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Area forecast discussion 
National Weather Service New York New York
1038 PM EST Thursday Dec 18 2014

Synopsis...
high pressure from the Great Lakes builds over the northeast
through the weekend. Low pressure will pass south of the area
Monday and Monday night. Strong low pressure will impact the
region Tuesday night through Wednesday night.

&&

Near term /through Friday/...
strato-cumulus remains over portions of northeastern New Jersey and
into the lower Hudson Valley. The cloud cover should persist under
a strong subsidence inversion. Also with light northwest wind of
5 to 10 knots continuing overnight and the cloud cover temperatures
not expected to reach forecast lows and raised a couple of
degrees.

&&

Short term /Friday night/...
cloud cover forecast is again the only issue seen as high pressure
builds in from the west. Northerly winds gradually diminish and
veer NE Friday night.

MOS blend seems very reasonable and was accepted for maxes and
mins. Temperatures are very close to...if not exactly...seasonable.

Note that the high clouds currently in Ohio will pass across the
local area this evening into the overnight. May have underdone
this in the sky cover grids - depending on if it turns more opaque
than expected.

&&

Long term /Saturday through Thursday/...
main feature during the long term period will be developing low
pressure that will impact the region on Christmas evening.

Surface high pressure currently over the Great Lakes will build east and
park itself nearly overhead this weekend. Meanwhile...a series of
500 mb shortwaves will pass through the region during this time.
With a lack of surface moisture and limited lift...not expecting much
than some light rain and/or snow...and will cap probability of precipitation at slight
chance for Saturday afternoon through Sunday. Temperatures this weekend
will be within a few degrees or normal...topping off in the upper
30s to around 40 on Saturday and in the low 40s on Sunday.

A new moon on Sunday...along with an onshore flow...may result in
minor coastal flooding for the start of the new week.

High pressure moves offshore on Monday. Deep upper trough will dig into
the central states with low pressure developing on Monday. Surface low pressure
will also develop at the base of the trough in the Gulf Coast
states. The secondary low moves towards the middle-Atlantic during the
day Monday before passing south of Long Island Monday night through
Tuesday. The parent low and deep upper trough will both continue to
track east early in the new week...and then another low will then
form over the middle-Atlantic as several strong shortwaves dive into
the base of the trough over the Gulf Coast.

This new low will intensify as it tracks along the coast on
Christmas evening. Models in good agreement with the low passing over
NYC and into New England. This will keep the region in the warm
sector and precipitation will be all rain...and may be heavy at times.
Cannot rule out convection and possible street flooding during the
day as well. A cold front will swing through the region Wednesday
night behind the departing low...ushering a colder air mass into the
region. Latest European model (ecmwf) has the low starting out as 993 mb near Cape
Hatteras at 12z Wednesday before ending up as a 965 mb low over
western Quebec at 12z Thursday. With a 28 mb drop in 24 hours...can
expect strong westerly winds...possibly to Wind Advisory criteria...
to develop on Christmas day.

Although models are in good agreement...this system is still a week
away...and many things can change before then.

&&

Aviation /04z Friday through Tuesday/...
deepening low pressure will drift through the Canadian Maritimes
through the taf period.

Overnight...scattered 030-040 ceilings. Occasional MVFR ceilings possible. Winds
generally 300-340 degree magnetic occasional gusts to 20 knots at NYC
metropolitan.

Friday...sct-bkn 035-040 ceilings...with low probability of MVFR ceilings. Winds
generally 320-360 degree magnetic with speeds of 10-15 knots gusts
near 20 knots.

Outlook for 00z Sat through Wednesday...
Friday night-Sat...VFR.
Sat night...MVFR or lower in ceilings. Light east winds.
Sunday...MVFR or lower in ceilings. Light east winds.
Monday...VFR. MVFR or lower possible in onshore southeast flow.
Monday night-Tue...IFR likely at times in rain...ceilings and visibilities. Southeast winds
10-20 knots.
Wednesday...high impact event possible...IFR likely with heavy rain and
strong gusty southeast winds 25kt+ shifting to west late.

&&

Marine...
the pressure gradient has weakened enough that the wind and gusts
across all the forecast waters have now diminished and were below
25 knots. Gusts remain below 25 knots in to Friday. The Small Craft
Advisory on the ocean waters has been cancelled.

High pressure builds from the west on Friday with tranquil conds on the
waters that continue into Monday.

Low pressure passes south of Long Island Monday night and Tuesday...and
conds may build to Small Craft Advisory levels during that time. A stronger low will
impact the waters Wednesday through Thursday...resulting in at least
Small Craft Advisory conds on the waters with gales possible
starting on Thursday.

&&

Hydrology...
no measurable precipitation through Sat with no Hydro impacts into early
next week.

1/4 to 1/2 inch of rain is possible Monday afternoon through Tuesday
as low pressure passes south of Long Island. Some wet snow is possible
Monday afternoon...and then again Monday night across the lower
Hudson Valley and interior portions of southern CT. No hydrological
impacts expected.

Rain on Wednesday may average 1-2 inches across the region. Minor
street flooding is possible.

&&

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

&&

$$
Synopsis...mps/tongue
near term...met/tongue
short term...tongue
long term...mps
aviation...Nevada
marine...mps/met/tongue
hydrology...mps/tongue

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