000
FXUS61 KOKX 031604
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
1204 PM EDT Wed Apr 3 2024
.SYNOPSIS...
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A secondary low developing over the Mid Atlantic today will deepen
while tracking slowly northeast. The low will pass south of Long
Island tonight, then tracks slowly northeast along the New
England coast Thursday into Friday. The low will slowly weaken
east of New England Friday into Saturday. High pressure builds
in from the west Sunday into Monday.-- End Changed Discussion --
&&
.NEAR TERM /THROUGH THURSDAY/...
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Next batch of rain moving into area with generally 0.1 to
0.2"/hr rates, but there are some heavier pockets (0.25 to
0.50"/hr) just about to move onshore across LI and working
northward from central and southern NJ.
Secondary surface low now taking shape over the Mid Atlantic
states, part of a deep cutoff upper low centered over the Great
Lakes. This low will strengthen and pass just south of our area
tonight, deepening to around 985mb. Expect periods of moderate
to occasionally heavy rain and a strengthening easterly flow
into this evening. An isolated elevated thunderstorm is also
possible.
Most of the model guidance is showing a strong easterly LLJ
anywhere from 60 to 70 kts at 925mb. Bufkit soundings show a
a deep enough mixed layer for the potential to bring 45-50kt
(50 to 60 mph) gusts to the surface. The highest winds are
forecast for Long Island, NYC, coastal CT and southern
Westchester. These locations remain under a High Wind Warning.
Elsewhere (except Orange County and Western Passaic County) a
Wind Advisory for 45 to 50 mph wind gusts remains in effect.
An additional 1.5 to 2 inches of rainfall is expected through
early Thursday with locally higher totals possible. The bulk of
this rain will fall this afternoon and evening. A Flood Watch
remains in effect for NE NJ, NYC metro and LI. Refer to hydrology
section below for additional details.
This low will also bring coastal flooding to the area. See
the tides/coastal flood section below.
As the low pulls away, cold air gets wrapped up into the system
and precip may end as a wintry mix across far northern and
western locations. At this time, there is potential for snow and
sleet to mix in. However, little to no accumulation is expected
due to warm surface temperatures.-- End Changed Discussion --
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY/...
A low with meander off of the New England coast Thursday night
into Friday as it gradually weakens. This will leave general
cloud cover in the area with a slight chance for rain showers
through Thursday night into the day on Friday. Winds will not
meet hazard criteria, but may be breezy at times with the low
meandering nearby.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
A blocky pattern will persist through the period courtesy of a
developing omega block over the CONUS and southern/central
Canada. Its eastern leg (the upper low associated with this
week`s storm) will be moving across Thu night, accompanied by
snow/rain showers especially in the evening. Another fairly good
chance for showers will come on Friday as a mid level vort max
trailing the upper low moves across. This disturbance will have
some low level instability to work with as model fcst sounding
show steep sfc-H7 lapse rates and available moisture above the
LCL, so have bumped up NBM PoP to at least 30 percent
throughout, and while fcst does not include this could not
entirely rule out some isolated thunder and/or graupel/small
hail with some of this activity.
Another vort max pinwheeling around the slow moving upper low E
of New England should bring another chance for showers on Sat
mainly across S CT and ern Long Island. Then fair and milder wx
likely for Sun-Tue with sfc high pressure finally building in
and heights rising aloft. Siding more with slower ECMWF vs
faster GFS solution with a weakening upper ridge axis sliding
across, and some mid level shortwave energy riding atop the
ridge axis in the afternoon. This means there could be a fair
amt of bkn high clouds present during the time of the solar
eclipse in the afternoon.
Temps a few degrees below normal Thu night through Sat should
moderate to near normal on Sunday, then warm up to a few
degrees above normal Mon-Tue, with highs in the lower/mid 60s
both days.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
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HIGH IMPACT AVIATION EVENT INTO TONIGHT...
A strengthening coastal storm approaches today and moves across or
just south of the region tonight into early Thursday.
Expect mainly IFR conditions with rain for much of the TAF period.
There could be occasional time windows of MVFR as well as lulls in
the rain. There is isolated thunderstorm potential this afternoon
into tonight. The rain could be mixed with wet snow at KSWF
late tonight into Thursday.
Increasing easterly winds and wind gusts today through this evening.
Winds increase to around 25 kt this afternoon into evening.
Gusts increase to near 40-45 kt this afternoon. Gusts 40-50 kt
forecast late this afternoon into this evening.
Overnight tonight, winds generally become more NE and decrease
to near 20-25 kt with gusts decreasing to near 30-35 kt. Winds
further decrease going into daybreak Thursday and become more
northerly. Sustained winds by that point will be closer to 20 kt
with gusts more in the 25-30 kt range.
Low level easterly jet moves in late this afternoon into this
evening with winds of 50-55 kt at 2kft for the coastal terminals.
NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Amendments likely through the TAF period for changing and possible
fluctuations in flight categories.
Thunderstorms too low confidence in timing and location to put in
TAFs. Relatively higher chance for afternoon into early evening.
OUTLOOK FOR 12Z THURSDAY THROUGH SUNDAY...
Thursday: MVFR or lower with lingering rain, possibly mixed with wet
snow at KSWF. NW gusts near 20 kt.
Friday: Mainly VFR. Possible rain showers but have snow showers
for interior including near KSWF. NW flow with gusts 15-20kt.
