230
FXUS61 KOKX 120551
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
151 AM EDT Fri Jul 12 2024
.SYNOPSIS...
A stationary front along the east coast, from Maine into the
southeastern states, remains into Saturday as a wave of low
pressure tracks slowly northward from the Carolina coast.
The front washes out just south of the area on Sunday,
otherwise a thermal trough will set up across the area each
afternoon for the start of next week. A frontal system will
then move into the area for the middle of the week.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Forecast remains on track with only minor adjustments to account
for the latest observations. Showers developing along the
offshore stationary front will slowly make their way into the
area overnight from southeast to northwest.
A stationary front will remain in close proximity to the area
overnight. As a weak wave of low pressure begins to develop on
the boundary south of the area showers will approach from the
south and southeast late tonight.
The low, and supporting upper level energy will track slowly
northward through Friday with probabilities of precipitation
increasing. Some instability does develop, especially inland, by
the afternoon, and scattered to isolated thunderstorms will be
possible. Precipitable water values increase to around 2 inches
Friday, and by late day there may be a few heavier
showers/thunderstorms. However, this becomes more likely Friday
night.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
Precipitable water values increase to near 2.25 inches Friday
night, and with an increasing low level jet and increasing warm
cloud processes, the probability of periods of moderate to
heavy rainfall will be increasing Friday night into Saturday
morning. Also, the southerly flow will increase inland
convergence, with heavier rain potential across northeastern New
Jersey into the lower Hudson Valley, and into southwestern
Connecticut. If the heavier rainfall occurs there is a chance of
local nuisance and minor urban and poor drainage flooding, and
present at least a low threat of flash flooding.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Main points:
* Potential heat wave Sunday into next week with hot and humid
conditions. Max heat indices forecast from mid 90s to low 100s.
Highest across urban and interior locations.
* Chances for showers and thunderstorms, mainly late afternoon into
early evening and to the north and west of NYC Monday and Tuesday.
A more widespread chance of showers and thunderstorms exists for
Wednesday into Wednesday night.
* Precipitable water values potentially in the 1.5 to 2" range for
early to mid next week, making heavy rain a possibility with any
thunderstorms that form.
While heights will not be necessarily anomalously high, the forecast
area will reside at the southern edge of the westerlies. This will
result in a deep-layered westerly flow, transporting anomalously
warm air into the region. 85h temps increase to around 20C by
Monday, and event a bit higher Tuesday into Wednesday. In addition,
the low-level flow will be more from the S-SW, which will lessen the
marine influence, especially just inland from the coast. High temps
for much of the area Monday into Wednesday will be in the low to mid
90s with the exception of immediate coastal locations, especially
across eastern LI and SE CT. Forecast stayed very close to the NBM,
even with the box and whisker temperature plots showing the
deterministic values below the median (50th percentile). In other
words, there may be the potential for even higher values. However,
did blend the NBM dew points with CONSALL to get the dew points down
some. With more of westerly flow than the past heat event, expect
some drier air to mix down each afternoon. NBM often can be on the
high side. This still results in widespread heat indices of 95 to
100 Monday through Wednesday with some locations even getting this
high on Sunday. Some of the interior and urban locations even flirt
close to 105 (Excessive Heat Criteria) for Monday and Tuesday.
Also, being at the southern edge of the westerlies will result in
less capping with the potential for diurnally driven convection
Monday and Tuesday afternoon, mainly north and west of the NYC
metro. A more widespread convective event is possible mid week as a
cold front approaches from the west and PWAT values increase to
around 2 inches.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --
A stationary front offshore drifts back west into Friday.
Mainly VFR tonight into Friday morning. SHRA development along
the approaching front expected to occur after daybreak for
eastern terminals, spreading west to NYC terminals toward 12Z or
just after. Possible conditions could lower briefly to MVFR,
but otherwise cigs and vsbys remain VFR. Thereafter, the
boundary shifts into the western terminals resulting in
continued scattered SHRA through much of the late morning and
early afternoon, with eastern terminals possibly staying dry.
Heavier showers are possible in the afternoon and early evening,
and chances for TSRA increase at this time mainly for NYC
terminals, KHPN, and KSWF, but timing and coverage is fairly
uncertain. A lull likely develops by the evening hours, before
coverage of showers and possible thunderstorms return overnight,
mainly after 6Z Sat, with conditions potentially lowering
toward IFR.
Light flow into Friday morning becomes predominantly southerly
with speeds generally increasing to 10 kt. Gusts up to 20 kt
will be possible in the afternoon, mainly for coastal terminals.
Gusts end in the early evening, with 10 kt or less southerly
flow persisting into early Saturday.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Timing of categorical changes could be off by several hours.
Low confidence in TSRA coverage and timing Friday and Friday
night.
Gusts Friday afternoon may be more occasional.
OUTLOOK FOR 06Z SATURDAY THROUGH TUESDAY...
Saturday: MVFR or lower with showers/thunderstorms early in the
day. Improvement to VFR by afternoon.
Sunday: VFR.
Monday and Tuesday: Mainly VFR. A chance of afternoon into
early evening showers and thunderstorms with MVFR possible,
mainly north and west of NYC terminals.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
Ocean seas remain elevated tonight into Friday with south to
southeast swells, and the SCA was extended through Friday. Seas
may be marginally near 5 feet into Friday night, and the SCA may
need to be extended. Southerly winds Saturday with a stationary
front nearby may keep ocean seas elevated even into Saturday.
Otherwise, for the non ocean waters winds and seas remain below
advisory levels tonight through Saturday.
Winds and seas will generally be below SCA criteria Sunday through
Tuesday in a S-SW flow that increases to 10 to 15 kt by Monday. A
few gusts to 20 kt will be possible on the ocean waters Tuesday.
&&
.HYDROLOGY...
Showers and thunderstorms Friday and Saturday, associated with a
wave of low pressure along a stationary front, could produce
periods of locally heavy rainfall, especially Friday night into
Saturday, that may lead to nuisance flooding in urban and poor
drainage areas. Isolated instances of flash flooding are
possible as well. WPC has outlined the region in a slight risk
of excessive rainfall Friday into Saturday.
With higher precipitable waters moving into place for early to mid
next week, heavy rain will be a possibility with any thunderstorms
that develop. The precipitable waters reach between 1.5 and 2.0
inches, below the max records but at times nearing the 90th
percentile. Too early to ascertain any specific rainfall amounts,
but localized heavier rainfall can be expected.
&&
.TIDES/COASTAL FLOODING...
There is a high risk of rip current development along all ocean
beaches through Friday with surf heights up to 5 ft (S swell 5ft
7-8s) and a southwest wind between 10 and 15 kt.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CT...None.
NY...High Risk for Rip Currents through this evening for NYZ075-080-081-
178-179.
NJ...None.
MARINE...Small Craft Advisory until 6 PM EDT this evening for ANZ350-
353-355.-- End Changed Discussion --
&&
$$
SYNOPSIS...MET
NEAR TERM...MET/MW
SHORT TERM...MET
LONG TERM...DW
AVIATION...DR/MW
MARINE...MET/DW
HYDROLOGY...MET/DW
TIDES/COASTAL FLOODING...