757
FXUS61 KOKX 130533
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
133 AM EDT Thu Jun 13 2024

.SYNOPSIS...
Weak high pressure over the area will shift offshore on
Thursday. A cold front approaching from the west on Friday will
move through Friday night. High pressure will then build in from
the Great Lakes this weekend, before sliding offshore early
next week.

&&

.NEAR TERM /UNTIL 7 AM THIS MORNING/...
Mainly clear skies from here on out for the overnight as
shortwave gets further east and offshore with mid and upper
level ridging working in from the west. For this update tweaked
up temps in the eastern rural sections a bit as dew points
closer to the coast are more elevated than previous guidance
suggested.

Light winds overnight with a non-existent pressure gradient.
Not much in terms of cloud coverage is expected. This will set
up more efficient radiational cooling within the valley and
western rural sections. Made these locations slightly cooler
than previously forecast. Lows forecast range from the lower/mid
50s in the interior valleys and outlying areas, to more in the
upper 50s to mid 60s most elsewhere.

Some patchy fog particularly within valleys and some rural
locations can be expected due to radiational cooling towards
early Thursday morning.

&&

.SHORT TERM /7 AM THIS MORNING THROUGH 6 AM FRIDAY/...
The high pressure moves out into the Atlantic Thursday. The
synoptic pattern will favor the development of the Ambrose Jet
with southerly winds for SW Long Island increasing to around 15
kt with otherwise a southerly wind near 10 kt elsewhere within
the forecast region during the afternoon. It is expected to be a
mostly sunny day with high temperatures getting well into the
80s for a majority of the region.

Winds weaken with a weakening pressure gradient Thursday night.
Again not much in the way of cloud coverage is expected. Lows
will only be within the 60s with a warmer airmass moving into
the area. Not as much low level saturation is expected so did
not mention any fog in the forecast.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
**Key Points**

* Showers and thunderstorms are expected to move through the region
  Friday afternoon and evening, with some potentially strong to
  severe and capable of producing damaging winds and large hail.

* Heat builds early to mid next week and heat indices could exceed
  100F at times, especially north and west of NYC.

An active start to the period with lowering heights as a trough digs
south out of Canada, and a shortwave swings east into the local area
on Friday. An associated cold front will advance toward the region
with it, passing through and offshore Friday night. Ahead of the
front, showers and thunderstorms are expected to develop in a warm,
moist air mass. Surface temperatures into the 80s during the
afternoon and dew pts in the mid to upper 60s should aid the
convective development, and BUFKIT soundings indicate CAPE
increasing across the interior to over 1000 J/kg by early afternoon.
SPC has areas north and west of NYC outlined in a slight risk,
indicative of the potential for scattered severe thunderstorms.
CSU`s machine learning output is in agreement with this assessment.
Timing of this threat looks to span from afternoon into the early
evening hours, earliest across the Lower Hudson Valley, and latest
along SE CT and eastern LI as the line advances south and east.

In addition to a threat for damaging winds and large hail with these
storms, increasing moisture will bring the risk of heavy downpours
with any storms. PWATs ahead of the front climb to as high as 2
inches, and with a warm cloud layer well above 10 kft, efficient
rain processes could aid in torrential downpour development. While
total QPF averages around a half an inch across the region with this
forecast, localized amounts could exceed an inch or two in a
relatively quick period of time, so rates will be key to any flood
threat. Fortunately, the speed of the system should preclude more
widespread hydro concerns, with the most likely solution being more
typical nuisance urban and poor drainage flooding. Isolated
instances of flash flooding can not be ruled out though, but
areal extent of this appears low at this time.

The front advances offshore into early Saturday and high pressure
builds in from the NW during the weekend with dry conditions and
more comfortable dewpoints. High temperatures will be pretty close
or just above normal on Saturday and Sunday. Ridging develops across
the East late this weekend and early next week, likely bringing the
most prolonged heat spell of the year thus far. Global ensemble
means peg H85 temperatures around 20C mid next week. Coupled with
dew points well into the 60s, heat indices could approach or exceed
100F at times mid next week, especially north and west of NYC. This
could eventually necessitate the first heat headlines of the season
and the threat will need to be monitored. Generally stayed close to
the national blend with only subtle adjustments for this update.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
VFR today with weak high pressure in the area. A low develops in
Quebec to our north which will lead to some gusty winds in the
afternoon/evening, particularly at the coast.

Light SW flow overnight. Winds strengthen to 10-15 kt by mid-
late morning and become gusty at around 20 kt for most terminals
in the afternoon to early evening in a more southerly direction.
A few at the coast could gust up to 25 kt. Thursday night,
gusts diminish. Winds may hover around the 10 kt range overnight
Thursday into Friday morning.

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

Timing of gusts may be off by a few hours.

Magnitude of gusts may be off by a few knots.

OUTLOOK FOR 06Z FRIDAY THROUGH MONDAY...

Friday: MVFR or lower possible in showers/tstms in the afternoon
and evening.

Saturday through Monday: VFR.

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

&&

.MARINE...
Conditions should remain below SCA thresholds on the waters
through Thursday night with a relatively weak pressure gradient
in place.

S winds may occasionally gust toward 25 kt on the ocean waters
on Friday, and seas could approach 5 ft. These conditions
improve by Saturday, and sub SCA conditions are then expected
on all waters thru early next week.

&&

.HYDROLOGY...
Showers and thunderstorms Friday afternoon and evening could
produce downpours that lead to brief minor flooding. A general
1/2 inch of rain expected with localized amounts that could
exceed 1-2 inches in areas that see longer duration of tstms.
Impacts will most likely be limited to minor urban and poor
drainage flooding due to the quick movement of this system, but
isolated flash flood instances can not be ruled out.

&&

.TIDES/COASTAL FLOODING...
There is a moderate risk of rip currents along the ocean beaches
on Thursday, becoming high on Friday with increasing S flow and
resulting surf heights.

&&

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

&&

$$

SYNOPSIS...BG/JM/DR
NEAR TERM...JE/JM
SHORT TERM...JM
LONG TERM...DR
AVIATION...BR
MARINE...BG/JM/DR
HYDROLOGY...JM/DR
TIDES/COASTAL FLOODING...