000
FXUS61 KOKX 062342
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
642 PM EST Wed Mar 6 2024
.SYNOPSIS...
A frontal system and associated low pressure moves through this
evening into tonight. The low will exit east of the area
through Thursday night. High pressure briefly builds in for
Friday, then low pressure impacts the region over the weekend.
High pressure builds in behind the low next week.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
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Over the next couple of hours, watching to see the wwd extent
of the rain development and as a result whether it will persist
across NJ zones which are always the most vulnerable to
flooding. Otherwise, IR and lightning data reveal a line of
convection over the Atlc from off the delmarva to off the SC
coast tracking nwd. No changes to the fcst attm.
A coastal low currently tracking northward off of the Carolina coast
will pass over the area this evening before a secondary low passes
overnight, then exiting northeast tomorrow. A 45-60 kt LLJ with the
approaching low will advect larger PWATs into the region with 12Z
guidance showing between 1.45 to 1.6 inches, with larger areas of
increased PWATs for eastern zones where the LLJ will be more
concentrated this evening and tonight. This exceeds the max moving
climatological average of 1.2 inches. We`ll also be in between
jet streaks with one to our northeast and another to our
southwest which may enhance synoptic lift. In the mid-levels, a
shortwave will pass this evening and tonight along with the
surface low, aiding in rainfall with positive vorticity
advection.
Most 12Z guidance and the 12Z HREF has shifted things eastward from
prior projections. Rainfall will likely persist this evening into
tonight before tapering off as the low exits tomorrow morning, .
There will be two rounds of moderate-to-heavy rainfall. The first
round will likely pass over much of the area as rates increase from
a strengthening LLJ. The second round of moderate-to-heavy rain
overnight will be more concentrated over eastern zones (primarily
Suffolk county, New London county and Middlesex county). This is
being pulled farther east than prior projections due to an eastward
shift in the LLJ and will lead to higher event totals in eastern
sections. This area may need to be watched for training showers
overnight tonight if the LLJ jet is slower to move eastward of the
area.
Maximum rain rates will likely reach 0.25-0.5"/hr for western areas
and closer to 0.5"/hr for eastern areas with isolated pockets
possibly reaching 0.75"/hr as the LLJ strengthens and enhances
forcing early tonight. The 12Z HREF shows probabilities for rain
rates at least 0.5"/hr at 80-90% for New London county, ~50% for
parts of Suffolk, Middlesex, and New Haven counties. The timing of
the heaviest rainfall will be this evening into early tonight, in
line with the greatest forcing.
Event total rainfall will likely range from 1-2" with isolated 3"
totals possible. Higher totals are expected for eastern areas with
lower totals over western areas. A Flood Watch remains in effect
until 6am, with the primary concerns now concentrated farthest east
than previously.
Temperatures will remain very mild with the rainfall and warm, moist
airmass with lows in the mid-40s. Highs tomorrow will reach the
upper-40s to lower-50s before cooler air starts to filter in behind
the exiting low. Lows Thursday night will still be slightly above
seasonal averages in the upper-to-middle 30s.-- End Changed Discussion --
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
Leftover drizzle or light rain is possible into the early
afternoon tomorrow as a coastal system exits to the east, with
rain tapering off west to east. High pressure centered over
northeast Canada noses in from northeast to southwest behind the
exiting low with winds shifting northwest in response. Winds
may become breezy Thursday afternoon before gradually weakening
late Thursday night. For Thursday night the clouds break up late
in the evening, with clearing from west to east later at night
with a drier north breeze. Cooler air does arrive with
temperatures still a few degrees above average, but noticeably
cooler late at night.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
A transitory high ridges into the region from Labrador on Fri. This
will keep the cwa dry. Unless a bank of marine stratus develops and
advects swwd into the area, it will be mostly sunny as well. The
onshore component to the flow will modify temps across ern areas,
keeping highs cooler than the rest of the cwa. The NBM with local
adjustments was used.
Subtropical pacific tap of moisture seen on water vapor gets here on
Sat. This will produce ovc skies ahead of the next chances for rain.
As a deepening nrn stream trof interacts with this surge of
moisture, rain develops late Sat, ending Sun mrng. The pcpn is
mainly on the front end of this sys with a significant dry slot.
