257
FXUS61 KOKX 300007
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
807 PM EDT Sat Jun 29 2024
.SYNOPSIS...
A warm front moves northeast of the region going into this
evening. A cold front approaches tonight into early Sunday and
moves across the area Sunday afternoon into Sunday night. High
pressure builds into the area from the northwest Monday through
Tuesday and pushes offshore late Tuesday into Tuesday night. A
warm front lifts north of the area on Wednesday. A cold front
approaches Wednesday night and stalls near the area through the
end of next week into the first half of next weekend.
&&
.NEAR TERM /UNTIL 8 AM SUNDAY MORNING/...
-- Changed Discussion --
Forecast is generally on track. Added a slight chance for
showers and thunderstorms a bit farther east than what was
previously in the forecast as some light showers have popped up
well ahead of the main line of showers and thunderstorms that as
of 745 pm were entering western portions of Orange County. HRRR
has this line weakening as it heads generally east of the Hudson
River, and that looks to have been the case over the past few
hours across northern CT.
Large scale numerical weather prediction models show a consensus
with mid level height falls tonight into Sunday morning. They show
highest mid level positive vorticity advection tonight with some
negative vorticity advection Sunday morning.
At the surface, a warm front will be moving farther northeast of the
region. The local region will become more within the warm sector of
low pressure system to the west.
The models indicate 0-6 km bulk shear around 30 kt tonight into
Sunday morning. Elevated instability as diagnosed from negative
Showalter Indices from the models are from near -1 to almost -4
degrees C. Some thunderstorms could be strong with potential for
gusty winds. There is a marginal risk for severe thunderstorms
north and west of NYC where shear will be relatively higher,
closer to 35 kt.
CAMs depict convection moving in this evening with much of the area
seeing convection in between 8pm this evening and 4am overnight.
PWATs increase to a little over 2 inches, generally near 2.2 to 2.3
inches. Flooding will be possible with thunderstorms but would
expect mostly localized minor flooding.
The temperatures will stay quite mild with increasing humid
conditions. Lows tonight are forecast to be mainly in the low
70s.-- End Changed Discussion --
&&
.SHORT TERM /8 AM SUNDAY MORNING THROUGH MONDAY/...
Large scale numerical weather prediction models show a consensus
with mid level height falls continuing Sunday afternoon through
Sunday night. This will be ahead of an approaching strong
shortwave from eastern part of the Great Lakes through SE Canada.
The height falls appear to occur more rapidly compared to the
previous night.
The models indicate a return of positive vorticity advection
Sunday afternoon into early Sunday evening.
At the surface, a cold front will be approaching from the west,
eventually moving Sunday afternoon and then moving west to east
across the region Sunday afternoon into Sunday evening. The cold
front passes southeast of Long Island late Sunday night.
The models show 0-6 km bulk shear increases to near 40-50 kt
and potentially above 50 kt as well. This combined with surface
instability as conveyed by CAPE values between 2000 and 4000
J/kg across the region near NYC and locations north and west.
Less CAPE to the east with more marine influence. There will be
potential for strong to severe thunderstorms with damaging winds
and large hail possible. Primary threat would be damaging
winds.
The forcing further is evident from the local region being
relatively closer to the right rear quad of an upper level jet
streak from SE to NE from New England into the Canadian
Maritimes. This will provide for greater divergence aloft.
CAMs show ongoing convection south of Long Island for early
Sunday morning in the 6am to 10am timeframe. Then, shower
activity sparse with mainly dry conditions thereafter until
around 1-2 pm. From 1-2 pm, convection starts to redevelop north
and west of the forecast and may start to move into parts of
the Lower Hudson Valley. Between 2 and 5pm, the convection
develops and solidifies into a squall line as it moves southeast
farther into the local region, reaching through Southern CT,
northeast NJ, Lower Hudson Valley, NYC into much of Long Island.
Convection expected to linger across much of the area Sunday
evening with much of the activity gradually shifting to more
eastern locations. Eastern Long Island and Southeast CT could have
some lingering showers and thunderstorms for the first half of the
overnight.
PWATs will remain a little above 2 inches Sunday into early
Sunday evening for much of the region, again near 2.2 inches.
Flooding will remain possible with thunderstorms.
Also to note, some indication with max updraft helicity across
parts of the region, mainly across interior. This signals a
potential for rotation within thunderstorms. A brief tornado
cannot be ruled out.
Regarding temperatures, this will be quite dependent on cloud
coverage. Still even with abundant cloud coverage, warm air
advection expected to have much warmer high temperatures
compared to the previous day. Forecast highs are well into the
80s for most locations with values more in the lower 80s along
much of the coastline. Some parts of NYC and northeast NJ are
forecast to reach the lower 90s. Max heat indices can be
expected to be a few degrees above the actual temperature,
keeping the forecast region below heat advisory criteria. The
highest heat indices are forecast to be mainly between 90 and 95
with some 95 to 97 degree heat indices for mainly parts of
northeast NJ.
