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fxus61 kokx 171655 

Area forecast discussion
National Weather Service New York New York
1155 am EST Mon Dec 17 2018

low pressure deepens as it moves near Nova Scotia through tonight
with a cold front moving across the local region tonight as well.
Deep low pressure over the Canadian Maritimes Tuesday gives way
to high pressure through mid-week. Another low impacts the area
Thursday night through Saturday. Weak high pressure then
returns for Sunday.


Near term /until 6 PM this evening/...
adjusted temperatures to be a little higher in line with current
obs. However, per satellite imagery the front edge of the cold
front is clearly demarcated, and cold advection is expected to
strengthen into the afternoon as the front moves through. It is
likely that high temperatures were achieved early, and that
temperatures will begin to decrease through the remainder of the

Otherwise, despite the strong vorticity maximum passing through
the area, conditions remain too dry to support precipitation,
with no returns observed on radar even with the front at this

Winds are expected to increase significantly into the


Short term /6 PM this evening through 6 PM Tuesday/...
the pressure gradient will tighten more tonight with low
pressure deepening as it moves into Nova Scotia in contrast with
the high building to the west of the region into the Ohio

Cold air advection continues as seen with 850mb temperatures.
The 850mb temperatures decrease by about another 6 degrees c

Used consensus for min temperatures tonight. Less spatial
variance is seen due to the well mixed boundary layer and
therefore gusty winds.

The high starts to build in from the west on Tuesday. More
subsidence is seen from the ridging trend aloft and negative
vorticity advection seen in the mid levels. This will promote
more sunshine.

However, another gusty day expected as the pressure gradient
remains rather tight. With a well mixed boundary layer,
adiabatically mixing down from much colder 850mb temperatures
will result in much colder surface temperatures compared to the
previous day despite the extra sun.


Long term /Tuesday night through Sunday/...
deep-layered ridging Tuesday night through Thursday morning will
keep any rain out of the forecast. A surface high approaches during
this period, with its axis shifting through here around Wednesday
morning. High temperatures on Wednesday will be near normal, then
above normal on Thursday. Some rain ahead of the next system may
sneak into the tri-state area by late in the day, but the trend has
been for the likelihood of rain starting Thursday night. Low
pressure is progged to move up along the Appalachians Thursday night
night into Friday as it strengthens. Rain is expected here during
this time, and it could potentially be heavy at times on Friday as a
low level jet enhances lift and a fairly strong upper jet streak
approaches. The storm's cold front passes through Friday night with
showers possible, then a drying trend follows for the upcoming
weekend. Still a low chance of a passing shower on Saturday, but
looking dry for Sunday. High temps above normal for Friday and
Saturday, then returning closer to normal on Sunday.


Aviation /18z Monday through Saturday/...
intensifying low pressure east of Nantucket will move northeast
today and then north into the Canadian Maritimes tonight. A
cold front will move across from late afternoon into early

Mainly VFR, although cigs could be closer to 3000 ft at times
today. Winds still expected to back to around 290-300 true, with
the strongest winds late this afternoon into tonight with the
cold fropa. Sustained winds increase to around 20 kt with gusts
30-35 kt.

... Metro enhanced aviation weather support...

Detailed information, including hourly taf wind component fcsts,
can be found at: http:/www.Weather.Gov/zny/n90

Kjfk taf comments: cigs may drop to around 3000 ft aft 17z.

The afternoon haze potential forecast is green, which implies
slant range visibility p6sm outside of cloud.

Klga taf comments: cigs may drop to around 3000 ft aft 17z.

The afternoon haze potential forecast is green, which implies
slant range visibility p6sm outside of cloud.

Kewr taf comments: cigs may drop to around 3000 ft aft 17z.

The afternoon haze potential forecast is green, which implies
slant range visibility p6sm outside of cloud.

Kteb taf comments: cigs may drop to around 3000 ft aft 17z.

Khpn taf comments: 1600 ft cigs should be E of the Arpt by
1615z. Cigs may drop to around 3000 ft aft 17z.

Kisp taf comments: cigs may drop to around 3000 ft aft 17z.

Outlook for 12z Tuesday through Friday...
Tuesday...VFR. Northwest winds 15-20g25kt.
Tuesday night...VFR. Northwest winds 10-15g20kt in the evening.
Thursday night...rain with MVFR or lower conds developing. East-southeast
winds g20kt late.
Friday...rain with MVFR or lower conds. Southeast winds g20kt
becoming S in the afternoon. Low level wind shear.


Small Craft Advisory in effect on the non-ocean waters with gales on the ocean
waters. Wind gusts start picking up late morning into this
afternoon. The non-ocean waters have gales for tonight through
Tuesday morning with conditions will return back down to Small Craft Advisory
levels Tuesday afternoon. The ocean prevails with gales through

Winds diminish Tuesday night as high pressure builds over the
waters. All waters should fall below advisory criteria by Wednesday
morning. Then as the center of high pressure nears and passes
through, tranquil conditions for Wednesday and Thursday. Low
pressure then approaches and probably brings at least Small Craft Advisory conds
Thursday night into Friday. A strong enough low level jet may also
bring the threat of gale force wind gusts during Friday. Confidence
is not high enough for a mention in the severe weather potential statement at this time.


mainly dry conditions expected through Thursday.

The next chance for significant rainfall of at least a half an
inch is expected to occur late in the week (thursday night-
friday). Still too early to determine if there will be any
hydrologic concerns with this potential late week event.


NYC Central Park winds are out of service until further notice.
Loss of data is due to a severed cable. Parts are on order.

NYC National oceanic and atmospheric administration weather radio station kwo35 (162.55 mhz) will remain off
the air for an extended period of time.


Okx watches/warnings/advisories...
New York...none.
New Jersey...none.
Marine...Small Craft Advisory until 6 PM EST this evening for anz330-
Gale Warning from 6 PM this evening to noon EST Tuesday for
Gale Warning until 6 PM EST Tuesday for anz350-353-355.


near term...MD/jm

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