059
FXUS61 KOKX 311801
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
201 PM EDT Sat Aug 31 2024
.SYNOPSIS...
A ridge of high pressure across the area today will continue to
gradually weaken and give way to an approaching frontal system.
The latter of which will move across the area tonight into Sunday
morning. A secondary cold front will then pass through the area
Sunday evening. Behind it, a large dome of high pressure over
the Upper Midwest will then build east through the middle of
next week, gradually moving offshore late next week.
&&
.NEAR TERM /THROUGH TONIGHT/...
Temperature have been adjusted upward by a couple of degrees
across eastern LI and SE CT, where mostly sunny conditions are
expected to prevail this afternoon. Rest of the forecast is
mostly on track.
Today will largely be dry with the area under the influence of a
retreating surface high and an upper level ridge. Guidance
continues to trend slower with the first frontal system that
will move across the area tonight into Sunday morning. In addition,
due to the slower timing and only weak instability to work
with, CAMs also continue to trend toward a poorly organized
convective event as showers and possible thunderstorms move into
the area later this evening first across western portions of
the Lower Hudson Valley. While there is modest large scale lift
in the middle and upper layers, the ingredients are simply not
there for strong and/or severe thunderstorms. In collaboration
with SPC, the slight risk has been shifted well west of the
forecast area. As for heavy rainfall concerns, PWATs increase to
around 2 inches, so showers with some downpours will be
possible during the overnight hours. Flooding concerns are
mainly of the minor nuisance variety. WPC does have locations
north and west of NYC under a marginal risk of excessive
rainfall. Any flash flooding is expected to be isolated.
Rainfall amounts are forecast to be under half an inch basin
average. Localized higher amounts will be possible, especially
north and west of the NYC metro.
Highs today will be near normal in the upper 70s to low 80s.
Due to cloud cover and increasing humidity, lows tonight will be
on the warm side in the upper 60s to around 70. It will also
become quite humid.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
Showers will likely linger in the morning hours Sunday, especially
across LI and CT. The trend has been slower. Uncertainty then
arises during the afternoon and early evening hours as a pre-
frontal trough and cold front move across the area. Drier air
advecting into the region could also be limiting factor if it
mixes down in the low levels. However, this may be late enough
with some of the 00Z guidance showing decent instability in the
afternoon. Mid level flow is about 30kt. SPC does have the area
in a marginal risk with the main threat being isolated damaging
winds.
Highs on Sunday will in the upper 70s to lower 80s. This a
slight nudge down due to the cloud cover persisting longer,
which will be a factor in the amount of destabilization in the
afternoon.
Cold front is forecast to move across the area the first half of
Sunday night. Behind it, a northerly flow with much cooler,
drier air coming in for the upcoming week. Highs on Monday will
be in the 70s with dew points falling through the 50s.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
High pressure will continue to build in behind the exiting front
from the Great Lakes region Monday night and Tuesday, leaving a very
sunny forecast for early next week. Overnight lows will drop into
the middle 40s across the interior to upper 50s into the NYC metro
area Monday night. Dewpoints drop into the 40s Monday night and
remain there through Tuesday, reinforced by northwest flow.
Most model guidance brings the high pressure overhead Tuesday night
into Wednesday morning, then gradually push it offshore Wednesday
night into Thursday, and remaining offshore Friday. This will lead
to a return flow from the south. This will mean continued sunny days
before cloud cover increases Thursday night into Friday. Southerly
winds will lead to increasing temperatures and dewpoints late next
week. Highs will be in the mid 70s to low 80s by Friday.
Most global models try to develop a coastal low along the mid-
Atlantic coast Friday and bring it near the forecast area Friday
night into Saturday, but this is still very far out and the models
do differ in strength, placement, and timing.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
-- Changed Discussion --
A pre-frontal trough slowly approaches tonight and slides
through Sunday into Sunday Night.
Gradual improvement to VFR through the late afternoon. A return
to MVFR/IFR conditions after 03-06z as showers chances
increase, continuing through Sun AM. Isolated tsra threat during
this time.
SE winds 10k or less, veering to S/SE this afternoon, then
shift to the S/SSW tonight into Sun AM.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Timing of return to MVFR or lower tonight, may be off by an
hour or so. Isolated TSRA threat for Sun AM/PM push.
OUTLOOK FOR 18Z SUNDAY THROUGH THURSDAY...
Sunday: Improvement to VFR likely in the afternoon with iso
shower/tstm threat into eve push.
Monday through Thursday: VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
Winds and waves will remain below SCA criteria through the
middle of next week. Behind a cold frontal passage Sunday
night, a large dome of high pressure builds east from the Upper
Midwest and into the area through midweek. Pre-and post-frontal
gusts Sunday into Monday could get near 20 kt.
&&
.HYDROLOGY...
Showers and possible thunderstorms tonight into Sunday morning
look disorganized. The flood threat will be mainly of the minor
nuisance variety. However, WPC maintains a marginal risk of
excessive rainfall north and west of the NYC metro. This means
there is the potential for isolated episodes of flash flooding.
&&
.TIDES/COASTAL FLOODING...
The risk threat has been adjusted downward today based several
sources of guidance. Also, an easterly swell of 2-3 ft parallel
to the coast should limit wave heights in the surf zone to 1-2
ft. Onshore flow will also become SE, but less than 10 kt. For
Sunday, plan to go low at this time, but a southerly flow around
10 kt could bring the risk closer to moderate.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...JP/DW
NEAR TERM...JC/DW
SHORT TERM...DW
LONG TERM...JP
AVIATION...NV
MARINE...JP/DW
HYDROLOGY...JP/DW
TIDES/COASTAL FLOODING...