Overnight Sunday night into early Monday, dry conditions
expected to eventually re-establish across the region from NW to
SE. Forecast lows range from the upper 50s to mid 60s.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
The cold front will continue to push offshore Monday morning as the
upper level trough over western and central portions of the
Northeast treks southeast. This will be the focus for some lingering
showers for eastern areas Monday morning and early afternoon. The
high continues to build in for Tuesday and pushes offshore late in
the day Tuesday into Tuesday night. Meanwhile, upper level ridging
over the Great Lakes noses into the Northeast. This allows a warm
front to lift north of the region sometime on Wednesday, and the
associated cold front to start moving through sometime on Thursday,
which then may stall somewhere near the area through the end of the
week.
With high pressure in place, conditions should be dry through
Wednesday as the warm front lifts north too far west to bring any
precipitation. Precipitation is expected with the approaching cold
front and chances for showers and thunderstorms look to continue
through the first half of next weekend.
As for temperatures, they are expected to be seasonable through
Wednesday. With upper level riding nosing in on Thursday, warmer
conditions are forecast, with highs in the upper 80s to lower 90s
away from the coast. Similar readings are expected through Saturday.
Humidity levels will also be on the rise. Prior to Wednesday night,
dew points will generally be in the 50s to around 60. From Wednesday
night onward, dew points rise into the 60s to around 70.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --
A warm front will continue to push NE through the terminals tonight.
A pre-frontal trough approaches tonight and settles nearby on
Sunday, followed by a cold front Sunday evening.
MVFR lowering to IFR tonight. Rain for an hour or two before
midnight, plus maybe a surviving rumble of thunder for the city
terminals as approaching convection weakens. Additional showers
overnight would be more likely for KISP and KGON, but may need to
add them for the overnight hours for at least KJFK and KBDR, and
possibly for other terminals as well. Improving back to VFR Sunday
morning, then a potential line of thunderstorms moves through in the
afternoon/evening hours.
S-SW winds 10-15 kt with gusts to 20kt early this evening. Gusts up
to 30 kt possible in/near a thunderstorm before midnight. Winds
diminish a little overnight. The winds are expected to become more
SW Sunday morning, increasing back to 10-15 kt.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
VCTS may not occur this evening. IFR start and end timing may be off
by 1-2 hours.
OUTLOOK FOR 00Z MONDAY THROUGH THURSDAY...
Sunday evening: Sub-vfr in TSRA potential early on, then VFR returns
by midnight.
Monday through Wednesday: VFR.
Thursday: Mainly VFR, with possible sub VFR later in the day and at
night in possible SHRA or TSRA.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
SCA in effect for all waters until midnight. Then SCA remains
on South Shore Bays and ocean through Sunday early evening with
other waters staying mainly below SCA criteria. The ocean has
SCA remaining through all of Sunday evening. Sub-SCA conditions
expected Sunday overnight into early Monday. In terms of
specially seas, just the ocean meets the SCA criteria through
Sunday evening with other waters staying well below SCA
thresholds for seas. Any SCAs for non-ocean waters are due to
gusty winds near 25 kt.
Winds and waves are expected to remain below SCA criteria from
Monday through Friday. However, late day winds in the NY Bight area
just E of Sandy Hook could gust close to 25 kt both Wed through Fri
afternoons.
&&
.HYDROLOGY...
Minor flooding possible with thunderstorms through tonight.
Minor flooding more probable Sunday into Sunday evening with
thunderstorms. Localized flash flooding cannot be ruled out.
Total rainfall amounts through Sunday evening between a half to
1 inch, with locally higher amounts possible.
Locally heavy rainfall may be possible Thu night into Fri with a
passing frontal system.
&&
.TIDES/COASTAL FLOODING...
-- Changed Discussion --
The rip current risk is high this afternoon and evening with
strengthening SE winds and building seas.
The high risk continues into Sunday with swells of 5-6 ft and 7
second period.
The high risk continues into Monday morning, but it looks like
most beaches will transition to moderate from late morning
onward.-- End Changed Discussion --
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...High Risk for Rip Currents through Sunday evening for NYZ075-080-
081-178-179.
NJ...None.
MARINE...Small Craft Advisory until midnight EDT tonight for ANZ331-332-
335-338-340.
Small Craft Advisory until 8 PM EDT Sunday for ANZ345.
Small Craft Advisory until midnight EDT Sunday night for
ANZ350-353-355.
&&
$$
SYNOPSIS...JM/JP
NEAR TERM...JM/JP
SHORT TERM...JM
LONG TERM...JP
AVIATION...JE
MARINE...JM/JP
HYDROLOGY...JM/JP
TIDES/COASTAL FLOODING...