000
FXUS61 KOKX 111130
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
730 AM EDT Fri Aug 11 2023
.SYNOPSIS...
High pressure will be in control today. Low pressure then passes to
our north this weekend, dragging a cold front through the region on
Sunday morning. Another frontal system moves across the area Monday into
Tuesday. High pressure then returns for mid week.
&&
.NEAR TERM /THROUGH TONIGHT/...
The forecast is on track for the most part. Hourly temperatures
and dewpoints were adjusted for the morning hours to account for
the latest trends.
The flow aloft transitions from zonal to slightly anticyclonic today
into tonight. This will allow for weak high pressure to build in at
the surface. As expected, NBM has trended warmer with today`s high
temperatures as compared to 24 hours ago along with less of a spread
between the 10th and 90th percentiles, bringing higher confidence in
its output. With sunny conditions, a downsloping wind, and 13-14C
still progged at 850mb, expecting highs mostly in the lower and
middle 80s. The wind direction will also help in holding dewpoints
to mostly 55-60 this afternoon, so it won`t feel as muggy as it
could in August.
Remaining dry tonight, and while some cirrus may prevent ideal
radiational cooling conditions, light to calm winds with a cooler
air mass will allow temperatures to fall into the mid to upper 50s
across the northernmost zones and the LI Pine Barrens. Most other
spots will have low temperatures ranging from the lower 60s to
around 70.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
Low pressure emerging from the Great Lakes shifts across SE Canada
this weekend, heading toward the Canadian Maritimes. This will push
a warm front across the forecast area on Saturday with a trailing
cold front passing through on Sunday morning.
Weak isentropic lift ahead of the warm front along with some mid
level PVA may combine with just enough moisture for a few showers to
break out across the area during Saturday morning. The better
chances however will be during the afternoon and nighttime. This is
when moisture and instability will be greater along with stronger
lift from a shortwave passing not too far to the north and the lift
associated with the cold front itself. CAPEs, conditionally unstable
mid-level lapse rates, and bulk shear values would support strong to
potentially severe thunderstorms. This could however be tempered by
a nighttime/early morning passage of the cold front. SPC has most
of the forecast area under a slight risk for severe thunderstorms
during this period.
The cold front exits east Sunday morning, ending the threat of
showers and storms. Behind it, more of zonal flow aloft with weak
high pressure building at the surface. Mostly sunny with less muggy
conditions for the afternoon.
NBM looked good for temperatures through the short term period.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
No significant changes in the long term and stuck close to the NBM
guidance.
The long term starts rather unsettled with the next frontal system
set to impact the region. A warm front will lift north of the region
during the day Monday, followed by a cold front early Tuesday
morning. Southerly winds behind the warm front will usher in a
rather moist and humid airmass. 00z GFS continues to indicate PWATS
increasing to 2.25 to 2.50 inches.
The 90% percentile from SPC`s sounding climatology page is 1.75"
with the max moving average around 2.15". This, along with
sufficient forcing along a cold front could lead to locally moderate
to heavy downpours, at times. WPC currently has the region under a
marginal risk for excessive rainfall. Its still a good ways away,
but worth watching to see if the signals for heavy rain trend
heavier or weaker. The good news is the system looks to be quite
progressive, which hopefully means we shouldn`t see any slow moving
showers. Thunderstorm activity should be isolated to scattered
with some of the strongest areas of forcing.
After the front clears Tuesday morning, clouds should clear allowing
for sunny skies to return for Tuesday afternoon. High pressure is
then expected for the middle of next week.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --
Weak high pressure over the terminals today.
VFR.
A W to WNW flow is expected through the early afternoon today.
A thermal trough is expected to develop this afternoon in which
a sea breeze appears likely for southern coastal terminals with
more uncertainty in occurrence for the remaining terminals. This
will likely affect the wind direction late in the day and early
evening. Winds become light and variable after 00z at all the
terminals.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Amendments possible for wind direction changes with low confidence
in timing this afternoon and evening.
OUTLOOK FOR 06Z SATURDAY THROUGH MONDAY...
Friday night: VFR.
Saturday-Sunday: Mainly VFR. Chance of showers, possibly
thunderstorms, late Saturday into early Sunday morning. VFR for
Sunday afternoon.
Monday: VFR early, then a chance of MVFR with a chance of showers
and thunderstorms.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
Sustained offshore winds mainly under 15kt will maintain sub-
advisory conditions across all of the local waters today. Winds
become lighter tonight with weak high pressure overhead, then
increase from the south on Saturday ahead of a cold front which will
pass through during Sunday morning. Sub-advisory conditions will
prevail, but a gust or two up to 25kt may be possible Saturday
afternoon/evening on the ocean.
SCA conditions will be possible Monday night into Tuesday, as seas
increase to 5 to 6 ft on the ocean waters. Otherwise, Sub-SCA
conditions are expected on all waters Monday through Thursday.
&&
.HYDROLOGY...
No hydrologic concerns are anticipated through this weekend.
Late Monday into Tuesday, brief periods of moderate to heavy
rainfall could occur ahead of a cold front leading to isolated
flooding concerns. After Tuesday morning, no hydrologic impacts
are expected for the rest of the forecast period.
&&
.TIDES/COASTAL FLOODING...
There is a moderate risk for rip currents on ocean beaches today
through this weekend.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...BC/JC
NEAR TERM...JC
SHORT TERM...JC
LONG TERM...BC/BR
AVIATION...BC/DBR
MARINE...JC
HYDROLOGY...BC/JC
TIDES/COASTAL FLOODING...