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Area forecast discussion 
National Weather Service Mount Holly New Jersey
1016 am EST Monday Jan 26 2015

Synopsis...
low pressure in North Carolina will track to the Virginia convective available potential energy
by noon then intensify rapidly in its northeast turn...nearing
Cape Cod at noon Tuesday and then weakening off to Nova Scotia on
Wednesday. High pressure from the west is forecast to arrive
Wednesday night. A weak low is expected to follow and pass over
our region Thursday night and early Friday. Another area of high
pressure is then anticipated for the start of next weekend.

&&

Near term /until 6 PM this evening/...
as of middle morning...a surface low/trough is over western NC/Virginia but pressure
falls continue off the middle Atlantic coast as low pressure starts to
re-form there. Light snow is being reported at numerous stations
around the area but so far amounts have been light...generally in
the 1 to 2 inch range. Light rain has been reported over southern Delaware
where temperatures are in the upper 30s.

No changes were made to the forecast at this time except to lower maximum temperatures
over southern Delaware to lower 40s with clouds, light precipitation and northeasterly winds.
Still looks like mostly light snow for today with the main part of
the storm developing tonight into Tuesday. Gusty NE winds are already
occurring from phl south...and winds will gradually increased
during the day today as the low starts to deepen offshore.

&&

Short term /6 PM this evening through 6 am Tuesday/...
the coastal system will deepen rapidly overnight as is moves from
off the NC/Virginia coast to the 40/70 benchmark. Steady/heavy snows will
affect mostly the eastern 2/3rd of the area with lighter snows and
blowing snow over the western/southwestern edges of the area. Our snow totals
are not much different than the ones issued Sun afternoon...perhaps
a few inches lower if anything. Warning criteria snow may or may
not occur across the farthest western warning areas(carbon and
lehigh)...but blowing snow across the higher elevations will make
things look warning-like. Plenty of travel impacts across the
region. Highest totals through 12z northern half of New Jersey and into extreme eastern
PA.

&&

Long term /Tuesday through Sunday/...
***blizzard coastal New Jersey will be ending Tuesday afternoon***

500 mb: deep occluded cyclonic circulation near the southern New
England coast Tuesday departs with ridging Wednesday. The next
trough forms southeastward to the East Coast Thu-Fri. Thereafter the Hudson
Bay vortex slides southeastward into Quebec by Monday.

Temperatures: calendar day averages will be below normal Tuesday
through Sunday with several days around 10 degrees below normal.

Forecast basis: unless otherwise noted within the dailies. This
forecast is a 50 50 blend of the 00z/26 mav/met for Tuesday-Wednesday.
The 00z/26 mex MOS was applied Wednesday night and Thursday. The
05z/26 wpc d4-8 elements of dewpoints/wind/sky/pop/Max-min temperatures
were not used for the longer range...but we did adjust probability of precipitation higher
Thursday afternoon into Friday morning for the next clipper.

The dailies...

Tuesday...bent back middle level front at 700-600 mb with fgen excessive
snowfall rates coastal central and northern New Jersey will be winding
down rapidly Tuesday afternoon with surface winds backing to northwest. Ideal
snow growth region near 650mb nnj northeastward with 1-3"/hour expected even
for the first few hours after sunrise Tuesday. But...how far west
of I 95 is it snowing Tuesday is still somewhat uncertain. Usually
with banding there are areas of strong subsidence and drying in
what you would otherwise consider a snowy environment. Those areas
of drying can surprise. This mesoscale meteorology we're not too good
at realistically and reliably detailing more than a few hours in
advance. Lets think of lighter snow occurring across the rest of
eastern PA and the Delaware-Maryland-Virginia Tuesday morning then drying out. Northwest wind
gusts 25-35 miles per hour. Considerable blowing and drifting of the snow
occurs, especially across New Jersey. Estimating drifts to 4 feet are
possible in exposed regions of coastal NE NJ, where snowfall
exceeds 18 inches.

Tuesday night...clearing...with gusty northwest winds 20 miles per hour. Drifting
snow continues, especially coastal nnj

Wednesday...MO/sunny with gusty northwest winds 20-30 miles per hour. Drifting snow
coastal nnj.

Thursday into Friday...a clipper system from the northwest and west
may bring a shot of light snow from late Thursday into Friday. For
now we are forecasting an event ... amounts under 2 inches
in this cf situation and for now mainly north of I 78.

Later Friday into Saturday...another shot of cold dry air is anticipated.

