443
FXUS61 KOKX 131302
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
902 AM EDT Mon May 13 2024

.SYNOPSIS...
High pressure moves out into the Atlantic today into this evening.
For tonight into early Tuesday, a warm front moves northeast of
the region. A cold front to the west of the region slows down
and becomes nearly stationary Tuesday through Tuesday night. Low
pressure developing west of the area eventually moves south and
then southeast of the region Wednesday into Wednesday night. Brief
high pressure follows for Thursday with several disturbances
moving through the area from late week through early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
The synoptic pattern across the local region conveys mid level
ridging today with surface high pressure moving farther out into
the Atlantic.

Southerly winds will increase and with veering low level profiles
and more sunshine compared to the previous day, a much warmer day is
expected compared to the previous day.

However, for eastern and interior sections of the region, more
clouds are forecast compared to locations to the west and along the
coast to the western parts of the region. Some subtle small
amplitude shortwaves could traverse these more interior and
eastern parts of the region and will be associated with more
clouds.

Taking a look at CAMs for today, the HRRR, HRW NSSL, HRW ARW, HRW
FV3, and NAM Nest all indicate within their forecast reflectivity
fields isolated to scattered coverage of showers moving across
mainly the northern half of the forecast region and also across much
of the eastern half of the region for this afternoon through this
evening.

The mechanism for convective initiation appears to be a small
shortwave embedded within the approaching ridge that moves NW to SE
across the forecast region latter half of this afternoon into this
evening.

Corresponding to this area of isolated to scattered shower activity
from the SREF conveying an area of higher level moisture between
850mb and 500mb along with weak Q vector convergence between these
same two vertical levels.

NBM was used for high temperatures noting some substantial warm
air advection and the NBM was higher than MOS also.

Mid level ridge axis moves overhead tonight with the ridge then
shifting east and farther out into the Atlantic overnight into
early Tuesday. An overall strong consensus of negative vorticity
advection is shown for the first half of the night, so this
will help with subsidence and thereby allow for decreasing
clouds.

At the surface, high pressure will continue to move offshore out
into the Atlantic. Low level SW flow will continue. Radiational
cooling will be partially mitigated along the coastal areas as
onshore flow and winds staying up within the boundary layer under
the eventually mostly clear sky.

For temperatures, used the NBM for lows tonight.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
More of a SW synoptic flow sets up tonight into Tuesday with mid
level ridge moving farther east of the region and an approaching
trough from the west. At the surface, a warm front moves northeast
of the region and a trailing cold front will slow down well west of
the region. This will keep the local area in the warm sector.
Continued SW low level flow will increase 850mb temperatures
compared to the previous day so likewise surface temperatures will
also trend a few degrees warmer. Forecast highs get more in the low
to mid 70s for a greater fraction of the region.

In the mid levels, a trough will continue to approach from the west
Tuesday night into early Wednesday and will slow down as it becomes
cutoff. The cutoff mid level low slowly traverses south and
eventually southeast of Long Island Wednesday into Wednesday
night.

Upper level jet streaks move in late Tuesday into Tuesday night.
The main upper level jet thereafter stays well south of the
region late Tuesday night through midweek.

Multiple areas of low pressure are expected to form along the
front with another frontal system approaching from the south
Tuesday night into early Wednesday. The main frontal system to
the south with its center of low pressure passes south and
eventually southeast of Long Island Wednesday into Wednesday
night.

The bulk of the rain is expected Tuesday night through
Wednesday with the increase in low level omega as well as some
increased divergence aloft. Rain intensity forecast as moderate
and also expected the mode of rain will transition from
convective to more stratiform. Low pressure moving farther
southeast of Long Island late Wednesday night with decreasing
POPs for rain. Rain could be heavy at times as layer
precipitable waters increase to near 1.1 to 1.4 inches, highest
along the coast.

Regarding thunderstorms, they will be possible across western
and interior sections of the region Tuesday afternoon into Tuesday
night. This is where temperatures are forecast to be relatively
warmer, leading to more surfaced based instability. The rain will be
more of a convective mode in showers.

