000
FXUS61 KOKX 031754
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
154 PM EDT Mon Apr 3 2023
.SYNOPSIS...
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Low pressure tracking through Canada sends a cold front
toward the area tonight, stalling to the north over southern New
England on Tuesday. The weakening boundary may sag south into
the region Tuesday night, before returning north as a warm front
on Wednesday. An attendant cold front moves through the region
Thursday. High pressure then dominates Friday into the weekend.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
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Increasing southerly flow continues this afternoon with surface
high pressure now centered offshore in the Western Atlantic.
Only minor adjustments made to account for current observations
and trends and forecast remains on track.
Southerly flow is expected today as the synoptic return more
southerly to southwesterly flow develops. There will likely be
sea breeze enhancements along the coast, especially with the
Ambrose Jet this afternoon. Therefore, expecting gusty winds
this afternoon along the coastline.
Model 850mb temperatures will be on an increasing trend this
afternoon and this more southerly synoptic flow will allow for
this warmer air to advect across the region. Model 850mb
temperatures indicate a range of near 3 to 6 degrees C going
into early this evening. With forecast soundings showing
adiabatic vertical mixing up to near 900 to 850mb away from the
coast, and more shallow, only up to near 950mb along the coast,
this will further convey a spatial temperature gradient that
will also show the marine influence of the more southerly
surface flow.
NBM50th percentile used for the max temperature forecast,
raised one degree across Northeast NJ, Lower Hudson Valley, and
Southwest CT where temperatures could trend higher with
subsequent forecast. Then blended this new forecast with the
previous forecast. Want to exhibit a more vast range between the
eastern and western sections of the forecast region to show
that maritime influence on the temperature gradient.-- End Changed Discussion --
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
For tonight, with a cold front approaching from the north and
west, clouds will continue to increase. Southerly flow will
remain steady along the coast and will be less farther inland.
Winds will weaken across the Lower Hudson Valley and Southern CT
earlier in the night. Warmer than normal temperatures are
expected for the forecast lows. Used a combination of NBM the
percentile (75 percent) and consensus of raw model temperature
(25 percent) for the low temperature forecast as it exhibits a
less vast range of temperatures across the region.
Late tonight as the cold front nears the northernmost portions
of the forecast region, there could be a few rain showers as
suggested by some of the mesoscale models and their reflectivity
fields. The parent low attached to the front will be filling in
and weakening so the front will weaken and slow down. The
pressure gradient will be weakening as well and even the
coastline southerly flow will lessen overnight into early
Tuesday morning.
On Tuesday, the front that is close to the northern parts of
the region weakens and eventually dissipates. The surface flow
remains southeasterly with more southerly flow along the coast.
However, the wind speeds will remain light and under 10 kts.
For Tuesday, the 850mb temperature increase to near 7 to 9
degrees C by early evening, which will be a few degrees warmer
than the previous day. Temperatures at the surface likewise are
expected to trend several degrees warmer than the previous day.
However, with limited vertical mixing and clouds lingering
around, did not go as high as NBM for the max temperatures.
Instead, blended NBM with consensus of MOS and then blended that
with previous forecast.
Flow becomes more easterly Tuesday night as high pressure
builds into Southeast Canada and into Northern New England as
well as Nova Scotia. Models are indicating the weak frontal
boundary to become a stationary front associated with the next
low pressure wave moving near the Great Lakes. Moisture
convergence increases along and near the front in the low
levels. Would expect widespread stratus to develop and chances
for rain to increase. This will keep low temperatures warmer
and less spatial spread across the area with a blend of raw
consensus and NBM the percentile for forecast lows.
On Wednesday, the front remains nearly stationary but easterly
flow increases in the area. The abundance of clouds and the rain
in the area will keep cooler temperatures compared to the
previous day. The front Wednesday becomes a warm front and moves
north of the area Wednesday into Wednesday night. The flow
becomes more southerly and further increases Wednesday night.
Rain chances continue Wednesday night.
Highs forecast Wednesday and lows forecast for Wednesday night
both utilized a blend of NBM and consensus of raw data.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
No significant changes made to the long term Thursday through the
upcoming weekend.
