Scientific Forecaster Discussion
Area forecast discussion
National Weather Service New York New York
943 PM EST Tuesday Dec 1 2015
low pressure south of the region will track northeast tonight. A
cold front approaches on Wednesday and works its way across the
region Wednesday night. The front moves east on Thursday. High
pressure then builds east for the end of the week and into the new
Near term /until 6 am Wednesday morning/...
minor adjustments to probability of precipitation to better reflect radar trends this evening.
Also more pessimistic with fog tonight than previous forecast.
Low pressure south of the region will gradually move to the
northeast tonight. Rain is becoming more spotty this evening as
expected...with just a chance of light rain or drizzle likely late
this evening into the overnight hours. Steady rain moves back in
across western portions of the forecast area late tonight.
Used a model blend for overnight lows...which will be slightly above
normal. Expect lows in the upper 30s and 40s.
Short term /6 am Wednesday morning through Wednesday night/...
an upper level trough and closed low approaches from the west on
Wednesday and move into the region Wednesday night. This system will
allow a surface cold front to approach on Wednesday and move through
the region Wednesday night. Forecast models are indicating a surface
low developing along this front and moving through the region
Wednesday afternoon and evening. Expect probability of precipitation to increase through the
day Wednesday with periods of rain. Some of the rain could be
moderate at times through Wednesday evening.
The front moves across the region Wednesday night...and probability of precipitation start
to taper off from west to east after midnight. Rainfall amounts will
generally be around 1 inch.
Temperatures will be above normal through the short term period.
Expect highs in the lower and middle 50s on Wednesday and lower and
middle 40s on Wednesday night.
Long term /Thursday through Tuesday/...
surface low pressure at about 1000 mb over the Gulf of Maine Thursday
morning will continue to track to the northeast and depart during
the day. Meanwhile...closed 500 mb low over New York state with several strong
shortwaves will track through the area during the day. Will keep
slight chance probability of precipitation for the lower Hudson Valley...southern CT...and
Long Island for early in the day...but any showers should taper off
1028 mb high pressure over the center of the nation then begins to build
east. A northwest pressure gradient will tighten over the region...and northwest winds
will increase to 15-20 miles per hour with 20-30 miles per hour gusts.
Winds diminish Thursday night as pressure gradient relaxes.
Thereafter...high pressure continues to build east to close out the work
week before moving nearly overhead over the weekend. Temperatures during
the period will be right around the seasonal norm with highs in the
middle to upper 40s and lows in the 30s.
The high drops into the southeast U.S. For the start of the new
week...and return flow sets up...allowing temperatures to creep up to
slightly above normal levels.
Aviation /03z Wednesday through Sunday/...
one wave of low pressure southeast of the Twin Forks of Long Island
will track northeast along the New England overnight. Another wave
of low pressure with an associated warm front will approach
Wednesday. The warm front is expected to remain south of the
terminals through Wednesday as the low tracks over the terminals
during the afternoon.
Light northerly wind will become light and variable across all the
terminals around midnight...or just after as the offshore low moves
away. Light rain and drizzle will continue.
Forecast remains uncertain with the timing and movement of the
lows and warm front with low forecast confidence.
IFR to LIFR ceilings remain overnight with MVFR fog and
rain...lowering to IFR. LIFR conditions in rain and fog will be more
likely Wednesday...especially in the afternoon...and vlifr will be
Outlook for 00z Thursday through Sunday...
Wednesday night...mainly MVFR but possible improvement to VFR by 12z Thursday.
Southerly winds shifting to the west.
Thursday...VFR. West-northwest flow 10-20kt. Gusts around 25kt.
Friday...VFR. Northwest flow generally blw 15kt.
Sat...VFR. Light north winds.
Sun...VFR. Winds becoming westerly.
cancelled Small Craft Advisory on the eastern sound and bays as conds are not
being met and winds are expected to continue to decrease this evening.
No changes to rest of headlines.
The gradient relaxes overnight as the low passes to the
northeast. Winds on the ocean will also fall below Small Craft Advisory
levels...but seas remain above 5 feet into Wednesday.
Seas may just fall below small craft levels on Wednesday for a brief
period before increasing once again Wednesday night as a cold
front approaches and moves across the area waters. For now...will
let the Small Craft Advisory on the ocean run until 15zz on
Wednesday...however this may need to be extended on the eastern
ocean waters into the afternoon. While there will be a decent amount of
time between small craft conds west of Moriches Inlet...there may
only be a few hours of sub-advsy conds east of Moriches
Inlet...but this will be dependent on how quickly seas subside.
Don't want a double headline...so will hold off issuing another
Small Craft Advisory and let the middle shift coordinate with surrounding offices.
Pressure gradient tightens behind low pressure departing to the northeast
and high pressure building in from the west. Northwest winds will gust 25-30 knots
on all waters...and there is the potential for gales on the ocean
waters Thursday afternoon and evening.
Conds slowly subside below Small Craft Advisory criteria Thursday night...but may
continue on the ocean waters through Friday morning.
Thereafter...with high pressure building in from the west...can expect
sub-Small Craft Advisory conds on the waters for the end of the week and through the
average rainfall amounts between 1/2 and 1 inch expected through
Wednesday evening. No flooding issues are anticipated. Dry
conditions are expected from Thursday afternoon through the start
of next week.
Marine...Small Craft Advisory until 10 am EST Wednesday for anz350-353-