Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus61 kokx 210234 

Area forecast discussion
National Weather Service New York New York
934 PM EST Mon Feb 20 2017

high pressure builds across the area through Tuesday morning,
then offshore in the afternoon. A warm front passes near or just
north of the area Tuesday night. A trailing cold front follows
and will remain near the region through Friday. The cold front
lifts north as a warm front Friday night into Saturday. Another
cold front moves across the region Saturday into Saturday night.
High pressure returns for the end of the weekend.


Near term /until 6 am Tuesday morning/...
tranquil weather overnight as high pressure both aloft and at
the surface builds in from the west. Clear skies and
diminishing northerly winds are forecast.

Overnight lows will return to near seasonable levels with
readings falling into the lower 20s well inland, to around
freezing NYC Metro. Latest guidance supports forecast, with
minor updates to latest trends.


Short term /6 am Tuesday morning through Tuesday night/...
surface high pressure builds offshore Tuesday afternoon with
the upper ridge following behind in the evening. Winds will
veer around from the NE to S/southeast by afternoon with coolers highs,
in the mid and upper 40s. This will still be several degrees
above normal.

Warm advection develops out ahead of a warm front that passes
across the eastern Great Lakes Tuesday evening and then near or
just north of the area overnight. Weak thermal forcing and lack
of deep moisture will result in a minimal chance of light rain
late, with the best chance being across the lower Hudson Valley.
Any rainfall will less than a tenth of an inch. The combination
of increasing cloud cover and winds veering around to the SW
will keep temperatures from falling too much lower than daytime
daytime highs on Tuesday.


Long term /Wednesday through Monday/...
the main story in the long term continues to be unseasonably warm
conditions. Mainly dry conditions are expected Wednesday through
Friday, and then a more unsettled weather pattern sets up for the
first half of the upcoming weekend.

A warm front will be moving through on Wednesday. Any light rain
with the front should dissipate by Wednesday morning. Trailing cold
front approaches, but will likely have a hard time moving through.
Lingering clouds should hold in the morning before at least some
partial clearing in the afternoon as the atmosphere dries out. Highs
in the middle to upper 50s expected across the NYC Metro and
interior lower Hudson Valley and NE New Jersey. A few 60 degree readings are
possible as well. Across Long Island and southern Connecticut,
onshore component to the wind will hold temperatures in the lower

Thursday still looks like the warmest day of the week with the
potential for record high temperatures. Surface high pressure will
be anchored off the southeast coast with upper ridging in place.
Unseasonably warm air continues to be transported around the ridge
and offshore high. As has been the case recently in anomalously warm
regimes, statistical guidance and model blends have been running too
cool. Will continue to forecast highs above guidance with upper 60s
to near 70 a good possibility in NYC, NE NJ, and the lower Hudson
Valley. Further east, winds off the ocean may hold temperatures down
in the upper 50s to near 60s. See climate section for record highs
on Thursday (feb 23rd).

The lingering cold front attempts to move through Thursday night as
a progressive high moves across southeast Canada. Confidence in this
is not high and it remains possible the boundary never fully moves
south of the area. The latest operational runs of the GFS and European model (ecmwf)
as well as several gefs members have the boundary nearby Friday
morning, then retreating north. Have lowered pops to slight chance
as overall moisture is limited. Highs will be dependent on the
amount of cloud cover and the placement of the boundary. Forecast
highs Friday are a bit cooler than Thursday although it should be
noted the latest ece MOS has highs in the middle to upper 60s across
the region.

The Retreat of the warm front is due to the amplification of a
shortwave trough across the central states and deepening surface low
moving through the Great Lakes. The timing of the trailing cold
front on Saturday is where there is greatest uncertainty to sensible
weather across the region. In collaboration with neighboring
offices, have raised pops to likely Saturday afternoon/evening as
there is decent agreement among the models and ensembles for
measurable precipitation during this time. Temperatures on Saturday
continue well above normal and will ultimately be dependent on the
timing of the precipitation and cold front.

The cold front moves across sometime late Saturday into Saturday
night with high pressure building for the end of the weekend. This
signals a return to more seasonable temperatures.


Aviation /03z Tuesday through Saturday/...
high pressure builds over the region overnight, then moves off the
northeast coast during Tuesday. A warm front approaches late Tuesday
night, and moves through Wednesday.

VFR through the taf period.

Northeast flow 10 knots or less becomes light and variable outside of
the NYC Metro terminals. A southerly flow develops during Tuesday

Outlook for 00z Wednesday through Saturday...
Tuesday night...VFR. MVFR ceilings possible at kswf after 05z,
and toward the coast toward 12z, with light rain.
Wednesday...MVFR possible early in the morning with light rain.
Then VFR.
Thursday-Friday...MVFR, possibly lower, in stratus and fog.
Saturday...MVFR likely with showers.


tranquil conditions are on tap as high pressure builds across
the area waters through Tuesday morning, and then offshore in
the afternoon. Northerly winds late this evening gradually
diminish with the gradient wind remaining weak through the end
of the week.

The next chance for Small Craft Advisory conditions will be Saturday as the next
low pressure and associated frontal system approaches.


no significant hydrologic impacts are anticipated through the
upcoming week.


the following are record high temperatures for Thursday February 23,

Central Park........70 (1985)
LaGuardia...........66 (1985)
Kennedy.............62 (1990)
Islip...............61 (2012)
Newark..............68 (1985)
Bridgeport..........60 (2012)


Okx watches/warnings/advisories...
New York...none.
New Jersey...none.


near term...dw/pw
short term...dw

National Weather Service Glossary of Abbreviations