Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus61 kokx 240010 
afdokx

Area forecast discussion
National Weather Service New York New York
710 PM EST Thu Feb 23 2017

Synopsis...
a weak cold front approaches tonight and then retreats back to
the north as a warm front on Friday. High pressure will remain
steady over the western Atlantic through Friday night. A
frontal system approaches Saturday and crosses the region
Saturday night. High pressure builds over the area during the
early part of next week. A warm front moves through Tuesday,
with the attendant low and cold front moving through by mid to
late week.

&&

Near term /until 6 am Friday morning/...
fog has dissipated across the region with the exception of
coastal New London County Connecticut, with only few to
scattered stratus around. The narre seems to have captured the
dissipating fog and stratus well and not indicating much
redevelopment tonight. An unseasonably warm and moist airmass
will remain in place. Light southerly flow will continue tonight
and soundings continue to hint at moisture becoming trapped
beneath an inversion. Overall, the setup is similar to last
night/this morning, however clouds and isolated showers were
moving into the region with a shortwave and cold front. Also,
winds aloft were in the 20 to 30 knots range, keeping the lower
levels mixed. So have gone with patch fog for the overnight, and
this may be too much.

Some middle and high level clouds may stream across the region,
which may lend to more of a low stratus situation than fog.
This shortwave and weak boundary could spark a few isolated to
scattered showers, mainly inland as there is some weak elevated
instability present in model forecast soundings. Temps will be
well above normal in middle 40s to near 50 degrees.

&&

Short term /6 am Friday morning through Friday night/...
weak frontal boundary retreats to the north as a warm front
during the day on Friday. Models have come into better agreement
with this scenario, which is reasonable given a stronger
southerly flow developing ahead of system strong shortwave
across the central states. Low stratus and areas of fog will
start the day with potential for dense fog during the morning
commute, especially near the coast.

The forecast uncertainly lies with how quickly the low stratus
and fog erode. As was the case on Thursday, it will likely
erode away north and west of the coast by early afternoon and
could linger near the coast into much of the afternoon. This
will play a role in high temperatures. With anomalously warm air
in place, highs should have no trouble reaching the middle and
upper 60s north and west of the NYC Metro. These numbers could
be higher dependent on how quickly clouds erode. Further east,
temperatures will likely be held down in the upper 50s and lower
60s due to onshore flow and longer duration of clouds/fog.

Stratus and fog are once again possible Friday night with
conditions remaining unseasonably warm. Some light rain or
drizzle is also possible as a stronger onshore flow develops
ahead of approaching cold front from the west.

&&

Long term /Saturday through Thursday/...
persistent low-level warm/moist advection will maintain a chance of
stratus, patchy fog and drizzle beneath the inversion through
Saturday morning. High temperatures will once again be close to 10
to 20 degrees above climatological normals, though perhaps a few
degrees colder than Friday closer to the coast due to onshore flow.
By Saturday evening, a potent vort Max and attendant cold front
approach the region. At this time it appears a narrow line of
showers and perhaps a few thunderstorms will move through ahead of
the front with a quick 0.25-0.50 inches of rain possible. A few
stronger gusts may mix to the surface as the front passes, given
wind speeds 30-40 kt just above the surface. Temperatures and dew
points will slowly fall Saturday night, though will still remain
above normal as winds remain strong and gusty through the night. The
stronger winds will continue through Sunday, with high temperatures
closer to climatological normals. High pressure will pass to the
south Sunday night into Monday, with increased cloud cover between
the high and an approaching area of low pressure to the west
maintaining mild temperatures across the region. Thereafter,
confidence decreases rapidly, though general consensus indicates a
warm frontal passage Tuesday followed by increasing chances of
precipitation ahead of the associated slowly approaching low
pressure and attendant cold front. However, model differences
are very large, as the systems for early to late week are still
over the data sparse areas of the Pacific, and are not yet
initialized well.

&&

Aviation /00z Friday through Tuesday/...
a cold front stalls north of the city terminals tonight before
shifting back north as a warm front Friday.

