Area Forecast Discussion
Issued by NWS Upton, NY-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KOKX 260633
Area Forecast Discussion
National Weather Service New York NY
233 AM EDT FRI AUG 26 2016
A weak front will approach tonight. The front will then move
across the area on Friday, followed by high pressure this
weekend. A cold front will approach early next week, and may then
linger nearby until another cold front moves through Wednesday.
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
Dry conditions over the next several hours with the next chance
of showers towards daybreak, mainly over the westernmost zones as
a stronger mid level shortwave approaches and elevated
instability increases. Activity should be isolated so will
continue with a slight chance of a shower/thunderstorm for late
Overnight lows will range from the upper 60s to the middle 70s.
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SATURDAY/...
Upper ridge builds this time frame, with high pressure remaining
well to the south, and a weak cold front passing across the area
during the day Friday. 12Z model suite seems to be in good
agreement on a slightly faster cold frontal passage for western
zones. What this means is lower humidity levels during the
afternoon hours as winds shift to the west/northwest.
In spite of hot temperatures in vicinity of NYC metro/urban NJ,
slightly lower dew points will preclude 100 degree heat indices
that are needed for issuance of a heat advisory. As such, no heat
advisory is planned at this time.
Higher humidity will occur ahead of the front, over portions of
southern CT and Long Island. However, temperatures will be a tad
cooler there due to southerly winds ahead of the front.
As for rain, still would expect isolated to possibly scattered
coverage just along the front, per high resolution models. Best
chance during max heating and highest surfaced based instability
would be from southern CT southwestward across NYC metro and Long
Island for a time, with lowering chances as the afternoon
Dry Wx Friday night as much drier air moves in and the front
High temperatures Friday will range from the mid 80s along the
coasts of eastern Long Island and SE CT, to the lower 90s in and
around NYC metro.
At night, temps should fall into the 60s and 70s across the area,
still quite warm for this time of year, late summer.
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Models continue to be in good agreement for the the long term
period. This period begins with weak surface high pressure over the
region, which pushes off the New England coast Sunday. Aloft, a
ridge will build in while a closed high is centered over the Mid-
A surface cold front approaches from the west late Sunday into
Monday, slowly crossing the region late Monday into early Tuesday
morning. This frontal boundary should then stall and meander
over/near the area into Tuesday night before the next cold front
pushes through on Wednesday.
As far as temperatures are concerned, with the lack of any real
strong cold air advection, it will be above normal through the
period, with normal highs now in the upper 70s to lower 80s. Highs
will be in the middle to upper 80s, with near 90 in the New York
City metro area possible on Monday. Humidity levels will be on the
high side, but nothing too extreme as the cold front does not make
it completely through the region. Heat index values should remain
below 95 through the long term.
One thing to watch is the tropical disturbance currently just north
of Hispaniola. If this system develops, it could get drawn up into
the frontal boundary that moves through our area Wednesday, after
potentially impacting the Gulf states. The operational models have
this system traveling the cold front and passing south of our region
late in the period. However, there is a great deal of uncertainty,
and if further model runs show this cold front to be slower to move
through, the area could be impacted with some rain from the system.
However, it is near the end of this time frame, so for now, it is
something to be watched.
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --A cold front over the eastern Great Lakes preceded by a pre-frontal
trough across eastern PA will slowly track towards the region
overnight, moving across the area on Friday. The cold front will
pass through the terminals from around 17Z northwest to 00Z east.
There may be a few showers or even an isolated thunderstorm this
morning with the pre-frontal trough and then again with the cold
frontal passage this afternoon.
Coverage of showers and thunderstorms is expected to be sparse
with a low chance, so not included in the TAFs at this time.
With a south to southwest flow less than 10 kt tonight there is a
chance of MVFR ceilings after 09Z mainly at the coastal terminals,
and possibly at KSWF. With shift to the northwest with the cold
.Outlook for 06Z Saturday through Tuesday...
.Friday night through Sunday...VFR.
.Monday into Monday Night...VFR. Potential cold frontal passage
with a few showers and thunderstorms.
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Conditions will be just short of advisory criteria before winds
and seas diminish further overnight.
Winds will be relatively light ahead of a weak cold front late
tonight and through Friday. A shift to the west will occur behind
the front late Friday and Friday night from west to east. Rough
ocean seas will subside late tonight and through Friday night.
Sub-advy conds generally prevail otherwise through the day Monday.
However, potential remains for long period (generally periods of 10-
18 seconds) SE tropical swell on the ocean from Sunday through at
Seas could build to 5-6 ft mainly Monday night through Tuesday
night. Wind gusts should remain below 25 kt.
No significant widespread precipitation is expected into and
through the long term period.