AFDOKX

Area Forecast Discussion
National Weather Service New York NY
503 AM EDT Mon Jul 8 2024

.SYNOPSIS...
A weak frontal boundary or surface trough will remain in close 
proximity to the area through Wednesday. A low pressure system 
approaches for Thursday with an associated cold front. This system
and its cold front are expected to slow down and weaken as they 
continue to approach through Thursday night. The frontal boundary 
becomes nearly stationary within or near the region going into 
Saturday before dissipating Sunday.

&&

.NEAR TERM /THROUGH TONIGHT/...
High pressure nosing in from the NW across NY state and into 
the forecast area this morning has allowed for a light northerly
flow. In return, the fog has not been as widespread across 
eastern LI and coastal CT and has been varying quite a bit. Any 
of this fog should quickly mix out after daybreak, with the 
possible exception of locations along the immediate coast. Low 
clouds/fog should generally park offshore during the daytime 
hours before making a return visit later tonight. A weak frontal
boundary and/or surface trough that has pushed south of the 
area this morning will return to the north or simply jump back 
into the thermal trough that sets up. A weak onshore flow 
develops by this afternoon. A few of the CAMs are hinting at a 
pop shower and or thunderstorm today north and west of NYC. 
Warming mid levels and still relatively dry air in the low 
levels will keep the area generally capped. 

More importantly though, it will remain very warm and humid 
through the middle of the week. Upper air pattern reflects a 
longwave trough centered over the midsection of the country and 
a strengthening subtropical ridge over the western Atlantic. 
Daytime highs will get into the lower 90s across portions of the
NYC/NJ metro and the interior, with the mid and upper 80s most 
other locations. The immediate south shore of LI will be cooler.
This results in widespread 95 to 100 heat indices today across 
much of the area except for coastal SE CT and eastern and 
southern portions of LI. This will also continue into Tuesday 
with values even a bit higher across NYC, NE NJ, and the Lower 
Hudson Valley. Thus, a Heat Advisory remains in effect through 
Tuesday. 

Lows by daybreak Tuesday will be in the low to mid 70s with dew
points nearly the same.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
Continued very warm and humid Tuesday with heat indices of 95 
to 100 and even a bit higher across portions of NE NJ and the 
Lower Hudson Valley. In additions, there is a good chance that 
head advisories will need to be extended into Wednesday for 
portions of the area. However, convective debris and a 
strengthening onshore flow presents some uncertainties at this 
time.

Airmass gradually destabilizes during this time with deepening 
low-level moisture. Warm heights still persist during this time 
but chances of breaking the cap increase. Any convection 
Tuesday afternoon/evening will be mainly north and west of NYC.
For Tuesday night, the coverage expands a bit with some warm 
advection, but chances remain low. Any convection will be 
capable of producing downpours with PWAT values increasing to 
above 2 inches as we get into Wednesday. This combined with a 
weak steering flow raises the potential for training of cells 
from SW to NE. In addition, with a weak shear, moderate to high 
CAPE environment north and west of NYC, pulse severe storms will
become possible. Once gain, most of the activity will be limited
to areas of the Lower Hudson Valley and interior NE NJ. However,
this is likely to expand east in the long term period.

Coastal low clouds and fog will also remain an issue, 
especially across coastal SE CT and eastern LI with very high 
dew point air traversing the cooler nearshore waters.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Wednesday night into Thursday we'll be warm sectored as a warm front 
passes to northward. The remnant low of Beryl will get absorbed into 
a trough over the Great Lakes Thursday into Friday, and continue to 
weaken into Saturday into Canada. The low will bring a cold front 
towards us on Friday, then stall and linger before dissipating on 
Sunday. However, a surface trough may remain into Monday. 

As the remnant low of Beryl passes into the Great Lakes Thursday 
into Friday, enhanced tropical moisture be advected into the area by 
a LLJ that develops as a result of the pressure difference with the 
remnant low to our west and a strong subtropical ridge to our east. 
This moisture will linger over the area Thursday into Friday, before 
the cold front arrives later on Friday lowering the PWATs to less 
anomalous values. A vast majority of the 00Z GFS, ECMWF, and CMC 
ensembles agree on very high maximum PWATs of 2.3-2.5" over the area 
on Thursday and Friday. While too far out to pinpoint any flooding 
concerns with much detail, since models still vary on timing and 
coverage, it is possible we could see occasional downpours in some 
showers and thunderstorms that come from this. However, the brunt of 
the heavy rainfall looks like it may occur much farther inland to 
our west and north. 00Z model sounds are showing weak LCL-EL (Cloudy 
Layer) winds and tall, skinny CAPE profiles with above average 
PWATS. They also show weak Corfidi Upshear, indicating 
backbuilding/training of showers and storms, despite strong Corfidi 
Downshear values, which indicates the forward propagation of storms. 

