981
FXUS61 KOKX 171821
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
221 PM EDT Wed Jul 17 2024
.SYNOPSIS...
A pre-frontal trough will linger nearby today, followed by a
cold front pushing through late tonight into Thursday morning.
The front slows down and lingers just offshore Thursday as high
pressure slowly builds and settles in on Friday. The high will
remain in control through the weekend, with a weak cold frontal
passage possible late Sunday into Monday. A warm front will move
through early next week.
&&
.NEAR TERM /THROUGH TONIGHT/...
A severe thunderstorm watch is now in effect for the entire
area, including the marine zones, until 800 PM EDT.
One more hot and very humid day on tap across the region. The
main question is how much cloud cover there will be for the
morning and early afternoon. However, this may not be as much of
a factor as it typically is with regard to the severe weather
risk for very late in the afternoon and evening. With the air
mass so anomalously humid, any breaks of sun will be enough with
forcing beginning to increase late in the day and evening. The
limiting factors regarding a widespread severe weather threat
are marginal mid level lapse rates with some warmer air aloft,
and marginal bulk shear. Guidance is suggestive of 0-6 km shear
values of 30, to perhaps 35 kt. Broken line and multi-cell
clusters are the primary expected storm modes. Although a
marginal supercell cannot be ruled out. The main hazard with any
storm will be strong to damaging wind gusts. The Storm
Prediction Center continues with a Slight risk for a good
portion of the area, with only the eastern 3rd of the region
(Central and Eastern LI and Eastern CT) under a marginal risk of
severe weather. There should be no shortage of instability with
MLCAPE values likely to range from 1500 to 2000 j/kg, DCAPE
values of 800 to 1000 j/kg, and LI values of -5 to 8. With
respect to timing, convective allowing models are alluding to
20-21z for convective initiation for western sections to as late
as 0-2z for eastern most sections.
Heat headlines continue for one last day. With dew points mainly in
the lower half of the 70s, and max temperatures expected to reach
close to 90 for CT and Central and Western LI, and lower and middle
90s across the NYC metro, NE NJ and far southern portions of the
Hudson Valley. This should correlate to heat index values of 95 to
100, with some 100 to 105 values across metro NE NJ. These values
could end up slightly lower with enough cloud cover. Overall the
expectation is that skies will average out the be partly cloudy for
the late morning and early afternoon.
The front is expected to slow some and gradually push east tonight.
Once the environment gets worked over and severe convection should
cease with leftover showers and any convection gets stratified. It
will remain muggy overnight with lows in the upper 60s to lower and
middle 70s.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
The real air mass change takes shape during the day Thursday. The
front slowly gets further east across the area, and eventually
offshore for the afternoon. Dew point readings will slowly get into
and fall through the 60s. So still humid, but nearly as oppressive
and muggy. Some clouds will linger, especially further east
throughout the morning. More sun moves through from the later
morning and early afternoon from west to east. Some high clouds will
linger into the afternoon, however skies should average out to be
mostly sunny for the second half of the day on a NW to W flow.
Temperatures will be more seasonable, with daytime maxes in the
middle and upper 80s marking the end of the heat wave.
Clear skies are expected Thursday night with more comfortable
conditions. Dew point readings will get into the more comfortable 55
to 60 range. Most minimum temperatures will be in the 60s.
During Friday look for a good deal of sunshine with high pressure
beginning to settle into the western part of the area. Another
seasonably warm day with mostly middle and upper 80s expected with
light winds due to a weak synoptic pressure gradient.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
High pressure settles over the region this weekend with a frontal
boundary remaining south of the region. Temperatures this weekend
will remain in the middle to upper 80s and lower 90s.
Late Sunday into Monday an approaching weakening cold front may pass
through the area, but will likely not result in anything other than
an isolated shower. At the same time, the aforementioned front
stalled offshore will start to make it`s way back north. This front
will return unsettled weather to the area with chances of
showers/thunderstorms Monday night through Wednesday.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
-- Changed Discussion --
A pre-frontal trough will linger nearby today, followed by a
cold frontal passage late tonight into Thursday morning. The
front will slow down and linger just offshore for daytime
Thursday.
Severe thunderstorm watch now in effect until 8 PM. Storms
already approaching KSWF and over ern PA and NW NJ will also
approach the metro area late this afternoon, with initial
timing 21Z-22Z at the metros and KBDR, 23Z KISP, and 00Z KGON.
TEMPO for most sites now includes strong winds and IFR vsby for
a couple of hours. Mention of tstms for the metros runs into the
evening as there could be a second round from about 00Z-03Z.
Showers with MVFR cond could follow until cold fropa late
tonight, then VFR expected for the AM push.
Wind prior to tstm arrival should be mostly S around 10 kt,
though latest obs do show winds backed to the SE at some of the
metros. Winds following tstms are uncertain and could be erratic
for a few hrs, then settle in on a NW flow just under 10 kt for
the AM push.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Confidence medium to high on tstm timing...AMD possible if fine
tuning is needed. Confidence low on winds and MVFR flight cat
following tstms overnight.
OUTLOOK FOR 18Z THURSDAY THROUGH MONDAY...
VFR.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
A severe thunderstorm watch is in effect for all the marine
forecast zones until 800 PM EDT.
Small craft conditions will become more widespread over the
ocean waters towards this afternoon and this evening, and
continuing for the western ocean through the first half of
Thursday, and lasting through Thursday afternoon for the more
eastern ocean waters. Sub small craft conditions then return to
the ocean Thursday night into Friday as ocean seas settle closer
to 3 ft.
Sub small craft conditions are expected to persist throughout the
weekend and into early next week.
&&
.HYDROLOGY...
Any strong thunderstorms for late today through this evening are
capable of producing localized heavy rain resulting in a limited
risk of flash flooding, mainly of the localized urban and poor
drainage variety in any stronger storms. The Weather Prediction
Center has placed the area in a marginal risk of excessive rainfall
for today and early tonight.
No hydrologic impacts are anticipated Thursday through the upcoming
weekend.
&&
.TIDES/COASTAL FLOODING...
A high risk of rip currents will remain through Thursday with
seas remaining elevated on a SE swell of up to 8 seconds.
&&
.CLIMATE...
Daily record high minimum temperatures for the next couple of
days:
...WED JUL 17...
Newark: 80/1968
Bridgeport: 77/1968
Central Park: 82/1870
LaGuardia: 79/1999
Kennedy: 79/2013*
Islip: 75/2021*
* = also in previous years
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Air Quality Alert until 11 PM EDT this evening for CTZ005-006-
009-010.
Heat Advisory until 8 PM EDT this evening for CTZ005>011.
NY...Air Quality Alert until 11 PM EDT this evening for NYZ067>075-
176-178.
Heat Advisory until 8 PM EDT this evening for NYZ067>075-
078>080-176>179.
High Risk for Rip Currents until 8 PM EDT this evening for NYZ075-
080-081-178-179.
NJ...Air Quality Alert until 11 PM EDT this evening for NJZ002-004-
006-103>108.
Heat Advisory until 8 PM EDT this evening for NJZ002-004-006-
103>108.
MARINE...Small Craft Advisory until 6 PM EDT Thursday for ANZ350.
Small Craft Advisory until 6 PM EDT Thursday for ANZ353.
Small Craft Advisory until noon EDT Thursday for ANZ355.
&&
$$
SYNOPSIS...BC/JE
NEAR TERM...JE/MET
SHORT TERM...JE
LONG TERM...BC
AVIATION...BG
MARINE...BC/JE/MET
HYDROLOGY...BC/JE
TIDES/COASTAL FLOODING...
CLIMATE...