. AND RAIN CENTERED
IN THE OHIO VALLEY ON FRIDAY WILL CONSOLIDATE INTO A LOW
PRESSURE/FRONTAL SYSTEM BRINGING POSSIBLE LOCALLY HEAVY RAIN TO THE
OHIO VALLEY/CENTRAL APPALACHIANS AND POSSIBLE HEAVY SNOW TO THE
NORTHEAST, ALONG WITH SOME FREEZING RAIN AND SLEET IN BETWEEN, FOR
THE WEEKEND. RAINFALL LOOKS TO REMAIN/GET RENEWED CENTERED OVER THE
TENNESSEE VALLEY INTO EARLY NEXT WEEK, WITH THE POTENTIAL OF
WINTRY PRECIPITATION FROM THE OHIO VALLEY TO MID-ATLANTIC.
TEMPERATURE- WISE, BROAD AREAS OF WELL ABOVE NORMAL TEMPERATURES
LATE THIS WEEK WILL SHRINK IN SCOPE TO THE SOUTHEAST EARLY NEXT
WEEK. MEANWHILE BELOW AVERAGE TEMPERATURES IN THE NORTHWESTERN AND
NORTH-CENTRAL U.S. ARE FORECAST TO TREND EVEN COLDER INTO MONDAY-
TUESDAY.
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE LATEST DETERMINISTIC GUIDANCE IS IN GOOD AGREEMENT WITH
RESPECT TO BOTH THE PATTERN AND SYSTEM PROGRESSION ACROSS THE CONUS
TO START THE MEDIUM RANGE PERIOD. FOLLOWING THE DEPARTURE OF A
SYSTEM OVER THE NORTHEASTERN U.S. INTO THE ATLANTIC LATE THIS WEEK,
GUIDANCE SHOWS THAT A PROGRESSIVE UPPER-LEVEL WAVE WILL MOVE
QUICKLY ACROSS THE CONUS FROM THE WEST COAST TO THE MIDWEST/GREAT
LAKES AND EVENTUALLY THE NORTHEAST THIS WEEKEND. GUIDANCE HAS COME
INTO BETTER AGREEMENT WITH RESPECT TO THE TRACK OF THE ACCOMPANYING
SURFACE SYSTEM, FOLLOWING A PATH FROM THE SOUTHERN PLAINS THROUGH
THE OHIO VALLEY AND INTO THE MID-ATLANTIC, AFTER THE GFS IN
PARTICULAR HAD BEEN SUGGESTING A MORE SOUTHERLY PATH. THERE REMAINS
SOME DISAGREEMENT WITH REGARDS TO POTENTIAL SECONDARY LOW
DEVELOPMENT OFF THE COAST AS THE SYSTEM REACHES THE MID-ATLANTIC
THAT COULD IMPACT THE AMOUNT AND TYPE OF PRECIPITATION RECEIVED IN
THE REGION.
GUIDANCE DIFFERENCES INCREASE IN THE MID- TO LATE PERIOD UPSTREAM
AS VARIOUS NORTHERN AND SOUTHERN STREAM ENERGIES TRAVERSE THE
WESTERN TO CENTRAL U.S. THE LATEST 00Z/06Z GFS TENDED TO BE WITHIN
THE MIDDLE GROUND AMONGST THE DETERMINISTIC GUIDANCE, ENSEMBLE
MEANS, AND VARIOUS AVAILABLE AI MODELS, WITH THE CMC MORE
PROGRESSIVE WITH NORTHERN STREAM ENERGY AND THE ECMWF WITH A MUCH
SLOWER, MUCH MORE AMPLIFIED PATTERN OVER WESTERN CANADA AND THE
NORTHEASTERN PACIFIC. THE MEANS TENDED TO FALL WITHIN THE MIDDLE OF
THE SOLUTIONS AND THE AI MODELS DEPICTED A SIMILAR VARIETY OF
POSSIBILITIES TO THE GFS/ECMWF/CMC. HOWEVER, THE GENERAL CONSENSUS
IS ONE (OR MORE) ENERGIES WILL PASS THROUGH THE WESTERN U.S. AND
LEAD TO AN EXPANDING AREA OF PRECIPITATION FROM THE PLAINS TO
SOUTHEAST/MID- ATLANTIC EARLY NEXT WEEK.
THE UPDATED WPC FORECAST USED A COMPOSITE BLEND OF THE
GFS/ECMWF/CMC/UKMET GUIDANCE GIVEN THE NOTED GOOD AGREEMENT THROUGH
THE UPCOMING WEEKEND. THE LATER PERIOD RELIED MORE ON THE 06Z GFS
AND A SIGNIFICANT CONTRIBUTION (60% BY DAY 7) FROM THE
GEFS/ECENS/CMC MEANS GIVEN THE SIGNIFICANT INCREASE WITH RESPECT TO
INDIVIDUAL WAVE SPECIFICS EARLY NEXT WEEK.
