• Nor'Easter rapidly developing

    From Dumas Walker@21:1/175 to All on Sunday, February 22, 2026 17:02:01
    FOUS11 KWBC 221952
    QPFHSD

    Probabilistic Heavy Snow and Icing Discussion
    NWS Weather Prediction Center College Park MD
    252 PM EST Sun Feb 22 2026

    Valid 00Z Mon Feb 23 2026 - 00Z Thu Feb 26 2026

    ...Central Appalachians, Mid-Atlantic, through Northeast... Days 1-2...

    *** Nor'Easter rapidly develops today as it slowly shifts north
    just off the Mid-Atlantic Coast. Heavy snow and blizzard
    conditions are expected for the Delmarva through the Northeast
    Urban Corridor into eastern New England through Monday. ***

    Forecast for a major impact Nor'Easter remains on track with
    significant snow and major impacts likely for areas along and east
    of I-95 from the Delmarva up through Eastern New England. Surface
    analysis at 18z indicates a strengthening 1001mb SLP about 70-80
    miles offshore of the VA/NC border. Expectation is for this low to
    undergo rapid intensification later this evening as the upper
    pattern to the west begins to tilt negative and steadily close off
    at 500mb and 700mb as it cuts across the state of VA, and as it
    nestles within the LER of a potent 140kt upper jet max currently
    pivoting east across the Carolinas. By 03z Mon, the upper levels
    will begin the process of "capturing" the surface low off the Lower
    Delmarva leading to the rapid intensification as the system becomes
    more vertically stacked with the 850-500mb height fields coming
    into alignment. By Monday morning, our surface low will be easily
    into the low-mid 970s with further intensification likely as it
    drifts to the northeast becoming positioned to the southeast of
    Nantucket by the afternoon hours. A 1050mb surface high pressure
    approaches Ontario tonight, setting up a great pressure gradient
    across the Great Lakes and Northeast leading to blizzard conditions
    for those along and southeast of the I-95 corridor from
    Philadelphia up through NJ/LI/NYC into all of Southeast New England.

    Beginning to see heavier precip bands across the Delmarva pivoting
    up into Southern NJ with any rainfall changing over to snow as
    diabatic cooling processes aid in the transition from liquid to
    solid hydrometeors. Areas across the Central Mid Atlantic will see
    a transition from rain to snow between 20-22z as the upper level
    dynamics mature and attendant height falls from the west contribute
    to swift top-down cooling processes to eventually change to setup
    to all snow. We'll see all snow the entire Northeast corridor by
    that point leading to steady accumulations from NoVA up through New England.

    Snowfall rates really increase this evening over the Delmarva/NJ
    and NYC from the combo of further low development and nocturnal
    trends with 12Z HREF snow rate probabilities of at least 1"/hr
    between 60-90+% over this area by 00Z with localized 2"/hr rates
    across southern DE into NJ by midnight. Late night snow rates
    further increase, exceeding 2.5"/hr over Long Island before
    shifting to southeast New England by 09Z. Day 1-1.5 snow probs for
    12" are 70-100% from the MD part of the Delmarva through
    the eastern two-thirds of Mass. Day 1-1.5 snow probs for >18" are
    highest across much of NJ through LI into eastern Mass with probs
    between 50-80%. One area to point out away from the area of highest
    impact is across portions of NoVA into west-central MD up into
    central PA where a localized, narrow band of heavy snowfall is
    forecast from a maturing norlun (inverted) trough axis that will
    setup well northwest of the surface low as low-level winds converge
    on the outer proxy of the surface cyclone and maturing 850mb low
    maturing nearby. Recent probabilities for >4" really denote this
    potential with a narrow corridor of 40-70% probs over the area of anticipated impact with ~80% across the Catoctin Mtns between
    MD/PA. Rates of 1-2"/hr with large dendrite production will likely
    occur in this band providing short term impacts later this evening
    when it materializes.

    Event peak snow rates per the HREF are 3"/hr early Monday, though
    the very high winds (with gusts potentially to 70mph) will limit
    the SLR, so that may not be realized, but it'll be quite impactful
    snow banding with oceanic enhancement. The low then pivots towards
    Nova Scotia with rates of 1-2"/hr through Monday afternoon. Monday
    evening north flow from the Gulf of Maine should allow a pivoting
    band of ocean enhanced snow into southeast Mass/Cape Cod further
    adding to the historic snow. Day 2 snow probs for >12" are 50-70%
    over eastern Mass and just off the Maine coast with 60-80% probs
    for >6" from southern NH through eastern Maine and down through eastern CT.

    Upslope snow through the central Apps will occur this afternoon,
    continuing through Monday evening. Snow rates generally stay below
    1"/hr, but the prolonged duration leads to some significant snow
    fall. Day 1-1.5 snow probs for >6" are 50-80% in the Laurels of PA
    through the Allegheny Plateau of central WV.

    ...Cascades and Northern Rockies... Days 1-3...

    General continuity from the previous forecast...Sprawling deep low
    continues to linger well off the WA coast today, directing Pacific
    moisture across the Northwest CONUS. This low then shears into a
    zonally oriented trough Monday which directs an atmospheric river
    (AR) into OR later Monday before shunting south through northern CA
    Monday night/Tuesday.

    Snow levels rise today to 3500ft in the WA Cascades, 5000-6000ft
    in OR, and 6500ft in far northern CA. Day 1 snow probs for >6" are
    50-90% in the WA Cascades (above pass level) and the highest OR/CA Cascades.

    A tighter baroclinic zone sets up Monday with snow levels dropping
    to around 2500ft at Snoqualmie Pass WA and to around 4000ft in
    northwest MT while rising above 7000/8000ft in the core of the AR
    in OR. Day 2 snow probs for >6" are 50% at pass level in the WA
    Cascades and for the ranges of northwest MT.

    The southward shift in the AR through Tuesday brings heavy precip
    to northern portions of CA and the Great Basin with CA snow levels
    over 9000ft with no snow impacts. Snow levels are closer to 7000ft
    in NW WY and central ID where Day 3 >6" snow probs are 50-80%.

    ...Great Lakes... Days 1/2...

    No change to the previous forecast. Inverted trough extending
    northwest from low over Lake Huron maintains NNWly flow and strong
    cold air advection over Lakes Superior and Michigan today. This
    expands east across Lake Erie tonight into Monday as the Nor'easter
    develops off the Mid- Atlantic coast. Day 1 snow probs for >4" are
    40-70% over the Porcupine and Huron Mtns as well as over far SW MI
    and northern IN. Day 1.5 snow probs for >4" are 40-70% southeast
    of Lake Erie in northeast OH, Erie Co PA, and Chautauqua Co NY.

    Day 3...

    An Alberta Clipper shift ESE from northern MN through MI Tuesday
    before reaching Upstate NY Tuesday night. Warm air advection ahead
    of the surface low will be into an Arctic airmass with plenty of
    DGZ available for snow crystal growth. Moderate snow rates from
    Lake Michigan enhancement can be expected in the eastern U.P. where
    Day 3 snow probs for >6" are 40-60%. LES begins on the back side
    of the clipper Tuesday night off Lake Superior, spreading across
    the Great Lakes then Wednesday leading to >6" snow probs between
    40-70% downwind of Superior across the central and eastern U.P. of Michigan.

    Kleebauer/Jackson

    ...Winter Storm Key Messages are in effect. Please see current
    Key Messages below...

    https://www.wpc.ncep.noaa.gov/key_messages/LatestKeyMessage_1.png

    $$
    --- SBBSecho 3.28-Linux
    * Origin: Capitol City Online (21:1/175)