Area Forecast Discussion
Issued by NWS Upton, NY

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FXUS61 KOKX 241149
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
649 AM EST Thu Jan 24 2019

.SYNOPSIS...
A cold front and low pressure cross the area today, followed by
high pressure tonight. High pressure moves east of the region
Saturday night. A cold front will approach and move across the
area on Sunday. Low pressure moving out of the Plains States on
Monday will approach Monday night into Tuesday, then pass north
of the region as its associated cold front moves across the area
Tuesday night into Wednesday morning.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Upper shortwave pivots northeast out ahead of main longwave
trough, passing overhead by early this afternoon. A wave of low
pressure develops along a front ahead of this aforementioned
shortwave and passes late this morning into the afternoon from
west to east.

Very strong low level jet progged by models and supported by
KOKX VWP moves to the east ahead of the front. Strong low level
lift in conjunction with upper support will result in rain to
become more widespread and heavier in intensity as the morning
progresses. Elevated instability noted, and high resolution
models continue to show a line of convection along the front,
timed 15-16Z western Orange county, 18-19Z NYC vicinity and
19-20Z eastern locations. A rumble of thunder could accompany
this line.

Increasing sustained winds are expected, with the strongest
winds occurring right along the coast. Could certainly see 25-35
mph sustained winds, and a gust or two in the 40-50 mph range.
The line will need to be watched, and with 60-80 kt LLJ, a few
severe gusts (58mph or greater) cannot be ruled out. General
thunderstorm risk per SPC remains to our south, but it is worth
watching.

All hazards, Wind advisory, flash flood watch, and coastal flood
hazards remain in effect.

Temps will warm into the 50s all locations as the strong
southerly winds prevail.

Rain will abruptly come to an end late this afternoon from west
to east behind the front, and winds turn to the W/NW.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
Upper low settles south from Hudson Bay as shortwaves pivot
around the base of the trough, passing across the region. With
height falls, colder air rushes in behind the cold front on W/NW
winds. Dry conditions are anticipated. Skies clear tonight, but
a few more clouds (strato-cu and mid/upper level clouds) move
in Friday as two shortwaves and associated PVA track across the
northeast.

Seasonably cold temps in the 20s tonight, and 30s Friday, are
expected, along with gusty westerly winds that will add to the
chill.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
The long term period starts off with high pressure over the region
Friday night and Saturday. This will result in dry and cold
conditions. Highs on Saturday will remain below freezing with highs
in the middle to upper 20s, and around 30 across coastal locations.
Lows Friday night will be in the teens.

The high moves offshore Saturday night, allowing an upper level
shortwave and associated cold front move across the area. This could
result in a few snow showers, will keep POPs at slight chance for
now. No accumulations at this time are expected with any of the snow
showers. Other than a few snow showers Sunday morning, the day will
generally remain dry with warmer conditions as SW flow develops.
Highs on Sunday are expected to be in the upper 30s and lower 40s.

Low pressure moving out of the Plains states will bring another
frontal system toward the area late Monday night into Tuesday.
Partial thicknesses and surface temperatures support idea of
precipitation beginning as snow, then transitioning to rain at the
coast and possibly a rain/snow mix well inland on Tuesday. Right now
it looks like the precipitation will gradually change back over to
snow from northwest to Southeast Tuesday night and early Wednesday
morning as the front moves across the region. No significant
snowfall is expected at this time.

Highs on Monday will range from the middle and upper 20s to lower to
middle 30s. On Tuesday, highs will be in the upper 30s to lower 40s.
The long term ends with temperatures in the upper 20s and 30s on
Wednesday.

&&

.AVIATION /11Z THURSDAY THROUGH MONDAY/...
AA cold front moves through this afternoon.

MVFR lowering to IFR this morning with rain. ISO TSTM with cold
front passage, which is expected to be near 19z-20z for the NYC
terminals. Conditions will gradually improve back to VFR following
the passage.

S/SW winds ranging mostly 15-25 kt, but More significantly, LLWS of
55-65kt at 2 KFT strengthens to 65-75kt late morning to early
afternoon, especially from KJFK eastward. LLWS may approach 80 kt
for KISP and KGON during this time. Winds then shift to WNW and
remain strong following the frontal passage. Gusty winds near 45-
55kt may be possible with the frontal passage.

...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: Occasional gusts 35-39kt possible before 15z.

The afternoon KJFK haze potential forecast is GREEN...which implies
slant range visibility 7SM or greater outside of cloud.

KLGA TAF Comments: Tempo MVFR cigs possible before 15z. Occasional
gusts 30-34kt possible before 15z.

