911
FXUS61 KOKX 262001
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
401 PM EDT Mon Aug 26 2024

.SYNOPSIS...
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A trough of low pressure moves through the region into tonight.
High pressure returns Tuesday, before a warm front moves
through Wednesday, followed by a cold front Wednesday night.
High pressure returns Thursday into Friday. A warm front
approaches to begin the weekend, with a cold front likely to
follow later in the weekend.
-- End Changed Discussion --

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
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Severe Thunderstorm Watch was hoisted for the eastern half of the
region, including all of southern Connecticut and Suffolk Co on Long
Island until 7 pm this evening. Primary hazards from this activity
are large hail and damaging winds. Farther west, isolated strong to
severe thunderstorms cannot be ruled out, but weaker forcing should
limit coverage.

Upper low drops south into northern New England, allowing for a
strong shortwave with substantial PVA to traverse the area into
this evening. A surface trough of low pressure should help serve
as a focus for storms. SPC mesoanalysis at 19Z has over 1500
J/kg of MLCAPE across interior CT, and with a relatively moist
air mass for the time of year and effective shear near 30 kt,
scattered thunderstorms have been popping up as forcing with the
trough and cold pool shifts south through the region.
Convective activity has blossomed across southern New England
and has been pushing through southern CT as of this update, with
several reports of embedded severe hail in Middlesex and New
Haven counties. This will be the primary threat from storms
across CT and eastern LI, though damaging wind gusts cannot be
ruled out as well. Locally heavy downpours with any storms and a
slow moving forward motion could introduce some hydro concerns
as well, primarily nuisance flooding of urban or poor drainage
areas.

Timing of this activity looks to continue through around 00Z
and any related thunderstorm threat should largely end by 9 pm
with loss of heating and best forcing shifting south. The
convection weakens and dissipate as it tracks south and offshore
into this evening, then dry conditions can be expected
overnight. With light and variable winds, clearing skies, and
moisture laden grounds in spots, likely will see some patchy fog
development as temperatures fall back mainly into the 60s.
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&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
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Drier conditions can be expected everywhere on Tuesday and heights
climb as the trough exits offshore and ridging begins to build in
from the Midwest. Weak high pressure recenters over the Eastern US
and western Atlantic and a light southerly flow becomes established
in response. This will keep a warm, moist flow oriented toward the
region, and temperatures will continue to run several degrees above
normal for late August. Afternoon highs top out in the low to mid
80s for most, and perhaps upper 80s in urban NE NJ, with a mix of
sun and clouds. Dew pts remaining in the 60s should keep conditions
feeling a bit humid. Temperatures remain mild overnight into
Wednesday, in the 60s and low 70s.
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&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
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No significant changes in the long term, with the national
blend mostly followed for this update. A low pressure system
begins to impact the area on Wednesday with a warm frontal
passage expected to move through Wednesday morning. Depending on
how quickly skies can clear out during the day will determine
how warm temperatures are able to rise. As of now, highs are
forecast to be in the middle 80s to middle 90s. Some spots in NE
NJ and the western half of the CWA may have heat index values
rise into the upper 90s to low 100s. Additionally, showers and
thunderstorms will be possible as ample heating and moisture
will allow for the development of instability. The cold front
associated with the low pressure is poised to move through the
area Wednesday afternoon into Wednesday night.

Behind the frontal passage, high pressure builds in from the north,
allowing for a much cooler and drier airmass to move in under a
primarily NE flow. WHile some scattered showers can`t be entirely
ruled out during the end of the week with the low pressure to the
south and an approaching frontal system to the west into the
weekend, much of the area should be dry as high pressure should be
able to remain in place over the area through Friday, however, a NE
flow will keep high temperatures cooler, generally only in the
middle to upper 70s for Thursday through Saturday.

Another frontal system may move in from the west going into the
weekend which may result in some additional showers and
thunderstorms. As of now, left chance PoPs for eventual refining of
timing and coverage of any precipitation.
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&&

.AVIATION /20Z MONDAY THROUGH SATURDAY/...
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Weak low pressure moves across the area this afternoon and evening.

Mainly VFR through the TAF period. Showers and thunderstorms across
eastern CT likely shift south across eastern Long Island this
evening. A few of these storms could contain strong gusty winds and
some hail. A few showers are possible at NYC metro and Lower Hudson
Valley terminals, but confidence in thunder is too low to continue
including in the TAF.

MVFR or IFR stratus is possible tonight, mainly across SE CT.

Mainly S-SE winds into this evening under 10 kt. Some inland
terminals likely remain light and variable or light W-NW into the
evening. Winds will weaken this evening and become light and
variable overnight.

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

Thunderstorm possible this evening, but coverage and confidence too
low to include in the TAF.

OUTLOOK FOR 18Z TUESDAY THROUGH SATURDAY...

Tuesday PM: VFR.

Wednesday: Chance of MVFR or lower in afternoon/evening
showers/thunderstorms.

Thursday-Friday: Mainly VFR. Slight chance of afternoon/evening
showers/thunderstorms north and west of the NYC terminals.

Saturday: Chance of showers, possible thunderstorms and MVFR.

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

.MARINE...
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With a weak pressure gradient across the coastal waters, conditions
are expected to remain below SCA criteria through this weekend.
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&&

.HYDROLOGY...
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Thunderstorms this afternoon and evening could produce heavy
downpours that lead to flooding, particularly across southern
Connecticut or Long Island, but also possible across the entire
region. While nuisance urban and poor drainage type flooding is most
likely in areas that see flooding, isolated instances of flash
flooding cannot be ruled. Outside convective maxima where a
quick inch or two of rainfall is possible, basin average amounts
are expected to remain below a quarter of an inch through
tonight.

Additional showers and thunderstorms ahead of a cold front late
Wednesday could produce heavy rainfall that once again results in
nuisance flooding. Rainfall amounts across northern portions of the
area could average close to an inch, with locally higher amounts
possible in association with any thunderstorms.
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&&

.TIDES/COASTAL FLOODING...
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There is a low risk of rip current development along Atlantic
facing beaches on Tuesday, increasing to moderate on Wednesday
wit slightly stronger southerly flow.
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&&

.OKX WATCHES/WARNINGS/ADVISORIES...
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CT...None.
NY...Air Quality Alert until 11 PM EDT this evening for NYZ078>081-
     177-179.
NJ...None.
MARINE...None.
-- End Changed Discussion --

&&

$$

SYNOPSIS...DR
NEAR TERM...DR
SHORT TERM...DR
LONG TERM...DR/MW
AVIATION...DS
MARINE...DR
HYDROLOGY...DR
TIDES/COASTAL FLOODING...DR