873
FXUS61 KOKX 130535
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
135 AM EDT Fri Sep 13 2024
.SYNOPSIS...
High pressure continues to maintain control across the region
through this weekend and into Monday, then will weaken going
into midweek as it gradually moves more offshore. A frontal
system approaches from the west but looks to stay mostly to the
southwest of the region Wednesday into Thursday of next week.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
Minor changes were made this this early night update.
Otherwise, the forecast remains on track.
Mostly clear sky conditions start tonight with high pressure
centered just offshore of southern New England. Onshore flow
persists into tonight, pushing dew points along the coast into
the upper 50s and lower 60s. This plus radiational cooling
should lead to more fog and low stratus late tonight. Capped at
areas of fog for now, but localized dense fog is possible,
especially in the valleys. Low temperatures tonight range from
the mid 50s inland and across a good deal of eastern Long
Island, to the lower 60s in the NYC metro area.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY NIGHT/...
Amplifying deep layer ridging over the Great Lakes translates
east across the region into the weekend while surface high
pressure remains centered just offshore.
No precipitation is expected in the period, but morning fog and
stratus possible each morning with the persistent, light onshore
flow. This burns off with heating and leads to abundant
sunshine both days, perhaps filtered through a bit of haze from
an elevated wildfire smoke plume passing through the Northeast.
Temperatures run several degrees above normal for mid September
as the ridge builds overhead. Highs on Friday top out within a
few degrees of 80, warmest across urban NE NJ. Saturday may be a
hair warmer, with low to mid 80s across the Tri-State. Overnight
lows bottom out in the 50s and 60s.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
Overall, weather remains mainly dry with the exception of Wednesday
and Thursday of next week, when there could be some rain showers.
Confidence not high on this however, so have just slight chance POPs
for rain showers as there is more model uncertainty with the
forecast. Otherwise, temperatures look to remain mostly near normal
as the airmass will not exhibit significant changes.
Each late night into the early morning, there will be potential for
fog formation especially outside of NYC. Have mentioned patchy fog
for much of the region outside of NYC for early Sunday morning as
well as for late Sunday night into early Monday morning. The same
cyclical fog formation and subsequent dissipation with diurnal
heating could very well occur for late night into morning of the
remainder of the forecast period.
Aloft, strong ridge over the region Sunday will linger into early
next week and then gradually shift offshore Tuesday into the middle
of next week. GFS and Canadian models are showing a trough
approaching the region for latter part of next week while the ECMWF
keeps a stronger ridge and a weaker approaching trough.
At the surface, high pressure continue to maintain control over the
weather across the region, keeping dry conditions Sunday through
early next week. By Wednesday and Thursday of next week, the
operational GFS and Canadian models are indicating more weakening of
pressure across the local region with high pressure farther out to
sea. These two models are conveying the approach of a frontal system
with some rain returning to the local region. The GFS model shows
less rain than the Canadian model for the local area. ECMWF
operational model keeps stronger high pressure closer to the area
and is much drier, keeping the area dry through next Thursday.
After noting a general increase across the area with regards to POPs
within the LREF, did slightly increase POPs spatially across the
region for Wednesday night through Thursday night. However, after
noting a shift to later in the week with the rainfall compared to
previous forecast, POPs remain in slight chance for showers. In
addition, the LREF 500mb height depiction and operational models do
not show too much of a decrease in the 500mb height, with the
operational Canadian models showing more of a negative anomaly with
respect to the LREF 500mb height percentile analysis, below the 25th
percentile. This leans the forecast to relatively less rain shower
chances, thereby keeping more continuity with the previous forecast
considering the increasing uncertainty for Tuesday through Thursday
of next week.
Temperatures throughout the long term are not forecast to deviate
much from normal values. High temperatures are generally in the
upper 70s to near 80 for most locations during the day. Lows for
late night into early morning are generally in the 50s and 60s. The
lows range from the mid 50s to low 60s Sunday night and Monday night
and then more in the upper 50s to upper 60s for Tuesday night and
Wednesday night of next week.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --
High pressure remains centered to our east through Friday.
VFR for much of the period.
There is a low chance that some IFR conditions develop between
08Z to 13Z Friday. Forecast guidance has started to back off on
this idea of development and will remove the prevailing IFR to
just TEMPOs. Will continue to monitor overnight.
Light and variable early Friday morning. Onshore flow will
redevelop mid to late Friday morning from the S-SE. KLGA may
stay from the NE into early afternoon.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
KLGA could hold on to NE winds 1-2 hours longer than currently
forecast.
Low confidence of MVFR/IFR early this morning.
OUTLOOK FOR 06Z SATURDAY THROUGH TUESDAY...
Saturday-Tuesday: Mainly VFR, but a chance of MVFR or lower
fog/clouds for each late night/early morning.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
Conditions on the waters are forecast to remain below SCA thresholds
through early next week with an overall weak pressure gradient
in place. Wind gusts are expected to remain below 20 kt and the
maximum seas forecast on the ocean is 4 ft. The 4 ft ocean seas
are forecast to be mainly in the Monday through Tuesday night
timeframe.
&&
.HYDROLOGY...
No hydrologic concerns through the middle of next week.
&&
.TIDES/COASTAL FLOODING...
With an approaching full moon for next week on September 17th,
astronomical levels will be rising leading up to that date. With the
continuous easterly flow, this will help build seas and allow for
some piling of water. Winds are expected to remain generally light,
near 10 kt or less. Thinking there will be a possibility for some
tidal locations to be near or at minor coastal flood benchmarks as
indicated by some surge models Sunday into early next week during
their respective times of high tide. This would be mainly for the
South Shore Bays and Western Long Island Sound shorelines and maybe
a few locations along the NY Harbor.
Regarding the rip currents, without much change in airmass and low
level winds over the next few days, forecasting a moderate risk of
rip currents at the ocean beaches Friday and Saturday. This will be
from a continuing easterly flow as well as slowly building ocean
seas getting to a range of 2 to 3 feet. Averages of rip current MOS
also were taken into account, with an overall moderate rip current
risk forecast.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...DR
NEAR TERM...JM/BR/DR
SHORT TERM...DR
LONG TERM...JM
AVIATION...BC
MARINE...JM/DR
HYDROLOGY...JM/DR
TIDES/COASTAL FLOODING...