089
FXUS61 KOKX 120949
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
549 AM EDT Sat Oct 12 2024
.SYNOPSIS...
High pressure will reside south of the area tonight. A cold
front swings through Saturday and stalls to the south Saturday
night. The front lifts north as a warm front late Sunday into
Sunday night along with developing low pressure. The low drags a
cold front through Monday morning into Monday afternoon, with
high pressure slowly building in thereafter.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
Forecast is on track with only minor changes needed.
Tranquil conditions continue today despite the passage of a cold
front this morning. Much of the dynamics associated with the front
will be limited well to north as its associated upper shortwave
trough moves through northern New England. The flow aloft looks to
become more zonal and progressive over southern New England and the
Northeast as a whole by this afternoon. With a northwesterly flow,
some downsloping off the higher terrain will allow temperatures to
warm to above normal levels today, with highs in the upper 60s to
middle 70s.-- End Changed Discussion --
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
High pressure builds in for the first part of tonight. The cold
front begins to move north late tonight, with a weak area of low
pressure over the mid-West riding the frontal boundary and heading
east. At the same time, an upper level trough dives south from the
western Great Lakes region and aid in some intensification of this
low over the Northeast. Most of the deterministic models show the
low intensifying as it rounds the trough and heads into northern New
England. A period of light rain showers is therefore in the forecast
from Sunday into Sunday night. Some lingering showers are possible
for eastern areas Monday morning. Some CAMs try to bring in some
showers late tonight into NYC and points east, however looking at
forecast soundings, instability does not look impressive to warrant
any POPs. Any showers should be limited to the interior for tonight,
with the best chances for any precipitation actually occurring
Sunday night.
There is also a brief period window for the possibility of thunder
for the first half of Sunday night as instability aloft increases to
a couple hundred J/kg, so continue to carry a slight chance for
thunder from 2 am to 8 am Sunday night into Monday morning.
Generally, light rain is expected with anywhere from 0.10"-0.50"
in the forecast. The highest amounts are expected across the
Lower Hudson Valley and inland CT, while lower amounts are
expected across NYC, NE NJ, and Long Island (eastern areas of
Long Island may be on the higher side of the aforementioned
range as the low intensifies east of the area, it could bring
some heavier showers in before it departs).
There is a decent temperature gradient across the forecast area on
Sunday, with area north and west of NYC seeing highs in the 50s,
while the city and coastal areas see highs in the upper 60s to lower
70s. This is because the frontal boundary is expected to be within
the forecast area on Sunday. However, there is a large spread in
temperatures seen in the NBM for Sunday (as much as 9 degrees in
some cases) as there is uncertainty in where the frontal boundary
will be. If it ends up farther north than is currently forecast,
then temperatures will likely be warmer than what is currently in
the forecast. If it remains to the south, then cooler temperatures
can be expected.
The cold front moves through on Monday and high pressure builds in
behind it. Precipitation will end from west to east through the day,
with dry conditions expected everywhere by sunset. Highs on Monday
will be seasonable, ranging from the upper 50s inland, to the upper
60s along the coast. With the strengthening low pressure to the
north and the high building in, a strong pressure gradient will set
up over the area, and breezy conditions are expected, with gusts of
20 to 30 mph.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Sunday evening starts out with a deepening upper level trough
approaching from our west. The associated surface low at that
time should be centered somewhere over western PA, with its warm
front extending just north of our area or over northern
portions of the area. The low will deepen as it approaches and
will likely pass just over or near the area early Monday
morning. Its cold front then passes through later Monday morning
into the afternoon, ushering in the coolest airmass of the
season.
