000
FXUS61 KOKX 091536
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
1136 AM EDT Tue Apr 9 2024
.SYNOPSIS...
High pressure gradually shifts offshore today along with a back door
cold front sliding down from the north and northeast. The front will
remain nearby as a stationary front into Wednesday and Wednesday
night. The stationary front lifts back north as a warm front on
Thursday as deepening low pressure draws closer over the Ohio
Valley. A cold front will move through early on Friday. As low
pressure departs the area, a secondary cold front swings through
early Saturday. High pressure then briefly noses in from the
south into Sunday. Another frontal system will potentially move
through late Sunday into Monday.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
-- Changed Discussion --
Main change with this forecast update was to increase cloud
cover a bit for this afternoon as cirrus moving in from the west
a bit more opaque. Not confident at this time that temps will
be much different than currently forecast.
With deep layer ridging remaining in place the stretch of dry
weather continues at least through today. A back door cold
front sort to speak approaches from the north and northeast this
afternoon into this evening. At the same time, a warm front
begins to approach from the west and southwest. The caveat later
this afternoon as the synoptic pressure gradient remains
relatively weak will be the timing and strength of a sea breeze
boundary. With 850 mb temps warming it does appear that temperatures
will be off to the races before the onshore flow becomes a
factor. For the afternoon interior places to the north and
northwest should get into the lower and middle 70s. An onshore
flow later in the day should initiate a sea breeze with
temperatures falling through the 60s, and 50s further east, with
some 40s during the early evening for immediate coastal
sections.
Clouds will be thicken tonight with the passage of the 500 mb
ridge axis as PoPs get introduced during the pre-dawn hours
mainly for the western half of the area with slight chance
increasing to chance towards daybreak further west. Any lift
would be weak, thus any rain would be very light and spotty as
there should remain some relatively drier layers in the profile,
especially in the mid levels. Lows tonight will in the 40s to
around 50.-- End Changed Discussion --
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY/...
With the ridge starting to get broken down a short wave is expected
to pivot through for Wednesday morning and perhaps into the early
afternoon. This will aid in lift somewhat and leads to a higher
chance of shower activity. For now thinking chance PoPs is a good
compromise with light rain showers. With a good deal of cloud cover
due to overrunning and more of an easterly onshore flow temperatures
will be noticeably cooler. Temperatures will therefore be closer to
normal with mostly middle 50s to around 60, with lower 50s for the
most part in eastern and southern coastal sections.
For Wednesday night PoPs start to edge up through the chance
category with the area getting on the western side of the upper
level ridge axis and some indications of PVA later at night and more
in the way of thickness ridging into the region. Any shower activity
that falls Wed night should be light with amounts generally under a
tenth or so. Low temperatures will remain a touch above normal with
middle 40s to lower 50s.
For Thursday introduce likely PoPs through the day, and categorical
PoPs for NW areas during the afternoon. Height falls take place back
to our west over the Ohio Valley and Great Lakes. This will
strengthen low pressure back to the west and lift a warm front
through the area. The area will be in the warm sector, but with a
easterly component to the southerly flow temperatures will only be a
few degrees warmer perhaps compared to Wednesday. Although later in
the day some warmer air getting into SW portions of the area is a
possibility. Low clouds should linger across the area with periods
of showers. The shower activity indicated by NWP appears to be
intermittent as showers with the stronger forcing now being
indicated for later Thursday night. Look for an unsettled day, with
the breeze picking up for the later in the afternoon and early
evening. Liquid amounts on Thursday should range from a few
hundredths to a couple of tenths.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
An approaching strong upper level trough will take on a negative
tilt as associated strong surface low deepens as it tracks well to
our north and west. With high pressure offshore, the pressure
gradient will be tightening quickly Thursday night as the low
approaches. A strong southerly low level jet develops along the Mid-
Atlantic coast, likely peaking over our area Friday morning. Latest
04/09 00z NAM, GFS and Canadian all show 70 to 75 kt at 925mb.
With this set up, expect winds to ramp up Thursday night and peak
late Thursday night into Friday morning. A low level inversion can
be seen in model soundings, but current thinking is that southerly
winds gusts will reach 40 to 45 mph across the coast. As for rain,
light rain will likely be ongoing at the start of the Thursday night
period, becoming moderate to locally heavy through the night. See
hydrology section below. With some elevated instability available,
kept mention of thunder.
