Scientific Forecaster Discussion
fxus61 kokx 151151
Area forecast discussion
National Weather Service New York New York
651 am EST Fri Nov 15 2019
a cold front will approach today and move across tonight,
followed by strong high pressure building toward New England
on Saturday. The high will retreat into southeastern Canada
from Saturday night into Sunday as low pressure approaches and
passes south and east of Long Island through Monday. Another low
may pass well south and east of Long Island mid-week.
Near term /until 6 PM this evening/...
showers associated with a cold front offshore have come close
enough to the coast to warrant slight chance pops across the
Twin Forks and souther New London County. Kgon reading 31
degrees as of 6 am, so there is a slight chance that if the
precipitation moves in to southern New London that freezing rain
may occur here until 7 or 8 am, by which time it will be warm
enough for rain. Otherwise, increased cloud cover, mainly for
coastal areas, with this update.
High clouds are quickly clearing out, with a mostly sunny day
expected. Flow ahead of an approaching cold front today should
remain westerly, which along with sunshine should allow temps to
rise to the lower 50s along the coast and upper 40s inland.
Short term /6 PM this evening through 6 PM Saturday/...
cold front passes through, with winds shifting northwest this evening
and then north overnight while increasing, with gusts 25-30 mph
after midnight. Lows tonight should fall to just below freezing
along the coast, and well down into the 20s inland, with wind
chills in the teens.
A brisk day expected on Sat, with NE winds gusting as high as 35
mph as strong high pressure builds to the north and low pressure
slowly rides up the Carolina coast. Highs only in the 30s.
Perhaps to near 40 across Long Island.
Long term /Saturday night through Thursday/...
Canadian high pressure will move over northern New England Saturday
night and then retreat into southeastern Canada as an area of low
pressure off the southeast coast develops and tracks northeast.
Deterministic models show the low tracking well south and east of
Long Island through Monday, therefore, confidence is increasing that
the area will be on the northern/western fringes of this storm.
However, there will continue to be some uncertainty with
precipitation amounts during this time frame with banded
precipitation moving into the area and how far west it may
progress. These details will be ironed out with further model runs.
As for precipitation, rain is expected along the coast, while a
wintry mix is possible across portions of northeast New Jersey and
the lower Hudson Valley Sunday night into Monday morning. Of concern
is the potential for freezing rain in these locations, which is
indicated in some of the model guidance. However, quantitative precipitation forecast amounts are
low out here since they are farther away from the low and large
uncertainty exists this far out with temperature, that naturally
leads to uncertainty in the exact precipitation type.
Northeast winds will increase Sunday as the pressure gradient
between the retreating high and incoming low increases, especially
across coastal locations such as Long Island and southeast
Connecticut. Sustained winds of 15 to 25 mph and gusts up to 35 mph,
with the highest winds across the Twin Forks.
Long amplitude trough in the mid-week period will allow disturbances
to ride along a frontal boundary over the western Atlantic. However,
eastern side of the trough will be well off shore, and any lows will
track well east of the area. An upper level low may bring some light
precipitation to the region for the mid-week period.
Temperatures will average well below normal for Sunday and Monday,
with warmer, yet still below normal temperatures expected thereafter.
Aviation /12z Friday through Tuesday/...
a trough of low pressure remains offshore early this morning
with a ceiling of 5-6kft at kisp and kgon. A cold front will
approach late today, then move through tonight. High pressure
then builds in from the northwest late tonight and into Saturday
West winds 5-10 kt or light and variable will increase to around 10 kt
by afternoon. Winds veer to the northwest/north in the evening, and increase
toward midnight. North to northeast increase to around 15 kt
with gusts 25 to 30 kt after 06z.
Outlook for 12z Saturday through Tuesday...
Saturday-Sunday...VFR. Wind NE around 15kt with gusts 20-30kt.
Late Sunday night-Monday...sub VFR possible. Chance of rain, with a
chance of freezing rain well inland into early Monday morning. NE
wind gusts 15-20 kt.
Tuesday...MVFR possible early with a slight chance of rain, then
quiet today with west flow and seas, which had been near 5 ft on
the far ern ocean waters, subsiding to 2 to 3 ft today.
Issued Gale Warning for late tonight into Sat for the ocean
waters, with Small Craft Advisory for the remaining waters extended into Sat
night, as winds increase following cold fropa, and as the
pressure gradient increases between building high pressure to
the north and low pressure to the south. Gusts up to 35 kt
expected on the ocean, and up to 30 kt on the remaining waters,
while ocean seas build to 6-8 ft on Sat per blend of wavewatch
Northeast winds will increase Saturday night into Sunday as the
pressure gradient between the retreating high and incoming low
increases. Gusts of 25 kt are expected across all waters during this
time frame, with the potential for gales to continue for the ocean
waters. Winds slowly diminish Sunday night through Monday, with all
waters coming below 25 kt by early Monday night.
Waves continue to increase Saturday night through Sunday night,
peaking at 8 to 13 ft across the ocean waters with 10 ft waves
possible for extreme eastern sections the eastern sound by Sunday
night into Monday. Waves diminish thereafter.
no hydrologic impacts are anticipated through the forecast
due to the likelihood of an easterly swell developing during the
weekend and a persistent NE wind into early next week minor coastal
flooding for some coastal locations cannot be ruled out. The best
chance at waters levels approaching minor coastal flood thresholds
would be for the South Shore western back bays and western sound
locations for mainly the late morning and late evening high tide
cycles on Sunday and potentially on Monday.
NYC National oceanic and atmospheric administration weather radio station kwo35 (162.55 mhz) is operating
at reduced power until further notice.
Marine...Small Craft Advisory from midnight tonight to 6 am EST Sunday
Gale Warning from midnight tonight to 6 PM EST Saturday for