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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KOKX 210540
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
140 AM EDT Wed Aug 21 2019

.SYNOPSIS...
High pressure across the region will shift east tonight. A warm
front will then move north of the area on Wednesday followed by
an approaching cold front late Wednesday night. A cold front
will slowly move through the area Thursday into Friday, followed
by high pressure into the weekend. Unsettled weather may return
early next week.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
High pressure across the area will shift east tonight as a warm
front approaches from the south. Both moisture and PoPs will
increase through the night, with short term model trends
continuing to indicate that the best chances of precipitation
will be after midnight, although even then shower/thunderstorm
coverage may be limited. Adjusted temperatures and dewpoints to
better capture current trends, with overnight lows ranging from
the upper 60s to mid 70s.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/...
As a warm front pushes north across the area on Wednesday, a
very humid airmass will usher in across the area with dewpoints
rising into the lower 70s in southerly flow. A weak shortwave
will interact with the warm front as it lifts north, which could
spark a few morning showers and thunderstorms. Given the moist
airmass, any thunderstorms will have the potential for gusty
winds and local downpours, especially north across of our CWA.

Thunderstorms will continue through Wednesday afternoon as an
upper trough over the Great Lakes sends a cold front towards
the area. Upper level jet support combined with mid level
shortwave energy will initiate convective development during
the afternoon. Forecast soundings showing >2000 J/kg of CAPE
into the afternoon along with increasing shear with the
incoming trough. With a favorable storm environment, the Storm
Prediction Center has placed the area under a slight risk.
Southwesterly flow will advect in precipitable water of near 2
inches, therefore heavy downpours are likely in any storm.

Showers will continue through Wednesday night as the cold front
approaches the area from the west.

Temperatures on Wednesday will be in the mid to upper 80s to
near 90. The combination of heat and increasing dewpoints will
result in heat indices in the low to mid 90s with the exception
of eastern Long Island and southeastern coastal Connecticut.

Wednesday night lows will be in the upper 60s to lower 70s.

There is a moderate risk of rip current development at ocean
beaches for Wednesday.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Cold front slowly pushes through the area Thu into Thu night.
Both GFS and NAM soundings are indicating a capping inversion
around H8 which would limit shower/tstm activity. This inversion
may weaken late in the afternoon and into the evening so have
highest pops during this time, although only chc appear
warranted at this time. The low chc showers continues Thu night
as the front moves through. It should clear the area by Fri
morning and appears to be far enough south to keep any pcpn
associated with weak waves of low pres riding along it to the
south as well. The heat and humidity will vanish as well as a
Cp airmass is ushered in behind the front.

Upper trough will remain over the Northeast into the weekend,
although increasing subsidence from strong sfc high pres
traversing eastern Canada will result in dry and pleasant
conditions. Have maintained a dry forecast into early next week
although an increasing easterly flow Sun/Mon could lead to low
clouds and perhaps some drizzle or light rain at the coast. The
12z EC is also less progressive with the upper flow and is now
cutting off the flow at H5 over the northeast. GFS does this as
well but over the Northern Atlantic. If the former pans out,
then there could be more shower activity around between Sun and
Tue as it is slow to depart. Temperatures are expected to be
below normal levels Fri through Mon, then near normal on Tue.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
A warm front passes this morning. A trough of low pressure
develops this afternoon ahead of an approaching cold front,
with showers and thunderstorms becoming likely.

Mainly VFR this morning, except in possible patchy stratus, or
with an isolated shower or thunderstorm. Coverage of showers
and thunderstorms will increase this afternoon, with MVFR or IFR
possible in any thunderstorm. Thunderstorm chances diminish
later this evening.

Southerly winds will be less than 10 kt early this morning,
with winds light and variable at the outlying terminals. Winds
increase to 10 to around 15 kt late this morning, with gusts to
around 20 kt possible at the NYC terminals during the
afternoon. Winds lighten from the SW this evening.

.OUTLOOK FOR 06Z THURSDAY THROUGH SUNDAY...
.Late tonight-Thursday night...Mainly VFR, MVFR or lower is
possible in showers and thunderstorms.
.Friday-Sunday...VFR.

&&

.MARINE...
Winds and seas will remain below SCA criteria through Wednesday with
seas increasing to SCA criteria by Wednesday night ahead of a cold
front.

Winds and seas on the ocean waters may reach marginal SCA levels Sun
into Mon due to an increasing easterly flow. Otherwise, sub-advsy
conds are expected through the remainder of the period.

&&

.HYDROLOGY...
Locally heavy rainfall is possible with thunderstorms that
develop Wednesday, which may result in localized flooding for
urban and poor drainage areas. No hydrologic impacts are
expected Thu through Tue.

&&

.EQUIPMENT...
NYC NOAA Weather Radio Station KWO35 (162.55 MHz) remains off
the air.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.

&&

$$
SYNOPSIS...Fig/24
NEAR TERM...FEB/Fig
SHORT TERM...Fig
LONG TERM...24
AVIATION...PW
MARINE...Fig/24
HYDROLOGY...
EQUIPMENT...