Scientific Forecaster Discussion
Area forecast discussion
National Weather Service New York New York
1037 PM EDT sun may 3 2015
high pressure will remain just off the middle Atlantic coast through
Monday...then move farther offshore Monday night into Tuesday as
a cold front begins its approach. The front will pass through late
Tuesday...followed by high pressure from Wednesday through Sunday.
Near term /until 6 am Monday morning/...
forecast on track with only minor tweaks to hourly temperatures.
Mostly clear (becoming mostly clear inland) skies overnight with
a full moon. Lows ranging from the middle/upper 50s in NYC...lower
50s in the surrounding metropolitan areas...40s most elsewhere...and near
40 in the Long Island Pine barrens.
Short term /6 am Monday morning through Monday night/...
upper level ridge axis moves east of the area on Monday. With SW
flow around offshore surface high...a breezy and unseasonably
warm day expected...with highs 80-85 from NYC north/west and the North
Shore of Long Island...and 70s elsewhere...upper 60s at the south
UVI for Monday is 8...which is very high. (Same sun angle as
A cold front will begin to approach late Monday night...with only
slight chance of a shower well inland north/west of NYC. Expect
lows in the lower 60s in NYC and in the 50s elsewhere.
See fire weather section for more information on Fire Weather
Long term /Tuesday through Sunday/...
the cold front sags south across the region Tuesday afternoon with
instability driven showers. Pop at 50 percent...but think we will
go higher as the event approaches. Jet dynamics are weak with the
jet streak displaced well north in southern Quebec. Li gets down
to about -1 and there are a few hundred j/kg of cape. With surface
temperatures into the middle 70s...have included thunderstorms for the
afternoon...consistent with Storm Prediction Center outlook.
The front sags south Tuesday night. The 12z GFS has a convective
induced vorticity maximum passing across New York state overnight. Based on
NAM/CMC/ECMWF and quick look at the latest sref...think this
feature is overdone in the GFS and have lowered pop overnight.
Thereafter...high pressure noses into the region with dry and
unseasonably warm temperatures. Highs generally in the middle 70s...except
cooler at the coast.
A back door cold front may lower temperatures for Sunday. Also...with the
approach of a cold front from the west introduce a low chance for rain showers
Sunday afternoon inland north and west of NYC.
Aviation /03z Monday through Friday/...
VFR as high pressure remains just off the middle Atlantic coast.
Light and vrb overnight. South-southwest winds Monday with speeds 10-20kt after 16z.
An occlusion gust above 20kt possible in the 18-01z period...especially
kjfk and klga.
Outlook for 00z Tuesday through Friday...
Monday night...VFR with decreasing SW winds.
Tuesday-Wednesday morning...MVFR or lower conds possible with any showers.
Low chance for thunderstorms Tuesday afternoon/evening.
seas will continue to diminish tonight into Monday morning...then
there will be two chances for marginal Small Craft Advisory conds on the ocean Monday
afternoon/night. First...southerly coastal jet could reach 25 knots
late Monday afternoon into early Monday evening on the ocean west of Fire
Island Inlet...then SW flow increasing to 15-20 knots ahead of an
approaching cold front could push ocean seas to 5 feet mainly east of
Moriches Inlet from late Monday night into Tuesday morning.
A cold front will move across late Tuesday...with an isolated thunderstorm.
Ocean seas should subside below Small Craft Advisory criteria early Tuesday.
Thereafter...expect tranquil weather with high pressure in control.
have issued Fire Weather Watch for most of the area Monday afternoon and
early evening...as min relative humidity falls to 25-30 percent and S-SW winds
increase to 15-25 miles per hour. Meteorological conditions are more
favorable in NE New Jersey...NYC Nassau and western Suffolk...especially
middle to late afternoon...but elsewhere fine fuels are very
dry...so marginal conditions could still lead to rapid fire
showers/isolated thunderstorms with a cold front Tuesday afternoon/evening should
produce basin averages of less than 1/4 inch. No impacts expected.
At this time...it appears dry from Wed-Sunday.
kokx radar remains out of service. Repairs will begin on Monday
once parts arrive. Updated estimate for completion of repair is
CT...Fire Weather Watch from Monday afternoon through Monday
evening for ctz005>009.
New York...Fire Weather Watch from Monday afternoon through Monday
evening for nyz067>075-078>081-176>179.
New Jersey...Fire Weather Watch from Monday afternoon through Monday
evening for njz002-004-006-103>108.