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fxus61 kokx 241425 
afdokx

Area forecast discussion
National Weather Service New York New York
1025 am EDT Fri Mar 24 2017

Synopsis...
a warm front moves across the region today, with an unsettled
weather pattern continuing through the weekend and into the
middle of next week. The warm front north of the region
retrogrades back into the region as a back door cold front
Saturday night and will be west of the area Sunday. The front
returns to the region Sunday night into Monday and then passes
east of the region Monday night. Another system approaches
Tuesday and moves across Tuesday night into early Wednesday.
High pressure returns thereafter.

&&

Near term /until 6 PM this evening/...
minor tweaks but no major changes made to the forecast. By the
time the precipitation fully moves into the region and starts
reaching the ground late this morning into early this afternoon,
this will be mainly rain as temperatures will have risen to
above freezing for most locations in the forecast region.

Extremely dry air evident on 00z soundings at okx and aly will be
very difficult to saturate initially this morning, so have delayed
the onset of precipitation. Isentropic lift associated with the
warm front and a passing short wave will eventually lead to the
development of light precipitation later this morning into the
early afternoon. Initially cold temperatures may support a brief
period of light snow, then perhaps ice pellets or minimal
accumulation of freezing rain as warm advection above the
surface rapidly increases amidst a strengthening low-level jet.
Eventually surface warm/moist advection will lead to above
freezing temperatures at all locations, and precipitation type
transitioning to rain. A warming trend is expected today into
Saturday, though high temperatures today will still be a few
degrees below climatological normals.

&&

Short term /6 PM this evening through 6 PM Saturday/...
any precipitation will quickly taper off by evening as the short
wave moves east of the area and the warm front moves to the
north. Dry conditions will be short-lived overnight. By
morning, an upper low approaches from the west, increasing
forcing for ascent, and in combination with a back door cold
front subsequently increases precipitation chances through
Saturday evening.

Temperatures tonight will be nearly steady as warm advection
continues through the night amidst southwesterly flow. By
Saturday afternoon temperatures will finally be close to
climatological normals, though a cooling trend will be noted
late in the day from northeast to southwest as the back door
cold front begins to move through.

&&

Long term /Saturday night through Thursday/...
overall, an increasingly maritime airmass will be getting entrained
into the region from a persistent easterly flow. Rain will
ultimately be intermittent with some drizzle from time to time for
the remainder of the weekend. Not much of a diurnal temperature
range expected for the remainder of the weekend either. Patchy
fog is expected Saturday night through Sunday evening as
boundary layer becomes saturated from the continuous easterly
flow.

Rain continues Monday with some more synoptic forcing ahead of the
shortwave and surface frontal system moving in. The chances for rain
lower Monday night as these aforementioned features move east of the
region. Chances for rain are slow to drop off because of increasing
uncertainty in the model precipitation fields this timeframe. Rain
could linger longer early next week if the frontal system is slower.

Aloft, there will be a flattening ridge with the polar jet moving
farther north of the region Saturday night. The flattening ridge
axis moves across on Sunday. An embedded shortwave on the back end
of the ridge approaches Sunday night and moves across Monday. Brief
ridging then takes place Monday night into Tuesday. There will be
another shortwave moving across Tuesday night. A ridge to the west
then starts to build in thereafter for midweek.

Starting Saturday night, the surface features to note will be a
front retrograding southwest within the region and strengthening
high pressure building southeast from Quebec into Maine. The front
is a back door cold front. On Sunday, the high pressure area will be
moving into the Gulf of Maine and easterly flow will keep a cool
marine airmass. The front moves east back into the area Sunday night
into Monday with a weak low developing along the front. The flow
becomes more southerly. The front and low along it move east of the
region Monday night. Another frontal system approaches Tuesday
afternoon and moves across Tuesday night. High pressure starts to
build in thereafter for midweek.

&&

Aviation /15z Friday through Tuesday/...
high pressure will slide further offshore today. Meanwhile, a warm
front will lift to the north.

Mainly VFR through the taf period. There is the potential for
some light precipitation late this morning into early
this afternoon. The best chances of precipitation will be at
kswf, where some ice pellets may briefly mix in at the very
start. Elsewhere, will use a tempo group to address any
rain/showers.

Light and variable winds increase out of the S-south-southwest this
morning to around or just over 10 kt. Gusts around 20 kt likely
this afternoon. Winds diminish overnight.

Conditions should remain fairly dry overnight.

New York 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: best chance of any precipitation will be between
16z-18z. Low chance for a brief MVFR cig.

Klga taf comments: best chance of any precipitation will be between
16z-18z. Low chance for a brief MVFR cig.

Kewr taf comments: best chance of any precipitation will be between
16z-18z. Low chance for a brief MVFR cig.

The afternoon kewr haze potential forecast is green...which implies
slant range visibility 7sm or greater outside of cloud.

Kteb taf comments: best chance of any precipitation will be between
16z-18z. Low chance for a brief MVFR cig.

Khpn taf comments: best chance of any precipitation will be
between 16z-18z. Low chance for a brief MVFR cig. Low chance
precipitation could start off as a rain/ice pellet mix.

Kisp taf comments: best chance of any precipitation will be between
16z-19z.

Outlook for 12z Saturday through Tuesday...
Saturday morning...chance of sub-VFR in stratus Saturday
morning.
Saturday afternoon-Monday...MVFR/IFR probable, possibly LIFR.
Monday night-Tuesday...MVFR or lower possible.

&&

Marine...
winds and seas increase this afternoon with the pressure gradient
tightening as high pressure moves east and an area of low pressure
approaches from the northwest. Expecting all but New York Harbor to see
Small Craft Advisory conds in the afternoon, with advisory conds continuing into the
night for the ocean, eastern sound and eastern bays. Isolated gusts
to 35 knots are possible east of Moriches Inlet for a brief period this
afternoon, though will likely not be widespread enough for a Gale
Warning. Lingering seas around 5 ft are possible on the ocean
waters through Saturday afternoon.

Initially Saturday evening features sub Small Craft Advisory conditions across the
waters. However, Small Craft Advisory conditions resume for the ocean waters late
Saturday night lasting through much of the remainder of the weekend
for the ocean with easterly flow increasing. Other waters stay below
Small Craft Advisory.

Sub Small Craft Advisory conditions return Monday and Monday night and stay that way
for non-ocean waters through Tuesday. The ocean will have a return
to Small Craft Advisory conditions Tuesday ahead of the next frontal system.

&&

Hydrology...
model run accumulation of rain could reach 0.75 to 1.5 inches with
locally higher amounts possible for the period Saturday through
early next week. This is over a long enough time period to not
have too much excessive runoff. Therefore, not expecting
flooding and there are no hydrologic concerns at this time.

&&

Okx watches/warnings/advisories...
CT...none.
New York...none.
New Jersey...none.
Marine...Small Craft Advisory until midnight EDT tonight for anz330-340.
Small Craft Advisory until 6 PM EDT this evening for anz335-
345.
Small Craft Advisory until 2 PM EDT Saturday for anz350-353-
355.

&&

$$
Synopsis...MD/jm
near term...12/MD/jm
short term...Maryland

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