In terms of weather, this system will bring rainy and windy
conditions. There is still some spread across the guidance,
but general consensus has the most likely period of rain being
Sunday night. PoPs don`t end until Monday night with the chance
for some lingering rain through the day on Monday and the
possibility of the front moving through later. With some
instability available and strong lift, thunder can not be ruled
out and have added to the forecast for Sunday night. The
heaviest totals will likely be well north of the area, with an
average total of a few tenths for us. Amounts will be locally
higher in any thunderstorms. We could see some gusty southerly
winds ahead of the frontal passage, but the stronger winds
likely come later on Monday behind the front with cold advection
in a W/NW flow. Even mixing down winds from halfway up the
model mixed layer supports gusts in the mid to upper 20 kts.
Blended in NBM 90th percentile gusts to show this. The gust
forecast could continue to trend up.
Dry conditions expected thereafter, with high pressure very
gradually building in. Gusty conditions could continue as the
pressure gradient remains relatively tight. Dewpoints drop to
the low to mid 30s by Monday night and likely stay there through
the end of the week. While the winds remaining elevated do not
support radiational cooling, the cool airmass itself will bring
lows in the mid 30s to low 40s for the rest of the week. This is
well below average for early October.
&&
.AVIATION /10Z SATURDAY THROUGH WEDNESDAY/...
VFR as a dry cold front approaches and passes through after
daybreak, and high pressure builds in during the afternoon and
at night.
W-WSW flow 10 kt or less should continue until fropa at 12Z-13Z,
with winds shifting out of the NW 10-15G20-25kt, diminishing late in
the afternoon. LLWS possible before fropa, with NW flow 35-40 kt at
FL020.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Stronger NW winds could last an hour or two longer into the
afternoon than fcst.
OUTLOOK FOR 06Z SUNDAY THROUGH WEDNESDAY...
Late tonight: VFR.
Sunday: Chance of showers with VFR for much of the time.
S winds 10-15G20kt in the afternoon at the metros and along the
coast.
Sunday night: Showers likely, possibly an evening tstm.
MVFR cond possible especially inland. S-SW winds 10-15G20kt in
the evening at the metros and along the coast.
Monday: Showers likely with MVFR cond in the morning,
especially at the Long Island/CT terminals, ending in the
afternoon. W winds becoming 15G20-25kt increasing to
15-20G25-30kt in the afternoon.
Monday night: VFR. W wind 15-20G25-30kt early, becoming NW
10-15G20kt by late evening.
Tuesday: VFR. W winds 15G20-25kt.
Wednesday: VFR. NW winds 10-15G20-25kt.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
Small Craft Advisories continue on the ocean waters today, mainly
for waves of 5 to 6 ft. Waves are expected to diminish from late
morning onward as the flow becomes more NW. The western ocean zone
will drop below 5 ft by mid morning, if not a bit earlier. The other
2 zones are staggered in time, with the central ocean zone falling
below by late this morning and the eastern ocean zone by early to
mid afternoon.
Conditions remain below SCA criteria on all waters through Sunday
morning. The approach of a frontal system to the south and then a
strengthening pressure gradient from Sunday afternoon into Monday
will mean a prolonged period of SCA on the ocean waters during
this time frame as waves build to 4 to 8 ft and wind gusts of
25 to around 30 kt are possible. By Monday afternoon, all waters
are expected to see SCA gusts. Did not issue SCA for this
period just yet as it was late third period.
SCA cond in NW flow should continue on all waters Mon night, with
gusts 25-30 kt and ocean seas 5-8 ft. Thereafter, SCA cond likely
on the ocean Tue into Wed night, with seas 3-5 ft and gust up to 25
kt. Could also see a brief round of SCA cond on the non ocean waters
especially the Sound late day Tue into Tue night, with gusts up to
25 kt.
&&
.HYDROLOGY...
There are no hydrologic concerns through the forecast period.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 4 PM EDT this afternoon for ANZ350-
353.
Small Craft Advisory until noon EDT today for ANZ355.
&&
$$
SYNOPSIS...BG/JP
NEAR TERM...JP
SHORT TERM...JP
LONG TERM...BG
AVIATION...BG
MARINE...BG/JP
HYDROLOGY...BG/JP