Area Forecast Discussion
Issued by NWS Upton, NY

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FXUS61 KOKX 231142
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
742 AM EDT Thu Mar 23 2017

.SYNOPSIS...
High pressure builds today, and passes to the east tonight. A
warm front moves across the region Friday. The warm front
north of the region Friday night and Saturday will move back
southwestward Saturday night into Sunday as a back door cold
front. A weak low develops along the front and the low and
front eventually move east of the region by Monday night and
Tuesday of next week. Another cold front approaches for next
Wednesday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
The forecast is on track this morning. Only slight adjustments
were made to temperatures and dewpoints to better match observed
trends.

The center of high pressure builds to our west, and passes to the
south this afternoon. Upper trough tracks further to the east.

A dry, chilly day is expected, with lighter NW winds than what was
observed yesterday. A few gusts are possible in the NW flow, but
winds will diminish this afternoon and back to the west as the high
tracks south.

Temperatures, after a cold start to the day, will rebound through
the 30s, but will peak about 10 degrees below normal, upper 30s to
lower 40s.

Plenty of sunshine is expected.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
Upper ridge to the west flattens tonight and Friday as closed low
moves across the mid section of the country. Surface high pressure
passes east of the area.

A warm front then approaches Friday morning, with a weak shortwave
riding along the top of the ridge, passing across the area Friday.

Winds remain light tonight as they become variable or light S/SW.
With cold airmass in place, temperatures will fall into the 20s
and 30s as high clouds increase. Some locations may radiate
into the teens. Still quite cold.

Increasing moisture riding over the top of the flattening ridge will
approach Friday morning. Light precip associated with warm air
advection is anticipated. Expect a brief period of light
precipitation to push through, with higher coverage NW zones, and
less SE zones per model consensus.

As for ptype, this could be problematic. Depending on when precip
moves in, looks like shortly after 12Z, a wintry mix is possible.
Snow, sleet and freezing rain is a good bet, especially away from
the coast. Again, depending on precip onset.

Temps near the coast should be warm enough for plain rain. QPF
should be under a tenth of an inch, so this is not a big event. But,
slick travel is possible as sfc/road temps may be cold enough for
some light icing.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Upper levels convey polar jet staying north of the region during
the long term.

Mid levels transition from zonal flow Friday night through Saturday
night to ridging Sunday, which will be followed by an approaching
shortwave on the back end of the ridge. The axis of this trough
moves across on Monday. Behind this shortwave, more quasi-zonal flow
will be established. There will be a larger shortwave approaching
from the northwest for the middle of next week.

At the surface, Friday night through Saturday will be when the
region is in the warm sector. The warm front will be north of the
region. Then, the front will start to shift southwestward, coming
back through the region as a back door cold front Sunday. The front
will stay west of the region and high pressure will stay well east
of the region going through Sunday evening setting up easterly
flow. For late Sunday night, the front will slide back east
with weak low pressure developing along it. The weak low and
front stay near the region Monday with more SE flow developing
ahead of the low and finally these move east of the region
Monday night and Tuesday. Another cold front approaches for the
middle of next week.

Overall, an unsettled weather pattern sets up leading to less
diurnal temperature range as the airmass becomes more cool
maritime from an increasing easterly flow with rounds of light
to perhaps moderate rain at times.

Temperatures are warmest on Saturday with area in the warm sector as
highs are forecast to range from the low 50s to low 60s. Sunday
looks to be the coolest day in the long term with a back door cold
front moving in as highs that day range from the low to mid 40s.
Otherwise the rest of the days feature highs in the upper 40s to
low 50s for most locations. Lows at night through the long term
are pretty consistent, in the upper 30s to low 40s for a
majority of the area.

&&

.AVIATION /11Z THURSDAY THROUGH MONDAY/...
VFR through the TAF period today.

NW Winds will increase this morning with gusts expected by mid-
late morning and this afternoon. Winds then diminish in the
evening and become more westerly as high pressure settles
across the area. Winds overnight become light and variable, then
become southerly early Friday morning.

Clouds increase late in the TAF period as low pressure passes north
of the region.

     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 may be higher than forecast.

KLGA TAF Comments: Occasional gusts may be higher than forecast.

KEWR TAF Comments: Occasional gusts may be higher than forecast.

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

KTEB TAF Comments: Occasional gusts may be higher than forecast.

KHPN TAF Comments: Occasional gusts may be higher than forecast.

KISP TAF Comments: Occasional gusts may be higher than forecast.

.OUTLOOK FOR 12Z FRIDAY THROUGH MONDAY...
.Friday...MVFR possible. Chance of SHRA. SW winds G25KT.
.Saturday...Mainly VFR. Chance of mid-late afternoon MVFR in
CIGs and -SHRA.
.Saturday night and Sunday...MVFR/IFR conds in rain. E-SE winds
G20-25KT.
.Monday...MVFR conds possible in showers.

&&

.MARINE...
As high pressure builds toward the waters this morning, then south
of the waters later today, winds will continue to diminish. Seas
subside as well. SCA remains up for the ocean waters this
morning.

The winds shift around to the west, then southwest tonight as the
high moves east. As the pressure gradient tightens Friday, expect SW
winds to increase, and SCA conditions are likely during the
afternoon, with gusts 25 to 30 KT. Seas, per guidance, will
build once again.

SCA chances are higher Friday night as well as late Saturday night
through Sunday night, mostly on the ocean. Otherwise sub SCA
conditions on other waters and other time periods for the marine
long term period covering Friday night through Monday.

Ocean seas with wave heights are forecast to stay in SCA range
Friday night into Saturday morning. Then the ocean seas are forecast
to get below SCA criteria Saturday afternoon through Saturday
evening before returning to SCA range late Saturday night through
Sunday and perhaps even into early Monday.

&&

.HYDROLOGY...
Unsettled weather from this weekend through early next week may
result in an inch or more of precipitation. However, this would
occur over a prolonged period and would be intermittent, so no
hydrologic concerns are anticipated. Snowpack melt in interior
sections will continue at a slow rate through Thursday with
most areas likely loosing any significant snowpack by Saturday
as temperatures rise to above normal readings and lows even
remain above freezing.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 11 AM EDT this morning for ANZ350-
     353-355.

&&

$$
SYNOPSIS...JM/PW
NEAR TERM...JM/PW
SHORT TERM...PW
LONG TERM...JM
AVIATION...BC
MARINE...JM/PW
HYDROLOGY...JM/PW


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