000
FXUS61 KOKX 122057
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
457 PM EDT Wed Jul 12 2023

.SYNOPSIS...
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Weak high pressure will remain offshore while a weak frontal
boundary washes out well inland. Another frontal system will
approach thursday night and move into the area on Friday before
passing east Friday night. Unsettled weather is expected much of
the time from Saturday through Wednesday as a series of frontal
boundaries move across.
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&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
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Bkn line of shower/tstms with an approaching weak boundary may
impact Orange/Putnam counties into this evening before weakening
with loss of strong daytime heating. After a day with all local
climate sites reaching 90, temps will bottom out in the upper
60s inland in the 70s elsewhere.
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&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
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Another very warm/hot and humid day expected on Thu with a S
flow. This plus a low level cap should inhibit convection except
perhaps well NW of NYC by late afternoon. Temps reaching the
upper 80s and lower 90s, with higher dewpoints than those of
Wednesday, should result in heat index values reaching the mid
90s in NYC and NE NJ, also in the valleys of Orange County.
Expect heat and humidity of this magnitude to last for one day
only, so no heat advy has been issued.

Frontal boundary approaches Thu eve and enters the area mainly
after midnight. Followed HREF idea of a convective line
weakening as it enters the area initially, then reinvigorating
late as it approaches the coast and encounters a plume of
instability and rich low level moisture. Rain could become heavy
at times especially across S CT, and stronger cells could
produce gusty winds.
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&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
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The Storm Prediction Center has placed the area in a marginal risk
for severe weather Friday with the main threat damaging wind gusts.
Small hail is also possible as thunderstorms move through the region.

The Weather Prediction Center has placed the area in a slight risk
for excessive rainfall, and flash flooding Friday.

An upper closed low over Hudson Bay Canada will be slowly moving
south and east into early next week as shortwaves rotate into the
base of the low from time to time Friday into next week. One
shortwave will be moving through Friday into Friday night. As the
shortwave rounds the base and moves into the eastern closed low mid
and upper flow gradually becomes nearly parallel to a surface cold
front. The area will be in a warm and humid airmass as the front
approaches, and CAPE will be increasing up to nearly 1700 J/kg, with
surface based instability as lifted indices lower to -5. There will
be little capping so any ongoing storms Thursday night, or
developing storms Friday into Friday night could be severe with
damaging wind gusts most likely. Hail CAPE will also be increasing
and wet bulb zero will be below 13Kft, so hail will also be a
threat. Have now included enhanced wording with the thunderstorms.
In addition, moderate to heavy rainfall will be possible as
precipitable water increases up to nearly 2 inches. While storm
motion is expected to be 20-25kt as the flow becomes nearly parallel
to the front training storms will be possible. Rainfall rates may be
nearing 1 inch per hour, and with training of storms flash flooding
and poor drainage flooding becomes possible. Additional rounds of
rainfall continue into early next week, and with antecedent moisture
at least a nuisance flood risk will remain.
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&&

.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
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A weak frontal boundary will begin to approach from the northwest
this evening.

A shower or thunderstorm is possible at KSWF late this afternoon and
evening. Any of this activity is expected to stay well NW of the NYC
metro terminals. Dry conditions expected the remainder of the TAF
period. An isolated TSRA can`t be ruled out on Thursday late
afternoon or evening but any activity should be well north and west
of NYC terminals. Probability is too low to include in any TAF at
this time.

Any sea breeze enhancements at KJFK, KISP, KBDR, and KGON will
diminish after sunset. Winds become light once again overnight. For
Thursday, winds will become WSW-SW 10-15 kt by midday with
additional sea breeze enhancements developing by afternoon.


 ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...

AMD possible for end time of gusts at EWR and TEB.


OUTLOOK FOR 18Z THURSDAY THROUGH MONDAY...

Thursday: Isolated chance of afternoon showers/thunderstorms with
MVFR mainly N and W of NYC terminals.

Thursday night and Friday: Showers/thunderstorms likely with MVFR,
IFR possible at times.

Friday night: Chance of evening showers/thunderstorms, then MVFR or
lower conditions possible.

Saturday: MVFR or lower possible in the morning, otherwise VFR with
a chance of showers/thunderstorms in the afternoon and evening.

Sunday and Monday: Chance of showers/thunderstorms with MVFR or
lower.

Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
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&&

.MARINE...
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Marginal SCA seas are possible on the ocean waters at times Thu
night Friday into Friday night as south to southeast swell
affects the waters. Saturday into early next week the ocean
waters likely remain below SCA levels. For the non ocean waters,
conditions will remain below advisory levels Friday into early
next week.
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&&

.HYDROLOGY...
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Multiple rounds of showers and thunderstorms are expected Thursday
night through Friday night. Moderate to heavy rain will be possible
especially Thursday night through Friday. The Weather Prediction
Center has placed the forecast area in a slight risk for flash
flooding during this time, as small streams and fast responding
rivers may flood, along with urban and poor drainage areas.

Additional rounds of moderate to heavy rain will be possible
Saturday and Sunday, and the threat of flash flooding and
nuisance and minor flooding of poor drainage areas remains.
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&&

.TIDES/COASTAL FLOODING...
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There is a Moderate risk of rip current development at all the
ocean beaches through Friday. Thursday afternoon the rip current
risk may be borderline High at the southwestern Suffolk county
ocean beaches as southerly winds and swell increase. Southerly
winds with southerly swells of 2-3 ft will be in place across
the ocean beaches during this time period.
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&&

.OKX WATCHES/WARNINGS/ADVISORIES...
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CT...Air Quality Alert until 11 PM EDT this evening for CTZ009>012.
NY...Air Quality Alert until 11 PM EDT this evening for NYZ069>075-
     078>081-176>179.
NJ...None.
MARINE...None.
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&&

$$

SYNOPSIS...BG/MET
NEAR TERM...BG
SHORT TERM...BG
LONG TERM...MET
AVIATION...IRD
MARINE...BG/MET
HYDROLOGY...BG/MET
TIDES/COASTAL FLOODING...MET