Area Forecast Discussion
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FXUS61 KOKX 210638
Area Forecast Discussion
National Weather Service New York NY
238 AM EDT Fri Oct 21 2016
showers today as a cold front gradually approaches from the west
and then moves through late tonight. Deepening low pressure will
track across New England into Quebec this weekend bringing windy
conditions to the Tri-State. A cold front will pass through on
Monday, followed by building high pressure through the middle of
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
Areas of Dense Fog is expanding. May need an advisory after all
for Suffolk County on Long Island and in the elevated areas of SE
CT, the Hudson Valley and into NE NJ. Will issue a Statement and
Upgrade to an Advisory if needed at 4 AM.
Otherwise, Occasional drizzle with a few light showers through
the overnight as seen on current KOKX WSR-88D. Winds continue to
veer as diffuse warm front passes through.
Temps are steady or rise slightly the rest of the overnight.
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SATURDAY/...
Amplifying trough tracks east as it becomes negatively tilted, and
cuts off tonight.
At the surface, frontal boundary and wave of low pressure tracks
east across the area this afternoon. Low pressure over the
Atlantic lifts northward, passing to the east. The front moves
slowly east of the area tonight as surface low develops across
eastern New England and deepens.
Coverage of showers remains in question, and axis of heavier rain
is in doubt. However, latest 12Z model suite does look drier
Marginal CAPE could be enough for isolated thunder this afternoon
as lift increases ahead of the trough.
Temperatures will be warm, in the lower to mid 70s during the day,
falling into the 50s at night. They could be lower depending on
speed of the front, and any cooler air arriving late at night.
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Windy and cooler weather expected this weekend as low pressure
deepens over New England and Quebec on Saturday, then drifts
toward Labrador Sunday night. The GFS, GEM and ECMWF are all very
similar with the evolution of the system, suggesting a 500
millibar closed low develops over central Pennsylvania Friday
night, tracks into upstate New York on Saturday, and then north of
Quebec City on Sunday.
For Saturday, the synoptic lift will be exiting the region.
However, very steep low level lapse rates will develop. In fact,
the GFS progs superadiabatic lapse rates in the approximately
15-21Z time period. This should result in at least broken cloud
cover and scattered showers. Across the northern tier, there may
be enough moisture to result in greater coverage and perhaps some
periods of steady rain. This precipitation will have to overcome
the downslope however on top of the synoptic subsidence, so
limited the rain to scattered showers.
Because of the expected cloud cover, this should help to temper
wind gusts a bit. As a result, wind gusts were capped at around
40 mph. This is essentially full mixing from 950 millibars in the
GFS. The best chance at this time for over-performing winds
reaching advisory criteria looks to be Saturday morning as the
pressure rapidly rises.
The precipitation winds down Saturday night as the low and
associated moisture gets too far away, but the gusty winds will
continue right through Sunday with the low still in the 980s over
A clipper type system will be racing towards the forecast area on
Monday. This will allow winds to back to the southwest and may allow
a quick warm up if the cold frontal passage is slow enough. The
12Z data however has the front coming through during the early
afternoon at the latest, so high temperatures close to those
expected on Sunday were forecast.
The airmass that builds in for the Tuesday and Wednesday time period
looks to be around 10 degrees below average, and will have the
potential to produce a freeze across much if not all of the
interior, possibly getting into some of the coastal zones.
A frontal system of Pacific origin may reach the area on Thursday
per the ECMWF. A slower timing is preferred for this type of a
system this far out however, so precipitation chances were
limited to slight chance.
.AVIATION /07Z FRIDAY THROUGH TUESDAY/...
A warm front lifts to the north early this morning, followed by a
cold front approaching from the west and a wave of low pressure
approaching from the south today. SE/ESE winds of 5 to 10 kt
through the day...becoming light and variable this evening.
Early Morning: Conditions improving to mvfr...except local ifr
interior terminals...in wake of warm frontal passage between 06z
and 08z. Then indications that conditions come back down to
widespread ifr/lifr towards daybreak...but some uncertainty on
Late Morning/Afternoon: Improvement to mvfr vsby with ifr cigs as
the morning progresses...continuing thru the afternoon. SHRA
likely. Low prob of an isolated tsra.
Evening: Potential deterioration to widespread LIFR or lower
conditions this evening. SHRA likely.
.Outlook for 06Z Saturday through Tuesday...
.Late Tonight...Improvement to MVFR conditions in wake of cold
frontal passage...with continued shower activity likely. NW winds
.Saturday...Becoming VFR. WNW-NW winds G25-30KT likely.
.Saturday Night...Most likely VFR with very low chance of MVFR.
WNW-W winds G30-35KT likely.
.Sunday...VFR. W winds G25-30KT likely.
.Sunday Night-Monday Night...VFR with isolated to scattered
showers possible. WNW-NW winds g20-25 kt possible at eastern
terminals Sunday night. NW winds g20-25KT possible Monday/Monday
.Tuesday...VFR with NW winds g20-25KT possible.
SCA out east on the Ocean through tonight as seas remain around 5
A frontal boundary slowly moves across the waters today, as winds
eventually turn toward the south. Expect a wind shift Friday
night, generally after midnight, to the west.
Seas build tonight, and a few gusts could approach 25 kt late at
night. SCA in effect west of Moriches Inlet for this.
Gales are likely over the weekend as deep low pressure spins
north of the waters. A gale watch has been issued for Saturday and
Saturday night, and gales may also extend into Sunday. A cold
frontal passage on Monday will have the potential to produce SCA
conditions though Tuesday, especially on the ocean where seas are
likely to at least remain in the 3-5 ft range.
Showers are today and today night. Totals should average around
1/2 an inch. No hydrologic problems are expected.
Less than a quarter of an inch of precipitation is expected over the
weekend. Mainly dry weather is expected thereafter.
The potential remains for isolated minor coastal flooding with
this afternoon`s high tide cycles. Generally 1-2 ft departures
are needed for minor flooding.
MARINE...Gale Watch from Saturday morning through late Saturday night
Small Craft Advisory from 6 PM this evening to 6 AM EDT
Saturday for ANZ353-355.
Small Craft Advisory until 6 AM EDT early this morning for