Scientific Forecaster Discussion
Area forecast discussion
National Weather Service New York New York
725 am EDT sun may 3 2015
high pressure moves off the middle Atlantic coast today through
Monday...as a broad...weak trough of low pressure remains over
the tri-state. A cold front approaches from the Great Lakes
Monday night...passing south through the region Tuesday into
Tuesday night. High pressure builds down from southern Canada
Wednesday through Thursday night. The high slowly retreats to the
east into the upcoming weekend as a slow moving frontal system
approaches from the west.
Near term /through tonight/...
forecast remains on track with only minor updates made to near
Heights aloft rise today as ridging builds into the northeast
states. Surface high pressure will move off the middle Atlantic
coast through the day. Daytime heating develops a thermal surface
trough across the far northwest interior...which may provide enough
convergence for an isolated shower to develop during the
afternoon along it. Otherwise...dry forecast for today.
Temperatures will continue to warm compared to the last several
days. Highs will reach the middle and upper 70s from NYC north and
west. Sea breezes will likely cap high temperatures near the coast
in the middle and upper 60s. These highs near the coast will
occur middle day to early afternoon with readings slowly falling for
the remainder of the day.
Mostly clear conditions forecast tonight with low temperatures in
the upper 40s and lower 50s for much of the area. Milder lows
in the middle and upper 50s forecast in NYC.
Short term /Monday through Tuesday night/...
upper level ridge axis moves east of the area on Monday. With SW
flow around offshore surface high...unseasonably warm temperatures
are expected on Monday. Highs will reach the lower 80s for the
NYC/New Jersey metropolitan and interior and middle to upper 70s near the coast.
A cold front approaches from the northwest Monday night into Tuesday
morning. The front should begin to move into the area during peak
heating Tuesday afternoon with temperatures rising into the 70s.
Moisture will also increase throughout the day. Models differ on the
amount of instability available for convection...but there should
enough elevated instability for a few thunderstorms to develop in
the afternoon and evening. The 00z GFS/NAM/CMC indicate a weak wave
developing on the front in the afternoon/evening. The 00z European model (ecmwf) does
not really show this wave. It remains to be seen if this feature
actually develops as it could enhance coverage of showers and
storms. Even if the wave develops...there is little to no support
for any organized severe convection. Have capped probability of precipitation at high chance
Tuesday afternoon and evening.
Showers may linger into Tuesday night as the front slowly moves
south of the area. Probability of precipitation slowly decrease through the night.
Long term /Wednesday through Saturday/...
northern stream ridging slowly builds over the area from Wednesday
through Friday...with its ridge axis then sliding to the east into
Saturday. Meanwhile...a southern stream trough/possible cutoff low
remains near the southeastern Seaboard.
Still appears there could be some lingering -shra over the area
Wednesday morning before the developing stationary front slides to
far S to have any impact on the area other than possibly some cloud
cover. It should then be dry through Saturday morning due to
subsidence under the ridge. The possible exception is far West Orange
County where there could be just enough forcing to warrant a slight
chance of -shra on Friday. An approaching warm front by late
Saturday warrants slight chance probability of precipitation over mainly the interior zones
For temperatures Wednesday through Saturday used a blend of
mex/ekd/ece/ecm and wpc guidance. Temperatures should be above
normal in this time range.
Aviation /11z Sunday through Thursday/...
a weak...broad trough of low pressure will remain over the area
VFR through the taf period.
Light and variable winds give way to SW-south-southwest flow under 10 knots by
middle morning to early afternoon...except west at kswf. A seabreeze
will impact all but kswf this afternoon...speeds generally around
10kt immediate S shore (both Atlantic and sound) terminals...and
under 10 knots elsewhere. Winds become light and variable again this
Outlook for 12z Monday through Thursday...
Monday-Monday night...VFR. SW winds g15-20kt possible Monday
Tuesday-Wednesday morning...MVFR or lower possible with any
showers. Low chance of thunderstorms Tuesday afternoon/evening.
ocean swells to 5 feet continue on the coastal ocean waters west of
Moriches Inlet. Have extended the Small Craft Advisory for hazardous seas there
until 16z. Seas east of Moriches Inlet at 44017 have stayed just
under 5 feet...with swells diminishing to only 3 feet at buoy 44097.
Given this...do not have confidence to extend the Small Craft Advisory any farther
Otherwise...sub Small Craft Advisory conditions are forecast on the waters through
Monday. The next chance for Small Craft Advisory conditions will be Monday night
ahead of a cold front...with wind gusts to 25 knots and seas building
to near 5 feet. 5 feet seas may linger east of Moriches Inlet on
Winds should be 10 knots or less on Tuesday night...then less than
10 knots Wednesday through Thursday due to a light pressure gradient
over the region. With no significant swell predicted to impact the
coastal ocean waters during this time frame...there should then be
sub-small craft conditions on all waters Tuesday night through
it should be mainly dry into Tuesday morning.
Locally heavy rainfall is possible Tuesday afternoon/evening with
showers and thunderstorms ahead of a cold front.
At this time it appears it should be mainly dry from Wednesday
the kokx radar is down for repair. Parts have been ordered...and
repairs will begin once they arrive. Initial estimate for
completion of repair is late Monday.
Marine...Small Craft Advisory for hazardous seas until noon EDT today