Area Forecast Discussion
Issued by NWS Upton, NY-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KOKX 210245
Area Forecast Discussion
National Weather Service New York NY
1045 PM EDT SAT AUG 20 2016
A weak frontal boundary sitting across the region will gradually
weaken tonight. A frontal system will approach from the Ohio Valley
on Sunday and move through the region Sunday night. High pressure
then dominates next week. A cold front approaches late next week.
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
A few showers have developed over southern CT this eve. There are
some outflow boundaries still lingering across the area from
earlier convection which may be triggering this.
Otherwise...expect dry conditions until late tonight.
There is some agreement amongst the guidance that a north to south
oriented line of showers develops after midnight. They are all
pointing to the area from western CT through western LI...so have
added chc pops here into Sun morning.
Stratus has also started developing across the east end of Long
Island and SE CT. This is expected to continue expanding across
the area through midnight with OVC conditions across the area by
Temperatures overnight fall into the 60s and lower 70s.
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
A cold front associated with Canadian low pressure approaches the
region Sunday...and then moves across the area Sunday night.
An increasingly moist airmass is expected on Sunday ahead of
approaching trough and cold front. Showers and thunderstorm are
expected to develop during the late morning/early afternoon and
increase in coverage through the afternoon and evening as the cold
front approaches and moves through.
The main threats with any thunderstorms appear to be torrential
downpours with any convection. The threat for strong to severe
storms appears to be quite low at this time due to late day/evening
timing and weak instability. If instability can build or line is
faster, cant rule out a storm or two with strong wind gusts for
areas mainly west of the Hudson late day/early eve. With
strengthening low-level veering wind profiles with weak wave
development and low lcl`s would have to monitor for any rotating
The front moves across the region Sunday night with most of the
precipitation coming to an end around or shortly after midnight. A
few lingering storms may remain into early Monday morning across the
far eastern sections.
Temperatures on Sunday will climb into the 80s, with Sunday night
lows falling into the 60s. A MAV/MET/ECS blend was used.
There is a moderate risk of rip currents along the Atlantic
.LONG TERM /MONDAY THROUGH SATURDAY/...
Cold front pushes well offshore Monday morning. Behind the front
expect dry weather conditions as high pressure builds in from the
west and dominates through the end of the week.
Less humid conditions returns on Monday as dew points drop into the
low to mid 50s behind the front. Humidity levels will increase by
the middle of the week in response to an onshore flow with dewpoints
back into the mid 60s to upper 60s.
As for temperatures, expect near or slightly below normal
temperatures on Monday and through the middle of the week, then back
to above normal thereafter.
A cold front approaches late in the week.
.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --High pressure slowly retreats to the northeast into Sunday
morning. A cold front approaches from the west later on Sunday.
Moderate to high confidence in MVFR conditions developing at all
terminals tonight. Have slowed onset time to mainly after midnight
- except at KGON where MVFR will just continue. Confidence in
timing where MVFR is not already occurring is low-moderate. Low
confidence in IFR overnight - except low-moderate at KGON - so
have a TEMPO group there for early Sunday monring.
MVFR conditions should linger through Sunday morning, then
possibly lift to low end VFR (3500-5000 ft) ceilings in the
afternoon. Showers/thunderstorms should move into western
terminals 19-20z and KISP/KBDR 21-22z.
There is also a low chance of isolated showers/drizzle at mainly
western terminals overnight. Confidence in this remains to low to
reflect in TAFs at this time.
SE flow less than 10 kt through Sunday morning. Speeds could
increase at city/coastal terminals to 10-15kt Sunday afternoon.
Western terminals should see winds veer towards the S late Sunday
.OUTLOOK FOR 00Z MONDAY THROUGH THURSDAY...
.Sunday night...Showers and thunderstorms likely with MVFR or
lower conditions in the evening, then becoming VFR from W to E
overnight. SE winds g20-25 KT possible. Higher gusts possible in
thunderstorms. Conditions improving to VFR after 05Z.
.Monday-Thursday...VFR. NW winds g15-20kt possible Monday
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Southeast winds tonight will continue into Sunday and increase to 10
to 20 kt. A cold front moves across the waters Sunday night, and
winds shift around to the NW behind the front Monday morning. A few
gusts to 20 to 25 kt are possible. Seas may also briefly build to 5
ft on the far eastern ocean zones. With low confidence of reaching
Small craft conditions, will hold off on any headlines for now.
High pressure builds Tuesday and Wednesday and winds lighten
Sunday afternoon through Sunday night, 1/2 to 1 inch of rain is
expected. Minor urban flooding would be the main hydrologic impact
from this rainfall...with a localized flash flooding threat from
any training cells.
Dry weather is then expected for much of next week.