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FXUS61 KOKX 170927 CCA
AFDOKX

Area Forecast Discussion...CORRECTED
National Weather Service New York NY
527 AM EDT Wed Jul 17 2019

.SYNOPSIS...
A warm front will push east of the area this morning. A cold
front and the remnant low of Barry then approach and slowly move
through the region tonight and Thursday. High pressure will then
remain centered over the Southeast into the weekend. Another weak
cold front moves slowly through the area Saturday night. A stronger
cold front approaches and moves through on Monday.

&&

.NEAR TERM /THROUGH TONIGHT/...
Upper level ridging flattens today as the remnant energy and
moisture from Barry approach the area. A sub tropical airmass
is already in place with dewpoints in the upper 60s to lower 70s
across the area in the wake of a passing warm front.

As the remnants of post T.C. Barry get caught up in the
westerlies, some enhancement to the low/mid-level flow is
expected later today. Midlevel lapse rates will be weak, but
substantial heating of a moist airmass (PW values generally
around 2 inches) will result in the development of moderate
instability. Widespread convection will develop west of the area
this afternoon, moving through the local area mainly this
evening. Latest CAMs disagree on the coverage of convection this
aftn, but are in better agreement this evening. Thunderstorm
clusters will be capable of damaging winds. Additionally, PWATS
of 2+ inches, a weakly sheared environment, an enhanced SW flow
at H85 and increased convergence along a cold front dropping
southward into the area could be enough for some training of
storms resulting in the potential for flash flooding. FFG values
across interior portions of the Lower Hud Valley and CT appear
to be too high for widespread issues, but the aforementioned
ingredients are enough to warrant an urban flash flood threat.
Have left Long Island and coastal CT out for now with guidance
indicating a weakening of the activity as the convection moves
east of NYC. Soundings are also indicating the potential for
buoyant parcels decreases after 03z or so bringing an end to
tstms. While moderate to occasionally heavy rainfall will likely
continue overnight, the flash flood threat would not be as
high, thus confidence is lower here. Day shift may have to
expand the watch if confidence increases later today.

Temperatures are tricky with partly sunny skies expected today.
However, any breaks will allow for strong heating, thus expect
highs of mid to upper 80s outside of the metro area, where lower
to mid 90s will be common. Heat index values will generally be
in the lower to mid 90s, close to 100 in the urban corridor of
NE NJ. Muggy conditions will continue tonight as lows only fall
into the 70s, and dew points remain mainly in the 70s as well.

There is a low rip current risk at the ocean beaches today.

&&

.SHORT TERM /THURSDAY/...
The remnant low of Barry is forecast to be near Montauk by 12z
Thu bringing the end of the widespread heavy rainfall potential
to an end. However, a lee trough may trigger additional sct
convection across western portions of the forecast area Thu
aftn. A weakly sheared environment will remain with the
potential for heavy downpours with PWATS remaining elevated. May
need to extend the FFA depending on how much rainfall is
received today. Abundant cloud cover will hold temps in the
upper 70s to lower 80s at most locations although it will remain
quite humid.

There is a low rip current risk at the ocean beaches for
Thursday.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Low pressure moves farther out to sea Thursday night, resulting in
diminishing rain chances during this time period. Drier weather is
expected by sunrise.

The main story in the long term then becomes the heat for Friday
through Sunday as high pressure builds southwest of the region.

As high pressure settles southwest of the region, heights aloft
build along with surface ridging. The A southwest flow will usher in
much warmer air, allowing temperatures to climb into the mid 90s for
the urban corridor of NE NJ, lower 90s for the city and Lower Hudson
Valley, and 85-90 for most of LI and CT. With dew points forecast to
be in the lower 70s, maximum heat indices will average in the upper
90s to around 100 for all but CT and most of LI.

The warmest day of the weekend will be Saturday, with highs around
100 for NE NJ, and some locations within the city, and 90s
elsewhere. Heat index values will likely reach at least advisory
levels everywhere, and a good portion of the forecast area could
potentially reach warning levels. Maximum Heat index values reach at
least 100 or more across most of the CWA, with metro NJ, approaching
HI values of 110.

A weak cold front is forecast to move through late Saturday night,
but this will do little to send any relief from the heat.
Temperatures are still forecast to reach near 100 once again for
some areas on Sunday, but for now will go with highs mostly in the
mid to upper 90s. Some areas could reach heat warning levels once
again, and most areas would probably reach advisory criteria.

