000
FXUS61 KOKX 122347
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
647 PM EST Tue Dec 12 2023
.SYNOPSIS...
A cold front moves across tonight. Strong high pressure then
starts to build in through midweek. High pressure continues to
build in on Thursday and remains in control through Saturday. A
cold front moves through late Saturday, with brief high pressure
building back in through early Sunday. Low pressure impacts the
area Sunday night through early next week.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
The forecast is on track this evening. Only minor adjustments
were made to capture the current obs and trends.
A cold front will be moving across tonight from west to east.
However, only a slight increase in clouds is forecast as there
will be a lack of moisture with all the westerly flow. Dry
conditions are expected to prevail.
Large scale models depict no precipitation across the local area
with the cold front. Mesoscale models indicate via their
reflectivity forecasts, shower activity staying north of the
forecast region, closer to the higher level mid level positive
vorticity advection.
Lows forecast are a blend of MAV/MET and NBM, ranging from upper
20s to mid 30s.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
On Wednesday, the mid level trough moves south into the area with
its associated positive vorticity advection. The trough axis moves
across the local region Wednesday night. Went above model
guidance with cloud coverage considering the cyclonic flow
aloft. Last week also had to go above model guidance with cloud
coverage based on observed trends. So, expecting stratocumulus
development with the increase in diurnal heating on Wednesday.
Used a blend of MET and MAV guidance and lowered by a degree for
the high temperature forecast, ranging mainly in the low to mid
40s.
The trough axis moves east of the region Wednesday night, with
more ridging aloft. This will promote more of a decrease in
cloud coverage late Wednesday night into early Thursday morning.
At the surface, pressure will continue to rise in the local area as
high pressure area builds in from the west. Large scale models
agree upon a strong near 1040mb high that will be forming and
moving into the Ohio Valley Wednesday into Wednesday night.
The center of this strong high stays well west of the region and
therefore a steep pressure gradient will be present. With
increased cold air advection Wednesday afternoon into Wednesday
night, westerly flow will become more gusty. For lows Wednesday
night, also used a blend of MAV, MET and NBM with a range from
the low 20s to low 30s.
Dry conditions are expected to prevail Wednesday through
Wednesday night.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
High pressure remains in control through much of the long term
period leading to quiet and dry weather. Low pressure then looks to
impact the area Sunday night through early next week.
Thursday starts off with a ridge building in aloft with high
pressure building in at the surface as an upper level trough axis
shifts east. By Friday night, with upper level energy moving well
north of the ridge in eastern Canada, the ridge starts to flatten
over our area as well as surface high pressure getting suppressed
farther south. The center of the high remains south of our area
through Saturday, but remains in control. Late Saturday a cold front
moves through the area dry with little moisture available. High
pressure then briefly builds back in. In terms of weather, dry
conditions are expected through at least much of Sunday.
Low pressure looks to develop well southwest of the area and deepen
over the southeast US under southern stream energy and then lift up
the east coast towards the area. Although model spread still exists
due to this event being Day 6 Night and later, there is decent
agreement on this being an all rain event. The GFS keeps the
northern stream and any cold air too far to our north. The ECMWF and
Canadian do wrap in some colder air with a deeper northern stream
trough phasing in with the system, but it happens too late. There is
then further disagreement of a lingering upper level/surface low
which will play a major role in any lingering precipitation.
Chance PoPs with this system start Sunday night and become likely
Monday morning, remaining likely through Monday before tapering off
slowly through Tuesday. The NBM currently has a 30-40% chance of
seeing 1 inch of rain over any 24 hr period through this event.
Temperatures through the long term will be above normal after
Thursday. Highs Friday through Monday will be in the upper 40s to
low 50s.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
A cold front moves through late tonight with high pressure
building in through the rest of the TAF period.
VFR through the TAF period. WSW or SW flow this evening around
10 kt in the metro terminals, diminishing to 10 kt or less
until the passage of the cold front late tonight that will
bring winds back up to around 10 kt through daybreak, and shift
winds more to the W, then NW by mid Wednesday morning. Speeds on
Wednesday increase to 10 to 15 kt with gusts 20 to 25 kt
possible. An isolated gust of 25 to 30 kt is possible Wednesday
afternoon.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
High confidence in wind direction and speed. Isolated gusts to
30 kt possible Wednesday afternoon.
OUTLOOK FOR 00Z THURSDAY THROUGH SUNDAY...
Wednesday Night: VFR. NW winds diminishing towards daybreak.
Thursday through Sunday: VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
SCA level conditions continue on the ocean with marginal 25 kt
gusts going into tonight. The SCA level ocean seas remain. The
near 25 kt gusts are expected to be occasional. More gusts to SCA
levels are expected Wednesday afternoon into Wednesday night.
SCA continues on the ocean and has been extended until 7am
Thursday. Non-ocean waters have SCA Wednesday starting at 12pm
and go through Wednesday evening. Outside of NY Harbor, which
has their SCA end at midnight Wednesday night, the rest of the
non-ocean waters SCA goes through all of Wednesday night.
Starting Thursday, high pressure will remain in control through
the weekend. This will lead to mainly sub-SCA conditions on the
waters. There is a brief period Friday where 25 kt gusts are
possible on the ocean waters, as well as waves briefly touching 5
ft. Low pressure then looks to impacts the area Sunday night
through early next week. Although the details still need to be
ironed out, it looks like there is potential for Small Craft to
Gale conditions across most waters.
&&
.HYDROLOGY...
Dry conditions prevail through the first half of this weekend.
At this time there are no hydrologic concerns through early next
week.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory from noon Wednesday to 6 AM EST Thursday
for ANZ331-332-335-340-345.
Small Craft Advisory from noon Wednesday to midnight EST
Wednesday night for ANZ338.
Small Craft Advisory until 6 AM EST Thursday for ANZ350-353-
355.
&&
$$
SYNOPSIS...JM/JT
NEAR TERM...JM/JT
SHORT TERM...JM
LONG TERM...JT
AVIATION...JP
MARINE...JM/JT
HYDROLOGY...JM/JT