000
FXUS61 KOKX 071331
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
931 AM EDT Fri Jul 7 2023
.SYNOPSIS...
A weak cold front approaches from the west today and stalls over
or near the area through the weekend. A wave of low pressure
develops along the front over the Mid Atlantic states on Sunday
and tracks across the area Sunday night into Monday. High pressure
will then build behind the system through the middle of next
week.
&&
.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
Forecast remains on track this morning. Still think any
convection will be scattered north and west of the NYC metro,
mainly across the interior Lower Hudson Valley and interior NE
NJ. Convection should be more isolated closer to the I-95
corridor in NE NJ.
Some of the latest CAMs indicate convection getting into the
interior middle to late afternoon, but the weak cold front
arrives late enough that not anticipating widespread convection.
Dynamics are weak as is the frontal forcing. A brief heavy
downpour can`t be ruled out with moderate instability and PWATs
increasing to around 2 inches. However, weak lapse rates and
wind shear suggest short-lived cells. Expect any lingering
activity to come to an end around or shorty after midnight.
It will be a bit cooler today with more of a maritime influence
as winds take on a bit more of easterly component from the SE.
However, while temperatures will be close to seasonable, high
humidity (dew points around 70) will make it feel uncomfortable
with heat indices around 90 for most locations if not a bit
higher.
Low clouds/patchy fog also possible tonight, especially eastern
LI/SE CT where the trajectory of warm, humid air traverses some
cooler waters. Lows will generally be in the upper 60s to lower
70s Saturday morning. However, metro NYC will be closer to 75.
This is about 5 degrees above normal.-- End Changed Discussion --
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
A persistence type of forecast will be on tap Saturday with
more humid weather and seasonable temperatures. Once gain,
convection will be scattered and mainly to the north and west
of the NYC metro.
It gets a lot more interesting on Sunday though as shortwave
energy at the base of a longwave trough over eastern Canada
into the Ohio Valley states approaches the area. A stalled out
boundary near western sections of the forecast area and frontal
wave development over the Mid Atlantic states will interact with
high PWAT air (around 2 inches) to produce showers and thunderstorms
across the area Sunday into Sunday night. There are discrepancies
in the placement of the highest rainfall between the global
scale models and the CAMs have not quite come into the picture
yet (minus the NamNest). The latter will have to be watched as
we move into their time range. The GFS is the most bullish with
an axis of 3 to 5 inches of rainfall from metro NY/NJ up into
eastern portions of the Lower Hudson Valley and western CT.
However, the ECMWF is much farther west (Orange County NY) with
the heaviest rainfall axis and has less rainfall. Bottom line,
PWATs near record highs interacting with a frontal boundary and
some semblance of a frontal wave/frontogenesis has to be
watched.
Using a blend of the NBM with WPC QPF yields an area of 2 inch
rainfall from NYC and points north and west. WPC has placed much
of the area under a slight risk for excessive rainfall, with the
exception of eastern LI/SE CT, which are under a marginal risk.
Sunday also looks to be cooler due to an increase in cloud cover
and increasing rain chances.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
The low pressure system and frontal system look to slowly move
out of the area on Monday. High pressure then looks to build
back in by Tuesday and into Wednesday, with a slight warming
trend toward the end of the week.
Given the pattern, high temperates will remain near or slightly
below normal for the period in the low to mid 80s.
&&
.AVIATION /13Z FRIDAY THROUGH TUESDAY/...
Weak high pressure pushes further offshore today.
Widespread low stratus over the area this morning with
widespread MVFR conditions will gradually improve to VFR through
15Z. VFR conditions are then expected during the day today with
sub-VFR conditions possibly returning after 00Z with low
stratus expected to redevelop.
KEWR may experience MVFR vsby at times today as there may be some
smoke some over part of the runway due to a nearby cargo ship fire.
It is unknown how long that smoke may last at the airport.
Light and variable winds become SE and increase to around 10kt for
the afternoon.
Chance of shra/tstm mainly NW of the city terminals late
day/evening. Best chance to see a TSRA is KSWF. Not enough
confidence in its occurrence near the city for a mention in the
TAFs at this time.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Extent of smoke in time and placement at KEWR is unknown. Amendments
possible for improving flight categories this morning due to
low stratus burning off.
OUTLOOK FOR 12Z SATURDAY THROUGH TUESDAY...
Saturday: MVFR possible early. Mainly VFR. Chance of
thunderstorms for all terminals in the afternoon into early
evening Saturday.
Sunday and Monday: MVFR possible with a chance of showers. A chance
of thunderstorms, mainly afternoon into early evening.
Tuesday: Becoming VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
Potential for areas of fog, especially for the eastern nearshore
and ocean waters in the coming nights will continue to be a
possibility. However, confidence in occurrence is not high at
this time.
Otherwise, conditions remain below SCA criteria through the
weekend with a weak pressure gradient over the area.
&&
.HYDROLOGY...
No widespread hydrologic issues are expected through Saturday.
Brief heavy downpours, mainly across western portions of the
Lower Hudson Valley, could produce localized flash flooding
late this afternoon into early this evening. The threat is
mainly confined to Orange County.
A more significant flood threat is possible Sunday into Sunday
night with the potential for the south to north training of
showers and thunderstorms along a slow moving frontal system.
Right now, then main threat for flooding appears to be from NYC
and points north and west.
&&
.TIDES/COASTAL FLOODING...
For today and Saturday, there is a low risk of rip current
development for all ocean beaches. Some guidance does show a 2
ft 9-10s SE swell moving in late today that could increase the
rip current risk to moderate, though it looks largely later on
tonight/early Saturday.
In terms of minor coastal flooding, the only threat now appears
to be localized across the south shore bays of Nassau for
tonight`s high tide cycle. No statements have been issued at
this time as confidence is low.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...DW
NEAR TERM...DS/DW
SHORT TERM...DW
LONG TERM...DBR
AVIATION...MW
MARINE...DBR/DW
HYDROLOGY...DBR/DW
TIDES/COASTAL FLOODING...