The afternoon KLGA haze potential forecast is GREEN...which implies
slant range visibility 7SM or greater outside of cloud.

KEWR TAF Comments: IFR cig timing may be off by 1-2 hours.
Occasional gusts 30-33kt possible after 15z.

The afternoon KEWR haze potential forecast is GREEN...which implies
slant range visibility 7SM or greater outside of cloud.

KTEB TAF Comments: IFR cig timing may be off by 1-2 hours.

KHPN TAF Comments: Gusts this afternoon may average around 5 kt
lower than currently forecast.

KISP TAF Comments: Occasional gusts up to 35kt before 15z.

.OUTLOOK FOR 12Z FRIDAY THROUGH MONDAY...
.Friday-Friday night...VFR. W G25KT daytime.
.Saturday...VFR.
.Sunday...VFR. WSW G20KT.
.Monday...VFR.

&&

.MARINE...
With increasing southerly winds ahead of low pressure and
associated cold front, gale force winds are expected today.
Gusts across the ocean may reach 45 kt. Seas build quickly, with
rough conditions on all waters expected.

The front passes this afternoon, and winds will shift to the
W/NW. Speeds will diminish, but SCA conditions are forecast
tonight and Friday. Seas will thus be slow to subside.

Small craft conditions will continue Friday night as gusty northwest
winds prevail. While winds fall below 25 on Saturday, there may
still be some leftover 5 ft seas, especially on the eastern ocean
waters.

Sub-SCA conditions are expected Saturday night and much of Sunday.

SCA conditions are expected to re-develop late Sunday night into
Monday on at least the eastern ocean/sound/bays after a cold frontal
passage. Some 5-ft seas may persist into Mon night.

&&

.HYDROLOGY...
1.25 to 2.25 inches of rain is forecast today, with locally
higher amounts possible. Most of this will fall late this
morning into early afternoon. Urban and poor drainage flooding
is therefore possible, as well as small stream and flashy river
flooding. Larger streams and main stem rivers should remain
below flood stage.

QPF up to 1/2 inch liquid equivalent possible late Mon night into
early Wed.

&&

.TIDES/COASTAL FLOODING...
Strong southerly winds ahead of an approaching strong cold front, as
well as southerly swells building to 15 ft, will present a threat
for minor coastal flooding during the times of high tide this
morning into afternoon.

With the recent full moon, tidal departures of only 1 to 1 1/2,
locally 2- 2 1/2 ft, are needed for minor coastal flooding.
Have leaned towards high end of Stevens guidance based on
water levels currently running on the high end of the surge
guidance, and past performance this season. ETSS is showing a
negative surge for Thu high tides, which seems unlikely.

Based on above surge and incoming swells, widespread minor coastal
impacts are likely for coastal locales along Jamaica Bay, Western
Great South Bay, and Southern CT and Westchester shorelines.
Elsewhere, localized minor impacts are expected.

Otherwise, high surf of 10 to 15 ft is expected along the
Atlantic oceanfront, with 2 to 4 ft along the CT shoreline and
out by the points of the Twin forks. This will likely result in
beach flooding and erosion, with minor damage possible to base
of dune structures. Splashover onto shoreline roads and
properties likely along the CT shoreline.

&&

.EQUIPMENT...
NYC Central Park winds are out of service until further notice.
Loss of data is due to a severed cable. Parts are on order.

NYC NOAA Weather Radio Station KWO35 (162.55 MHz) will remain off
the air for an extended period of time.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Flash Flood Watch until 6 PM EST this evening for CTZ005>012.
     Wind Advisory until 6 PM EST this evening for CTZ009>012.
     Coastal Flood Advisory from 11 AM this morning to 3 PM EST
     this afternoon for CTZ009>012.
NY...Flash Flood Watch until 6 PM EST this evening for NYZ067>075-
     078>081-176>179.
     Wind Advisory until 6 PM EST this evening for NYZ071>075-
     078>081-176>179.
     Coastal Flood Advisory from 11 AM this morning to 3 PM EST
     this afternoon for NYZ071.
     Coastal Flood Advisory until 2 PM EST this afternoon for
     NYZ178-179.
NJ...Flash Flood Watch until 6 PM EST this evening for NJZ002-004-
     006-103>108.
     Wind Advisory until 6 PM EST this evening for NJZ006.
MARINE...Gale Warning until 6 PM EST this evening for ANZ330-335-338-
     340-345-350-353-355.

&&

$$
SYNOPSIS...BC/PW
NEAR TERM...PW
SHORT TERM...PW
LONG TERM...BC
AVIATION...JC
MARINE...PW
HYDROLOGY...PW
TIDES/COASTAL FLOODING...
EQUIPMENT...


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