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Area forecast discussion 
National Weather Service Mount Holly New Jersey
340 am EST Thursday Feb 11 2016

Synopsis...

High pressure will build eastward into the region today and then
move through the region tonight. An Arctic cold frontal boundary
will then move through the area Friday night. By Sunday, another
area of high pressure will build southward into the region as low
pressure forms across the southern United States by Monday. This
area of low pressure will then track up the East Coast Tuesday into
Wednesday.

&&

Near term /until 6 am this morning/...

For a relatively quiet weather day, still have three main stories to
talk about for the today period.

Snow...as mentioned by the previous shift, low to middle level lapse
rates will be quite steep across the Poconos and northern New Jersey through
at least middle day. In addition, the middle and upper level short wave
trough will be crossing the region through this time. These factors
are conducive for scattered snow showers, or maybe even a fast
moving snow squall, across the northern half of our region. With
persistent dry air advection, moisture is limited. So even though
snow/liquid ratios could be above normal thanks to the very cold air
in place, still expect snow accumulations to remain below one inch.

Winds...a tight pressure gradient will remain over the region
through at least 18z before it starts to decrease as the surface low
lifts further away from our region. Thus, expect windy conditions
through the day. At this point though, Wind Advisory conditions
(sustained winds of at least 31 miles per hour for at least one hour or gusts
of 46 mph) are not anticipated, since the tightest pressure gradient
will be early in the day before the mixing layer gets very deep.
Having said that though, the GFS does show that the sustained
criteria could be reached for locations adjacent to the Delaware Bay,
since the direction is a favored direction for the funneling effect
over the Bay. For now though, confidence is low that it will be
reached so will not issue an advisory at this time.

Cold...today begins the cold stretch which we are expecting to
continue into the weekend. While today will probably be the warmest
of the next 4 days, the region should stay below freezing, and
portions of the Poconos and northwest New Jersey may not get out of the teens.
This will be 15 to 20 degrees below normal. Given the windy
conditions, wind chill values across the region will only top out in
the teens at best.

&&

Short term /6 am this morning through 6 PM Friday/...

High begins to build in, and consequently winds diminish, and clouds
will dissipate. As a result, should see considerable radiational
cooling, with lows in the single digits and teens and wind chill
values in the single digits above and below zero.



&&

Long term /Friday night through Wednesday/...

The extended will feature both the prospects for the coldest air of
the season centered on Sunday morning and a strengthening low
pressure system tracking up the East Coast early next week.

Friday and saturday: high pressure will move through the region on
Friday. This high pressure system will give way to another Arctic
cold front Friday night. The cold front should provide enough
lift and moisture for some scattered snow showers to develop.
These may produce some light accumulations of under an inch.

Behind the front, it will be a very cold and windy period with
some additional snow showers and/or flurries in association with
the northwest flow off of the eastern Great Lakes. The favored regions to
see snow showers are in the high terrain areas of eastern PA and
northwest New Jersey. BUFKIT analysis yields the potential for 30-40 miles per hour gusts
Saturday afternoon across the region with the GFS being the most
aggressive with the gust potential. The strong cold air advection will not allow
temperatures to rise much during the day.

Saturday night through Sunday night: another potent area of Arctic
high pressure will build into the region with the coldest shot of
air of the season so far. Modeling has been holding steady on the
idea that 850 mb temperatures look to dive below -25c. Will
nudge temperatures a couple of degrees cooler than most ensemble
guidance through the weekend due to the degree of the cold air
being modeled. Strong northwest wind gusts, though not as strong
as on Saturday will continue in the wake of the departing system.
The cold and wind will result in wind chills from -10 to -30 below
zero Saturday night and Sunday morning. Please to make sure to
prepare for the cold weather that is coming. Preparations include
checking pipes and making sure your vehicle is in good working
condition. Low temperatures Sunday morning will likely near or
below zero as well. Please refer to the climate section on record
potential.

Presidents day through Tuesday night: high pressure will gradually
move east of the region and will give way to a storm system that is
currently modeled to form across the southern United States and
intensify as it moves up the East Coast. The 00z 2/11 operational
models have narrowed the goal posts of possibile tracks from earlier
model runs. This also matches or is just east of the 12z 2/10 European model (ecmwf)
ensemble mean track. This track GOES from south central Alabama/Georgia
northeast to the Carolina coastline then due north up the East
Coast into southern New England. Two main features are present to
track with regards to models or respective ensembles changing the
forecast track of this system in future runs. This first is a
leading shortwave which moves into the the Ohio Valley on Monday
and the second is the degree of middle- level height rises that
occur ahead of the storm system. A stronger shortwave would tend
to push the overall trough with this storm further east. While a
weaker shortwave would allow for higher middle- level height rises
leading to a further west track of the low. Right now the favored
track would result in snow changing to rain across most of the
region with the highest chances for precipitation Monday night and
Tuesday. It will likely be windy as well with the strengthening low
pressure system tracking near the region.