The cold front swings through sometime late Friday morning. The
upper level trough lingers a bit and some embedded shortwaves swing
through later Friday and Saturday with some reinforcing shots of
cold air. Slight chance PoPs linger north and west of NYC through
Saturday, with the rest of the area likely dry by Friday night.
High pressure then briefly noses in from the south leading to dry
conditions Saturday night through most of Sunday. Thereafter is when
model guidance starts to disagree a bit more. There looks to be
potential for another, weaker, frontal system to move through the
area late Sunday into Monday that could unsettled weather to the
area.
&&
.AVIATION /16Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --
VFR with high pressure today.
Light N to NW winds give way to sea breezes late this morning into
early afternoon. Winds mainly 10kt or less through the day. Winds
then back more SE to E tonight, remaining under 10kt.
NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Amendments possible with sea breezes this morning/afternoon.
OUTLOOK FOR 12Z WEDNESDAY THROUGH SATURDAY...
Wednesday: Chance of showers/MVFR or lower cond.
Thursday and Friday: Showers with MVFR or lower cond. Tstms
possible. SE to SW winds G30-35kt. LLWS possible.
Saturday: Mainly VFR with only slight chance of showers mainly NW of
the NYC metros. W winds 15-20 kt with G20-30kt.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
A relatively weak pressure gradient will remain in place for today
and tonight with seas mainly at 2 to 3 feet, with a residual 10
second swell remaining in place. Sub small craft conditions should
take place right through Wednesday. Light winds continue through the
day Wednesday, with a slight uptick in the winds mainly for the
southern and eastern ocean waters Wednesday night. As low pressure
gets better organized to the west on Thursday and a warm front lifts
north expect a stronger south to southeast flow to develop with
small craft conditions becoming increasingly likely later in the
day.
Winds will be ramping up Thursday night with the approach of a
strong low pressure system. Southerly winds will peak late Thursday
night into Friday morning with sustained winds 30 to 35 kt and gusts
40 to 45 kt. Added a mention of gales to the HWO for this period.
Waves on the ocean waters peak Friday morning around 12 to 14 ft.
Waves on the LI Sound will also likely reach 5 to 7 ft, with the
higher waves close to the CT coast given the southerly flow.
Small Craft Advisories will likely linger on all waters through
Saturday as wind gusts remain around 25 kt. Sub SCA conditions then
expected thereafter, except on the ocean waters where 5 to 7 ft
waves could linger.
&&
.HYDROLOGY...
There are no hydrologic concerns through the day Thursday.
Moderate to locally heavy rain is possible Thursday night through
early Friday. Given the progressive nature of this system, at this
time only minor urban and poor drainage flooding is expected, along
with the potential for minor flooding at flashy small
streams/rivers. Current storm total rainfall forecast is 1 to 1.5
inches across the area, with much of that falling in a 6 to 9 hour
period.
&&
.TIDES/COASTAL FLOODING...
Astronomical high tides remain elevated with the new moon / spring
tide set up from early this week. Additional rounds of minor
flooding appear likely through mid to late week for the same
areas that experienced any coastal flooding from previous high
tide cycles, as tidal departures needed for minor drop as low as
1/4 ft thru Wed eve high tide. Localized pockets of moderate
coastal flooding remains a possibility for the western south
shore back bays.
Coastal Flood Advisories have been issued for tonight`s high tide
cycle for coastal northeast NJ, southern Queens, southern Nassau,
southern Westchester and southern Fairfield. Up to 1 to 1.5 foot of
inundation above ground level is expected in the most vulnerable
locations near the waterfront. Coastal Flood Advisories have been
issued elsewhere except the Bronx, northeast Suffolk and southern
New London.
Strengthening SE-S flow with a storm system late Thursday into
Friday morning may force more widespread minor to moderate coastal
flooding.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Coastal Flood Advisory from 10 PM this evening to 2 AM EDT
Wednesday for CTZ009.
NY...Coastal Flood Advisory from 10 PM this evening to 2 AM EDT
Wednesday for NYZ071.
Coastal Flood Advisory from 7 PM this evening to 1 AM EDT
Wednesday for NYZ178-179.
NJ...Coastal Flood Advisory from 7 PM to 11 PM EDT this evening for
NJZ006-104-106-108.
MARINE...None.
&&
$$
SYNOPSIS...JE/JT
NEAR TERM...JE/DW
SHORT TERM...JE
LONG TERM...JT
AVIATION...JC/JT
MARINE...JE/JT
HYDROLOGY...JE/JT
TIDES/COASTAL FLOODING...