000
FXUS61 KOKX 111834
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
234 PM EDT Fri Aug 11 2023
.SYNOPSIS...
A weak cold front approaches from the northwest today and stalls
out across the area tonight. Low pressure north of the Great
Lakes on Saturday will then track across eastern Canada through
Sunday, sending the front back north as a warm front Saturday,
followed by a cold frontal passage on Sunday. Another frontal
system moves across the area Monday into Tuesday.
&&
.NEAR TERM /THROUGH TONIGHT/...
An upper trough lifts out of the Northeast today, while
shortwave ridging builds in from west. At the surface, a weak
cold front approaches from the northwest and stalls close to
the area tonight. There will be few clouds today with mostly
sunny, dry conditions. Weak high pressure builds to the north
of the area tonight.
Have stayed close to the previously forecast highs (NBM). 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
airmass 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.
&&
SYNOPSIS...BC/JC
NEAR TERM...JC/DW
SHORT TERM...JC
LONG TERM...BC/BR
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
Weak high pressure over the terminals today, VFR. Series of
fronts may bring MVFR or lower conds Sat PM.
W to WNW flow through the afternoon today, with the exception of
southern coastal terminals where sea breeze has backed flow to
the SW. Speeds around 10 kt, with a few gusts toward 20 kt into
late afternoon. Winds become light and variable after 00z at
all the terminals, before southerly flow develops by late Sat
AM. Potential for showers and thunderstorms Saturday afternoon
and evening may bring MVFR or lower conds at times.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Amendments possible for wind direction changes with lower
confidence in timing this afternoon and evening.
Low confidence in coverage and timing of showers and tstorms on
Saturday. Adjustments likely.
OUTLOOK FOR 18Z SATURDAY THROUGH MONDAY...
Saturday - Sat Night: Mainly VFR, potentially becoming MVFR or
lower at times with showers and thunderstorms possible from the
late afternoon into the overnight.
Sunday: VFR. W flow around 10 kt.
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 passing to the
north, then increase from the south on Saturday ahead of a cold
front which will pass through on Sunday. 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.
&&
$$
UPDATE...DW
AVIATION...DR