Scientific Forecaster Discussion
fxus61 kokx 192044
Area forecast discussion
National Weather Service New York New York
344 PM EST Tue Nov 19 2019
low pressure passes to the south and east of the region through
Wednesday. High pressure moves across the area Wednesday night
through Thursday. A cold front will then cross the area on
Friday afternoon, followed briefly by high pressure Saturday. A
coastal low pressure may affect the region late Saturday into
Sunday, before high pressure returns for early next week.
Near term /until 6 am Wednesday morning/...
the region will still remain under an upper trough tonight with a
Broad Cut-off low developing overhead by Wednesday morning. This
will keep a mostly cloudy to cloudy forecast overnight with
temperatures in the low 30s inland and middle and upper 30s
Short term /6 am Wednesday morning through Wednesday night/...
the trough and upper low will swing through sometime late Wednesday
morning. Low pressure passing south and east of the region will
strengthen as it passes further offshore. Hi-res models are
indicating light precipitation developing across the eastern part of
the region through the afternoon. Most of the precipitation should
fall in the form of light rain or possibly drizzle, however its
possible some snow showers may mix in away from the coast across
south eastern Connecticut. No accumulation is expected. Abundant
cloud cover from the upper low should keep temperatures in the low
to mid 40s. It will be a breezy afternoon as winds pick up gusting
to around 20 kts, mainly along the coast as the gradient increases
between the departing system and incoming ridge.
Skies will begin to clear from the west as the upper trough finally
moves out and high pressure pushes into the region Wednesday night.
Temperatures will drop into the upper 20s across the interior where
winds will be light. Temperatures across the NYC Metro and the coast
will stay in the 30s.
Long term /Thursday through Tuesday/...
models in good agreement with a progressive flow through the period,
with main sensible weather differences lying in nature of phasing
between the northern and southern stream.
The first feature of interest is a vigorous northern stream
shortwave diving through the Great Lakes Thursday night into Friday
morning, which then intensifies as it phases with southern stream
energy and swings through New England Friday into Friday night. At
the surface, a resultant strong low pressure system tracks through
southern Ontario and Quebec, with its trailing cold front
approaching the region Friday afternoon and swinging through in the
Ahead of this feature, a tranquil and seasonably cool day is
expected as high pressure slides to the south. Return flow develops
Thursday night and continues into Friday afternoon ahead of the
approaching cold front, with increasing clouds but mild conditions
as temps run several degrees above seasonable. Rapid movement of the
front should limit shower coverage, but a quick shot of shower looks
likely in the afternoon/early evening particularly with
entrainment of southern stream energy and moisture.
In the wake of the front a quick shot of cold advection on gusty
westerly winds is expected. Winds gusts to 40 mph are possible
Friday night, subsiding Saturday morning. Chilly but tranquil
conditions on Saturday, as high pressure moves across.
Northern and southern stream shortwave energy approaches Saturday
night, with still some differences in degrees of interaction between
the branches, and amount of amplification of the trough as it swings
through the region. This will of course have implications on
intensification and track of a southern low as it tracks up the
coast Sat night/Sunday. This should come into better focus mid to
late week, with sensitivity lying in the interaction of the east Pacific
closed low and a northern Pacific shortwave diving down the West Coast
in the next 24 hrs. Increased phasing would mean a more intense and
closer to the coast or over the coast track. Spread of current
solutions indicate a progressive but potentially strong event with
1/2 to 1 1 1/2 inch qpf possible. A track to the southeast of Li would
bring potential for rain/wet snow mix across the interior with a
marginally cold airmass in place.
In the wake of the trough axis, mean troughing lingers through
Monday, with a gradual transition to ridging possible heading into
midweek. At the surface, high pressure builds in behind the low
Sunday afternoon into Tuesday, with initially below seasonable temps
gradually moderating to near seasonable.
Aviation /21z Tuesday through Sunday/...
MVFR conditions will continue for much of the afternoon with
some breaks of VFR expected by early evening. A brief period of
VFR conditions will continue through about midnight, then a
return to high end MVFR/low end VFR is expected for the second
half of tonight and Wednesday.
Westerly winds 10kt or less will become more northwesterly
tonight. Winds on Wednesday will increase 10-15kt with some
gusts to around 20kt possible.
New York Metro enhanced aviation weather support...
Detailed information, including hourly taf wind component forecasts,
can be found at: http:/www.Weather.Gov/zny/n90
Kjfk taf comments: changing flight categories may be off by an
hour or two.
Klga taf comments: changing flight categories may be off by an
hour or two.
Kewr taf comments: changing flight categories may be off by an
hour or two.
Kteb taf comments: changing flight categories may be off by an
hour or two.
Khpn taf comments: changing flight categories may be off by an
hour or two.
Kisp taf comments: changing flight categories may be off by an
hour or two.
Outlook for 18z Wednesday through Sunday...
Wednesday afternoon-Thursday...VFR/MVFR. Some gusts to near
20 kt possible Wed afternoon.
Friday...chance MVFR in rain showers. SW gusts 20-25 kt PM.
Saturday...chance MVFR/IFR in rain PM hours.
Sunday...chance MVFR/IFR in rain in the morning.
Small Craft Advisory remains in effect until 10 PM tonight on the
ocean waters east of Fire Island. Seas may fall below 5 feet
sooner and there is a chance the Small Craft Advisory will be cancelled earlier.
Winds and seas then increase again Wednesday afternoon to Small Craft Advisory
levels as low pressure passes offshore.
Winds and seas subside on Thursday as high pressure moves across the
waters. Small Craft Advisory conditions expected to develop on the ocean Fri morning
ahead of an approaching frontal system, possibly with marginal Small Craft Advisory
gusts for all waters. Small Craft Advisory winds expected on all waters in the wake
of the cold front Friday night, potentially a period of gale gusts.
Winds should quickly subside Saturday as high pressure builds across
the waters, with ocean seas gradually following suit through the
The respite will likely be brief, with a coastal low likely to
affect the waters Saturday night into Sunday with rough conditions
no hydrologic impacts are anticipated through Saturday.
1/2 to 1 1/2 inches of qpf are possible Saturday night into Sunday
with a coastal low.
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 until 10 PM EST this evening for anz350-