Scientific Forecaster Discussion
Area forecast discussion
National Weather Service New York New York
343 PM EDT Tuesday Apr 28 2015
a low pressure system will remain well to the east through
Wednesday night. Meanwhile...a weak low pressure trough over the
area will pass to the south tonight...and a back door cold front
will move across from the east late Wednesday afternoon into
Wednesday night. Another low pressure system will slowly pass to
the south and east later this week. High pressure will build in
for the weekend. A weak cold front may approach early next week.
Near term /until 6 am Wednesday morning/...
stacked low pressure will remain southeast of Nova Scotia...with the County Warning Area
remaining on the western periphery of this system. An associated
weak surface trough over the area late this afternoon will pass to the
south this evening.
Complicated wind forecast this afternoon...with north-northwest winds gusting to
20-25 miles per hour inland...while sea breezes have developed right along
most south facing shores in the weak pressure gradient in vicinity of the
Fair weather cumulus over southeast CT/Long Island and west of the Hudson should
dissipate this evening and winds will diminish. After daytime
highs highs in the 60s to some lower 70s in NYC and NE New Jersey...expect
lows in the lower 50s in vicinity of NYC...40s elsewhere...and upper 30s in
the Long Island Pine barrens...a little colder than MOS guidance
outside of NYC metropolitan.
Short term /6 am Wednesday morning through Wednesday night/...
as the closed low meanders southeast of Nova Scotia...a spoke of upper
level energy/moisture will pinwheel around it across New
England...and help drive a back door cold front through eastern
sections late day Wednesday...then across the rest of the area Wednesday
night. Associated moisture should also lead to an increase in
clouds especially out east...and chance for a few showers across
southeast CT and eastern Long Island from late day Wednesday into Wednesday night.
Before the cold frontal passage...expect a mostly sunny day on Wednesday...with
highs 70-75 in most places..except upper 60s away from south
facing shores. Enhanced clouds and onshore flow across southeast CT and
The Forks of Long Island should hold temperatures down in the lower and
middle 60s...but those areas could end up warmer if daytime
heating/mixing can hold off cold frontal passage until nighttime.
Long term /Thursday through Tuesday/...
upper low over the Great Lakes dives into the southeast...carving
out an upper trough for the northeast for the end of the week. Surface
low pressure develops at the base of the trough...and that low will move
offshore and slowly track to the north during this time. Both the
GFS and the European model (ecmwf) keep the low south of the 40/70 benchmark...but
there are some signs within a couple of the gefs members that
indicate the low would track a bit closer to the coast than models
are indicating. Onshore flow will develop on Thursday and Friday...
and with widespread cloud coverage and easterly flow...can expect
below normal temperatures Thursday and Friday with highs Thursday in the
low 60s and highs on Friday in the 50s.
The bulk of the precipitation will remain offshore...but light quantitative precipitation forecast is
possible each day...and will continue to carry chance probability of precipitation through
the end of the week.
The low continues to move offshore on Saturday as high pressure over the
central U.S. Slowly builds east. Possible for clouds to linger
across the area as the low will be slow to depart. Heights will rise
through the weekend...and temperatures will be closer to normal on Saturday
with highs in the low to middle 60s...and then with downsloping flow on
Sunday...temperatures will be quite warm with highs in the lower 70s for
areas west of the Hudson River...in the upper 60s most elsewhere...
and in the lower 60s closer to the coasts. Afternoon sea breezes
would result in cooler temperatures as the afternoon progresses.
A few week surface troughs or weak cold fronts will slide through the
region early in the new week. With limited surface moisture and a lack
of upper level support...not expecting much in the way of widespread
showers. But west to southwest flow will usher strong warm air advection into the
region with above normal temperatures for most of the local region.
Aviation /20z Tuesday through Sunday/...
high pressure remains over the region.
VFR. North winds backing towards northwest this afternoon and diminishing slightly
by late. Sea breezes have formed and will probably confined to
kisp/kbdr/kgon. Still a chance that it passes through kjfk.
... 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: winds north of 310 mag through the day. Chance
of sea breeze moving through near 23-00z - winds would then shift S-
Klga fcster comments: winds north of 310 mag through the day.
Kewr fcster comments: winds north of 310 mag through the day.
Kteb fcster comments: no unscheduled amendments expected.
Khpn fcster comments: no unscheduled amendments expected.
Kisp fcster comments: timing of when winds shift back west-northwest-northwest could
be off by an hour or two.
Outlook for 18z Wednesday through Sunday...
Wednesday...VFR. Afternoon sea breezes.
Thursday-Thursday night...VFR. NE winds g15-25kt possible late
Friday-Friday night...low chance MVFR or lower in any rain showers. NE-north
winds g25-30kt possible.
quiet through Wednesday night. A back door cold frontal passage from the east late
day Wednesday into Wednesday night should be followed by winds shifting east and
gusting to 20 knots Wednesday night. The easterly flow will increase Thursday
into Friday as low pressure passes to the south. Small Craft Advisory conds are
likely for the ocean waters...and are possible for the South Shore
bays. Lingering swells thereafter will keep ocean seas above
Small Craft Advisory levels into the weekend.
significant precipitation not expected through Wednesday. Light rain is
possible Thursday-Friday as low pressure passes to the south.