429
FXUS61 KOKX 121439
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
939 AM EST Tue Nov 12 2024
.SYNOPSIS...
Strong high pressure builds in today through tonight. High
pressure slowly moves farther northward away from the region
Wednesday into Wednesday night. A weakening frontal system will
approach from the west on Thursday while an ocean storm passes
well to the east and moves into the Canadian Maritimes. This
storm will then remain over the Canadian Maritimes into Monday
as another high builds into the region Sunday into early next
week.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Forecast mainly on track this morning. Just adjusted clouds with
larger coverage in the forecast after noting IR satellite
trends, keeping more clouds north and west of NYC.
Mid levels show a strong positive vorticity advection shifting
offshore with more negative vorticity advection moving in as
ridging takes place. This will lead to subsidence with mostly
sunny sky conditions expected by this afternoon.
Strong high pressure builds in today. Steep pressure gradient
between the high pressure over the Great Lakes and low pressure
over the Canadian Maritimes. This will create very gusty NW
flow.
More sun, more drying expected today. Fire weather much more of
concern today with a red flag warning in effect for all forecast
zones. See fire weather section for more details.
Used a blend of MAV and MET mos for high temperatures which will
be much cooler than the previous day, staying in the 50s.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
A consistent mid level ridging trend continues tonight through
early Thursday. At that point, mid level ridge axis will be
overhead and weakening. A cutoff mid level low approaches from
the west with lowering heights across the local area.
High pressure will continue building into the region tonight.
Steep enough of a pressure gradient to keep gusty winds but
magnitude will be decreasing after the first few hours of this
evening.
Dry conditions continue but the winds will help mitigate
radiational cooling with mostly clear sky conditions.
Forecast lows a blend of MAV and MET, ranging from mid 20s to
upper 30s.
For Wednesday through Wednesday night, the high pressure will
slowly move farther northward away from the local region. Dry
conditions will continue. Ridging aloft with a weakening of the
surface pressure gradient will allow for winds to decrease and
gusty to lower.
Colder airmass will continue to encompass the region with high
temperatures forecast to only reach upper 40s to near 50. For
Wednesday night with nearly clear sky conditions continuing plus
diminishing winds, efficient radiational cooling is expected.
More vast range of lows are forecast from upper teens to upper
30s. Outside of NYC, frost can be expected. However, within the
NYC Metro and where there is still active growing season,
surface will be too dry for frost to form despite temperatures
in the 30s.
For Thursday, clouds increase as a weakening frontal system
approaches. Conditions are forecast to remain dry with most
vertical forcing expected to be well south of the region.
Forecast highs will be relatively similar to the previous day.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
Mainly dry weather continues through much of the extended
period with only slight chances of precipitation across portions
of the region Thursday night through Friday morning.
Precipitation across western portions of the region during this
time frame will be associated with a weakening frontal system,
and little to no precipitation may fall, as forcing is weak, and
weakens as the system passes to the southwest. Low end chance
is possible across the south fork of Long Island Friday night as
an offshore low retrogrades into the Canadian Maritime under a
weakening Omega block, pushing some moisture toward the forecast
areas.
Temperatures below normal Thursday, slightly above normal for Friday
and Saturday, and 5 or more degrees above normal Sunday into the
beginning of next week.
With the NBM handling the weather rather well, with little deviation
from the deterministic, and with most parameters similar to the
previous forecast, have mainly followed the NBM. Only deviation was
for winds and gusts during the northwest and north flow regimes
Saturday and Monday as high pressure builds into the region.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --
High pressure builds in from the Great Lakes region with its
center passing north into Wednesday morning.
VFR through the TAF period.
NW winds of 15 to lower 20s kt with gusts into lower 30s kt.
Some isolated gusts of 35 to 40 kt are possible. The gusts are
expected to remain into Tuesday evening, ending late tonight.
NY Metro (KEWR/KLGA/KJFK/KTEB)TAF Uncertainty...
Isolated gusts to 35 to 40 kt are possible into the early
afternoon.
OUTLOOK FOR 12Z WEDNESDAY THROUGH SATURDAY...
Wednesday-Thursday: VFR. Slight chance of a shower Thursday Night
near the coast.
Friday-Saturday: VFR. NW wind gusts 15-20 kt possible Friday and NW
wind gusts 20-25 kt possible Saturday.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
SCA in effect for all forecast waters through tonight. Then on
Wednesday, a gradual decrease of winds is expected. First waters
to drop below SCA will be NY Harbor and Western LI Sound (by 6AM
Wednesday). This will be followed by the rest of the non-ocean
zones dropping below SCA (by 9AM Wednesday). Then the western
ocean (Sandy Hook NJ to Fire Island Inlet NY) drops below SCA by
12PM Wednesday and lastly the rest of the ocean zones east of
Fire Island Inlet dropping below SCA (by 6PM Wednesday). There
is potential for SCA conditions lingering on the ocean east of
Fire Island Inlet for Wednesday night and Thursday with
otherwise sub-SCA conditions for the local waters.
For today into this evening, there will be occasional gales.
Timeframe for these will be this morning as well as late
afternoon into early evening. Both the temporal and spatial
coverage is not high enough to warrant inclusion of ocean in a
gale warning but trends will be monitored for any potential
upgrades of SCA to gale.
Winds and seas will be below advisory levels on the waters into late
Friday. Late Friday into Saturday there is the potential for
marginal SCA conditions on the eastern ocean waters as northwest
winds and gusts increase as offshore low pressure passes to the
east.
&&
.FIRE WEATHER...
With low levels drying out today as NW winds increase with more
frequent gusts, the environment will become more conducive to
brush fire spread. Minimum RH is forecast to lower to near to just
below 30 percent for much of the region with frequent wind gusts
of near 30 to 35 mph expected as well. Due to these expected
conditions and after coordination with surrounding forecast
offices with input from land managers, a red flag warning is in
effect for the entire local forecast region including NE NJ,
NYC, Lower Hudson Valley, Southern CT and Long Island from 9AM
this morning to 6PM this evening.
&&
.HYDROLOGY...
Moderate drought conditions continue per US Drought Monitor.
Stream flows are generally below the 25th percentile of normal
for this time of year. There are no hydrologic concerns through
early next week.
&&
.TIDES/COASTAL FLOODING...
With an upcoming full moon on November 15th, astronomical levels
will be on a rising trend. Winds in the low levels will be a
factor and the proximity of offshore lows will play a role.
There is a chance for some sites to experience minor to locally
moderate coastal flooding with high tide cycles for early
Thursday, especially within the South Shore Bays, lower NY
Harbor and Western LI Sound shorelines.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Red Flag Warning until 6 PM EST this evening for CTZ005>012.
NY...Red Flag Warning until 6 PM EST this evening for NYZ211>213.
NJ...Red Flag Warning until 6 PM EST this evening for NJZ002-004-
006-103>108.
MARINE...Small Craft Advisory until 9 AM EST Wednesday for ANZ331-332-
340-345.
Small Craft Advisory until 6 AM EST Wednesday for ANZ335-338.
Small Craft Advisory until 6 PM EST Wednesday for ANZ350-353.
Small Craft Advisory until noon EST Wednesday for ANZ355.
&&
$$
SYNOPSIS...JM/JP
NEAR TERM...JM
SHORT TERM...JM
LONG TERM...JP
AVIATION...IRD
MARINE...JM/JP
FIRE WEATHER...
HYDROLOGY...JM/JP
TIDES/COASTAL FLOODING...