Area Forecast Discussion
Issued by NWS Upton, NY

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FXUS61 KOKX 200257

Area Forecast Discussion
National Weather Service New York NY
957 PM EST Mon Feb 19 2018

High pressure remains anchored over the western Atlantic through
mid week as a slow moving frontal system approaches from the
Mississippi Valley. The associated warm front will work north
across the area this evening. A cold front moves across
Wednesday night. A series of lows will be moving through the
Northeast late this week into the weekend.


Fog continues to move into the area, with visibilities of 1/2
mile noted in some obs. Have issued an SPS for patchy dense fog
for portions of northeast NJ, Lower Hudson Valley, and southwest
CT. Will continue to monitor trends with the possibility of
issuing a Dense Fog Advisory later tonight. A more likely
scenario would be to issue an SPS over other areas of the CWA
where patchy dense fog develops later tonight. Otherwise,
forecast is on track.

A record warm pattern sets up as an anomalously strong upper
ridge over the western Atlantic strengthens through mid week. At
the same time, a slow moving frontal system associated with an
upper trough over the western states work east from the
Mississippi Valley. This will place the region in a warm, deep-
layered SW flow.

A warm front will move across the area tonight preceded by light
overrunning rain. Much of the rain will exit the area by
midnight with areas of fog and patchy drizzle forming.

Temperatures will remain steady if not slowly rise overnight.
Lows will be about 15 to 20 degrees above normal, in the 40s.


Low clouds, fog, and patchy drizzle will likely start the day
on Tuesday with some clearing expected in the afternoon as some
warmer, drier air mixes down from aloft. The high res NAM (3km)
maintains a strong low-level inversion across the area and
maintains saturated low-levels for all but the far interior.
This is likely overdone based on past performance and the
preference is to go with some improvement. There is though more
uncertainty near the immediate coast.

Temperatures in this type of airmass will also be tricky with
an onshore flow keeping coastal areas much cooler than the
interior, where highs will be near record levels. Preference
was toward the a MET/MAV MOS along the coast, and the warmer MAV
across the interior. Some interior locations will approach 70.

Areas of fog and drizzle are likely to develop Tuesday night in
the warm, moist airmass, as dew points get into the lower 50s.
This will be due to both an advection fog off the cooler marine
waters, and radiation fog inland where the SW flow becomes
light. Lows Tuesday night will approach 30 degrees above normal,
generally in the 50s. These readings will likely break record
warmest lows.


The very active and mild weather pattern will remain in place but
will become less mild late this week into the weekend. This is due
to a strong Southwest Pacific jet that will remain north of the
region through the long term period. It`s quite strong looking at
model projections of this jet which convey 190+kt extending from
Great Lakes northeast through Canadian Maritimes Wednesday through
Thursday. Thereafter, the jet structure remains the same but the
magnitude decreases.

At the surface, a very busy weather period is in store with several
systems moving across. Some notable features include areas of fog
going into Wednesday especially along the coast and very warm
temperatures continuing Wednesday. Forecast highs Wednesday upper
50s for the Twin Forks of Long Island to lower 70s N/W of NYC. The
warmth is not as much for the rest of the forecast period but highs
most days looking at Thursday through early next week are forecast
to be about 5-10 degrees above normal. The other remarkable feature
will be chances of rain which is forecast Wednesday afternoon into
Wednesday night as well as Thursday and then again Friday afternoon
through the weekend. The periods of rain look to be mostly light to
perhaps moderate at times. Early next week, drying conditions are

High pressure moves farther southeast into the Western Atlantic
Wednesday. A cold front moves across Wednesday night. The front
moves south of Long Island Thursday but stalls with an area of low
pressure developing along it. The low and front move farther
offshore southeast of Long Island Thursday night with high pressure
briefly building in from the north. The high will be moving quickly
off the New England coast Friday with another frontal system moving
in from the west. Once again, there will be a lingering front behind
the system and another low developing along it for the weekend.


A warm front approaches the area tonight, then lifts north of
the terminals on Tuesday.

Conditions expected to deteriorate to IFR or lower overnight
into morning push. Gradual improvement to MVFR then VFR during
later in the morning into afternoon for NYC/NJ and NW
terminals, but eastern terminals may remain IFR all day.

S/SW gusts to 20 kt possible for KEWR/KTEB/KSWF in the
afternoon if VFR conditions develop. Late day S15g20kt coastal
jet development possible for JFK into LGA. Elsewhere occasional
SW gusts of 15 to 20 kt possible.

LLWS possible for SW winds around 2 kft at 35-40 kt.

     NY Metro Enhanced Aviation Weather Support...

Detailed information, including hourly TAF wind component forecasts,
can be found at: http:/

KJFK TAF Comments: Timing of improvement to MVFR in the morning
and then VFR in the afternoon may be 1 to 2 hrs slower than
forecast. Possible southerly coastal jet of 15g20kt in the late

KLGA TAF Comments: Timing of improvement to MVFR in the morning
and then VFR in the afternoon may be 1 to 2 hrs slower than
forecast. Possible southerly coastal jet with g15-20kt in the
late afternoon.

KEWR TAF Comments: Timing of improvement to MVFR in the morning
and then VFR in the afternoon may be 1 to 2 hrs slower than
forecast. SW gusts to 20 kt possible in the afternoon.

KTEB TAF Comments: Timing of improvement to MVFR in the morning
and then VFR in the afternoon may be 1 to 2 hrs slower than
forecast. SW gusts to 20 kt possible in the afternoon.

KHPN TAF Comments: Timing of improvement to MVFR in the morning
and then VFR in the afternoon may be 1 to 2 hrs slower than

KISP TAF Comments: IFR conditions may persist through the day.

.Tue Night...IFR or lower in stratus/fog possible at night.
.Wed...Improving to VFR. Chance of showers with MVFR in the
evening. SW wind G15-20KT possible. Winds shift to the N at
.Thu...MVFR in rain. NE wind G15 KT possible.
.Fri...CHC MVFR in rain.
.Sat...CHC MVFR in rain.


Patchy fog is possible over the waters tonight. Will have to
watch for the possibility of dense fog developing later tonight
with abundant low level moisture.

A prolonged period of S-SW winds ahead of a slow moving frontal
system approaching from the Mississippi Valley will produce
marginal SCA conditions later tonight into Wednesday night on
the ocean waters east of Fire Island Inlet. However, current
SCA only goes out through the day Wednesday as confidence at
this time is too low to extend into Wednesday night.

Aside from Wednesday into Wednesday evening with some seas of 5 ft
on the ocean, sub-SCA conditions are forecast across the waters for
the rest of the week into the weekend. It`s a relatively quiet
period with the pressure gradient remaining weak.


Less than 1/4 inch of rainfall is expected through tonight.
Several rounds of rain are possible late this week into the
upcoming weekend, but no significant hydrologic impacts are
anticipated at this time.


Temperatures may approach or break record highs in a few spots
Tuesday and Wednesday.

Record Highs for Tuesday February 20, 2018

Central Park........69/1939

Record Highs for Wednesday February 21, 2018

Central Park........68/1930


NYC NOAA Weather Radio Station KWO-35 (162.55 MHz) is off the
air for an extended period of time.


MARINE...Small Craft Advisory until 6 PM EST Tuesday for ANZ350-353.


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