A stronger cold front and wave of low pressure moves into the area
on Monday, with a chance of showers and thunderstorms. Highs on
Monday will be in the in the upper 80s to lower 90s.

Any left over precipitation should end late Monday night with drier
conditions on Tuesday. Highs on Tuesday will be a few degrees cooler
than on Monday.


&&

.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
A warm and humid airmass will remain in place today. A weak low
moves into the area late this afternoon into tonight, as a backdoor
cold front begins to move into the region toward the end of the
forecast period.

VFR until late this afternoon. Showers and scattered
thunderstorms will be developing late in the day and into the
evening with MVFR conditions, and local IFR possible.

Widespread MVFR conditions remain Wednesday night with showers
and more isolated thunderstorms. Local IFR is also possible.

Southwest wind overnight 5 to 10 kt, increase to 10 to 15 kt
this morning. Sea breezes likely this afternoon.


...NY Metro Enhanced Aviation Weather Support...

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

KJFK TAF Comments: Sea breeze development may be an hour or so
later than 15Z. Thunderstorms become likely this evening with
heavy rainfall and gusty winds.

The afternoon KJFK haze potential forecast is YELLOW, which
implies slant range visibility 4-6SM outside of cloud.

KLGA TAF Comments: The sea breeze through the airfield may be an
hour or so later than 19Z. Thunderstorms become likely this evening with
heavy rainfall and gusty winds.

The afternoon KLGA haze potential forecast is GREEN, which implies
slant range visibility P6SM outside of cloud.

KEWR TAF Comments: Gusty southwest winds at 16Z may be more
occasional Thunderstorms become likely this evening with heavy
rainfall and gusty winds.

The afternoon KEWR haze potential forecast is GREEN, which
implies slant range visibility P6SM outside of cloud.

KTEB TAF Comments: Thunderstorms become likely this evening with
heavy rainfall and gusty winds.

KHPN TAF Comments: Thunderstorms become likely this evening with
heavy rainfall and gusty winds.

KISP TAF Comments: No unscheduled amendments expected through
this afternoon. Thunderstorms become likely later this evening,
around 01Z, with heavy rainfall and gusty winds.

.OUTLOOK FOR 06Z THURSDAY THROUGH SUNDAY...
.Tonight-Thursday...Showers likely, with low potential for
thunderstorms Wednesday night into Thursday evening with
MVFR/IFR conditions possible.
.Friday through Sunday...VFR. Isolated showers and
thunderstorms will be possible Sunday.

&&

.MARINE...
A relatively weak pressure gradient will be across the forecast
waters through Monday with winds and seas remaining below SCA
levels.

&&

.HYDROLOGY...
There is the potential for moderate to heavy rainfall later
today and tonight which may produce flash flooding mainly in the
urban corridor of NE NJ and NYC this evening. FFG values are
relatively high across interior locations, however the watch may
need to be expanded to include portions of coastal CT and Long
Island later today. Rainfall totals generally between 1 and 2
inches are expected across the area, with locally higher
amounts.

Additional sct showers and tstms on Thu could also produce
heavy rainfall but there is lower confidence in a flash flood
threat at this time.

&&

.CLIMATE...
The following are records for this weekend:

Record highest minimum temperatures for Saturday, July 20:

NYC: 82 in 2015
LGA: 83 in 2015
JFK: 79 in 2015
EWR: 80 in 2015
ISP: 78 in 2013
BDR: 79 in 2013

Record high temperatures for Saturday, July 20:

NYC: 101 in 1980
LGA: 101 in 1991
JFK: 96 in 2013 (Also occurred in previous years)
EWR: 101 in 1980
ISP: 97 in 1991
BDR: 95 in 1001

Record highest minimum temperatures for Sunday, July 21:

NYC: 82 in 1980
LGA: 83 in 1980
JFK: 79 in 2017
EWR: 81 in 1980
ISP: 76 in 1980
BDR: 76 in 1994

Record high temperatures for Sunday, July 21:

NYC: 104 in 1977
LGA: 100 in 1991
JFK: 99 in 1991
EWR: 103 in 2011
ISP: 101 in 1991
BDR: 98 in 1991

&&

.EQUIPMENT...
NYC NOAA Weather Radio Station KWO35 (162.55 MHz) remains off
the air.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...Flash Flood Watch from 2 PM EDT this afternoon through late
tonight for NYZ071>075-176-178.
NJ...Flash Flood Watch from 2 PM EDT this afternoon through late
tonight for NJZ002-004-006-103>108.
MARINE...None.

&&

$$
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