000
FXUS61 KOKX 262342
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
642 PM EST Tue Dec 26 2023
.SYNOPSIS...
Weakening high pressure will depart to the east tonight. Low
pressure moving up the coast on Wednesday will pass nearby
Thursday morning, move to the east later Thursday through
Friday, and head up into the Canadian Maritimes this weekend. Weak
high pressure will then start to build this weekend and into the
first few days of the new year.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Tricky fcst regarding fog tonight. Think vsbys will lower once
again after dark given plenty of moisture beneath an H9
inversion and a light onshore flow developing as high pressure
departs to the east, especially across Long Island and S CT
where a dense fog advy has been issued for late this evening
into Wed morning. Skies have cleared somewhat from NYC
north/west and mid level clouds area about to move in from the
west, which may limit radiative effects enough there to keep the
fog from becoming dense, so have held off on any advy there for
now.
Rain with the approaching low pressure system should hold off
for the most part, but there could be some areas of drizzle
mainly east of NYC.
Low temps tonight should range from the mid 30s inland to the
lower 40s in/around NYC.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY/...
Fog/drizzle will still be ongoing as rain with the frontal
system also move into the area. Siding more with the NAM/ECMWF
idea of the low moving directly up the coast, with its forcing
more directly impacting the area than more out-to-sea model
solutions. Rain is likely from NYC west by midday, the across
the entire CWA by evening, and the rain could become heavy at
times Wed night from late evening into the overnight as the low
moves up the coast, via coupling of jet streaks over New England
and the Mid Atlantic region, also via combo of H7-8
frontogenesis and H8 theta-e advection passing through.
Forecast rain totals from late Wednesday through Wednesday
night range from 1 to 1 1/2 inches, with the higher totals in
the NYC metro area and NE NJ. The 18Z HRRR and 3-km NAM both
suggest higher totals of 2 to 2 1/2 inches may be possible in
this area, and some of the flashier rivers and streams in NE NJ
could surpass minor flooding benchmarks if rainfall leans toward
this scenario. Otherwise, just minor urban and poor drainage
flooding is likely.
The rain will taper off from west to east early Thursday morning.
A consensus of the modeling puts the steadier/heavier rain east
of NYC metro by 12 Thu, and throughout by afternoon. Shower
chances will linger through the day on Thu via combo of weak sfc
troughing lingering in the wake of the departing low, and
organized areas of lift from weak energy ejecting from the upper
low.
Temperatures continue above normal with highs mostly in the
upper 40s and lower 50s.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
An exiting upper level jet streak Thursday night will be
followed by another wider upper level jet streak approaching
Friday into Friday night. Then, the jet streak shifts east of
the area for the weekend. Upper level heights trend from slight
ridging for the rest of the weekend to quasi-zonal flow going
into early next week. Another less wide jet streak potentially
moves across late Sunday into Monday.
The mid level height pattern will remain in a trough across the
region Thursday night through early Saturday with SW flow. A mid
level vorticity maximum moves through Saturday with a
transition to more zonal flow thereafter through early next
week. One embedded shortwave may potentially move across late
Sunday into Monday.
At the surface, low pressure will linger northeast of the region
Thursday night through Friday night. The low eventually moves
through the Canadian Maritimes this weekend. Across the local
region, weak high pressure will start to build in from the west
this weekend and into early next week.
Regarding weather, rain showers will linger around,
intermittent, Thursday night through Friday night. Drier
conditions expected for the weekend and into early next week.
The upper level disturbance may present a few rain and/or snow
showers early next week but probabilities are just slight
chance.
Daytime high temperatures are forecast to exhibit a gradual
cooling trend. Daytime highs Friday are forecast to be in the
mid to upper 40s and by Tuesday, forecast highs range from upper
30s to lower 40s.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
Conditions continue to deteriorate this evening with mainly
LIFR developing and some VLIFR. A few pockets of IFR at times
for the next couple of hours, but it should not last.
Vsbys tonight for many terminals will fall to under a mile with
widespread 1/2 - 1/4sm expected. Best chance of VLIFR
conditions tonight into Wed morning is for coastal terminals,
with a lower probability for inland terminals like KSWF.
Conditions will improve a little Wednesday afternoon. Thinking
the best we see will be to MVFR for a few hours before
conditions fall back to IFR in rain Wednesday night.
Winds will be light and variable into this evening, with the
winds going light out of the east late tonight into Wed
morning.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Amendments highly likely for changing flight categories
throughout TAF period.
OUTLOOK FOR 00Z THURSDAY THROUGH SUNDAY...
Wednesday night: Rain with IFR and pockets of LIFR conditions.
E-SE winds G20kt possible late at the coastal terminals.
Thursday: MVFR possible with chance of showers. E winds G20kt
possible in the morning at the CT/Long Island terminals.
Friday: MVFR possible with chance of showers. N / NE winds.
Saturday: Mainly VFR. NW winds G20-25kt.
Sunday: VFR.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
Marine dense fog advy has been extended to all waters through
Wed morning. E-SE winds increasing Wed night as low pressure
approaches may produce some gusts up to 25 kt on the ern
ocean/Sound waters late Wed night into early Thu morning.
SCA level ocean seas forecast Thursday night and Friday, and
then mainly the eastern ocean waters for Friday night. Ocean SCA
level seas return for much of the weekend. SCA level wind gusts
are forecast mainly across the ocean for the first half of the
weekend.
&&
.HYDROLOGY...
Storm total rainfall 1.0-1.5 inches is likely from Wed afternoon
into Thu morning, with the higher amounts more likely to occur
around and just NW of NYC. Due to recent heavy rainfall and
continued high streamflows, there is a concern for minor
flooding along a few quick responding rivers in NE NJ and
potentially the Lower Hudson Valley. Rainfall of at least
1.5-2.0 inches as depicted by the last couple of cycles of the
ECMWF/NAM as well as the 12Z/18Z HRRR would bring the Saddle
River at Lodi and the Ramapo River at Mahwah above minor flood
stage. Otherwise, minor urban and poor drainage flooding should
be the main hydrologic impact.
&&
.TIDES/COASTAL FLOODING...
The potential remains for minor coastal flood impacts for
vulnerable coastal communities on Thu with a passing low.
The threat exists for mainly the morning high tide,
particularly along the south shore of Nassau and Queens, and
possibly along the SW CT coastline on the Western Sound and NY
Harbor. Tidal departures of 1.25-1.50 ft are needed for minor
flooding, and 2.25-2.50 for moderate flooding during the morning
high tides. About 1 ft additional surge is needed for the
evening high tides.
The threat for dune erosion appears to be low and isolated with
this event.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CT...Dense Fog Advisory until 11 AM EST Wednesday for CTZ005>012.
NY...Dense Fog Advisory until 11 AM EST Wednesday for NYZ078>081-
177-179.
NJ...None.
MARINE...Dense Fog Advisory until noon EST Wednesday for ANZ331-332-335-
338-340-345-350-353-355.-- End Changed Discussion --
&&
$$
SYNOPSIS...BG/JM
NEAR TERM...BG
SHORT TERM...BG
LONG TERM...JM
AVIATION...BC
MARINE...BG/JM
HYDROLOGY...BG/JM
TIDES/COASTAL FLOODING...