The pattern on Thursday will feature a strong ridge departing the
eastern seaboard with deep upper level low/trough tracking across
southeastern Canada. A surface cold front will likely be situated
just NW of the region Thursday morning. The modeling is in
relatively good agreement on the cold front moving across the area
in the afternoon and early evening. Large scale support is limited
with the upper low/trough well north of the area. Convergence along
the front appears to be the main focus for shower development
especially in the afternoon/early evening. The region will be in the
warm sector, but as is usually the case, there are uncertainties
regarding the amount of instability. The current consensus of the
guidance supports the addition of a slight chance of thunder from
around the NYC metro into NE NJ and the Lower Hudson Valley. While
surface winds look to be SSW-SW, the flow off the colder ocean
should limit instability further east. Shear is not as strong as the
last event this past Saturday, but 40 to 55 kt of middle level flow
could help with storm organization. Will have to monitor trends with
instability over the next few days to see if a more organized line
of convection is possible. Otherwise, highs on Thursday should reach
the lower to potentially middle 70s along and west of the Hudson
River. Further east, highs will be held down from maritime influence
with readings in the upper 50s to middle 60s.
The cold front moves offshore Thursday night with high pressure
building in from the midwest through Friday. The high should
dominate the surface pattern for the upcoming weekend with dry
conditions as well. Temperatures Friday through the weekend will be
closer to seasonable levels for this time of year.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
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Offshore high pressure continues to move east through tonight,
then remain in the western Atlantic Tuesday. A cold front
approaches north of the terminals late tonight.
VFR, except brief MVFR ceilings possible at KGON toward Tuesday
morning.
Southerly winds, with gusts, continue with sea breeze
enhancement this afternoon. Winds diminish after 00Z, even
becoming light and variable at the outlying terminals.
morning. Southerly winds develop Tuesday morning 10kt or less.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Occasional gusts possible at KJFK, more likely sustained winds
increase to around 20kt around 21Z. Gusts at KEWR, KTEB, and
KLGA may be a few kts higher mid to late afternoon.
Winds at KLGA become light E and NE late tonight.
Low confidence in any low clouds developing late tonight, and
removed from the forecast.
...OUTLOOK FOR 18Z TUESDAY THROUGH SATURDAY...
Tuesday afternoon-Tuesday night: VFR. MVFR developing, and
lowering to IFR, LIFR possible toward Wednesday morning. Light
rain possible late.
Wednesday: IFR likely. A chance of showers during the afternoon
and night.
Thursday: MVFR possible. Showers likely in the afternoon/evening.
Slight chance of a thunderstorm NYC terminals and NW in the
afternoon/evening. SW gusts 15-25 kt, becoming W-NW at night.
Friday: VFR. W-NW G20-25kt.
Saturday: VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90.-- End Changed Discussion --
&&
.MARINE...
High pressure shifts offshore today as a frontal boundary
meanders just north of the waters through Tuesday.
SCA conds expected for all waters this afternoon into early
evening, lingering for ocean tonight. Gusts 25-30 kt can be
expected everywhere during this time, with seas building to
around 5 ft on the ocean. Sub-SCA conditions then Tuesday
through Wednesday, with SCA conditions developing again
Wednesday night. The ocean and wind gust forecast SCA levels for
ocean, just wind gust forecast SCA level for non- ocean waters.
Modest S-SW flow ahead of a cold front Thursday will bring the
continuation of SCA conditions on the ocean and potentially the LI
Bays and Eastern Sound. Winds should fall below SCA levels Thursday
night behind the cold front passage, but elevated seas may linger
into the first half of the night. NW winds then pick up on Friday
with high pressure building in from the midwest.
Winds may reach marginal SCA levels.
&&
.HYDROLOGY...
No hydrologic concerns are expected through next weekend.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
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CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 9 PM EDT this evening for ANZ331-
332-335-338-340-345.
Small Craft Advisory until 6 AM EDT Tuesday for ANZ350-353-355.-- End Changed Discussion --
&&
$$
SYNOPSIS...JM/DR/DS
NEAR TERM...JM/DR
SHORT TERM...JM
LONG TERM...DS
AVIATION...MET
MARINE...JM/DS
HYDROLOGY...DS