942
FXUS61 KOKX 241716
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
116 PM EDT Wed Jul 24 2024
.SYNOPSIS...
-- Changed Discussion --
A stationary boundary lingers near the area through tonight,
with a wave of low pressure moving through potentially tonight.
A cold front moves through the area Thursday through Thursday
night. High pressure then builds in from the west Friday and
Saturday, pushing offshore Saturday night into Sunday, and
remains offshore into the beginning of next week.-- End Changed Discussion --
&&
.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
Minor update to temps/dewpts to better reflect observation
trends. Otherwise, the forecast remains on track.
The area remains on the eastern side of a broad upper level trough
through the near term period. Multiple embedded shortwaves will
continue to move through from the southwest along with associated
weak surface frontal waves.
The next frontal wave will pass to the south and east this morning.
The widespread activity and heaviest rainfall totals should end up
well offshore. This has continued to trend further south in the
latest guidance and matches up well with current satellite
imagery showing deep convection well offshore. Generally light
to moderate rain shower/stratiform activity for the local area
early this morning, but can`t rule out an embedded localized
heavy shower/thunderstorm.
After daybreak we start to destabilize. The HREF once again shows
mean SBCAPE values peaking in the Lower Hudson Valley around 1000
J/kg. This combined with a shortwave moving through aloft and the
lingering frontal boundary will likely result in some isolated to
scattered showers and thunderstorms, with the best chances being
across the Lower Hudson Valley. The 00z OKX sounding from Tuesday
evening recorded a 1.80in pwat value. Pwats are expected to increase
and peak early this afternoon around 1.9 to 2 inches per 00z NAM and
GFS, before potentially lowering again for the evening based on
front placement. Given this moist airmass, any stronger shower
or thunderstorm that develops could potential produce rainfall
rates up to 2 inches per hour. Due to low confidence in coverage
and placement, the overall flash flooding risk remains low. The
WPC continues to outline the area in a marginal risk of
excessive rainfall.
Given higher shear over the area than the past several days (0-6km
shear 35 to 40 kt per latest HREF run), there is potential for
some storms to become strong to severe. The SPC has outlined the
western half of the area in a marginal risk of severe thunderstorms.
The primary threat is the potential for damaging wind gusts.
Another shortwave and associated frontal wave may move south and
east of the area again tonight, but the bulk of any
shower/thunderstorm activity should stay offshore. Only slight
chance PoPs after about midnight tonight.-- End Changed Discussion --
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
A cold front will move through the area Thursday through
Thursday night. High pressure will follow and finally give us a
break from this unsettled pattern. While its axis shifts east
closer to the area, the upper level trough remains over the
northeast through Friday night.
Have lowered PoPs to chance for Thursday in collaboration with
neighboring offices. The latest CAMs are not too excited and
QPF has lowered in the global guidance as well. This likely has
to do with the cold front trending a bit faster. The front could
be moving through northwestern portions of the area by the
afternoon. The best shot at any showers or thunderstorms will
probably end up being for eastern zones, as they may be able to
destabilize a bit ahead of the cold front. Again, any stronger
showers or thunderstorm could produce locally heavy rainfall,
but potential for flash flooding remains low.
High pressure builds in, bringing us some lower dewpoints and dry
conditions. Friday will be the pick of the week. Mostly sunny skies,
highs in the low to mid 80s and dewpoints in the upper 50s to low
60s.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
Surface high pressure moves over the region on Saturday, pushing
offshore Saturday night into Sunday. Meanwhile, an upper ridge over
the Central US slides east toward the region through the weekend.
This will allow a much more tranquil, and drier pattern to take
hold. In fact, the next chance of any precipitation may not arrive
until next Tuesday, depending on the timing and placement of a
potential shortwave rounding the ridge, but even this is not a
guarantee at this point.
Temperatures will be seasonably warm for the weekend, with highs in
the middle to upper 80s. Highs around 90 are possible in the urban
NE NJ corridor by the second half of the weekend into the beginning
of next week. Humidity levels creep up very gradually thru the
period, with afternoon dew points around 60 to start, increasing
into the middle to upper 60s by Monday as the high slips offshore
and return flow sets up.
&&
.AVIATION /17Z WEDNESDAY THROUGH SUNDAY/...
A stationary front will linger nearby through tonight and
briefly lifts north as a warm front Thursday before a cold front
passes later in the day.
Residual IFR/MVFR will become VFR briefly this afternoon for
the metro terminals. Eastern terminals (KBDR, KISP, KGON) may
not see a return to VFR at all, with improvement only to MVFR.
Conditions deteriorate once again tonight (mainly after 00Z
Thursday) to IFR or lower, with the lower conditions farther
east.
A chance of showers and isolated thunder is possible at any
time through the TAF period, however there remains significant
uncertainty exactly where and when. Chances for TSRA are lower,
this afternoon and not included in the TAF. However, occurrence
cannot be completely ruled out.
Light/variable winds become SE-S 5-10 kt this afternoon, then
SW by tonight and Thu, though most terminals will become light
and variable once again overnight.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
AMD likely for flight categories deviating from fcst.
OUTLOOK FOR 12Z THURSDAY THROUGH SUNDAY...
Thursday: MVFR or lower, mainly for eastern terminals. Isolated
SHRA or TSRA
Friday: MVFR or lower possible in the morning with SHRA, otherwise
VFR.
Saturday and Sunday: VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
With a weak pressure gradient over the area, winds and seas/waves
remain below Small Craft Advisory criteria through the weekend.
Moderate to heavy showers and thunderstorms will be possible with a
wave of low pressure passing near the area this morning into the
afternoon.
&&
.HYDROLOGY...
The area continues to be outlined in a marginal risk of excessive
rainfall today and Thursday. A washout is not expected, and neither
is widespread heavy rainfall. Chances of showers and thunderstorms
continue the next two days with a lingering frontal boundary
over the area and then a cold frontal passage on Thursday. Any
stronger shower or thunderstorm that does develop could produce
heavy rainfall given pwats ranging from 1.75 to 2.00 inches.
There continues to be a low risk of flash flooding, with minor
urban and poor drainage flooding instances more likely.
No hydrologic impacts are expected Friday through the middle of
next week.
&&
.TIDES/COASTAL FLOODING...
A moderate risk of rip current development at the ocean beaches will
remain through Thursday as a 3 to 4 ft S/SE swell at 7 to 8 seconds
continues. Rip activity could be locally high due to the Spring
tides.
Water level guidance was too low with Tuesday night`s high tide
cycle and some locations in the western Long Island Sound ended
up just touching minor. This was likely due to the persistent
easterly flow. Given a similar setup for tonight, went closer to
the NYHOPS 95th percentile for many sites. This gave similar
water levels as Tuesday night. Still thinking the South Shore
Bays should fall just below minor flooding benchmarks, but a
gauge or two may just touch minor across the western Long Island
Sound.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$