Area Forecast Discussion
Issued by NWS Upton, NY-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KOKX 280627
Area Forecast Discussion
National Weather Service New York NY
227 AM EDT THU JUL 28 2016
Weak high pressure overnight will give way to an approaching cold
front Thursday. A wave of low pressure approaches and passes
nearby Friday. This low moves east of the region Friday night.
Weak high pressure briefly builds into the region for Saturday.
Unsettled weather returns for the end of the weekend and start of
next week with the passage of another low pressure system. Drier
weather is expected for Tuesday and Wednesday as high pressure
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
Mostly clear conditions remain late tonight with temperatures and
dewpoints still within a few degrees of forecast values. Only
slight adjustments were made to better match observed trends,
notably with dewpoints. These have increased a few degrees along
the coast over the last few hours. The forecast overall remains on
Aloft, the upper trough moves across the upper Great Lakes
region. A surface cold front accompany this features moves well to
the north. Meanwhile, another weak frontal boundary remains to our
south, with a series of weak lows along it.
Weak high pressure remains offshore, and a light south flow
prevails across the region. Dew points increase slightly, and as
temperatures fall overnight under mostly clear skies, patchy fog
formation is possible as boundary layer begins to saturate. Not
quite sure of extent of any fog, but it is possible as hinted at
by the models with their light moisture conveyed in the QPF fields
between 06Z and 12Z.
Lows tonight will range from the lower 60s well inland, to the
middle 70s in NYC metro.
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM FRIDAY/...
Through this time period, upper trough axis extending south
across the great lakes region/Ohio Valley and into the upper
Mississippi Valley will move east, with embedded Vorts in the mid
and upper level flow tracking east. Frontal boundary to the south
remains Thursday, as a series of low pressure centers ride along
it, the strongest of which approaches Thursday night and Friday.
Better jet support Friday, and enhanced lift along with abundant
moisture advecting east/northeast will allow for rain/possibly
Prior to that, isolated thunder per high resolution models
develops along seabreeze boundary Thursday afternoon. Kept pops
in slight chance range as coverage should be isolated, and this
assumes ample moisture up the column materializes.
One more warm to hot day is expected Thursday, with highs in the
upper 80s to around 90 under partly sunny skies. With higher
humidity levels, heat indices will run a degree or two above
actual air temps.
Temps will remain seasonably warm Thursday night, and not quite as
much of a range is expected as clouds increase, and rain chances
With the passage of a wave of low pressure, possibly just to our
south, temperatures on Friday will be cooler, upper 70s to around
80 thanks to clouds and rain. This has trended lower than previous
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Low pressure moving across the region moves east Friday night, with
just some left over showers and possibly a thunderstorm. Weak high
pressure briefly returns on Saturday, with most of the forecast
guidance keeping conditions dry. As a result, will keep conditions
dry on Saturday.
Unsettled weather returns Saturday night into Monday, as another
shortwave and low pressure system moves across the region. Expect
another round of showers and thunderstorms, with some storms
producing locally heavy rainfall.
High pressure builds back into the region early next week, providing
Temperatures will remain seasonable Saturday through Wednesday with
temperatures climbing into the 80s each day.
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --Light southerly flow at city terminals overnight with light and
variable winds at outlying terminals. Winds will become southerly
at most terminals daytime Thursday, and increase to around or
just over 10 kt near the coast in the afternoon with sea breeze
enhancement. Exceptions to the rule will be KLGA, with an ENE morning
sound breeze, and KEWR/KTEB, where SE sea breezes close to 10 kt
expected mid to late afternoon.
Low clouds/fog beginning to develop off the NJ coast should spread
northward, and could impact KJFK/KISP with IFR cigs up to around
daybreak. KGON could also be impacted as well, but confidence not
as high attm.
Cannot totally rule out an isold shower or tstm this afternoon,
mainly near sea breeze boundaries on Long Island. KISP could
experience brief vicinity impact.
.OUTLOOK FOR 06Z FRIDAY THROUGH MONDAY...
.Late Thu Night into Fri Night...IFR likely in showers/tstms. Rain
heavy at times. Tstms could produce strong winds in the morning
NYC metro terminals and KISP.
.Saturday Night into Monday...Iso-sct showers/tstms possible.
-- End Changed Discussion --
The forecast remains on track. Conditions will remain below SCA
with a weak pressure gradient in place.
As a weak front approaches, and weak wave of low pressure moves
by Thursday night and Friday, expect sub SCA conditions to
continue across the area waters.
A light pressure gradient over the area waters will result in sub-
sca conditions this weekend and early next week. However, any
thunderstorms that develop on the waters may produce brief SCA
There is potential for significant rainfall from late Thursday
night into Friday night. Locally heavy rainfall is possible, which
could cause flooding. Exact evolution of this potential storm
remains unclear, so it remains too early for specifics.