010
FXUS61 KOKX 041052
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
652 AM EDT Sun Aug 4 2024
.SYNOPSIS...
Low pressure moves east, bringing a weakening cold frontal
boundary into the region today, eventually dissipating
southeast of Long Island tonight. Another cold front then
approaches on Monday and passes through late at night. The front
then stalls nearby through Tuesday night. A front pushes just
south and east of the area Wednesday into Wednesday night as a
weak area of low pressure passes south of the area. The frontal
boundary and remnants from a tropical system slowly approach
from the south through the end of the week and into the weekend.
&&
.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
Forecast mainly on track this morning. Mostly cloudy conditions
present with temperatures mostly in the low to mid 70s.
A mid level trough approaches today and from late afternoon
through this evening, the axis of this trough moves across along
with its positive vorticity maximum. The trough axis moves east
of the area overnight with a quasi-zonal flow returning.
For today, first lingering weak cold frontal boundary will give
a chance for showers and thunderstorms in the morning, mainly
late. The chances appear to be low after noting that CAMs
generally depict isolated to at most widely scattered convective
coverage at not until late morning into early afternoon.
Next this weak cold front makes more eastward progression within the
region for this afternoon. This will act as a focus for low
level convergence and allow for the development of showers and
thunderstorms. This timing appears to have trended later than
previously forecast with NW to SE progression this afternoon
into early this evening. CAMs do show an increase in convection
and appear to organize the convection along a line that
traverses the region from NW to SE late afternoon into early
evening. Numerical weather prediction models in the mid levels
depict main trough axis moving across the region afternoon into
evening, which will enhance lift.
However, outside of that convective line, coverage appears to
be mostly scattered. So, will reserve likely POPs to depict
this line. The shift in timing and noting tall CAPE and
downdraft CAPE increases towards early evening lead to some
potential for stronger winds to get brought down to the surface
with any stronger thunderstorms. Bulk shear 0-6 km AGL gets to
near 30 kt. Will have a mention of heavy rain and gusty winds
for thunderstorm attributes. There is a marginal risk of
damaging winds with some thunderstorms as well as marginal risk
of flash flooding with PWATs near 2 inches in place.
Regarding temperatures, with the shift in timing of convection
and coverage mostly scattered outside of the line late, these
will trend a few degrees higher compared to previously forecast.
Will use the warmer MAV MOS and NBM for the highs compared to
cooler MET MOS. Any showers or thunderstorms will mitigate
temperatures as well as associated cloud coverage. Close call
for heat advisory but forecast has all locations achieve maximum
heat indices of less than 95 degrees.
For tonight, the front moves southeast of Long Island while
continuing to weaken. Showers and thunderstorms will taper off
from NW to SE by mid to late evening. Convective coverage will
lower during the evening. Main convective activity will be
pushing off of Long Island in the evening with some more pop-up
convection potentially with mid level shortwave for some
locations north and west of NYC. Expecting mainly dry conditions
overnight. Lows will be relatively cooler than recent nights
with clouds decreasing overnight into early Monday. Using
MAV/MET for lows. Also, will be getting somewhat less humid as
PWATs drop to more within the 1 to 1.5 inch range by early
Monday.-- End Changed Discussion --
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
Mid level flow remains nearly zonal Monday through Monday night
with more of a negative trend Tuesday through Tuesday night. A
longwave trough begins to push south towards the area Tuesday
through Tuesday night.
At the surface, the airmass will once again transition back to a
very warm and humid airmass. A cold front will be approaching
from the north late in the day and then will move into the
region Monday night. The front then stalls near to south of the
area Tuesday through Tuesday night.
Temperatures Monday rise back into the upper 80s to lower 90s
with widespread heat indices forecast in the mid to upper 90s.
Some isolated 100 degree heat index values are forecast within
parts of NYC and NE NJ. However, with uncertainty of a few
degrees with temperatures, held off on any heat advisory
issuance.
Showers will come back to the forecast Monday night and will be
likely Tuesday through Tuesday night. There will be chances for
thunderstorms as well. Tropical airmass with high PWATs,
potentially still near 2 inches, will lead to enhanced rain
potential. See hydrology section for more details.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
A front from Tuesday will stall or slow to our south on Wednesday
morning. As a low pushes east, it may help to push the front just
south of the area Wednesday afternoon and night. Showers and
thunderstorms from Tuesday will continue into Wednesday until the
front has cleared.
