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-- Discussion containing changed information from previous version are highlighted. --
705
FXUS61 KOKX 201402
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
1002 AM EDT Wed Jun 20 2018

.SYNOPSIS...
High pressure retreats to the east, as an area of low pressure
riding along a stalled frontal boundary tracks from the Ohio
River Valley today to near the Mid-Atlantic Coast by Thursday
morning. This low exits to the east on Thursday as a separate cold
front pushes to our south, followed by weak high pressure
building over the region into Friday. A frontal system will
slowly approach the area on Friday, as the high retreats to the
northeast, and then impacts the region over the weekend. High
pressure will build in behind the system into next Tuesday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Forecast on track with just some minor adjustments to reflect
latest observations. Expect a mostly cloudy day WNW flow aloft
this morning, flattens as a northern stream shortwave approaches
from the west this afternoon. There could be some stray showers
by late afternoon as the shortwave approaches, mainly across
far western zones.

Highs today should be near normal, mainly from the mid 70s to
around 80 across the region.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
A northern stream trough builds into the area tonight, this
coupled with some low level instability (focused mainly over the
southern 1/2 of the CWA) should bring some showers to the
region tonight, and possibly a rumble of thunder as well (mainly
to the southern 1/2 of the CWA). Precipitable Waters increase
to from 1.75 to around 2 inches (with values around 2 inches
focused over the southern 1/2 of the CWA), so locally heavy
rainfall is possible, especially in association with any
stronger convection overnight. Refer to the hydrology section
of the AFD for details on expected rainfall amounts and any
impacts.

There is some uncertainty on the timing of the showers tonight,
but for now a consensus timing would be for the most numerous
showers and best chance for any locally heavy rainfall to occur
from around 9pm- 5am.

The timing for the end of the rainfall has slowed, with showers
now expected to linger into Thursday morning. The showers
likely should come to an end by mid-late morning, as the axis
of the northern stream trough exits to the east, allowing for a
drying NW flow to set up over the region by afternoon.

Lows tonight and highs on Thursday should be near to slightly
above normal.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
The models are in good agreement with the general pattern in the
long term, although some timing and placement issues remain. An
approximately 1020 hi will be set up from the Maritimes swwd to cntrl
New England Fri. At the same time, sw flow aloft develops as an h5
low spins over the Midwest. This will result in increasing thetae
and chcs for shwrs and tstms Fri and particularly Fri ngt. The upr
support arrives Sat and Sat ngt. The GFS is a bit faster than the
ECMWF. Likely pops have been included during the day on Sat based on
a blend of all of the model data. As the upr trof arrives on Sun and
Mon, there will be additional chances for pcpn. These appear to be a
bit more diurnally focused, with daytime heating providing the added
instability boost needed. High pres then builds in on Tue and dries
out the area. The NBM was used for temps thru the period.

&&

.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
High pressure will be offshore today, with a weak surface trough
just to the west.

VFR today, then mostly MVFR tonight in -shra/-ra.

Light and variable winds shifts SE-S this morning, increasing
to around 10 kt by noon.

     NY Metro Enhanced Aviation Weather Support...

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

KJFK TAF Comments: Timing of wind shift to S could be off by 1-2
hours.
The afternoon KJFK haze potential forecast is GREEN...which implies
slant range visibility 7SM or greater outside of cloud.

KLGA TAF Comments: Timing of wind shift to S could be off by 1-2
hours.
The afternoon KLGA haze potential forecast is GREEN...which implies
slant range visibility 7SM or greater outside of cloud.

KEWR TAF Comments: Timing of wind shift to SE could be off by 1-2
hours.
The afternoon KEWR haze potential forecast is GREEN...which implies
slant range visibility 7SM or greater outside of cloud.

KTEB TAF Comments: Timing of wind shift to S could be off by 1-2
hours.

KHPN TAF Comments: Timing of wind shift to SE then S could be off by
1-2 hours.

KISP TAF Comments:Timing of wind shift to S could be off by 1-2
hours.

.OUTLOOK FOR 12Z THURSDAY THROUGH SUNDAY...
.Thursday...MVFR early with showers ending, then becoming VFR.
.Friday...VFR.
.Saturday...A chance of showers, possibly a thunderstorm, Sat
into Sat night.
.Sunday...VFR expected. Slight chc of a shower.

&&

.MARINE...
A relaxed pressure gradient over the waters will generally limit
winds to around 10 kt or less through Thursday. The possible
exception is over the coastal ocean waters west of Moriches
Inlet this afternoon and evening, where sustained winds up to
around 15 kt are possible.

Winds and seas will remain below Small Craft Advisory (SCA)
levels Thu night, then increase to SCA levels, mainly on the
ocean, Fri thru Sun.

&&

.HYDROLOGY...
Dry this morning. Then expect around 1/4 to 1 inch of basin
average rainfall from this afternoon into Thursday morning. The
lowest amounts will be across northern interior portions of the
Tri-State and heaviest amounts across NYC/Long Island and NE NJ.

With very high precipitable waters forecast, there is the
potential for locally heavy rainfall with any stronger
convection. Areas experiencing locally heavy rainfall could
experience minor flooding of mainly urban and known poor
drainage areas. There is also a very small (generally around 10%
or less) of localized flash flooding, with the highest
potential (around 10%) across NYC/NE NJ/Long Island.

No significant widespread hydrologic impacts are currently
expected from Thursday afternoon through Tuesday.

&&

.EQUIPMENT...
NYC NOAA Weather Radio Station KWO-35 (162.55 MHz) remains off
the air for an extended period of time.

&&

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

&&

$$

SYNOPSIS...JMC/Maloit
NEAR TERM...BC/JMC/Maloit
SHORT TERM...Maloit
LONG TERM...JMC
AVIATION...JC/DW
MARINE...JMC/Maloit
HYDROLOGY...JMC/Maloit
EQUIPMENT...//