For temperatures, used the NBM for highs Tuesday, and then a
combination of NBM and CONSRaw for lows Tuesday night, followed
by CONSRaw only for Wednesday and Wednesday night. Wanted to
convey lower diurnal range of temperatures Wednesday into
Wednesday night and the Wednesday daytime temperatures expected
to be well below normal with the more easterly flow.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
The area remains under an upper level trough by Thursday morning,
though it is slowly making its way east of the area during the day.
Models disagree with the speed at which the trough moves away and
thus differ on the extent of the surface low pressure`s impact on
the area. The GFS and CMC have the low far enough offshore where
there shouldn`t be much shower activity, though the ECMWF keeps the
low closer to the area allowing for continued chance of showers
during much of the day Thursday and Thursday night.

By Friday, another large scale trough brings another frontal system
into the area from the west. While the day may be mostly dry,
showers once again become possible later in the day and into Friday
evening. The upper trough moves overhead slowly through the weekend
allowing for several frontal waves and areas of low pressure to pass
by. This likely continues the chance for rain showers through the
weekend and into early next week.

Temperatures will largely be at or slightly below average for the
extended period. Each day is expected to feature highs in the upper
60s to low 70s with each night in the 50s.

&&

.AVIATION /13Z MONDAY THROUGH FRIDAY/...
Weak high pressure pushes offshore today.

Generally VFR. Any MVFR or IFR cigs early this morning for
western terminals scatter out around 14-15Z. Low chance of
returning IFR low stratus to KGON late tonight into early
Tuesday.

Light winds this morning become S or SW and increase during the
afternoon. Gusts 15 to 20kt develop during the afternoon,
peaking late in the day. Stronger winds with sea breeze
enhancement likely at KJFK. Gusts end by 02Z.

 ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
IFR/MVFR ceilings should scatter out 14-15z.

Gusts in the afternoon may be more occasional. Sustained winds at
KJFK may be a few knots higher, especially late in the day.

OUTLOOK FOR 12Z TUESDAY THROUGH FRIDAY...

Tuesday: Mainly VFR. Chance of showers late. MVFR or lower possible
in mainly afternoon showers. S wind gusts 15-20kt near the coast
late.

Tuesday night: MVFR or lower in showers. S wind gusts 15-20kt near
the coast in the evening.

Wednesday: MVFR or lower likely in showers. Slight chance of a
thunderstorm.

Wednesday night: Chance of showers with improvement to VFR possible.
NE wind gusts 15-20kt.

Thursday: Mainly VFR. NE wind gusts 20 kt possible.

Friday: VFR.

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

&&

.MARINE...
Persistent low level inversion will limit gusts across the waters
late today into tonight. While most gusts will be in the range of 15
to 20 kt this afternoon into this evening, only localized gusts
reach closer to 25 kt over parts of the ocean. The areal coverage of
these SCA level gusts is not large enough to warrant the issuance of
the SCA.

Conditions remain below SCA thresholds in the short term through
Tuesday night. Wind gusts could get close at times to 25 kt over
parts of the ocean but most gusts should be mostly limited to
20 kt due to the persistent low level inversion limiting the
vertical mixing.

Wind gusts are forecast to remain generally 15-20 kt with more
easterly flow developing Wednesday and then pick up Wednesday night
with winds increasing and becoming more northerly. SCA wind gusts
will be possible Wednesday night especially on the ocean. From
prolonged onshore flow and fetch, ocean seas are forecast to
build to SCA levels Wednesday into Wednesday night.

Throughout the entire short term, non-ocean waters are expected to
remain at sub-SCA conditions.

Looking at the long term marine forecast period from Thursday
into the start of the weekend, lingering SCA waves on the ocean
subside by Friday with sub-SCA conditions on all waters through
Saturday.

&&

.HYDROLOGY...
No hydrologic problems expected.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.

&&

$$

SYNOPSIS...JM/MW
NEAR TERM...JM
SHORT TERM...JM
LONG TERM...MW
AVIATION...DS/MW
MARINE...JM/MW
HYDROLOGY...JM/MW