000
FXUS61 KOKX 092039
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
439 PM EDT Sun Jul 9 2023
.SYNOPSIS...
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A wave of low pressure slowly moves into the region tonight
into Monday and then will slowly move northeast of the area
going into Monday night. For Monday night, weak high pressure
will gradually build in from the south and west. The center of
high pressure moves across Tuesday night into Wednesday then
offshore for the end of the week. This will give way to the next
frontal system and wave of low pressure.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
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The flood watch has been expanded to include all of Long Island
from 8PM tonight until 2PM Monday. The flood watch remains in
effect for Northeast NJ, NYC, and the Lower Hudson Valley until
6AM Monday. The flood watch remains in effect for Southern CT
from 8PM tonight until 2PM Monday.
Forecast guidance shifted east with heavy rain.
Numerous showers and thunderstorms have developed across
interior Northeast NJ and the Lower Hudson Valley. The MCS
structure appears to be a broken line with trailing stratiform.
There has been merging and coalescence of thunderstorms to
produce larger areas of heavy rain. Looking farther back, the
line extends farther southwest through SE Pennsylvania and into
Maryland.
So far, the Lower Hudson Valley has received the most rainfall
thus far with 1 to 3 inches in different locations with some
localized higher amounts. There has already been reports of
flooding within this location.
The farther southwest section of the line is set to make its
way into Northeast NJ and into NYC this evening. For Lower
Hudson Valley, the showers and thunderstorms will continue into
this evening. For Long Island and Southern Connecticut, the line
is forecast to break apart partially but with another area of
showers and thunderstorms approaching from the south late this
evening. Further convective development is expected over parts
of the Lower Hudson Valley, parts of NYC, Southern Connecticut,
and Long Island overnight.
The forcing is positive vorticity advection from two shortwaves,
one moving across this evening and a stronger one approaching
overnight. This will be during a time when the precipitable
waters across the region remain near 2 inches.
Forecast lows in the upper 60s to lower 70s.-- End Changed Discussion --
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
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Showers and thunderstorms continue but to start will be mainly
east of NYC, Northeast NJ, and Lower Hudson Valley. The CAMs
have the convection pushing east of Long Island and Southern CT
late in the morning. More pop-up shower and thunderstorm
activity remain in the forecast, most likely across eastern
sections for the afternoon.
The maximum precipitable waters shifts east of the area Monday
Monday afternoon into Monday night. The cold pool aloft with the
upper level trough axis moving into the region Monday afternoon
into early Monday night.
Forecast highs in the upper 70s to lower 80s.-- End Changed Discussion --
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
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The upper low and trough move east of the region Monday night.
At the surface, low pressure is slow to move east of the area.
There still remain a bit of uncertainty with just how quickly
conditions clear out. Will maintain at least some chance POPs
early Monday night and they will gradually taper off after
midnight from west to east.
Any leftover showers across the far eastern sections of the CWA
come to an end early Tuesday morning. Then, we should get into
drier period of weather as high pressure builds over the area.
The next wave of low pressure along with a cold front will
approach Thursday and continue into the weekend. Chances for
showers and thunderstorms return to the forecast.
Temperatures will remain at or slightly above through the long
term. The warmest two days in the long term will be Wednesday
and Thursday with forecast highs in the upper 80s to lower 90s.
Heat index values remain below heat advisory criteria.-- End Changed Discussion --
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
A slow-moving frontal system will approach from the west today
and move across the area tonight into Monday.
VFR to MVFR cigs expected through much of the TAF period. Showers
and thunderstorms have already developed west of the NYC
terminals and are expected to move eastward impacting the
terminals later this afternoon, evening and the first part of
tonight. A second round of showers and thunderstorms are
expected early Monday morning mainly from about 08z-12z,
slightly later further east. This second batch of precipitation
is associated with the front itself. Once that area moves east
of the area, winds will turn and improvement back to VFR is
expected.
Winds will be mainly S-SE near 5-10 kt through tonight. Then
winds become more north/northwesterly behind the cold front.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Amendments likely for changing flight categories. Low
confidence of when any changes occur with storms.
Any thunderstorms may be capable of producing strong gusty
winds.
OUTLOOK FOR 18Z MONDAY THROUGH FRIDAY...
Monday: MVFR or lower possible at times. A chance of
thunderstorms late in the afternoon and evening.
Tuesday and Wednesday: Mainly VFR.
Thursday and Friday. MVFR or lower possible with a chance of
showers and thunderstorms, mainly afternoon into night.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
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The short term forecast period through Monday will remain below
SCA thresholds for all forecast waters with a relatively weak
pressure gradient in place.
Much of the long term period will remain below SCA conditions on all
waters. For Thursday late afternoon into early Friday morning, winds
and seas increase with marginal SCA conditions across the ocean.-- End Changed Discussion --
&&
.HYDROLOGY...
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Already have had 2 to 4 inches of rain with locally higher
amounts in parts of the Lower Hudson Valley.
Total additional rainfall forecast of 2 to 3 inches across
parts of Northeast NJ, Lower Hudson Valley and Southwest
Connecticut is forecast through Monday night with around 1 to
1.5 inches for much of the remainder of the forecast area to the
southeast. There will likely be localized higher amounts. For
the Lower Hudson Valley, and Northeast NJ, the bulk of this rain
will be through tonight. For Southern Connecticut and Long
Island the bulk of the rain will be late this evening through
Monday morning.
Flood chances are highest through tonight for Lower Hudson
Valley, Northeast NJ, and NYC and flood chances are highest
this evening through Monday morning for Southern Connecticut and
Long Island.
Some rivers and streams may remain elevated and near bankfull
Monday after the rainfall has ended.
WPC has moderate excessive rain across Northeast NJ, Lower
Hudson Valley, Southwest CT and Nassau NY through tonight and a
slight risk for excessive rain for much of Southern CT and Twin
Forks of Long Island a marginal risk elsewhere for Monday into
early Monday night.
Otherwise, no significant widespread rainfall expected Tuesday
onward.-- End Changed Discussion --
&&
.TIDES/COASTAL FLOODING...
There is a low risk of rip current development for all ocean
beaches thru Mon.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Flood Watch from 8 PM EDT this evening through Monday
afternoon for CTZ005>012.
NY...Flood Watch from 8 PM EDT this evening through Monday
afternoon for NYZ078>081-177-179.
Flood Watch through late tonight for NYZ067>075-176-178.
NJ...Flood Watch through late tonight for NJZ002-004-006-103>108.
MARINE...None.
&&
$$
SYNOPSIS...BC/JM
NEAR TERM...JM
SHORT TERM...JM
LONG TERM...BC
AVIATION...BC
MARINE...BC/JM
HYDROLOGY...BC/JM
TIDES/COASTAL FLOODING...