Wednesday: the region should gradually begin to clear out as
another high pressure system builds eastward toward the region.
Some uncertainty though as 2/11 00z European model (ecmwf) brings another system
into the region by this period.

&&

Aviation /08z Thursday through Monday/...
the following discussion is for kphl, kpne, kttn, kabe, krdg,
kilg, kmiv, kacy and surrounding areas.

VFR conditions are expected today and tonight. There is a small
chance of a snow shower moving into kabe, krdg, or kttn through 21z,
but these locations are on the very southern end of where we expect
any snow showers, so confidence is too low to include a mention in
the tafs at this time.

Northwesterly winds will increase shortly after sunrise, with gusts
up to 30 knots possible between 15 and 00z. After 00z, expect winds to
diminish considerably but remain westerly or northwesterly.

Outlook...

Friday: VFR.

Friday night and saturday: mainly VFR, possibile MVFR restrictions
in scattered snow showers. Northwest winds increasing Saturday from
15-25 knots with gusts up to 40 knots Saturday afternoon.

Saturday night and Sunday...VFR conditions expected. Northwest winds
10 to 25 knots.

Monday...VFR conditions for most of the day then becoming MVFR and
IFR by evening with rain and snow.

&&

Marine...

Gale force gusts are expected to begin on the Bay and coastal waters
shortly and continue through the evening hours. Westerly and
northwesterly winds are expected through this time, with gusts up to
40 knots possible, especially further away from the coast. An Small Craft Advisory will
likely be needed for much if not all of the over night hours once
the gales subside.

Also of concern today and tonight will be the freezing spray
expected on the Bay as well as the near coastal waters. At this
point, expect light freezing spray so have held off on an advisory
at this time, but observations will be monitored closely through the
morning hours.

Outlook...

Seas and winds will start out fairly light on Friday. However, a
quick ramp up is expected after the passage of an Arctic cold
frontal boundary Friday night. Northwest winds will increase and
reach gale force by Saturday and continue near gale force through
Saturday night. Confidence for gales on Saturday is currently
high. Seas may reach five feet for a period as well on Saturday.
Seas and winds are expected to decrease on Sunday. Wave heights
will likely start increasing again by Monday night in response to
a developing low pressure system to our south.

&&

Climate...
near record cold is expected for portions of our area Sunday
morning and by far the coldest air of the season so far.

Anticipating temperatures throughout our forecast area within several
degrees of zero (wind is the equalizer) anytime from midnight
through 8 am Sunday except colder kmpo (near -12f). This has been
advertised by the GFS/European model (ecmwf) 2m temperatures cyclically since at least the
00z/7 operational cycles. Therefore, best chance for record
equaling or exceeding for Valentines day the 14th would be kabe,
kttn, kphl and kmpo.

Snow cover may help a bit I-95 northwestward...and we'll see
where we are with snow cover by Thursday evening. New dustings
appear on the way the next 30 hours.

Site 2015-16 coldest so far record low Feb. 14th
---- ---------------------- --------------------

Abe 8 -1 in 1979

Acy 10 -6 in 1979

Phl 12 +2 in 1979

Ilg 12 -4 in 1979

Ridge 10 -4 in 1983

Ttn 9 0 in 1916

Ged 13 -7 in 1979

Mpo -1 -12 in 1970

So, this will be wind driven cold with many areas experiencing
wind chill values of 15 to 25 below zero...possibly 30 below in
the hills and mountains of northwest New Jersey and northeast
Pennsylvania.

&&

Phi watches/warnings/advisories...
PA...none.
New Jersey...none.
Delaware...none.
Maryland...none.
Marine...Gale Warning until 1 am EST Friday for anz450>455.
Gale Warning until 11 PM EST this evening for anz430-431.

&&

$$
Synopsis...franck
near term...Johnson
short term...Johnson
long term...Gaines
aviation...Gaines/Johnson
marine...Gaines/Johnson
climate...

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