..WEATHER/HAZARDS HIGHLIGHTS
PRECIPITATION IS LIKELY TO CONTINUE IN THE WESTERN U.S. ON FRIDAY
AS A COUPLE OF LOW PRESSURE/FRONTAL SYSTEMS MOVE THROUGH. RAINFALL
MAGNITUDES WILL FINALLY LESSEN IN COASTAL CALIFORNIA, BUT FARTHER
INLAND SNOW WILL BE POSSIBLE ACROSS THE CASCADES/SIERRA NEVADA AND
FARTHER EAST ACROSS THE NORTHERN AND CENTRAL ROCKIES. BY THE
WEEKEND, MUCH LESS PRECIPITATION IS FORECAST FOR THE WEST, WITH
JUST SOME LIGHT AMOUNTS IN THE PACIFIC NORTHWEST AND PARTS OF THE
NORTHERN/CENTRAL ROCKIES. THE CENTRAL ROCKIES MAY SEE SOME HIGH
WINDS IN THE POST-FRONTAL PATTERN ON SATURDAY.
FARTHER EAST, SOME SNOW IS FORECAST TO SPREAD INTO THE DAKOTAS
FRIDAY AND INTO THE UPPER MIDWEST FRIDAY-SATURDAY TO THE NORTH OF
DEVELOPING LOW PRESSURE IN THE SOUTH-CENTRAL PLAINS. MEANWHILE
MOISTURE PRESENT ACROSS THE OHIO VALLEY AND VICINITY WILL LEAD TO
SOME LIGHT TO MODERATE RAIN FRIDAY. SOME GUSTY WINDS WILL BE
POSSIBLE FOR HIGHER ELEVATIONS OF THE CENTRAL APPALACHIANS AND
NORTHERN NEW ENGLAND AS A LOW PRESSURE SYSTEM DEPARTS THE REGION.
THEN AS THE SURFACE LOW TRACKS NORTHEAST, MODERATE TO HEAVY SNOW IS
FORECAST TO DEVELOP ACROSS THE GREAT LAKES AND THE NORTHEASTERN
U.S. ON SATURDAY. PROBABILITIES OF PLOWABLE SNOW/SLEET CONTINUE TO
INCREASE ACROSS THE NORTHERN MID- ATLANTIC INTO THE NORTHEAST,
ESPECIALLY IN HIGHER ELEVATIONS OF THE CATSKILLS, ADIRONDACKS, AND
BERKSHIRES. SLEET AND FREEZING RAIN ARE ALSO A POSSIBILITY ACROSS
PORTIONS OF THE MID- ATLANTIC, NEW YORK, AND SOUTHERN NEW ENGLAND.
TO THE SOUTHWEST, RAIN IS LIKELY ACROSS THE OHIO VALLEY AND CENTRAL
APPALACHIANS. POTENTIALLY HEAVY RAIN WILL BE MOST CONCERNING IN
THE CENTRAL APPALACHIANS WHERE THERE ARE WET ANTECEDENT CONDITIONS
ALREADY, PLUS AMPLE RAINFALL IN THE SHORT RANGE PERIOD. MULTIPLE
ROUNDS OF RAIN ARE POSSIBLE DUE TO CONVECTION WELL AHEAD OF AND
THEN ALONG THE COLD FRONT. THUS A MARGINAL RISK IS DELINEATED IN
THE DAY 5/SATURDAY ERO CENTERED IN WEST VIRGINIA. THE PATTERN LOOKS
TO BECOME INCREASINGLY FAVORABLE FOR PRECIPITATION ACROSS THE
SOUTHERN HALF OF THE MISSISSIPPI VALLEY TO TENNESSEE VALLEY AND
SOUTHERN MID- ATLANTIC INTO EARLY NEXT WEEK. THERE IS AN INCREASING
SIGNAL FOR THE POTENTIAL OF LOCAL TO WIDESPREAD HEAVY RAINFALL
FROM THE MISSISSIPPI VALLEY TO TENNESSEE VALLEY, AND POTENTIALLY
DISRUPTIVE WINTRY PRECIPITATION ALONG THE NORTHERN SIDE OF THE
PRECIPITATION SHIELD FROM THE OHIO VALLEY TO MID-ATLANTIC.
COLDER THAN AVERAGE TEMPERATURES ARE FORECAST FOR NORTHWESTERN AND
NORTH-CENTRAL PARTS OF THE LOWER 48 THROUGH THE PERIOD. THE COLD
WILL BE ESPECIALLY PRONOUNCED ACROSS MONTANA AND NORTH DAKOTA,
ESPECIALLY BY EARLY NEXT WEEK WHEN ANOTHER SURGE OF COLD AIR IS
LIKELY. BY MONDAY-TUESDAY, LOWS ARE FORECAST TO BE IN THE -10S AND
-20S, ALONG WITH SOME BELOW ZERO HIGHS. MEANWHILE, AREAS FROM
THEFOUR CORNERS STATES ACROSS THE SOUTH ARE EXPECTED TO SEE
UNSEASONABLE WARMTH AS HIGHS AND LOWS THAT ARE 20-30 DEGREES ABOVE
AVERAGE BECOME WIDESPREAD. THESE ANOMALIES COULD SET DAILY
RECORDS. EXACT TEMPERATURES/ANOMALIES VARY SOMEWHAT AT ANY
PARTICULAR PLACE FRIDAY-SATURDAY, BUT BY SUNDAY-MONDAY THERE
SHOULD BE A MORE PRONOUNCED COOLING TREND ACROSS THE FOUR CORNERS
AND SOUTH-CENTRAL U.S. TO THE MID-ATLANTIC BEHIND A STRONG COLD
FRONT. BY TUESDAY WARMER THAN AVERAGE TEMPERATURES SHOULD BE
LIMITED TO THE CENTRAL GULF COAST TO FLORIDA.
PUTNAM/TATE
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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