Area Forecast Discussion
Issued by NWS Upton, NY
FXUS61 KOKX 251500
Area Forecast Discussion
National Weather Service New York NY
1100 AM EDT Sun Sep 25 2016
High pressure settles over the area through tonight. The high
slides offshore on Monday followed by a frontal system moving
through on Tuesday. The front may linger near or just offshore
through the end of the week.
.NEAR TERM /THROUGH TONIGHT/...
The forecast was on track this morning with no major changes made.
Deep upper trough continues to track SE across far eastern Canada
today with high pressure settling over the area at the surface.
Northerly flow will continue to usher in an autumn airmass with
dew points in the 30s today under clear skies. These dew points
will combine with temperatures in the middle and upper 60s for
most locations. A few readings near 70 are likely in the NYC metro
and Urban NE NJ.
There is a moderate risk of rip current development at ocean
Excellent radiational cooling conditions tonight with high
pressure overhead, nearly calm winds, and mostly clear skies.
Coldest locations across the interior and Long Island Pine Barrens
fall into the upper 30s. Elsewhere, lows will generally be in the
lower and middle 40s with readings in the upper 40s and lower 50s
closer to the NYC metro.
.SHORT TERM /MONDAY THROUGH TUESDAY/...
Deep layered ridge axis moves over the region on Monday as the
surface high begins to slide offshore. This will set the stage for
another seasonable autumn day with temperatures in the upper 60s
and lower 70s.
Models continue to come into better agreement with the evolution
of a deep upper low settling over the Great Lakes/Southern Ontario
late Monday into Monday night. A frontal system associated with
the upper low approaches Monday night with increasing warm
advection and moisture. Overall, deterministic and ensembles agree
on the front moving across on Tuesday morning/early afternoon.
However, there are some members that are a bit slower. Have
increased PoPs to categorical Tuesday morning, decreasing to
chance in the afternoon. This system already has shown signs of
a deep plume of moisture across the central states where it is
currently located. PWATs are forecast to range between 1.5 and 2
SD above normal ahead of the front with moderate to heavy rain
possible. A low amount of elevated CAPE is noted on NAM BUFKIT
profiles, with more stable profiles on the GFS. An isolated rumble
of thunder cannot be ruled out, but the chance appears very low at
this time to include in the forecast.
Some clearing is expected Tuesday afternoon as much drier air
begins to work in behind the front.
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
There remains a general agreement on the upper low sitting near or
over the Great Lakes/Ohio Valley region through midweek...before
models diverge in evolution and opening on the low for the late
With this in mind, forecast uncertainty continues for the mid to
late week on evolution of the closed low and how quickly it opens
up and move through the east coast. A more progressive scenario
would allow high pressure to return for the late week with mainly
dry and seasonable conditions. Meanwhile a less progressive or
cutoff scenario would result in potential for additional waves of
low pressure to develop along the cold front and affect the region
mid to late week. The forecast continues to be weighted towards a
dry solution, but have noted the 00z models have indicated the
more unsettled solution may hold a little more weight. Rainfall
chances may need to be increased in subsequent forecasts as
confidence increases in the outcome.
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
Northerly winds around 10 kt this morning will gradually veer
around to the NW this afternoon. For the NYC terminals, winds
have been varying 10-40 degrees to the right of true north. This
should be short lived.
KEWR wind direction this AFTN will vary either side of 310
Magnetic, but gusts do not appear likely to occur with the speed
averaging below 10 KT.
KJFK wind direction may back more to W for or during the INTL
.Outlook for 12Z Monday through Thursday...
.TUE...MVFR w/areas of IFR in the morning. Becoming VFR from West to
.THU...Potential IFR/MVFR CIGS with RA. NE Wind 15-20 KT.
Northerly winds will continue across the waters through tonight
with wind gusts around 20 kt still possible, mainly on the ocean
this morning. Long period SE swells from distant tropical cyclone
Karl will continue to impact the ocean waters with seas right
around 4-5 ft. The SCA has been replaced with a small craft
advisory for hazardous seas as wind criteria is not expected to be
Sub-SCA conditions are likely on Monday with SCA conditions
Monday Night into Tuesday on ocean waters ahead of a frontal
system. The possibility also exists for SCA winds on near shore
Sub sca conditions likely return for Wednesday and Thursday as
the pressure gradient weakens although there is a great deal of
uncertainty regarding the forecast during this time period.
A frontal system moves through Tuesday with a general 1/2 to 1 inch
of rain likely...with locally higher amounts possible. Any
hydrologic impacts will be minor as the system will move through
MARINE...Small Craft Advisory for hazardous seas until 6 PM EDT this
evening for ANZ350-353-355.