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FXUS61 KOKX 141403
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
1003 AM EDT Sun Jul 14 2024
.SYNOPSIS...
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High pressure will be in control this afternoon with a thermal
trough setting up over the region Monday and Tuesday. A cold
front approaches from the west on Wednesday, moving through
Wednesday night into Thursday. High pressure then builds in for
the end of the week.-- End Changed Discussion --
&&
.NEAR TERM /THROUGH TONIGHT/...
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Currently watching some convection closer to the frontal
boundary off to the west over Eastern PA. Will have to continue
to monitor this activity for western and southwestern portions
of the CWA for this afternoon. Only a very slight adjustment was
made with PoPs. Did also adjust dew points down slightly,
especially further east across the area with a light NE flow
which should switch around later this afternoon. Will be
interesting to see if portions of the area currently under a
Heat Advisory for today reach 95 degree heat indices criteria.
Thus no changes for the heat advisory criteria for today, at
least at this time as numbers should be very close, although
possibly a tad short. Previous discussion follows.
A stationary front remains over the region today, but without much
of consequence as high pressure will be the main feature today. It
should be a dry day for most, if not all of the forecast area. The
only exception would be a low chance of a shower or thunderstorm
this afternoon west of the Hudson River as MLCAPE increases to 500-
1000 J/kg and a weak shortwave approaches from the west, perhaps
providing just enough lift and instability to overcome a mid-level
cap. CAPE and CIN will be more favorable just off to our west, so
anything that develops there could drift into the forecast area.
Models continue to show 850 mb temps mostly 17-19C during the
afternoon, highest west of the NYC metro. Afternoon sea breezes
are likely to develop, so dew points near coastal locations may
not be able to have dew points mix out a bit. There is a good
consensus among the guidance for highs to reach the upper 80s
and lower 90s, warmest across NE NJ, NYC, and interior Lower
Hudson Valley and interior southwest CT. Heat indices will peak
at or just above 95 over the urban corridor in NE NJ, NYC metro,
and Nassau. It is possible that some locations near the south
coast fall just short of a 95 heat index. Elsewhere, max heat
indices should reach the upper 80s and low 90s. No changes with
the Heat Advisory for today.
Warm and muggy conditions for tonight. Will leave fog and stratus
out of the forecast as winds just above the boundary layer look too
strong for the most part. Should any occur, it would more likely be
over eastern LI and SE CT.-- End Changed Discussion --
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
Similar setup both days with a thermal trough over the area, and
shortwaves bringing shower/thunderstorm potential in the afternoon
and evening hours. Somewhat better chances of thunderstorms on
Monday versus Tuesday with the main threat being strong gusts both
days.
Based on an average of deterministic and ensemble guidance,
expecting 850mb temperatures of 20-21C on Monday and 21-22C on
Tuesday. Any potential convective debris clouds would probably occur
late enough in the day to have too much impact on potential high
temperatures. Highs Monday around 90 along the coast, ranging into
the middle and upper 90s for a good portion of inland areas. Tuesday
a degree or two higher in most cases across the area, with spotty
100 degree readings in NE NJ.
As for dewpoints, both days feature SW-WSW surface winds outside of
locations with an onshore flow. Dewpoints at the top of the boundary
layer are not exactly low enough to have high confidence that
surface dewpoints would lower 5 or so degrees during peak heating,
but then again they`re not prohibitively high either. Pretty good
agreement however that there`s better mix-out potential on Tuesday as
models are showing lower afternoon dewpoints at the top of the mixed
layer as compared to Monday.
No changes to the Heat Advisories for Monday and Tuesday. Heat index
values generally around 100 in the advisory area on Monday. For
Tuesday, heat indices increase by a couple of degrees, with spotty
105 readings in NE NJ, NYC and perhaps in the Lower Hudson Valley.
Not enough coverage and confidence to upgrade to an Excessive Heat
Watch anywhere at this time.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
Key points:
* Heat wave likely continues Wednesday with hot and humid
conditions. Max heat indices in the mid to upper 90s for much of
the region.
* Showers and thunderstorms develop ahead of a frontal passage late
Wednesday, bringing the risk of strong to severe thunderstorms and
heavy rainfall that could lead to flooding into Wednesday night.
