Area Forecast Discussion
Issued by NWS Upton, NY-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KOKX 311200
Area Forecast Discussion
National Weather Service New York NY
800 AM EDT TUE MAY 31 2016
A weak cold front moves across the area this morning and then
washes out just to the south. A second cold front moves through
this evening, followed by high pressure building down from
southeast Canada through Thursday. A cold front moves across the
region Friday night. Weak high pressure then builds through the
region on Saturday. Unsettled weather on tap for the start of the
new week as low pressure slowly works through the Northeast.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Extended the fog into mid morning across far eastern LI/SE CT due
to widespread fog in the adjacent marine waters. The fog will
dissipate and diminish in coverage with the onset of daytime
Areas of fog across eastern Long Island, in particular the south
shore, will dissipate with a cold frontal passage by mid morning.
Localized dense fog is possible.
A weak cold front just north of the Lower Hudson Valley this
morning will pass to the south of Long Island by mid morning.
There is little upper support and surface high pressure remains
north of the Great Lakes. Model consensus take this front just
south of the area where it washes out by afternoon with sea breeze
development at the coast and a thermal trough inland. An
isolated shower can not be ruled out with he frontal passage,
however with weak forcing and minimal instability, it seems
Another mid level short wave trough passing across eastern Canada
today will send a second cold front toward the area this evening.
This will be a dry frontal passage.
Used a MOS blend today for highs which produces values of 75-80
at the coast, and the low to mid 80s inland. This is almost 10
degrees above normal.
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
Cold frontal passage this evening will be dry, followed by Canadian
high pressure building southeast across the area through mid
week. Riding both aloft and at the surface will produce dry,
tranquil conditions with lows tonight and highs on Wednesday 5-8
degrees cooler, still though slightly above normal. A subsidence
inversion around 850-800 mb and daytime heating may allow for some
afternoon clouds Wed as easterly winds transport moisture off the
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
High pressure remains over eastern Canada Wednesday night through
Thursday. Meanwhile, a cold front approaches from the west as low
pressure tracks across Canada. Dry weather on tap through Thursday
evening, and then rain chances increase after midnight Thursday
night as that cold front moves into the region. Showers taper off
Saturday morning, and then weak high pressure moves across thew
region Saturday afternoon and evening.
Deep upper trough and low pressure then digs into the Great Lakes
during the day Sunday, and then slowly works east through Monday.
Whether a secondary low develops remains to be seen, but showers
will overspread the region Sunday and Monday.
Near to slightly above normal temperatures expected for the long
term period, with highs generally topping off in the upper 70s to
low 80s and lows in the 60s.
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --A weak cold front will wash out over the area today. High
pressure will build from the NW tonight.
The weak surface front is still NW of NYC metro. Winds at 1-2 kft
AGL are N-NW, so with some daytime heating these winds will mix to
the surface before 15Z, but not for long as sea breezes develop at
usual times or perhaps an hour later, especially farther east.
IFR/LIFR cigs at KGON/KISP will lift/scatter this morning as
drier air moves in aloft and slow daytime heating takes
place. Otherwise VFR conditions expected.
...NY Metro Enhanced Aviation Weather Support...
Detailed information...including hourly TAF wind component fcsts
can be found at:
KJFK TAF Comments: Sea breeze could develop an hour later
KLGA TAF Comments: No unscheduled amendments expected.
KEWR TAF Comments: No unscheduled amendments expected.
The afternoon KEWR haze potential forecast is green...which
implies slant range visibility 7SM or greater outside of cloud.
KTEB TAF Comments: No unscheduled amendments expected.
KHPN TAF Comments: No unscheduled amendments.
KISP TAF Comments: Unscheduled amendments possible to fine tune
improvement in flight cat this morning and sea breeze onset this
morning, which could occur an hr later than fcst.
.OUTLOOK FOR 12Z Wednesday through Saturday...
.Thursday...VFR. E winds occasionally gusting to 15-20 kt along
the coast and at the NYC metros.
.Thursday Night...Chance of showers mainly after midnight with
.Friday...Chance of mainly afternoon and evening showers/tstms
with brief MVFR or lower conds.
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Areas of dense fog will continue across the waters this morning
with particular emphasis across the eastern waters. A cold frontal
passage by mid morning will bring drier air into the region and
should dissipate the fog. This front however is weak and washes
out in close proximity to the waters by early afternoon.
Winds are forecast to remain light from the south this afternoon,
then become NE late tonight into Wednesday at 10-15 kt.
Sub-SCA conditions will continue from Thursday through the
weekend. Seas may build to 5-7 feet for the start of the new work
week as low pressure passes through the waters.
Scattered showers and thunderstorms will pass through the region
Thursday night through Saturday morning. In general, up to 1/4
inch QPF is possible with locally higher amounts in convection.
Another round of showers will impact the region for the start of the
new week. It is too soon to determine QPF amounts at this time.
MARINE...Dense Fog Advisory until 11 AM EDT this morning for ANZ330-340-