000
FXUS61 KOKX 021813
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
213 PM EDT Sun Jul 2 2023
.SYNOPSIS...
A warm frontal passage today will result in unsettled weather. A
cool front will then pass or dissipate over the area on Monday.
Weak high pressure will then build in for the middle of the
week. Another frontal system may impact the area late in the
week into next weekend.
&&
.NEAR TERM /THROUGH TONIGHT/...
There has not been much change to the forecast reasoning this
afternoon. The early morning showers have largely moved out of
the region except for a few lingering across parts of northern
New Haven county in CT. The warm front was analyzed across
southern CT at this hour, and 70s dewpoints have begun to
overspread now into southern CT. Low clouds have given way to a
widespread cu field and the additional insolation is allowing
for some marginal destabilization across NJ NYC and Long Island.
NYS mesonet profilers are showing some erosion of CIN and a bit
of an increase in CAPE this hour with a few hundred J/kg noted
across a few of the sites. Back to the west, as as a weak
shortwave approaches the threat for shower and thunderstorm
development will increase by mid to late afternoon, with the
largest threat continuing to be gusty winds and locally heavy
rainfall. This is supported by the KOKX 12Z RAOB which depicts a
PWAT over 2".
After the aftn/eve activity, another round of development is
possible overnight as dpva with the approaching upr trof
provides a trigger. This is perhaps the lowest confidence pcpn
fcst in the near term as previous convection will have an
impact on the environment and the airmass may be too worked
over. On the other hand, activity could be stronger if aftn/eve
tstms don`t materialize.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
H5 low approached Montreal Mon mrng, with the associated upr
trof om the doorstep of the cwa. Llvl flow veers swly, allowing
the area to heat up. Went abv the NBM based on the flow and the
mid lvl heat ridge over the area. Although the models may be
having a difficult time with initiation, it seems the pattern
should be conducive to aftn and eve tstms. The limiting factor
in the models right now is some weak shrtwv ridging at peak
heating. Have continued with the blended approach and gone with
NBM pops. 0-6km bulk shear increases to 20-30, not huge but
enough to yield a BRN blw the multicellular lvl at times.
The weak sfc front/trof comes thru Mon ngt. Still some chances
for shwrs and tstms Mon ngt, but lesser intensity likely attm.
The front does not have much of an airmass change, and it should
be hot again on the 4th. With relatively low heights and an
unstable airmass, tstms possible in the aftn and eve. Went with
isold coverage in the fcst for now, although coverage may be
closer to sct, especially across the interior, if the scenario
holds.
Went with the MEX for temps on the 4th.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
For the mid week period, mid level ridging and 85h temps around
18C, will result in surface temps 5-8 degrees above normal.
This places much of the area, with the exception of the
immediate south shore of LI and the twin forks well into the 80s
and likely around 90 for NYC metro and points north and west.
Airmass looks to dry out enough with a W/SW flow to keep heat
indices close to the ambient temperature. So at this time, the
threat for heat advisory criteria is low. However, the NBM box
ands whisker plots shows the median temps several degrees warmer
than the deterministic. In some cases, the deterministic is
below the 25th percentile. Thus, the potential is there for
higher temperatures.
For the end of the week, heights fall with the approach of
another upper trough. Temperatures will be cooler in the 80s,
largely due to an increase in cloud cover and chances for
convection and onshore flow.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
-- Changed Discussion --
A warm front has lifted north of the forecast area. A cold front
slowly approaches from the west on Monday.
Outside of some widely scattered showers this afternoon,
conditions should be mainly VFR until later this evening, when
an area of showers and thunderstorms are expected to move
through the terminals. MVFR to IFR conditions are expected with
these. They will be associated with heavy rain and gusty winds.
For now, limited gusts to 30 kt, though if the storms become
strong to severe, winds of 40-50+ kt are possible for a brief
time. The timing of these showers and thunderstorms is later
than previous forecasts, and now think that they will move
through the metro terminals from 23Z-03Z this evening. This of
course may be off by +/- an hour or two.
Thereafter, MVFR conditions likely persist through the night,
with a return to VFR by 12Z Monday. More showers are possible
around daybreak, but no restrictions to visibility or ceilings
are expected. Outlying terminals may drop to IFR, especially for
eastern terminals.
Winds are pretty consistent during the TAF period, with a S-SW
flow near 5-10 kt for much of the TAF period. There could be a
few gusts 15-20 kt this afternoon.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
There is uncertainty concerning the timing of categorical
changes as well as thunderstorms during the TAF period. Timing
of the categorical changes and thunderstorms could be +/- an our
or two off from indicated in TAF.
There is additional uncertainty on MVFR conditions overnight
tonight in regards to timing and how low conditions become.
OUTLOOK FOR 18Z MONDAY THROUGH THURSDAY...
Sunday night: MVFR to IFR with periods of showers and
thunderstorms. A few S gusts 15-20 kt early.
Monday: MVFR or lower at times day into early evening with chances
of showers and thunderstorms, showers and thunderstorms likely north
and west of NYC terminals afternoon into early evening. Showers
and thunderstorms taper off later in evening with VFR
returning. Some SW wind gusts 15-20 kt afternoon into early
evening.
Tuesday: Mainly VFR. Slight chance of showers and thunderstorms with
MVFR or lower possible day into early evening north and west of NYC
terminals.
Wednesday: Mainly VFR.
Thursday: Mainly VFR. Slight chance of showers and thunderstorms
with MVFR or lower possible afternoon into evening near NYC
terminals and to the north and west of NYC terminals.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
Winds and seas are expected to generally be below SCA levels
through the upcoming week. Waves on the eastern ocean zone may
approach 5 ft tonight into early Tue with a southerly flow
building seas.
&&
.HYDROLOGY...
There is a chance for areas of minor flooding this aftn and eve
with tstms developing across the area. There is a low flash
flood risk, with areas from nern NJ to the Hudson Valley most
prone.
Some localized minor flooding will be possible on Mon if tstms
develop across the area.
No hydrologic issues are expected thereafter attm.
&&
.TIDES/COASTAL FLOODING...
A moderate risk of rip currents is expected through Mon,
although there is the potential rips could reach high on Mon,
particularly ern beaches.
Astronomical tides continue to increase with the approach of a full
moon on Monday. Minor coastal flooding looks likely for tonight`s
high tide cycle, resulting in a coastal flood advisory for southern
Queens and Southern Nassau counties. Meanwhile, a statement has been
issued for southern Fairfield in CT as a few locations may just
touch minor thresholds.
Another round of minor coastal flooding is expected for the Monday
night high tide.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...Coastal Flood Advisory from 7 PM to 10 PM EDT this evening for
NYZ178-179.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...JMC/DW
NEAR TERM...JMC/DBR
SHORT TERM...JMC
LONG TERM...DW
AVIATION...JP
MARINE...JMC/DW
HYDROLOGY...JMC/DW
TIDES/COASTAL FLOODING...