000
FXUS61 KOKX 231747
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
147 PM EDT Sun Apr 23 2023
.SYNOPSIS...
A cold front and associated wave of low pressure will move
through today. This low will move east of New England tonight
while a secondary cold frontal passage takes place. The weak low
will meander east of New England into mid week as high pressure
slowly approaches. Then low pressure will pass offshore on
Thursday, followed by high pressure passing to the north on
Friday. Another low could approach on Saturday.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Rain showers continue to advect broadly east per latest KOKX
returns across SE CT and the twin forks of Long Island. Surface
low located offshore SW of KISP was also heading slowly east-
northeast with clearing noted from western Nassau County on
west. With westerly flow and clearing behind the low,
temperatures have risen into the lower 60s, but remain in the
50s where cloud cover remains slower to move out.
Later this afternoon, a potent mid level shortwave trough and
secondary cold front will pass through the region. Shower and
perhaps an isolated thunderstorm are again possible for mainly
areas north and west of NYC through early evening. At this
time, do not expect coverage of precipitation to be widespread,
and any activity should weaken with the loss of daytime heating.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
All in all a drier/cooler air mass will take hold during this
time, with lows in the 40s tonight, then temps rising to the
upper 50s/lower 60s both Mon/Tue. A few showers are possible
mainly inland with the passage of another mid level shortwave
trough Mon afternoon, and even cooler air will follow for Mon
night, with lows in the mid 40s in NYC, lower 40s most elsewhere
closer to the coast, and 35-40 inland with some frost.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
A mid level low hovering in Southeast Canada will result in a
quasi zonal mid level flow across the region through much of
the week. More of a ridging pattern shown by forecast models for
Friday next week in the mid levels but potential for the ridge
to breakdown with trough development to the south and west for
next Saturday.
At the surface, low pressure slowly moves farther north and east
of the area early into midweek. Meanwhile, high pressure will
slowly approach but its center will stay to the south and west.
The pressure gradient will be not be that tight without much
change in the center magnitude of the high and low pressure
areas so both the high and low will not be that strong.
High pressure will weaken across the local area with low
pressure that is forecast to pass well south and east of the
area Thursday into Thursday night.
High pressure stays north of the region Friday with low pressure
possibly impacting the area from the south going into the start
of next weekend.
Weather conditions are forecast to be mainly dry but there could
be an isolated rain shower from time to time, mainly daytime
into evening, in response to periodic shortwave positive
vorticity advection early into midweek. The forcing towards late
week will be with one low pressure passing offshore and with
another low at the surface approaching towards next weekend. By
next weekend, the synoptic flow becomes more southerly ahead of
a larger trough.
The forecast has higher chances of rain showers Thursday into
Thursday early evening and Friday afternoon into Friday early
evening as well as next Saturday.
There is a lot of model uncertainty, including significant
differences between yesterday`s 12Z ECMWF deterministic and its
previous cycle with regards to the MSLP field for late next
week.
Temperatures in the long term forecast do not exhibit much
deviation from normal values. Air mass appears to transition
from more of a continental airmass early in the week to more
of a maritime one from mid to late week. This will be as low
level winds transition from more westerly early in the week to
more easterly thereafter.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
-- Changed Discussion --
Shower activity is gradually ending from southwest to northeast
across the region this afternoon as a wave of low pressure and
cold front advance northeast.
Cigs/vsbys improve to VFR behind the showers, and have already
seen this improvement at city terminals.
Winds have shifted to the NW or WNW behind the low, with the
exception of KGON, where SE flow continues for several more
hours until the front moves through. This flow then continues
through tonight, backing a bit to the W or SW Monday afternoon.
Speeds largely 10-15 kt, with a few gusts up to 20 kt this
afternoon, and around 10 kt on Monday. A few widely scattered
showers are possible Monday afternoon, with highest chances
across the interior, particularly KSWF, though cannot be ruled
out elsewhere.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Timing of category improvement may be off by an hour or two
early this afternoon.
Gusts may be more occasional this afternoon and early evening.
OUTLOOK FOR 18Z MONDAY THROUGH FRIDAY...
Monday Aft/Eve: VFR. W wind around 10 kt.
Tuesday through Friday: VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
SCA conds expand to all ocean waters today with seas building as
high as 6-8 ft S of Montauk and 5-6 ft west of there. SCA also
continues into early afternoon for the easternmost Sound with
SE flow gusting up to 25 kt at least until cold fropa.
Hazardous ocean seas should linger into tonight, possibly into
daytime Mon E of Moriches Inlet.
&&
.HYDROLOGY...
Have already seen max rainfall amts 2-3 inches in spots,
especially in New Haven County CT, and also along or just west
of the Hudson River from about upper Manhattan northward into
Rockland and parts of Westchester. Rainfall of 1-2 inches with
the convective band likely this AM across SE CT and ern Long
Island, causing additional poor drainage and urban type
flooding.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 3 PM EDT this afternoon for ANZ332.
Small Craft Advisory until 6 AM EDT Monday for ANZ350-353.
Small Craft Advisory until 2 AM EDT Monday for ANZ355.
&&
$$
SYNOPSIS...BG/JM
NEAR TERM...BG/DBR
SHORT TERM...BG
LONG TERM...JM
AVIATION...DR
MARINE...BG/JM
HYDROLOGY...BG/JM