763
FXUS61 KOKX 191943
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
343 PM EDT Mon Aug 19 2024
.SYNOPSIS...
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A cold front moves in late this afternoon into early this evening
and then shifts east of the region overnight. High pressure then
slowly builds in from the Great Lakes Tuesday into Tuesday
night. Weak New England low pressure on Wednesday. High
pressure moves in Wednesday night from the Great Lakes and
remains the predominate feature through Saturday night. High
pressure may lose hold as weak low pressure passes to our north
Sunday into Monday.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
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The cold front will be moving in late this afternoon into early
this evening. This will act as a focus for more shower and
thunderstorm development.
Clouds have been more abundant today, limiting insolation and
thereby CAPE. There is enough instability though for
thunderstorms and with forecast 0-6 km AGL bulk shear of 25-30
kt, there is potential for strong to severe thunderstorms. The
severe thunderstorms are a marginal risk through this evening.
Layer PW values decrease more to 1.5 to 1.75 inch range and
without a strong low level jet, the efficiency for heavy rain
production will be less than what was seen the previous day.
Still though, a marginal flood threat will exist with rain
showers.
Highest POPs for showers between 4PM and 11PM with chances for
thunderstorms during this timeframe as well. Due to limited
instability and less low level forcing, limited probabilities for
thunder to chance.
Drier air makes its way into the region tonight via NW flow behind
the cold front. However, for Southern CT and Long Island some rain
showers could linger around late tonight. Have slight chance POPs.
This is due to forecast increase in upper level jet streak and
some extra lift provided due to upper level divergence.
Lows overnight expected to be mainly in the upper 50s to mid
60s.-- End Changed Discussion --
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
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Tuesday will feature slow moving and weakening low pressure
within the Canadian Maritimes that will keep the cold front from
moving too far offshore. Further weakening of this low is
expected Tuesday night.
Relatively cooler temperatures are forecast Tuesday and Tuesday
night. Forecast highs mainly in the 70s and forecast lows
mainly in the upper 40s to around 60. The forecast highs are
around 5 degrees below normal and the forecast lows are around 5
to 10 degrees below normal.
A westerly flow will be maintained across the region but is not
expected to be too gusty. Much drier air is expected as
dewpoints lower into upper 40s to mid 50s across much of the
region. Dry weather expected for Tuesday through Tuesday night.
Used consensus of MOS and NBM for temperatures.-- End Changed Discussion --
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
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Cooler and drier air remains in place on Wednesday with a trough and
strong cold air advection aloft. 850mb temps will be 7-10C below
average at around 6-4C with a northwesterly flow at the surface.
This will make it feel like a false start to fall with highs on
Wednesday in the mid-70s to upper-60s followed by Wednesday night
lows in the 50s.
Showers and thunderstorms are also possible Wednesday afternoon and
evening. There are several factors working both for and against the
chance for rain on Wednesday. We`ve got a weak surface low in New
England with a surface trough expecting to extend across the area
that may provide a source of lift for shower and thunderstorm
development. We`ve also got vorticity advection along the
500mb low/trough in New England aiding in development of rain.
However, cold air aloft, cooler surface temps, weak instability, and
PWATs at or below 1 inch will work against the showers and
thunderstorms. Expecting mainly isolated coverage with possible
scattered coverage for far northern zones closer to the low.
Surface high pressure builds into the region from the Great Lakes
Wednesday night and remains in place through Saturday. This will
lead to an extended period of dry weather. A trough exits to the
east on Thursday as a ridge takes over. This will lead to gradually
warming temperatures. NW flow continues on THursday under high
pressure which will keep temperatures on the cool side with highs in
the upper to low-70s. Upper-70-s to lower-80s return on Friday as
ridging builds aloft and surface winds become more westerly,
eventually southwesterly by the afternoon. Westerly to southerly
flow continues into the weekend allowing for further warming with
highs in the low/mid-80s.
Global models are not in a consensus Sunday in to Monday. The GFS
has a trough develop over the area, GDPS/ECMWF have the trough
farther displaced from our area to the northeast, ICON does not have
a trough develop and keeps us under a ridge. Only the GFS solution
would bring a chance for rain. Given the divergence in model
guidance, have kept POPs out of of the ending periods in the
extended forecast.-- End Changed Discussion --
&&
.AVIATION /20Z MONDAY THROUGH SATURDAY/...
A cold front will pass through the terminals late this afternoon
(KSWF) into this evening.
KGON IFR ceilings may linger another 2-3 hours, otherwise mainly
VFR this afternoon into this evening. A broken line of showers and
thunderstorms associated with the cold front may produce brief
sub-VFR conditions with downpours and gusty winds late this
afternoon into this evening. There also looks to be a period of
post-frontal MVFR ceilings from about 04Z to 13Z. This could be
more occasional than frequent.
W/SW winds this afternoon around 10 kt with a few G15-20kt.
Local seabreeze enhancements likely. E/SE winds may linger to
around 21Z at KBDR and KGON. Winds shift to the W and NW behind
the cold frontal passage this evening. Some gusts to near 20kt
will be possible behind the front tonight into Tuesday.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
A few gusts up to 20 kt possible this afternoon ahead of the
cold front. Timing of post-frontal NW gusts may vary by 1-2
hours.
A pop up shower or thunderstorm is possible anytime this
afternoon, but the main line of showers and thunderstorms this
afternoon/evening may be off in timing by 1-2 hours.
MVFR ceilings forecast overnight may be more occasional than
frequent.
OUTLOOK FOR 18Z TUESDAY THROUGH SATURDAY...
Tuesday Afternoon: A few NW G15-20kt possible.
Wednesday-Saturday: VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
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SCA conditions are expected to remain across the ocean mainly
due to seas through Tuesday. Non-ocean expected to remain below
SCA through Tuesday. Conditions below SCA expected for Tuesday
night for all waters.
Sub-SCA conditions are expected Wednesday into the weekend as high
pressure builds into the region.-- End Changed Discussion --
&&
.HYDROLOGY...
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Rain showers through tonight are forecast to produce mostly
around a quarter to half inch with locally higher amounts. These
locally higher amounts could easily get to 1 to 2 inches. A
marginal flash flood threat persists.
No hydrologic concerns expected thereafter Tuesday through next
weekend.-- End Changed Discussion --
&&
.TIDES/COASTAL FLOODING...
A high rip current risk is in place through Tuesday due to
elevated, long period swells from Ernesto.
Ocean seas are forecast to be highest through Monday, and with
surf heights up to 6 ft, local beach erosion is possible.
A full moon today as well as swell from distant Ernesto will
also elevate total water levels this week.
Additional minor flooding is possible with the high tide cycles
(especially the evening/nighttime cycles) through much of this
week. Additional advisories/statements will likely be needed.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
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CT...None.
NY...High Risk for Rip Currents until 9 PM EDT this evening for NYZ075-
080-081-178-179.
Coastal Flood Advisory until midnight EDT tonight for NYZ178-
179.
NJ...None.
MARINE...Small Craft Advisory until 6 PM EDT Tuesday for ANZ350-353-355.-- End Changed Discussion --
&&
$$
SYNOPSIS...JM/BR
NEAR TERM...JM
SHORT TERM...JM
LONG TERM...BR
AVIATION...DW
MARINE...JM/BR
HYDROLOGY...JM/BR
TIDES/COASTAL FLOODING...