000
FXUS61 KOKX 282142
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
542 PM EDT Fri Jul 28 2023
.SYNOPSIS...
High pressure over the area weakens tonight and gives way to
approaching frontal system for Saturday. A cold front moves through
the area Saturday night. High pressure slowly builds into
early-to-middle parts of next week from the west and north. A
frontal system could impact the area late next week.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
-- Changed Discussion --
Near term forecast remains on track. Temperatures and dewpoints
have been adjusted only slightly to account for the latest
observations.
Temperatures are currently in the low to middle 90s with heat index
values in the upper 90s to near 100 in locations in and around the
NYC metro. Elsewhere, widespread temperatures in the upper 80s to
near 90 are resulting in heat index values in the middle to upper
90s. Temperatures are looking to remain elevated tonight with lows
only dropping into the middle 70s for much of the area. Portions of
the NYC metro may not drop below 80 tonight.
Dry conditions are expected at least through the first half of
tonight. There is a lot of uncertainty with the development of
convection to the southwest of the area tonight and into the
overnight that may try to work its way into the western portions
of the area late tonight and into tomorrow morning. As such,
kept a slight chance of showers and thunderstorms for the area
late tonight and into early Saturday morning.-- End Changed Discussion --
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
The extent of coverage of thunderstorms around the area in the
morning depends nearly entirely on if upstream convection from over
the Ohio Valley sustains itself overnight. This will also impact
both the convection potential for the remainder of the day and how
high the temperatures rise during the afternoon. If there are more
showers and thunderstorms in the morning, increased cloud cover may
limit the rising temperatures a bit into the afternoon if skies
don`t clear out for a time. This may also result in decreased
instability for the cold front in the afternoon to spark new
convection.
As of now, the thinking is that the approaching shortwave is strong
enough to spark convection into the afternoon with a fair
amount of instability and shear in place. SPC has but much of
the area in a slight risk for severe thunderstorms, mainly
tomorrow afternoon and into the evening. The primary threat for
any storms would be damaging wind gusts, but hail and a brief
tornado can not be ruled out.
As for the heat, temperatures are expected to rise into the low to
middle 90s for much of the area again. A southerly flow ahead of the
approaching front may drive dewpoints slightly higher than they were
on Friday so heat index values of 95-100 will be once again
widespread. As such, heat advisories remain in effect for the entire
area.
The cold front moves through in the evening ushering in drier and
a more seasonable airmass Saturday night. Lows are expected to drop
into the upper 60s to low 70s.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
Through much of the long term forecast the Northeast will be under
the influence of a long-wave upper-trough. This will prevent
temperatures from warming too significantly. Highs will be in the
low-80s to upper-70s early next week. Winds will also remain from
the north through Wednesday which will help keep the humid, warmer
air away. In fact, dewpoints appear to drop into the mid, even low-
50s some days early next week, which means we will have a very dry
airmass in place. This is also helped by building surface high
pressure to the west and north. This should allow for some
radiational cooling in some interior spots and in the LI Pine
Barrens. The 12Z GFS indicates PWATs remaining under 1" Tuesday and
Wednesday, and at times nearing 0.6 or 0.55", indicating very dry
air for a few days next week. Other models concur with drier air
possible. According to SPC`s Sounding Climatology Page the Min
Moving Average for PWAT is 0.5" in early August. Mostly sunny
conditions are likely at this time with less moisture available.
Winds return from the south ahead of a frontal system associated
with an upper and surface low in Canada after Wednesday. This will
increase dewpoints and cloud cover late Wednesday into Thursday. I
have forecasted increasing shower and thunderstorm chances into the
day on Thursday, but given its at the end of the forecast period
timing and strength of the approaching frontal system may still
change until models come into better agreement on these points.
&&
.AVIATION /22Z FRIDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
A cold frontal passage occurs Sat aftn and eve.
VFR thru this eve. CIGS could develop late tngt, but bases appear to
remain VFR attm. SCT-BKN thru the day on Sat, with VFR CIGS most
likely. Shwrs and tstms likely to develop invof the front, but sct
activity cannot be completely ruled out late tonight, in the
mrng, and early aftn. For now, the best chances are with the
front, so a PROB30 was used for this in the 18-00Z time period.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
CIGS could drop to around 3000 ft aft 4Z thru the day on Sat, but
the prob is low attm. Tstms could be strong to severe in the aftn.
OUTLOOK FOR 18Z SATURDAY THROUGH WEDNESDAY...
Rest of Saturday: Tstms possible with MVFR or lower. Storms could be
strong to severe. Winds shift to the NW Sat ngt.
Sunday-Monday: Mainly VFR. Slight chance of shwrs, primarily in the
aftn.
Tuesday-Wednesday: VFR.
Detailed information. including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
-- Changed Discussion --
A Marine Weather Statement continues for Long Island Sound. The
US Coast Guard still indicates a large debris field caused by
recent flooding across New England.
Sub-SCA conditions are expected on all waters through Saturday
morning. Wind and seas may approach SCA thresholds for the
central and eastern ocean zones Saturday afternoon into the
early evening ahead of a cold frontal passage. Was not confident
enough at this time to issue a SCA but one may be needed.
Sub-SCA conditions are once again expected by Sunday and lasting
through at least the middle of next week.-- End Changed Discussion --
&&
.HYDROLOGY...
-- Changed Discussion --
Locally heavy rain which could lead to localized flash flooding
is possible with the cold frontal passage on Saturday afternoon
and evening. The area remains in a marginal risk for excessive
rainfall with the northern portions of the area, mainly southern
Connecticut and Putnam and Orange counties, in a slight risk
for excessive rainfall.
No hydrologic concerns are expected Sunday through next week.-- End Changed Discussion --
&&
.TIDES/COASTAL FLOODING...
On Saturday, with an increasing SW flow and building waves,
there is a high rip current risk for Suffolk beaches, with a
moderate risk west towards Nassau and NYC beaches. The rip
current risk remains high on Sunday for Suffolk beaches and
increases to high for Nassau beaches, remaining moderate for NYC
beaches.
&&
.CLIMATE...
Today`s (July 28) Record High Temperatures
Central Park...97 (1892, 1931, 1949, 1999)
LaGuardia......98 (1949)
JFK............98 (1949)
Newark........101 (1949)
Islip..........96 (1999)
Bridgeport.....95 (1949)
Today`s (July 28) Record High Minimum Temperatures
Central Park...80 (2020)
LaGuardia......83 (2020)
JFK............79 (2020)
Newark.........80 (2020)
Islip..........77 (2020)
Bridgeport.....77 (2020)
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CT...Heat Advisory until 8 PM EDT Saturday for CTZ005>012.
NY...Heat Advisory until 8 PM EDT Saturday for NYZ067>075-078>081-
176>179.
High Rip Current Risk from Saturday morning through Saturday
evening for NYZ080-081.
NJ...Heat Advisory until 8 PM EDT Saturday for NJZ002-004-006-
103>108.
MARINE...None.-- End Changed Discussion --
&&
$$
SYNOPSIS...BR/MW
NEAR TERM...BR/MW
SHORT TERM...MW
LONG TERM...BR
AVIATION...JMC/DW
MARINE...BR/MW
HYDROLOGY...BR/MW
TIDES/COASTAL FLOODING...
CLIMATE...