Scientific Forecaster Discussion
Area forecast discussion
National Weather Service New York New York
1052 am EDT Wednesday Oct 22 2014
low pressure off the middle Atlantic coast will slowly drift
northeastward through Thursday...then lifts into the Canadian
maritime provinces late this week and into the weekend. A cold
front will moves across the area Saturday into Saturday night. High
pressure builds south of the region for the start of the new week.
Near term /until 6 PM this evening/...
upper low and associated vorticity maxes rotating through the low were
moving slowly to the east to southeast with the northern
precipitation shield across the northwestern portions weakening
and moving south while showers were rotating north into eastern
long. Have adjusted probability of precipitation through this afternoon to account for the
current trends with the low. Clouds persist...temperatures will be
nearly steady...and dew points remain close to forecast.
There are still some differences in the track of the surface low as
tracks towards the 40n 70w benchmark this afternoon. The NAM is the
furthest north today and becomes the furthest west and slowest to depart
Highs today were a blend of the MOS guidance which looked
Short term /6 PM this evening through 6 PM Thursday/...
low becomes nearly vertically stacked tonight and Friday as it
meanders near the 40n 70w benchmark. Best chc's of rain will be
during this time. Models in good agreement that a band pushes from
east to west overnight...then weakens in the morning with another vorticity
maximum producing additional showers Thursday afternoon. Therefore have likely
to Cat probability of precipitation for much of the period.
Strong northerly winds continue this evening...then weakens slightly
overnight and Thursday as the pressure gradient weakens with the low
nearby. It will still remain gusty however...although not as
strong as this afternoon and evening.
Temperatures tonight and Thursday were a blend of the mav/ecs as the NAM
looked too cold with cloud cover and precipitation.
Long term /Thursday night through Tuesday/...
nearly vertically stacked low approximately 130 miles southeast of Montauk
Point Thursday evening moves into the Canadian Maritimes Thursday
night through Friday. Showers taper off from west to east during
this time. Although most precipitation should be over by late Friday
morning...a few lingering showers are possible north and east of NYC
as upper trough/shortwave combo depart.
High pressure then builds into the Ohio Valley on Friday before sagging
into the southeast U.S. On Saturday as a cold front approaches from
the west. That front slides through the region Saturday night. Think
most precipitation should stay north of the area and the front comes
through dry...but the 00z GFS/00z European model (ecmwf) indicating some light
High pressure then builds into the middle-Atlantic Sunday and Monday...and
then moves offshore on Tuesday. Dry conds on tap for the start of
the new week...and a cold front approaches for the middle of next
Highs will be right around normal on Friday...topping off in the
lower 60s...and then will warm up slightly on Saturday into the low
to middle 60s. Behind cold front...temperatures drop back into the upper 50s
and low 60s on Sunday...and then temperatures will be milder for the start
of the new work week with highs in the middle to upper 60s.
Aviation /15z Wednesday through Sunday/...
low pressure passes just south and east of Long Island today into
Persistent convection remains south of the region. Will continue
to monitor for any northward progression.
Expect predominately MVFR ceilings today...between 1 and 2 kft
possibly improving to 2 to 3 kft this afternoon. Do not foresee
visibility restrictions under 3 miles...unless any Airport
experiences local heavy rain for a time.
Depending on what happens with the large area of convection...expect
hit or miss showers today moving from southeast to northwest through the day.
More organized rain may approach from the east late this afternoon
and into tonight.
Winds are increasing this morning to 10 to 15 kts. Gusts become
frequent after 14-16z. Gusts 20 to 25 knots expected.
These winds should increase somewhat late this afternoon and into
this evening. Wind direction remains north/northeast this
morning...then due north this afternoon. Winds back slightly to the
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: amendments are likely today for wind gust
Klga fcster comments: gusty north to northeast winds today.
Kewr fcster comments: amendments are likely today for stronger
wind gust timing.
The afternoon kewr haze potential forecast is green...which implies
slant range visibility 7sm or greater outside of cloud.
Kteb fcster comments: amendments likely for changing flight categories.
Khpn fcster comments: amendments likely for changing flight categories.
Kisp fcster comments: amendments for winds and possible showers
through the day.
Outlook for 12z Thursday through Sunday...
Thursday through Thursday night...MVFR or lower conditions in
periods of rain. North-northwest winds g25-30kt possible.
Friday-Friday night...most likely VFR...with low chance spotty
MVFR. Northwest winds g20-25kt possible.
Saturday-Saturday night...VFR. Northwest-west winds g25-30kt possible.
Sunday...mainly VFR. Northwest winds g20-25kt possible.
wind and seas forecast on track. Probability of precipitation across the waters adjusted
through this afternoon for current track of the low movinf east to
southeast off the middle Atlantic coast.
A Gale Warning for the ocean waters from 18z this afternoon through
10z tonight remains in effect. Models are in good agreement on
the strength of the low offshore and believe freq 35 knots gusts will
result. The Gale Warning may need to be expanded into eastern Li sound
and bays...just did not have the confidence in frq 35 knots gusts
here. No changes to the Small Craft Advisory on remaining waters in effect through
the day Thursday.
Gusty north-northwest flow with gusts up to 25 knots continues Thursday night
through Friday with seas around 5 feet on the ocean. By Friday
night...conds subside to sub-Small Craft Advisory conds and sub-Small Craft Advisory conds will
continue through Saturday.
A cold front moves across the waters Saturday night...and then northwest
winds will gust to 25 knots on Sunday with 4-6 feet seas on the ocean
High pressure then builds into the waters for the start of the new work
week...and tranquil conds will return.
as mentioned above localized flash flooding is currently
occurring due to a backbuilding storm off the South Shore of Long
Island. This activity is expected to drift S and east this morning
with scattered activity likely until late this afternoon and tonight.
Additional basin average rainfall amounts ranging from 3/4 across
western areas to 1 1/2 inches in eastern areas is expected through
Mainly expect nuisance urban or poor drainage flooding with any
heavier showers after the activity ends early this morning.
Light precipitation will taper off Thursday night into Friday with about
1/10 inch of additional quantitative precipitation forecast.
Marine...Small Craft Advisory until 6 am EDT Thursday for anz330-335-
Gale Warning from 2 PM this afternoon to 6 am EDT Thursday for