667
FXUS61 KOKX 040627
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
227 AM EDT Sun Aug 4 2024
.SYNOPSIS...
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Low pressure moves east, bringing a weakening cold frontal
boundary into the region Sunday, eventually dissipating
southeast of Long Island Sunday night. Another cold front then
approaches on Monday and passes through late at night. The front
then stalls nearby through Tuesday night before pushing 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.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
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Convection has weakened with more stable low level conditions.
Patchy fog possible towards daybreak Sunday but thinking this
will be limited with the abundance of mid and upper level clouds.
Temperature forecast generally on track with most lows expected
to be within and near the range of 70-75 degrees.-- End Changed Discussion --
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM MONDAY/...
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Sunday, 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. Will have a mention of heavy
rain and gusty winds for thunderstorm attributes.
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.
Sunday night, 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.
850mb temps are progged at 18-19C. There should be enough
sunshine and SW flow for mid 90s in the normally warmest spots
with mostly upper 80s to lower 90s elsewhere for highs Monday.
Wind direction and low enough boundary layer RH should allow for
surface dewpoints to mix out a few degrees during peak heating,
so max heat indices will be generally in the lower and middle
90s. With neither 100 degree heat indices on Monday, nor 2-day
criteria of 95+ indices, no heat advisories are anticipated.-- End Changed Discussion --
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
A cold front will be draped across the area Monday night. A weak
area of low pressure along the frontal boundary over the Central
Plains states will move east along the boundary, passing south of
the Great Lakes during the day Tuesday, then just south of the
forecast area by Wednesday morning. As the low pushes east, it may
help to push the front just south of the area Wednesday afternoon
and night. Unsettled conditions are expected Monday night through
Wednesday with the front in the vicinity, then low pressure moving
nearby. However, the best chances for any showers and thunderstorms
will be with the low Tuesday night into Wednesday.
Chances for precipitation then drop off, 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 the potential tropical system 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.
Low pressure over southeastern Canada, will slowly trek northeast
into the Canadian Maritimes by this evening. This will allow a cold
front to slowly approach today, moving through late in the
afternoon into the evening.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
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Weak low pressure, along with a stationary front, remains in
the vicinity into Sunday evening, shifting east late Sunday
evening.
Showers have ended for all terminals except for KGON and KSWF
that may see additional light showers through 08Z. MVFR to IFR
cigs are being observed at most terminals and may linger into
the early afternoon 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 Sunday. VFR expected Sunday
night except for KGON.
A light S to SW flow continues overnight with the winds becoming
more SW toward morning and during Sunday. Afternoon sea breezes
are expected to develop. Afternoon winds expected between 8-12
kt. A light SW flow returns Sunday night.
NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Amendments expected for MVFR/IFR ceilings all morning and
possibly into the early afternoon due to uncertainty regarding
timing.
Amendments are possible later Sunday for timing of thunderstorms
after 18Z.
OUTLOOK FOR 06Z 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-- End Changed Discussion --
&&
.MARINE...
No changes to the winds and seas at this time,. Updated for
weather, mainly to remove the chances for thunderstorms over the
non ocean waters.
Sub-SCA conditions expected for non-ocean waters through Monday
night. For the ocean, southerly fetch and swell will maintain
seas of at least 5 ft through Sunday evening. Have extended the
SCA west of Fire Island Inlet to go through midnight Sunday
night, and extended the SCA through all of Sunday night farther
east. Sub-SCA conditions follow for Monday.
Waves build on the ocean waters Monday night into Tuesday as low
pressure approaches and moves over the waters. Waves diminish
Tuesday afternoon as the low pushes east of the region. Waves
increase again later in the week with building long period
southerly swells from a tropical cyclone. Refer to latest
forecast information from the NHC.
&&
.HYDROLOGY...
Rainfall rates of 1-2 inches per hour and locally higher will be
possible into this evening. Given 1 and 3-hour flash flood guidance,
isolated to scattered instances of flash flooding will be possible
during this time, then generally dry conditions overnight.
Another round of showers and thunderstorms is anticipated Sunday
afternoon, potentially lasting into the evening. The extent of
potential flash flooding will partly depend on what occurs
through this evening, but it appears at least isolated flash
flooding can occur. No hydrologic issues are expected after
early evening Sunday through Monday night.
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.
Another round of heavy rainfall is possible for the end of the week
into the beginning of next weekend with the remnants of the
tropical system. There is even more uncertainty with this feature.
&&
.TIDES/COASTAL FLOODING...
A high risk of rip currents continues into this evening and is
expected to continue all the way through Monday evening. This is
due to southerly swells of around 5 feet.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
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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.-- End Changed Discussion --
&&
$$
SYNOPSIS...JC/JP
NEAR TERM...JM
SHORT TERM...JM/JC
LONG TERM...JP
AVIATION...BR
MARINE...JC/JP/MET
HYDROLOGY...JC/JP
TIDES/COASTAL FLOODING...