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weatherguysc

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  1. 2 minutes ago, strongwxnc said:

    The heavy snow discussion came out 15 minutes after GSP update

    I think they wrote that near term part at 2:45, the discussion came out at 3:37a. Sleep deprived I didn't pay attention to it lol.

    Quote
    .NEAR TERM /THROUGH TONIGHT/...
    As of 245 AM EST Sunday: At the time of this writing

     

  2. From GSP discussion at 2:45a

    Quote
    Continued snowfall is expected across the Upstate and Piedmont
    through the next several hours, gradually changing over to sleet
    and freezing rain as WAA atop the cold wedge dynamically produces a
    warm nose in profiles.  This warm nose is expected to push in from
    the southeast and make its way to perhaps the I-85 corridor.  Thus,
    the current thinking is that by dawn, most sites south of I-85 will
    primarily be seeing ice, while points farther north will likely see
    more of a mix.

     

  3. Just now, burgertime said:

    The CAD we all dream of and everyone is praying Freddy Krueger doesn't show up. 

    Exactly and it is so close to being a monster of storm but that is part of getting snow in the southern states everything has to line up perfectly down to the stars it seems like.

  4. 2 minutes ago, burgertime said:

    Just had a look at the Hi-Res NAM precip type and it's a descent dump of snow for WNC then lots of ice with probably a flip back to snow? 

    qK2tROy.gif

    Looks like 8-9 hours of snow then a changeover and probably a change back to snow after hour 60.

  5. GSP Short Term...doesn't sound good for ZR amounts in the current thinking for most outside the mountains.

    Quote
    .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
    As of 315 am Friday: Light precip could develop over the region as
    early as Sat afternoon, as warm conveyor belt region matures to the
    northeast of intensifying Deep South cyclone. This would primarily
    be a concern over the mountains, which would be the first area to
    see the low levels moisten in response to low-to-mid level
    frontogenesis. Anything that falls Sat afternoon will be light and
    of the rain/snow variety (depending upon elevation), with any accums
    likely confined to the higher elevations through 00Z Sunday.
    
    Conditions will then go downhill in a hurry Sat night, as intense/
    deep layer forcing overspreads the area in response to deepening
    cyclone moving east near the Gulf Coast. Sufficient cold air should
    be in place by the time the precip develops late Sun night to
    support mostly snow across the mountains and much of western North
    Carolina, northern upstate SC, and the northeast GA mountains,
    although some locations along/near the I-85 corridor may see precip
    begin as rain before the wet bulb effect forces a transition to
    snow. In classic Carolina winter storm fashion, cold air will be
    reinforced, if not enhanced Sunday morning by developing classical
    (or at least strong hybrid) cold air damming, as 1030-ish mb surface
    high pressure moves into New England beneath confluent upper flow.
    
    As the cyclone continues to deepen early Sunday, 50-60 kt E/SE flow
    is expected to develop above the surface, resulting in intense
    isentropic lift/warm advection flow. In general, guidance continues
    to trend (as it often does as these events draw nearer) toward a
    more prominent warm nose pushing into the forecast area early
    Sunday. This is expected to allow a narrow transition zone of
    sleet/wintry mix to develop over the Piedmont Sun morning, which
    will steadily shift north and west throughout the morning.
    Unfortunately, this trend also suggests more freezing rain potential
    for locations from roughly the northeast GA and SC Piedmont through
    the southern NC Piedmont, as developing strong CAD should support
    surface temps cold enough for icy condition despite the expectation
    of a stronger warm nose. Damaging accumulations of ice therefore
    appear more likely along and south of a line from Anderson to
    Spartanburg to Gastonia, to Salisbury, including Charlotte and
    vicinity. Northwest of there, morning snow/sleet followed by a
    likely transition to freezing rain/drizzle of a few hours is
    expected to result in a somewhat narrow zone of a wintry slurry of 2
    to 5 inches.
    
    Finally, little has changed regarding the forecast for the mountains
    and NC foothills, where 8-12 inches/locally higher amounts of mostly
    snow continue to look like the best bet. Strong cold advection
    combined with snowpack in some locations will result in min temps
    Sun night 10-15 degrees below climo...or well below freezing in most
    areas, so little improvement in road conditions can be expected
    through the end of the short term. A brief, moist northwest flow in
    the wake of the departing cyclone could result in additional light
    accums across mainly the high elevations of the TN border counties
    Sun night.
    

     

  6. GSP Discussion

    Quote
    .SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
    As of 300 am EST Thursday: The forecast will not change a great deal
    this morning, with all models on track for a major winter storm
    across the southeast during mainly the latter half of the weekend.
    First though, a shortwave ridge will cross our area on Friday
    between a departing, offshore trough and the next developing low
    pressure system digging southward across the Plains. Northerly flow
    at low-levels on Friday will allow thicknesses to begin cooling
    across the region.
    
    The Plains system will then detach from the northern stream flow
    over the Arklatex Region Saturday, with the 500 mb closed low center
    deepening as it translates across the Deep South Saturday night.
    Meanwhile, 1040 mb surface high pressure settling southeast across
    Ontario Friday will move into a classical cold air damming position
    by Saturday. Upglide well ahead of the approaching low pressure
    system may get started on Saturday as moisture slowly deepens near
    the pre-existing baroclinic zone draped across our region. Will
    gradually bring PoPs back from the west on Saturday, with chance
    values across the mountains and at least slight chances east. Onset
    could be as light snow in the mountains and across the cooler I-40
    corridor area late Saturday.
    
    The operational models are in relatively good agreement with the 500
    mb low center track atop our area late weekend. The GFS remains a
    few hours faster than the ECM/CMC solutions, but they all lift the
    system across the western Carolinas and northeast Georgia late
    Sunday and Sunday night. The ECM/CMC mean sea level pressure
    prognostics have a slightly farther south/southeast track of the
    associated surface low center, mainly across the coastal plain. This
    is favored given the strength of the low-level ridge north of the
    forecast area and it will likely contribute to slightly colder
    profiles and boundary layer temperatures than indicated on the
    operational GFS. QPF will be robust in the 06Z to 18Z Sunday period,
    with strong upper jetlet divergence, deep-layer QC convergence, and
    strong warm advection at low-levels. Anticipate that the zero degree
    850 mb isotherm may pivot near the NC/SC line to create a very sharp
    gradient in snowfall from the NC foothills down into the Upstate,
    but this remains highly subject to change.
    
    The current thinking is that most of NE GA, Upstate SC, and the
    Charlotte metro area will see some degree of warm nosing to undercut
    potential snow totals and generate more sleet, with more freezing
    rain especially likely at times along and southeast of I-85. 850 to
    700 mb frontogenesis will likely sharpen up along and east of the
    mountains to enhance precipitation rates Sunday morning. The phasing
    process of this southern system back into the northern stream may
    accelerate the low passage. That could be a slight limiting factor,
    but it may not matter much given the otherwise excellent potential
    for significant wintry accumulations across the region as it stands.
    
    Anticipate a mix back over to scattered snow showers before the
    larger scale precipitation ends Sunday night. Additional western
    mountain snow accumulations are expected in moist NW upslope flow
    Sunday night, with windy conditions developing across the mountains.
    Conditions may well be treacherous across the region by daybreak
    Monday with snow and ice on the ground and temperatures in the 20s
    throughout.

     

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