Chances for precipitation drop off after Wednesday, and may drop off
further with more model runs if high pressure nudges more into the
forecast area than is currently forecast. However, given uncertainty
in this time frame onward, did not veer too far from NBM.
Thereafter, even more uncertainty in the forecast given the location
of the remnants of Tropical Storm Debby and its interaction with the
frontal boundary leading to uncertainty in placement of any
potential for heavy rain during this time frame, so again stuck
close to the NBM. Therefore, unsettled weather is possible from the
middle of the week through the beginning of next weekend.
Easterly flow develops during this time frame, and in addition to
clouds and rain, this will lead to cooler conditions. Highs during
this time frame may will average below normal, and may not go above
80 for much of the region Wednesday, with slightly warmer, but still
below normal temperatures on Thursday. Conditions will still be
humid, but not like the extremely humid conditions we have been
experiencing as of late.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
Weak low pressure, along with a stationary front, remains in
the vicinity into Sunday evening, shifting east late Sunday
evening.
MVFR to IFR cigs are being observed at most terminals and may
linger all morning given the recent rainfall. However, there is
much uncertainty regarding this and amendments are expected.
Another round of showers and thunderstorms with MVFR is likely
mid afternoon into the early evening. VFR expected tonight
except for KGON.
A S to SW 5-10 kt flow continues this morning with the winds
becoming more SW toward later this morning and into the
afternoon. Afternoon sea breezes are expected to develop.
Afternoon winds expected between 8-12 kt. A light SW flow
is expected tonight.
NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Amendments expected for MVFR/IFR ceilings all morning due to
uncertainty regarding timing.
Amendments are possible later Sunday for timing of thunderstorms
after 18Z.
OUTLOOK FOR 09Z MONDAY THROUGH THURSDAY...
Monday: VFR.
Tuesday-Wednesday: MVFR or lower possible in SHRA/TSRA.
Thursday: Mainly VFR. Chance of MVFR or lower in SHRA/TSRA.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
-- Changed Discussion --
SCA conditions expected to continue through this evening across
all ocean waters, and just east of Fire Island Inlet through late
tonight. Otherwise, mainly sub-SCA conditions expected through
Tuesday night, although there will be potential for additional
SCA conditions Monday night into Tuesday for portions of the
ocean.
Waves increase mid/late week with building long period southerly
swells from a tropical cyclone. Refer to latest forecast information
from the NHC.-- End Changed Discussion --
&&
.HYDROLOGY...
There will be marginal risk of excessive rain for western
portions of the region today into this evening. Minor flooding
of low lying and urban areas will be possible. Localized flash
flooding cannot be ruled out. Total rainfall between a quarter
to three quarters of an inch with locally higher amounts likely.
There is the potential for heavy rainfall Tuesday into Wednesday as
a weak area of low pressure moves along a stalled frontal boundary
in the vicinity of the forecast area. However, there remains a good
deal of uncertainty in exactly where the axis of heavy rain will set
up. There will be potential for flooding considering the
tropical airmass but too much uncertainty for to give precise
locations of higher rainfall amounts.
Another round of heavy rainfall is possible for the end of the week
into the beginning of next weekend with the remnants of a tropical
system. There is even more uncertainty with this feature.
&&
.TIDES/COASTAL FLOODING...
A high risk of rip currents is expected to continue all the way
through Monday evening. This is due to southerly swells of
around 5 feet.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...High Risk for Rip Currents through Monday evening for NYZ075-080-
081-178-179.
NJ...None.
MARINE...Small Craft Advisory until 6 AM EDT Monday for ANZ350-353.
Small Craft Advisory until midnight EDT tonight for ANZ355.
&&
$$
SYNOPSIS...JM/BR
NEAR TERM...JM
SHORT TERM...JM
LONG TERM...BR
AVIATION...BR
MARINE...JM/BR
HYDROLOGY...JM/BR
TIDES/COASTAL FLOODING...