Saturday: MVFR possible with possible rain showers. Northerly
gusts near 20-25 kt.
Sunday: VFR with northerly gusts near 20 kt.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
A Storm Warning is then in effect starting Wednesday morning on
all waters. Strong low pressure will pass over or just south of
the waters and bring a period of 50 kt wind gusts, mainly from
Wednesday afternoon through he first half of Wednesday night.
Waves on the ocean waters likely reach 15 to 17 ft on the ocean
waters and 9 to 11 ft across the Sound.
Winds drop below Gale criteria by Thursday morning, with
lingering SCA criteria mainly in the form of elevated ocean
seas persisting into Thu night-Fri night. Some gusts up to 25 kt
are also possible in NW flow Fri afternoon and early evening
on most waters, and later into Fri night on the ocean.
&&
.HYDROLOGY...
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An additional 1.5 to 2 inches of rainfall is expected through
early Thursday with locally higher totals possible. The bulk of
this rain will fall this afternoon and evening. A period of
higher rainfall rates will be possible this afternoon into this
evening, with 0.25" to 0.50"/hr. Localized and brief higher
rates of 0.75"/hr will be possible. The best location for these
higher rates will be in NE NJ, NYC metro and LI, where the Flood
Watch is in effect. The most recent HRRR continues to supports
these potential rates. 12Z SPC HREF probabilities > 1"/hr less
than 10%.
Poor drainage and urban flooding is possible, as well some minor
flooding the faster responding smaller rivers, creeks, streams
across NE NJ. NE NJ, the NYC metro and LI are under a slight
risk of excessive rainfall (from WPC).-- End Changed Discussion --
&&
.TIDES/COASTAL FLOODING...
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Around 2.5-3 ft of surge is needed for minor coastal flood this
aft/eve and around 3.5-4 ft for moderate coastal flooding. With
easterly winds ramping up to storm force during the time of
high tide, as well as building wave action, widespread moderate
coastal flood thresholds are likely to be eclipsed along the
southern and eastern bays of Long Island and along the western
Sound. Elsewhere widespread minor coastal flooding likely. In
addition, the combination of heavy rain and elevated water
levels this afternoon and evening may enhance the localized
flash flood threat along some shoreline roads and properties.
Easterly winds gradually subside late tonight as low pressure
moves over the area, and then switch to NW gales behind the low
Thu AM. High easterly swells will likely inhibit drainage,
particularly bay areas, bringing potential for widespread
moderate flooding (locally major for the southern and eastern
bays of Long Island) late tonight into early Thu morning. The
coverage and areas of greatest coastal flood impact will be
highly dependent on track of the low, and timing of the wind
shift from easterly SCA/Gales to northwest gales. Forecast is
based on a 75th percentile of Stevens, blended with ETSS, STOFS
guidance, which applies a bit of margin for safety. This will be
refined over the next 24 hours.
Along the oceanfront, breaking waves of 6-10 ft this afternoon
into Thursday morning, along with elevated water levels, will
result in widespread beach flooding and erosion. Scattered areas
of dune erosion with localized overwashes are likely during the
times of high tide Wed afternoon into Thursday morning.
Along Long Island Sound, breaking waves of 3-7 ft this evening,
along with elevated water levels, will result in beach erosion
with damage to shoreline structures possible. Wave splashover
over bulkheads and seawalls will likely exacerbate flooding of
shoreline roadways and properties. A similar threat exists for
the twin forks, with breaking waves of 4-8 ft this evening and
Thursday morning.-- End Changed Discussion --
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
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CT...Wind Advisory until 6 AM EDT Thursday for CTZ005>008.
High Wind Warning until 6 AM EDT Thursday for CTZ009>012.
Coastal Flood Warning from 4 PM this afternoon to 10 AM EDT
Thursday for CTZ009-010.
Coastal Flood Watch from late tonight through Thursday morning
for CTZ011-012.
NY...Wind Advisory until 6 AM EDT Thursday for NYZ068>070.
High Wind Warning until 6 AM EDT Thursday for NYZ071>075-
078>081-176>179.
Coastal Flood Warning from 4 PM this afternoon to 10 AM EDT
Thursday for NYZ071-073-078-176-177.
Flood Watch from 4 PM EDT this afternoon through late Thursday
night for NYZ072>075-078>081-176>179.
Coastal Flood Advisory from 2 PM this afternoon to 7 AM EDT
Thursday for NYZ072-074-075.
Coastal Flood Warning from 2 PM this afternoon to noon EDT
Thursday for NYZ079>081-179.
Coastal Flood Advisory from 2 PM this afternoon to 7 PM EDT
this evening for NYZ178.
Coastal Flood Warning from 3 AM to 7 AM EDT Thursday for
NYZ178.
NJ...Wind Advisory until 6 AM EDT Thursday for NJZ004-103>108.
High Wind Warning until 6 AM EDT Thursday for NJZ006.
Flood Watch from 4 PM EDT this afternoon through late Thursday
night for NJZ002-004-006-103>108.
Coastal Flood Advisory from 2 PM this afternoon to 7 AM EDT
Thursday for NJZ006-104-106-108.
MARINE...Storm Warning until 6 AM EDT Thursday for ANZ331-332-335-338-
340-345-350-353-355.-- End Changed Discussion --
&&
$$
UPDATE...DW
AVIATION...JMC/JM