Next Sunday and Monday...it might get interesting again? It does
not look necessarily straightforward with the southeast evolution of the
polar vortex and what might develop to our south ahead of the
possible arrival of bitterly cold air here early next week.

&&

Aviation /15z Monday through Friday/...
the following discussion is for kphl, kpne, kttn, kabe, krdg,
kilg, kmiv, kacy and surrounding areas.

**High impact event, especially tonight and Tuesday morning**

Persistent light snow has lowered visibilities into the IFR range at most
of our taf sites and ceilings have also lowered to MVFR...and IFR at
Acy/miv. Conds not likely to get any better today and will
definitely get worse tonight with IFR/LIFR ceilings and visibilities
expected. Northeasterly winds are already somewhat gusty from phl southward and will
gradually increase this afternoon through tonight.

The Nor'easter will affect the terminals beginning late this
afternoon and into Tuesday. Widespread LIFR with snow and blowing snow
common. Strong NE winds tonight and into Tuesday.

Outlook...
Tuesday...significant morning snowfall and IFR conditions probably
confined mainly to New Jersey from vicinity kphl-kacy line northward and that
snow will be ending in the afternoon. Becomes VFR everywhere during
the afternoon but with blowing and drifting snow. Northwest wind gusts
25-30kt.

Tuesday night...VFR scattered or broken at or above 4000 feet. Northwest wind gusts 20 knots.

Wednesday...VFR scattered at or above 4000 feet. Northwest wind gusts 20-30 knots.

Thursday into Friday morning...VFR to start Thursday then a chance
of snow showers late Thursday or early Friday when conditions may lower
into the MVFR or IFR range for a time. SW wind Thursday afternoon shift northwest
Friday.

&&

Marine...
significant Nor'easter to affect the waters later today and tonight.
Marine flags will remain as they are with the morning package. Storm
warnings for most of the coastal waters and gales for del Bay and
the southern two coastal zones. Beginning and end times continue to
look good.

Outlook...
Tuesday...a marine Storm Warning is in effect for our ocean waters
off New Jersey to start the day. A Gale Warning is in effect for the
waters off Delaware and for Delaware Bay. Winds diminishing in the afternoon.

Tuesday night...leftover northwest gales during the evening with slowly
diminishing wind overnight. Freezing spray.

Wednesday...Small Craft Advisory conditions are expected with
freezing spray.

Wednesday night through Thursday...no marine headlines are
anticipated.

Friday...an Small Craft Advisory should eventually be needed by late Friday as a
northwest flow of cold air advection develops behind the northeastward
departing clipper low.

&&

Tides/coastal flooding...
coastal flooding...coastal flood watches were converted to warnings
with the 330 am forecast. Widespread minor with a few areas of low-end
moderate tidal flooding expected. The tide cycles tonight and Tuesday
morning are the most likely one to have flooding concerns...the
greater threat of moderate flooding being tonights midnight high tide
cycle.

&&

Climate...
record (vulnerable) daily snow fall for our long term climate
sites. Tuesday 1/27.

Acy 4.0 1946
phl 4.1 1941
ilg 2.9 2004
Abe 8.0 1897



&&

Phi watches/warnings/advisories...
PA...Winter Storm Warning until 6 PM EST Tuesday for paz070-071-
103>106.
Winter Weather Advisory until 3 PM EST Tuesday for paz060-101-
102.
Winter Storm Warning until 3 PM EST Tuesday for paz054-055-061-
062.
New Jersey...Winter Storm Warning until 6 PM EST Tuesday for njz001-007>010-
015>019-021>025-027.
Coastal Flood Warning from 11 PM this evening to 7 am EST
Tuesday for njz012>014-020>027.
Blizzard Warning until 6 PM EST Tuesday for njz012>014-020-026.
Delaware...coastal Flood Warning from 11 PM this evening to 7 am EST
Tuesday for dez002>004.
Winter Weather Advisory until 3 PM EST Tuesday for dez001>004.
Maryland...Winter Weather Advisory until 3 PM EST Tuesday for mdz008-012-
015-019-020.
Marine...Storm Warning until 6 PM EST Tuesday for anz450>453.
Gale Warning until 6 PM EST Tuesday for anz430-431-454-455.

&&

$$
Synopsis...drag
near term...amc/O'Hara
short term...O'Hara
long term...drag
aviation...drag/O'Hara/amc
marine...drag/O'Hara
tides/coastal flooding...
climate...drag 648a

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