Low confidence in flight categories tonight. It appears that conds
are trending better than originally forecast. Will continue to
forecast eventual IFR at all terminals, but it is possible that some
terminals end up prevailing at VFR all night. -Shra possible north
of the city, but not significant enough to include in tafs.

Winds will be S-SW under 10 kt for coastal terminals, and light and
variable elsewhere.

For Friday, eventually becoming VFR by afternoon - if sub-VFR
conditions actually materialize tonight.

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: VFR potentially lasts the entire night or at
least sub-VFR is delayed until 06-09z.

Klga taf comments: VFR potentially lasts the entire night or at
least sub-VFR is delayed until 06-09z.

Kewr taf comments: VFR potentially lasts the entire night or at
least sub-VFR is delayed until 06-09z.

Kteb taf comments: VFR potentially lasts the entire night or at
least sub-VFR is delayed until 06-09z.

Khpn taf comments: VFR potentially lasts the entire night or at
least sub-VFR is delayed until 05-08z.

Kisp taf comments: VFR potentially lasts the entire night or at
least sub-VFR is delayed until 05-08z.

Outlook for 00z Saturday through Tuesday...
Friday night-Saturday...sub-VFR possible Friday night into Saturday
morning before improving back to VFR.
Saturday night...MVFR likely with rain.
Sunday...VFR.
Monday...VFR early...becoming MVFR. Chance of rain or snow.
Tuesday...possible MVFR in showers.

&&

Marine...
fog has dissipated across the forecast waters and narre not
indicating much redevelopment through tonight. Limiting the fog
development is a shortwave and cold front approaching with
clouds moving over the area. Also, low level winds were
stronger, in the 20 to 30 knots range. So, thinking is that there
will not be dense fog on the waters tonight, and have gone with
patchy 1 nautical mile restrictions, and this may be too low.

Otherwise, high pressure over the western Atlantic brings a
persistent southerly flow through Friday night, but winds and
seas will fall below small craft levels.

Winds and seas will increase to Small Craft Advisory levels Saturday
ahead of a cold front, and likely remain elevated through Sunday
following the frontal passage. Winds and waves will gradually
subside Sunday night into Monday as high pressure moves south of the
area. The next chance of Small Craft Advisory conditions will be
Monday night into Tuesday as winds strengthen following a warm
frontal passage. Winds and seas may remain at or near Small Craft
Advisory conditions through late week ahead of a cold front.

&&

Hydrology...
a quarter to one half of an inch of rain is likely Saturday. No
hydrologic impacts are expected through the next week.

&&

Climate...
the following are record high temperatures for Friday February 24,
2017 along with the forecast high temperature.

Record high temperature forecast high temperature
----------------------- -------------------------
Central Park........75 (1985) 64
LaGuardia...........73 (1985) 63
Kennedy.............60 (1984) 60
Islip...............59 (2000) 58
Newark..............73 (1985) 66
Bridgeport..........60 (2016) 58

The following are record maximum minimum temperatures for Friday
February 24, 2017 along with the forecast minimum temperature.

Record Max minimum temperature forecast minimum temperature
------------------------------ ----------------------------
Central Park........54 (1985) 54
LaGuardia...........51 (1985) 54
Kennedy.............47 (1984) 50
Islip...............44 (1984) 49
Newark..............47 (1985) 53
Bridgeport..........39 (1984) 47

The following are record maximum minimum temperatures for Saturday
February 25, 2017 along with the forecast minimum temperature.

Record Max minimum temperature forecast minimum temperature
------------------------------ ----------------------------
Central Park........51 (1930) 48
LaGuardia...........49 (1996) 48
Kennedy.............46 (1996) 47
Islip...............47 (1996) 46
Newark..............47 (1996) 47
Bridgeport..........44 (1996) 46

&&

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

&&

$$
Synopsis...MD/ds
near term...ds/met
short term...ds
long term...Maryland

National Weather Service Glossary of Abbreviations