As the cold pool aloft moves in Sun ngt, pcpn chances transition to
shwrs. H85 gets to -8C so shsn possible. Similar setup on Mon with
steep lapse rates. Went abv the NBM and kept the whole area in at
least 20 pops for shra, with some ip possible as well, thru the day.
The models often do not handle this scenario well.
A ridge then builds across Tue and Wed keeping the area dry and
allowing for a warming trend.
The NBM was followed for temps Sat-Wed with a few local
adjustments.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
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Low pressure passes across the terminals tonight, tracking offshore
on Thursday.
LIFR to IFR through tonight in rain. The rain may be moderate to
heavy at times, especially the first half of tonight. The
window for heaviest rain looks to be between 00-02z in the NYC
metro and 01- 05z elsewhere. The heaviest rain should shift to
the northeast after 05-06z, but periods of rain are likely to
continue through the early morning hours. The rain should taper
off 12-15z with improvements to MVFR by mid to late morning. VFR
should return in the afternoon although KGON may stay MVFR into
the evening.
NE flow around 10 kt will become N tonight. Gusts 17-20 kt develop
early this morning and then increase after day break as the system
departs to the east. N winds 10-15 kt with gusts 20-25 kt expected
Thursday morning into the afternoon. The gusts could initially be
occasional before becoming frequent through the day.
NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Amendments likely for changing flight categories tonight. Timing
of improving conditions on Thursday may be off by 1-3 hours.
MVFR could prevail longer into the afternoon.
The onset time of gusts early Thursday morning may be off by
1-3 hours and the gusts may be more occasional early Thursday
morning.
OUTLOOK FOR 00Z FRIDAY THROUGH MONDAY...
Thursday Night: VFR with N-NE gusts G20-25kt ending.
Friday: VFR.
Saturday: VFR into the afternoon, then becoming MVFR or lower with
rain developing late.
Saturday Night: IFR and rain. SE gusts 20-25 kt possible.
Sunday: MVFR or lower with rain in the morning with possible
improvements to VFR in the afternoon. S winds become W into the
afternoon. Gusts 20-25 kt, especially in the afternoon.
Monday: Mainly VFR. NW G25-30 kt.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
Small craft conditions will prevail on the ocean waters with mainly
4 to 6 ft seas this evening into tonight. Seas will climb
higher tonight into Thursday. Small craft gusts may be possible
Thursday morning on the non-ocean waters.
Seas will remain elevated on the ocean Fri, so the sca was extended
thru the day. Cond improve Fri ngt into early Sat, then winds and
seas increase late Sat thru Sun with low pres tracking thru the
region. There is a chance for a period of gales with the sys. It
remains windy on Mon with at least sca winds. Gales possible. Winds
gradually diminish on Tue.
&&
.HYDROLOGY...
WPC maintains a slight to marginal risk of excessive rainfall today
and tonight. A flood watch remains in effect. Widespread minor
flooding is expected for eastern areas while western areas it
may be more scattered, with some river flooding as well as more
significant flash flooding possible.
An additional 1 to 2 inches of rain could fall with the storm system
this weekend. Impacts with this event are still somewhat uncertain
as it will depend on where the heaviest rain falls with the
Wednesday/Wednesday night system.
&&
.TIDES/COASTAL FLOODING...
As we head into the closest new supermoon of the year on March 10,
at least minor tidal flooding can be expected this weekend. The sys
over the weekend could enhance tides further. The ensemble spread
suggests moderate to isold major possible in spots, particularly
those typically most vulnerable.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
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CT...Flood Watch until 6 AM EST Thursday for CTZ005>012.
NY...Flood Watch until 6 AM EST Thursday for NYZ068>075-078>081-
176>179.
NJ...Flood Watch until 6 AM EST Thursday for NJZ002-004-006-103>108.
MARINE...Small Craft Advisory from 10 AM Thursday to midnight EST
Thursday night for ANZ331-335-338-340-345.
Small Craft Advisory from 10 AM Thursday to 6 PM EST Friday
for ANZ332.
Small Craft Advisory until 6 PM EST Friday for ANZ350-353-355.-- End Changed Discussion --
&&
$$
SYNOPSIS...JMC/BR
NEAR TERM...BR/JMC
SHORT TERM...BR
LONG TERM...JMC
AVIATION...DS
MARINE...JMC/BR
HYDROLOGY...JMC/BR
TIDES/COASTAL FLOODING...