* Cooler, drier conditions expected behind the front Thursday
and into the weekend.
The heat and humidity persists Wednesday before a frontal boundary
moves through Wed night, ushering in a cooler, drier regime late in
the week. Temperatures Wednesday afternoon, while likely a few
degrees lower than Tuesday, still top out in the low to mid 90s away
from the immediate coast. Deep mixing and more of a S/SW low-level
flow should help to transport some slightly lower dew point air to
the surface, so applied CONSALL rather than NBM with this update,
keeping dew points in the upper 60s to lower 70s during time of max
heating. This should still yield max heat indices to once again
approach or exceed 100F in many areas. An extension of the Heat
Advisory appears probable at the moment.
Meanwhile, a digging H5 trough will push a cold front toward the
region late Wednesday and increase convective chances as it does so.
Showers and thunderstorms become likely ahead of the boundary
Wednesday evening and night. As often the case this time of year,
conditions appears conducive for at least the possibility of strong
to severe thunderstorms, as well as torrential downpours given the
deep moisture in place.
The front moves through into early Thursday, and high pressure
begins to build in behind it, with the resulting N/NW flow advecting
in a drier air mass that should knock temperatures down to more
typical values for mid July, generally mid 80s both Thursday and
Friday. Conditions appear to remain dry late this week and
potentially thru the weekend with high pressure remaining in
control.
&&
.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
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High pressure remains in control through tonight.
Mainly VFR through the TAF period. There is a chance for IFR-
LIFR conditions across eastern Long Island and southeast
Connecticut terminals tonight into early Monday morning.
Light northerly flow becomes S or SSW into early afternoon with
speeds largely at or under 10 kt. Light SSW or SW flow continues
tonight.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Timing of wind shift to the S may be off by 1-2 hours.
OUTLOOK FOR 12Z MONDAY THROUGH THURSDAY...
Monday through Tuesday: Mainly VFR. A chance of afternoon into
early evening showers and thunderstorms and MVFR, mainly from
NYC metro on NW. SW wind gusts 15-20 kt afternoon into early
evening on Tuesday.
Wednesday: VFR to start. MVFR or lower in showers and
thunderstorms late afternoon into the evening.
Thursday: A chance of showers and thunderstorms with MVFR possible.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
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Winds and seas remain below SCA criteria through Tuesday night
with a relatively weak pressure gradient in place and lack of a
significant swell.
A period of SCA conditions is possible, mainly on the ocean,
Wednesday afternoon and Wednesday night with increased southerly
flow ahead of a frontal passage. Ocean seas may linger at or above 5
ft Thursday before subsiding.-- End Changed Discussion --
&&
.HYDROLOGY...
No hydrologic concerns are anticipated for today.
Given an abundantly moist air mass in place, any thunderstorms that
develop early to mid next week will have the potential to produce
locally heavy downpours that result in nuisance flooding,
particularly in urban and poor drainage areas.
&&
.TIDES/COASTAL FLOODING...
A high rip current risk continues through this evening for the
beaches of southeastern Suffolk County. A southerly swell of 4 ft 7s
will be slow to subside into Monday. RCMOS and NWPS are generally in
good agreement with the high risk for the far eastern beaches. A
moderate risk can be expected elsewhere.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
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CT...Heat Advisory from noon Monday to 10 PM EDT Tuesday for
CTZ005>011.
NY...Heat Advisory from noon Monday to 10 PM EDT Tuesday for
NYZ067>071-078>080.
Heat Advisory until 10 PM EDT Tuesday for NYZ072>075-176>179.
High Risk for Rip Currents until 9 PM EDT this evening for NYZ081.
NJ...Heat Advisory from noon Monday to 10 PM EDT Tuesday for NJZ002.
Heat Advisory until 10 PM EDT Tuesday for NJZ004-006-103>108.
MARINE...None.-- End Changed Discussion --
&&
$$
SYNOPSIS...JC/DR
NEAR TERM...JC/JE
SHORT TERM...JC
LONG TERM...DR
AVIATION...DR/DS
MARINE...JC/DR
HYDROLOGY...JC/DR
TIDES/COASTAL FLOODING...