587
FXUS61 KOKX 311330
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
930 AM EDT Wed Jul 31 2024
.SYNOPSIS...
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A weak cold front approaches from the west today and moves
across and dissipates tonight. A series of weak fronts will
follow from Thursday into Monday.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
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A weak front remains in the vicinity through this evening.
A few showers remain possible this morning, but a better combo
of instability and forcing should be present this afternoon and
evening, particularly across Western Long Island extending
back west through NE NJ including the NYC Metro as well as the
Lower Hudson Valley and SW CT. Convection looks to be in the
form of pulse cells and should remain below severe limits. Any
storm could produce a brief, locally heavy downpour.
Heat Advisory has been issued for much of NE NJ, NYC metro, and
Nassau County through Thursday evening. Combination of
temperatures around 90 and dew points in the lower to middle 70s
should yield a heat index around 95 this afternoon, likely
occurring again on Thursday.
Have temperatures reaching upper 80s to near 90 along with
dewpoints in lower 70s for this afternoon within much of NE NJ,
NYC, and Nassau NY. Heat indices forecast in the low to mid 90s.-- End Changed Discussion --
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
Backside of trough tonight, with negative vorticity advection,
drying out, clouds decrease. More ridging expected Thursday with
more nearly steady height tendency thereafter through Friday
before next shortwave trough approaches Friday night. This will
bring potentially more coverage of showers and thunderstorms.
For Thursday and Friday, more sun expected in the morning with
the possibility of afternoon into early evening showers and
thunderstorms. Thursday max temperatures forecast are in the
low to mid 90s. For Friday, max temperatures more in the upper
80s to lower 90s, which are a few degrees cooler than previous
forecast but dewpoints are forecast to be slightly higher than
those of Thursday. Friday, showers and thunderstorms remain
probable for a longer time through Friday night.
850mb temperatures trend a few degrees warmer, closer to 19
degrees C, compared to 850mb temperatures forecast for
Wednesday. Expecting more widespread 95 to 100 degree heat
indices both days. However with a relatively higher chance of
showers and thunderstorms Friday, more uncertainty on Friday`s
temperatures.
Considering Wednesday`s mid 90s heat indices forecast, there is
satisfaction of criteria for heat advisory for much of NE NJ,
NYC and Nassau NY as heat indices forecast for Thursday for
these locations will be around 100. Heat advisories may very
well need to be extended into Friday with later forecasts but
forecasts for Friday high temperature did trend a few degrees
lower compared to previous forecast. So confidence at this time
not high enough to extend heat advisory into Friday.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
Key Points:
* Multiple rounds of showers and thunderstorms possible each day
into Monday.
An active upper flow will be in place through much of the period,
with the area on the southern fringe of the westerlies and several
upper level disturbances moving through, which should bring diurnal
convection each day through Monday. The best days for convection
look to be Thu and again Sat/Sunday. Coverage may be more limited on
Fri as any lead disturbances ahead of a closed low over the Ohio
Valley will be moving through downstream shortwave ridging.
The closed low is poised to affect the area through the weekend.
Temps for the weekend may not be quite as warm but could be offset
by higher dewpoints to yield 95+ heat index values in spots,
especially NE NJ and in/around NYC.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
An upper level low will move into southern Canada. Meanwhile, a
weak cold front approaches the area today.
MVFR or IFR will continue through the morning push, then an
improvement to VFR is expected, mainly between 14-17z. There is
an area of showers across central NJ, which is moving
northward. Expect some scattered showers through about 14z.
Will include a tempo for this rain. VFR conditions are then
expected to return for the afternoon.
Another round of showers and possible thunderstorms are then
expected again after 18z with the approach of a weak cold
front.
S to SW winds 08-12 kt expected today. Some gusts can not be ruled
out at the coastal terminals. Any gusts should reach about 20kt.
Winds become a bit more SW-W tonight, with winds falling below 10kt.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Amendments will be possible for timing of any precipitation today as
well as timing any flight category changes, especially this
morning.
Occasional gusts to near 20 kt possible.
OUTLOOK FOR 12Z THURSDAY THROUGH SUNDAY...
Thursday: VFR.
Friday-Sunday: Chance of MVFR or lower in afternoon/evening
showers/tstms.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
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An SCA is in effect for the ocean waters with building seas to
around 5 ft and marginal gusts to 25 kt into this evening.
Elevated seas continue into tonight. Otherwise, winds and seas
will remain below SCA levels through Saturday with a relatively
weak pressure gradient.
Increasing/persistent S-SW flow may allow ocean seas to build
to 5-6 ft late Sat night into Sunday.-- End Changed Discussion --
&&
.HYDROLOGY...
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Multiple rounds of showers and thunderstorms are possible
through this weekend. While widespread flood impacts are not
expected, localized urban and poor drainage flood impacts are
possible.-- End Changed Discussion --
&&
.TIDES/COASTAL FLOODING...
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A high rip current risk continues into this evening with S flow
15 kt and incoming 5 ft/7-sec period swells. Winds diminish and
turn more SW-W on daytime Thu, but still expect at least a
moderate risk, possibly high into Thu morning, due to residual
3-ft swell.-- End Changed Discussion --
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
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CT...None.
NY...Heat Advisory from 1 PM this afternoon to 8 PM EDT Thursday
for NYZ072>075-176>179.
High Risk for Rip Currents until 9 PM EDT this evening for NYZ075-
080-081-178-179.
NJ...Heat Advisory from 1 PM this afternoon to 8 PM EDT Thursday
for NJZ004-006-103>108.
MARINE...Small Craft Advisory until 6 AM EDT Thursday for ANZ350-353.
Small Craft Advisory until midnight EDT tonight for ANZ355.-- End Changed Discussion --
&&
$$
SYNOPSIS...BG/JM
NEAR TERM...JM/DS
SHORT TERM...JM
LONG TERM...BG/NV
AVIATION...BC
MARINE...BG/JM
HYDROLOGY...BG/JM
TIDES/COASTAL FLOODING...