Scientific Forecaster Discussion
Area forecast discussion
National Weather Service New York New York
937 am EDT Thursday Oct 30 2014
high pressure builds over the area through tonight. Low pressure
develops off the middle Atlantic coast Friday...then tracks
northeast to east of Cape Cod by Saturday evening. Meanwhile a
secondary low forms off the middle-Atlantic coast Saturday...then
tracks northeast to the Canadian maritime provinces by Sunday
evening. High pressure builds in behind this storm through Monday
night...then moves offshore on Tuesday. A warm front crosses the
area Tuesday night...followed by a cold front approaching on
Near term /until 6 PM this evening/...
updates on latest T/dew point rends...and clouds. Early morning fog has
burned off. Passage of 700-500 hpa trough axis will only produce
scattered clouds at around 10kt. Downslope boundary layer flow
serves as a limiting factor.
Latest hourly guidance in line with forecast highs. Expect highs
to be near to slightly below normal.
Short term /6 PM this evening through 6 PM Friday/...
a 850-500 hpa shortwave ridge crosses the area tonight...with
associated subsidence promoting minimal cloud cover and
diminishing winds. As a result...have trended towards lower of
met/mav/ecs guidance and NAM 2-meter temperatures for lows. Not
quite certain enough of a completely clear sky and light winds to
go colder at this time. Lows should be near to slightly below
A weak inverted trough extends north-northwest from coastal low developing off
the Virginia/NC coast Friday towards Long Island. This coupled with a
passing weak 700-500 hpa shortwave warrants increasing cloud cover
over the entire region and slight chance probability of precipitation for -shra over
mainly Long Island Friday afternoon.
For highs Friday...a blend of mav/met/ecs guidance with NAM
2-meter temperatures and a mix down from 900-875 hpa per BUFKIT
soundings. Highs should be around 5 degrees below normal.
Long term /Friday night through Wednesday/...
a strong shortwave energizes a surface low emerging off the
Carolina coast late Friday night. Model consensus and their
respective ensemble means strengthen this storm as it heads
NE...passing southeast of the 40n/70w benchmark late Saturday night into
Sunday morning. A surface trough first brings a chance of showers
to the area Friday night. At least chance probability of precipitation remain on Saturday
with some middle level lift...although model quantitative precipitation forecast output suggests
that coastal areas warrant likely probability of precipitation...being closer to the
storm center. Chances of rainfall then diminish through Saturday
night as the storm shifts farther out to sea...with dry weather
by Sunday morning.
Thermal profiles suggest an all rain event. By the time freezing
levels and wet bulb zeroes lower enough to support a mix of rain
and snow...precipitation will have ended or will just about to
end. This would be the case for elevations above 1000 feet north
and west of the city. With such limited coverage of a low
probability event...have removed the mention of snow from the
Winds will end up being the bigger story...and will be at their
strongest from Saturday afternoon through Sunday afternoon. Could
get close to Wind Advisory criteria at some point during this
period...so will need to keep an eye on this.
With high pressure in control...Sunday through Tuesday is
expected to be dry. Highs on Sunday averaging at least 10 degrees
below normal...with wind chill values around 30 degrees for the
first half of the morning. The growing season then probably ends
for more of the zones outside of the city Sunday night with lows
around the freezing mark. Temperatures then begin their climb back
towards normal on Monday...before reaching near normal on Tuesday
with a SW flow.
Next chance of showers then arrives Tuesday night into Wednesday
with a warm front passage followed by the approach of a cold
front on Wednesday.
Aviation /14z Thursday through Monday/...
hi pressure builds over the metropolitan today. Low pressure begins to develop S
of the region Friday.
VFR through the taf period.
Mainly northwest winds at or below 10kt. Some backing to the west-northwest this
afternoon...especially S coasts. Direction veers to the north overnight.
New York metropolitan enhanced aviation weather support...
Detailed information...including hourly taf wind component forecasts can
be found at: http:/www.Erh.NOAA.Gov/zny/n90 (lower case)
Kjfk fcster comments: winds generally right of 310 magnetic
today...possibly wavering between 290 and 310 magnetic between 18z
Klga fcster comments: winds generally right of 310 magnetic
Kewr fcster comments: winds generally right of 310 magnetic
today...possibly wavering between 290 and 310 magnetic between
18z and 23z.
The afternoon kewr haze potential forecast is green...which
implies slant range visibility 7sm or greater outside of cloud.
Kteb fcster comments: winds generally right of 310 magnetic
Khpn fcster comments: no unscheduled amendments expected.
Kisp fcster comments: no unscheduled amendments expected.
Outlook for 06z Friday through Monday...
Friday...ceilings lower through the day with MVFR possible late.
Friday night-Sat night...MVFR or lower. Precipitation mainly rain...but snow may
mix in across the interior at night. NE-north winds 15-20g25-35kt.
Sunday...VFR. Northwest winds 20-25g30-35kt.
Monday...VFR. West winds 5-10 knots.
the forecast appears on track. A relaxed pressure gradient over
the waters around Long Island will result in winds 10 knots or less
through Friday. The only exception to this is possibly over the
far eastern coastal ocean waters on Friday afternoon...where NE
flow could strengthen to up to 15 knots. As a result...sub-small
craft conditions are expected on all marine zones through Friday.
Small Craft Advisory conditions are likely to develop on all waters from Friday
night into Sat morning as NE flow strengthens...then expect
northerly gales on the ocean by Sat afternoon...and north-northwest gales on
all waters - especially the ocean and the eastern sound/bays Sat night
into Sunday. Conditions should then gradually subside from Sunday
night on...with sub-Small Craft Advisory conditions on the sound/Harbor/bays by Monday
morning...and on the ocean by Monday night.
dry through Friday morning. There is a slight chance of at most a
few hundredths of an inch of rainfall Friday afternoon mainly
across Long Island.
Rainfall from Friday night through Saturday night is expected to
remain under a half inch with the higher amounts generally across
the coastal areas. No significant hydrologic impact is expected.