096
FXUS61 KOKX 111427
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
1027 AM EDT Fri Oct 11 2024
.SYNOPSIS...
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High pressure builds south of the region this afternoon, then a
dry cold front passes through on Saturday. Low pressure then
approaches from the west and passes to our north, sending a cold
front into the region Sunday night into Monday morning. High
pressure then builds in through Wednesday.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
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For this update just tweaked temps down a degree or two for this
afternoon as temps are lagging a bit behind previous fx numbers.
The more obs based near term model fx numbers support this.
Otherwise, fx remains on track with plenty of clear skies with
the center of sfc high pressure parked just back to the SW
along the western slopes of the Central Appalachians. Previous
discussion follows.
A flattening ridge in the 500mb pattern shifts towards us this
afternoon, with surface high pressure building to our south.
Mainly sunny with perhaps some cirrus streaming in from the west
by very late in the day. The sunshine and westerly winds will
push high temperatures back up to near normal - mostly 64-69,
which is around 3-5 degrees warmer than what was observed
yesterday.
Increasing cirrus tonight, and with a light WSW wind, tonight`s low
temperatures will be warmer than last night`s - ranging from around
50 across the northern zones to the upper 50s in the city.-- End Changed Discussion --
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
A cold front passes through the area Saturday morning with moisture
limited to the upper levels, so no showers occur with its passage
over here. Although 850mb temperatures fall to 7-8C in the afternoon
behind the front, WNW-NW downslope winds should add a little
compressional heating. Have therefore bumped up the deterministic
NBM by a few degrees in most spots. Highs in the upper 70s for the
typically warmest spots in NE NJ and some areas in the city, with
lower to middle 70s elsewhere.
Saturday night will feature a zonal flow in the 500mb longwave
pattern, however 850-700mb moisture and shortwave lift approach us
from the west late at night. This along with decent isentropic lift
could produce showers NW of the city by the end of the night. The
longwave pattern then begins to amplify on Sunday courtesy of an
upper jet streak diving south from central Canada along with a 500mb
shortwave shifting into the Great Lakes region. These in turn will
energize a surface low shifting east across the lower Great
Lakes/upper Ohio Valley regions. Models disagree as to where the
center of this low eventually tracks, but favor a path north of us.
This scenario would then send a cold front into the forecast area
late Sunday night. Rain chances generally increase through the day
with the higher chances over the northern zones. Then as the cold
front approaches and a low level jet increases offshore, rain
becomes likely Sunday night. Won`t include thunder in the forecast
just yet during Sunday night, but upward forcing with the llj
combined with a little elevated instability and progged
conditionally unstable mid-level lapse rates may contribute a rumble
of thunder mainly east of the city. NBM was used for temperatures
Saturday night through Sunday night.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
The the cold front continues to move through the forecast area into
early Monday morning, pushing offshore later in the morning into the
early afternoon. This far out of course, there are timing
differences among the models. This will lead to some lingering
showers, mainly for eastern locations, with perhaps a slight chance
of showers for most other locations Monday morning.
Low pressure associated with the cold front treks into southeastern
Canada as high pressure from the center of the US slowly builds in
at the surface and troughing sets up aloft for the eastern third of
the country, which amplifies as head into the midweek period. This
will allow for a continued period of cold air advection from Monday
through Wednesday, leading to the coldest airmass of the early fall
season thus far. Then surface high pressure builds to the south and
a return flow sets up with temperatures moderating for Thursday.
Temperatures will be near normal on Monday, then drop to 5 to 10
degrees below normal Tuesday and Wednesday, with high temperatures
hard pressed to break 60 on both days. Slightly warmer, but still
below normal highs are expected for Thursday. Lows during this time
frame will be in the 30s and 40s. If winds let up enough, some
isolated locations in the outlying areas could drop to freezing or
slightly below. Frost therefore is a possibility, however there is a
good deal of uncertainty in both how low temperatures will drop as
well as wind speeds and any cloud cover, and there is thus
uncertainty in where any frost will develop at this time.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
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Higher pressure continues over the terminals. A cold front
approaches tonight and moves through on Saturday.
VFR.
WNW winds remain near 10 kt for most terminals shifting to the
W then WSW to SW (mainly for coastal terminals, inland terminals
will remain more W) into this evening. Winds shift back to the
NW Saturday morning at 10 to 15 kt after the frontal passage.
LLWS may occur late tonight, between 06Z to 12Z, but not enough
confidence to put in TAFs just yet. If it does occur, it would
likely be at 030 at 40-45 kt at or just below 2 kft.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
No unscheduled amendments expected.
OUTLOOK FOR 12Z SATURDAY THROUGH TUESDAY...
Saturday: VFR. W-WNW winds G15-20kt during the day.
Sunday: VFR for much of the day, SE / S winds G15-20kt in the
afternoon. Chance of showers with possible MVFR late and mainly at
night.
Monday: Mainly VFR, brief MVFR possible early in showers. W to NW
winds 10 to 15 kt, with gusts 15 to 20 kt.
Tuesday: VFR. NW winds.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
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Sub-advisory conditions with a NW to W flow under 15kt this
afternoon. Westerly winds then pick up tonight ahead of an
approaching cold front. The front shifts through Saturday
morning, then veering winds become lighter through the rest of
the day. Expecting advisory- level conditions on the ocean
starting this evening and lasting into Saturday, so SCAs have
been issued accordingly. There could be occasional gusts to 25kt
over central and eastern LI Sound, but will hold off on an
advisory. Winds further subside Saturday night, then a probable
return to SCA conds on the ocean for Sunday in advance of an
approaching low pressure system and cold front.
Small craft conditions on at least the ocean waters lasting into
Monday as a cold front moves through. Gusts of 25 to 30 kt are
likely on the ocean, and possible on all other waters. Waves of
4 to 8 ft on the ocean waters begin to slowly diminish Monday
afternoon, not falling to below 5 ft by Monday night into
Tuesday morning (mainly for the eastern ocean waters).-- End Changed Discussion --
&&
.HYDROLOGY...
No hydrologic concerns expected through the middle of next week..
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory from 10 PM this evening to 6 PM EDT
Saturday for ANZ350-353.
Small Craft Advisory from 10 PM this evening to noon EDT
Saturday for ANZ355.
&&
$$
SYNOPSIS...JC/JP
NEAR TERM...JC/JE
SHORT TERM...JC
LONG TERM...JP
AVIATION...DBR
MARINE...JC
HYDROLOGY...JC/JP