000
FXUS61 KOKX 120002
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
802 PM EDT Thu May 11 2023
.SYNOPSIS...
High pressure builds to our south this evening moving offshore
tonight as a shortwave trough passes to our northeast. Weak low
pressure tracks through northern New England Friday into Friday
Night with a weak trailing front approaching and then
dissipating over the area. A stronger cold front approaches from
the north Friday night. The front moves through the region
Saturday as a weak wave of low pressure passes to the south.
High pressure builds in late Saturday through Sunday and weakens
Monday as a cold front approaches from the north. The front
moves through Tuesday into Tuesday night. High pressure returns
for Wednesday and Thursday.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
Updated for current conditions and short term trends.
Surface high pressure remains to our south and west this
afternoon and evening as a mid-level shortwave trough located to
our northeast tracks close-by. This will provide enough lift
for an increase in cloud cover this evening, particularly for
eastern Long Island and SE Connecticut. Nearly all CAMS bring
isolated to scattered showers to eastern Massachusetts, but none
make it to our area as the shortwave is just too far away to
bring any moisture. Cloud cover may remain higher for eastern
areas along the periphery of the shortwave before its exit.
We`ll remain dry tonight as surface high pressure maintains its
influence and even builds slightly as the shortwave exits to
our east. This could lead to a clearing of any clouds in the
area. After looking at mid-level moisture, most deterministic
models bring higher 700 RH values on Friday morning from deeper
trough to our north which could lead to clouds building back in
the area early on Friday. This was shown in the forecast by
taking a blend between the deterministic NBM and the 90th
percentile, as cloud cover appeared a bit on the low side with
only the deterministic.
With cloud cover increasing again tomorrow morning, radiational
cooling will be limited, so this has been reflected in the grids
by mostly using NBM for temperatures, which seemed to fall in
line with my thinking quite nicely. I did blend some consensus
MOS for low temperatures, but even MOS guidance was not picking
up on radiational cooling. Overall temperatures will be warmer
tonight with more warm air advection occurring from light
westerlies. Only this afternoon and evening differ on
forecasted hourly temperatures. Here I used a blend between the
HRRR and NBM to better account for the sea breeze circulation.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
A weak northern stream shortwave sinks southeast towards the region
late tonight and slides southeast Fri morning into early afternoon.
Weak shortwave ridging builds in Fri eve, before a strong northern
stream low pivots into northern New England and shearing
southern stream shortwave approaches Friday Night.
At the surface, a weak surface wave approaches northern New England
tonight, and slowly slides through Friday into Fri Night. Its
trailing weak cold front/trough approaches the area from the NW Fri
Am, and then stalls/dissipates overhead across the interior.
Continued WAA in WSW flow will have 850 hpa temps a couple of
degrees warmer than today, with continued deep mixing and ample
sunshine allowing for temps to rise well into the 80s away from the
south coasts. Gusty WSW flow will give way to afternoon seabreeze
development once again, capping temps in the upper 70s/lower 80s
(cooler along immediate south shorefront). Temps should stay below
records on Fri (upper 80s/lower 90s), but may get within a couple
degrees at LGA.
With shortwave aloft, and moisture pooling ahead of dissipating front,
CAMs/soundings indicate potential for an isolated shra/low topped
tstm developing off higher terrain in the afternoon. Localized
strong wind gusts with any convection would be primary threat with
dry mid-level and inverted V soundings.
Any convection dissipates early Fri eve in wake of shortwave, with
unseasonably mild conditions under continued waa sw flow and
increasing high/mid deck. Low temps generally in the 60s.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
A cold front pushes south of the region during Saturday as a
wave of low pressure moves out of the Ohio Valley to the
Delmarva. A slight southward trend continues with the low and
inland portions of the forecast area will be on the northern
periphery of the precipitation shield, as there is little
moisture of frontal lift along the cold front. Any precipitation
that occurs will be light, especially inland as the lower
levels will be rather dry across the area. Removed the mention
of thunder with little to no instability or CAPE. With the
slower movement of the front temperatures should be well above
normal, reaching into the upper 70s and lower 80s. Raised
temperatures, leaning toward the MOS guidance, as winds will
initially be more westerly.
High pressure builds in from the northwest Saturday night into
the beginning of next week. An upper low over eastern Canada
sheers out monday into Tuesday as surface high pressure weakens.
Meanwhile, low pressure moving out of the northern plains and
into the mid Atlantic Monday is suppressed farther to the south,
and will keep the area dry. Another cold front moves out of
Canada Tuesday and through the area Tuesday night. Once again
there will be little moisture or lift with the front, and at
this time will have just slight chance probabilities per the
NBM. A cooler airmass moving from central Canada will return
temperatures to seasonal normal levels for Wednesday and
Thursday, after temperatures being above Saturday through
Tuesday.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --
A surface trough remains across the area through Friday.
VFR. Winds will veer to the WSW this evening at less than 10 kt.
KHPN and KSWF will likely become light and variable. On Friday,
with the onset of daytime heating winds will initially be W and
increase to around 10kt, then veer to the SSW at the coastal
terminals due to a seabreeze in the afternoon at 10-13kt. Gusts
of 15-18kt will be possible in the afternoon.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Timing of seabreeze on Friday could be off by 1-2 hours. Winds
may also be more to the left than forecast at KJFK and KLGA in
the afternoon.
...OUTLOOK FOR 00Z SATURDAY THROUGH TUESDAY...
Friday night...VFR.
Saturday...Low chance of showers with MVFR possible, mainly in
morning/early afternoon.
Sunday-Tuesday...VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
Made a few minor adjustments to the winds and gusts over the
ocean waters to reflect current conditions.
Sub SCA conditions continue through Friday night under a weak
pressure gradient. A brief period of marginal SCA gusts possible
nearshore Friday afternoon into early evening with enhanced sea
breeze development.
Winds and seas remain below SCA levels Saturday through Monday.
With an increasing southwest flow ahead of an approaching cold front
Monday night into Tuesday wind gusts will increase to near SCA
levels on the ocean waters and seas will build to near 5 feet,
especially on the waters east of Moriches Inlet.
&&
.HYDROLOGY...
No hydrologic impacts are expected through Wednesday of next
week.
&&
.CLIMATE...
Record Maximum High Temperatures for Friday, May 12th
-----------------------------------------------------
Newark NJ..........92 (1959)
Bridgeport CT......88 (1991)
Central Park NY....93 (1881)
LaGuardia NY.......88 (1991,1948)
Kennedy NY.........89 (1991)
Islip NY...........87 (1991)
Record Maximum Low Temperatures for Saturday, May 13th
-----------------------------------------------------
Central Park........69 (1956)
LaGuardia...........67 (1956)
Kennedy.............64 (1991)
Islip...............60 (1991,1985,1975)
Newark..............68 (1985,1956)
Bridgeport..........59 (1985)
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...BR/MET/NV
NEAR TERM...BR/MET
SHORT TERM...NV
LONG TERM...MET
AVIATION...DW
MARINE...BR/MET/NV
HYDROLOGY...BR/MET/NV
CLIMATE...//