Scientific Forecaster Discussion
Area forecast discussion
National Weather Service New York New York
201 PM EDT Tuesday may 5 2015
a stalled out front across the area this afternoon will pass to
the south late tonight...then become nearly stationary south of
the area Wednesday. High pressure builds over the region for the
end of the week...and then shifts offshore this weekend. A cold
front will slowly approach from the north and west late Sunday
Near term /until 6 PM this evening/...
a weak frontal boundary stalled near NYC/Long Island will
interact with weak instability for the potential of isolated
showers for the remainder of this afternoon. Latest mesoanalysis
shows interior NE New Jersey...the lower Hudson Valley...and interior SW
CT with convective available potential energy up to 250 j/kg. Seabreeze along the coast may just
cap any convection.
Highs have been adjusted up into the lower 80s across the
interior...the 70s near the coast...and in the 60s along the South
Shore of Li/east end/and southeast coastal CT.
Short term /6 PM this evening through 6 PM Wednesday/...
the best chance for precipitation comes late tonight and Wednesday morning. Remnant mesoscale convective system
appears to be the trigger and additional moisture source. There
could be enough elevated instability due to the thetae advection
to allow for an isolated thunderstorm. Otherwise...the sluggish surface front
just S of the County Warning Area will continue to produce weak convergence...so
have kept schc for showers for the rest of the time. Cooler with NE
flow developing behind the front. Temperatures close to gmos25.
Long term /Wednesday night through Monday/...
the synoptic pattern for the long term period over the northeastern
United States will be dominated by deep layered ridging aloft.
Surface high pressure builds on Thursday and then begins to slide
offshore Friday into the weekend. Southwesterly flow around the high
transports warmer air into the region this weekend. This pattern
brings above normal temperatures and mainly dry conditions.
The next frontal system sets up to our northwest late this weekend.
There appears to be a very weak push of the front south with ridging
holding strong over the western Atlantic Sunday into Monday. The 00z
GFS weakens the ridge enough on Sunday for the front to sink into
the area. The 00z European model (ecmwf) and 00z CMC keep the ridge stronger...and
this has agreement with the 00z gefs mean. Have sided with a slower
progression of the front with this forecast package. With this in
mind...probability of precipitation increase to low chance by Monday for showers and
thunderstorms as the front moves closer to the region.
Temperatures Thursday and Friday will range from the lower 70s near
the coast to the middle and upper 70s in the city and points north
and west. For Saturday and Sunday...highs will warm into the upper
70s and lower 80s away from the coast. Afternoon sea breezes will
keep coastal locations in the lower to middle 70s. With a bit more
cloud cover and possible showers/storms Monday...highs will be a bit
cooler than the weekend in the lower to middle 70s.
Aviation /18z Tuesday through Sunday/...
stationary front remains across the local terminals today.
VFR. Isolated showers late this afternoon primarily for kteb/kewr/klga/kjfk.
Coverage too low for mention in tafs.
Winds around 10kt or less. Wind directions are a lower confidence
forecast due to local sea breezes interacting with the stalled front.
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: chance variable or north winds at times before 19z. Brief
3-5sm visibilities in -shra possible from approx 21-23z.
Klga fcster comments: chance variable or north winds at times before 21z. Brief
3-5sm visibilities in -shra possible from approx 21-23z. Timing of shift to
S in sea breeze could be off by an hour or two.
Kewr fcster comments: brief 3-5sm visibilities in -shra possible from
approx 21-23z. Timing of shift to southeast in sea breeze could be off by
an hour or two.
Kteb fcster comments: brief 3-5sm visibilities in -shra possible from
approx 21-23z. Sea breeze shift timing to S could be off by an hour
Khpn fcster comments: no unscheduled amendments expected.
Kisp fcster comments: no unscheduled amendments expected.
Outlook for 18z Wednesday through Sunday...
Wednesday afternoon...VFR likely.
Wednesday night through Sat...VFR.
Sun...chance MVFR or lower. Chance rain.
seas continue to remain below 5 feet on the ocean this morning...and
should continue to subside through the day. In addition...the
cold stable waters are limiting wind gusts per the buoy data. With
a cold front settling over then S of the waters tonight and
Wednesday...winds and seas will stay blw Small Craft Advisory levels. High pressure will
move over the waters Thursday through Saturday allowing for sub
Small Craft Advisory conditions. A few 20 knots gusts are possible Friday and Saturday
afternoon across the near shore waters due to afternoon sea
basin Ave rainfall of around a half inch is possible late tonight
into early Wednesday if a remnant convective complex impacts the region.
Otherwise...precipitation will be scattered and light. Mainly dry conditions are
expected Thursday through the weekend. Chances for showers and
thunderstorms begin to increase Sunday night into Monday.