A 30-40 kt LLJ has been resolved by model 00Z global guidance over 
our area Thursday into early Friday which, aside from helping advect 
in more moisture, will also lead to breezy conditions. Currently 
forecasting wind gusts 25-30 mph Thursday into early Friday.

Overall, its looking very muggy late this week into this weekend 
thanks to warm temperatures and high dewpoints. 

Aside from Thursday and Friday, rain chances will continue into 
weekend thanks to a lingering frontal boundary on Saturday. While it 
should dissipate on Sunday, a lingering surface trough could lead to 
continue isolated chances of rain on Sunday, before a hint of a 
drier pattern on Monday. 


&&

.AVIATION /08Z MONDAY THROUGH FRIDAY/...
A frontal system remains stalled nearby through Monday.

VFR for terminals north & west of NYC this morning. KJFK, KLGA,
and KBDR may touch IFR through the morning, at times. LIFR is
possible, but uncertain at KJFK and KBDR. KISP is at LIFR as of
6Z and could switch between IFR to LIFR through 12Z. KGON is
likely to stay LIFR through 12Z.

After 12, VFR expected. Possibly back to IFR/LIFR conditions in
the same areas Monday night/Tuesday morning.

Light and variable winds this morning. A light NE flow may 
develop after 12z before shifting to the S-SE 5-10 kt late 
morning into the afternoon with a light sea breeze. Most go
variable or settle with light S winds Monday night/Tuesday 
morning.

 ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... 

Flight category amendments may be needed to KJFK and KLGA 
through 12Z giving uncertainty in the westward development of 
IFR/LIFR conditions. 

Timing of S-SE winds Monday may be off by 1-2 hours. 

OUTLOOK FOR 06Z TUESDAY THROUGH FRIDAY...

Tuesday morning: VFR.

Tuesday afternoon through Friday: MVFR or IFR possible at times
with periods of showers/thunderstorms.

Detailed information, including hourly TAF wind component forecasts, 
can be found at: https:/www.weather.gov/zny/n90

&&

.MARINE...
A Dense Fog Advisory is in effect for the LI Sound east of the 
CT River and for all ocean waters. The advisory expiration 
varies from late morning to early afternoon and could very well
be extended for some portions. Episodes of fog and low clouds 
will likely remain an issue through the week due to high dew 
point air moving over the cooler waters. 

With a relatively weak pressure gradient in place, conditions 
on the waters are otherwise expected to be below small craft 
advisory thresholds through Tuesday. A strengthening southerly
flow on Wednesday could bring marginal SCA conditions, 
especially for the waters west of Fire Island Inlet. 

For Thursday through Friday night, another low pressure system and 
associated cold front approach but are expected to weaken. An 
initial increase in the pressure gradient Thursday into early 
Thursday night will weaken Friday through Friday night.

Possible SCA ocean seas Thursday with higher chances for SCA ocean 
seas Thursday night through Friday night. Non-ocean waters stay 
below SCA thresholds for seas and wave heights. For wind gusts, 
possible SCA level wind gusts Thursday into Thursday night for ocean 
waters and South Shore Bays.

So, SCA potential for ocean Thursday through Friday night. SCA 
potential for South Shore Bays Thursday into Thursday night. 
Otherwise, other waters are forecast to remain below SCA thresholds.

Below SCA waves and winds are expected this weekend. 


&&

.HYDROLOGY...
There are no hydrologic concerns through Tuesday morning. Thereafter,
moisture increases along a stalled boundary and/or surface
trough nearby Tuesday afternoon, and even more so later in the 
week with the approach of another frontal boundary. This will 
bring a chance of minor/poor drainage flooding as well as 
potential localized flash flooding Tuesday afternoon/evening to 
the north and west of NYC.

Extended period with 2+ inch PWATS Wednesday night through Friday 
and perhaps even through Friday night. Highest forecast PWATS 
Thursday into Thursday night with potentially up to 2.5 inches. Any 
thunderstorms Wednesday night through Friday will be capable of 
producing heavy rain. There will be chances for minor flooding and 
low probability, marginal risk, for localized flash flooding.

&&

.TIDES/COASTAL FLOODING...
There is a low rip current risk today with light winds and seas
2 to 3 ft. There is a moderate rip current risk on Tuesday as 
southerly winds increase and seas may build a bit compared to 
Monday.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Heat Advisory from noon today to 8 PM EDT Tuesday for 
     CTZ005>010.
NY...Heat Advisory from noon today to 8 PM EDT Tuesday for 
     NYZ067>075-078-176>178.
NJ...Heat Advisory from noon today to 8 PM EDT Tuesday for NJZ002-
     004-006-103>108.
MARINE...Dense Fog Advisory until noon EDT today for ANZ332-350-353.
     Dense Fog Advisory until 10 AM EDT this morning for ANZ355.

&&

$$

SYNOPSIS...BR/DW
NEAR TERM...DW
SHORT TERM...DW
LONG TERM...BR
AVIATION...BR
MARINE...BR/DW
HYDROLOGY...BR/DW
TIDES/COASTAL FLOODING...