Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

000 
FXUS61 KOKX 241134
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
634 AM EST Sat Feb 24 2018

.SYNOPSIS...
Weak low pressure tracks across the region late today into this
evening. A warm front moves towards the region tonight, with a 
frontal system affecting the region Sunday. High pressure builds
from the Midwest Sunday night and remains in control through 
the middle of next week. A low pressure system may approach for 
the end of the week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Near zonal upper flow today, with northern stream shortwave tracking 
from Ontario into Quebec, and southern stream energy rotating around 
southern ridging. At the surface weak high pressure over the region 
this morning, will give way to approach of low pressure/s from the 
Tennessee/Ohio Valley along a stalled warm front. This will
spell a shot of rain from SW to NE this afternoon into evening.
Forcing with this system is not too strong, so expecting 
overall a a light rain event. 

Temps will run above seasonable with mild airmass in place,
Generally upper 40s to lower 50s. If several hours of sunshine 
are experienced this morning, temps could rise into the lower 
to mid 50s.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
Phasing Sub-tropical and Pac Jet Energy will lift towards the 
Great Lakes and NE US tonight into Sunday, with a strong mid-
level shortwave tracking through the Great Lakes tonight into 
Sunday Morning. At the surface, strengthening low pressure will 
take a similar track, eventually stacking under closing upper 
energy across northern Ontario by late Sunday. It trailing cold 
front will approach on Sunday with warm front lifting towards 
the region late tonight into Sunday, and signal for triple 
point low tracking over NYC/LI or just south Sunday aft/early 
Sun evening.

Expect increasing likelihood for rain from w to e late tonight 
as WCB and divergent upper flow transport and lift a +3-4 std 
pwat airmass into the region. This rain will be moderate to 
heavy late tonight into Sunday as moisture/lift is focused to 
the north of the warm front and in vicinity of the triple pt low
late tonight through Sunday. 1 to 1 1/2 inches of rainfall 
likely areawide, with locally higher amounts from orographic 
enhancement.

Cold air damming and evaporational cooling early Sunday morning
will likely have temps falling into the mid 30s across interior
valleys, perhaps localized lower 30s. At this point threat for 
any freezing rain looks to be low, brief and localized.
Otherwise, temps will likely be hard pressed to rise into the
lower 40s across the interior, particularly valleys, on Sunday,
while coastal areas should be able to rise into the mid to upper
40s. S LI could flirt with 50 degrees if warm front can lift
north.

Shortwave energy pivots NE Sunday evening with the triple pt low and 
cold front pushing east, and rainfall tapering off.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
The CONUS pattern of troughing in the west and ridging east of 
the Rockies looks to continue into next week. The upper pattern 
then appears to transition mid to late week next week as a 
closed low pres system moves onshore in California early, 
continues into the Plains mid week, and then possibly to the 
east coast by late week. Uncertainty abounds in the evolution of
this upper energy as the week progresses. 

In terms of sensible weather, dry weather returns Sun night as 
low pres departs and high pres builds from the Midwest. The high
will remain in control through the middle of next week,
resulting in a continuation of above normal temperatures. Rain 
chances will begin to increase Thu as a WAA pattern ensues, although 
due to the aforementioned uncertainty in the upper pattern, precip 
could very well hold off until Thu night. Predictability is low on p-
type this far out, but lack of cold air supply would favor liquid vs 
frozen at this point.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
High pressure will build to the north today as a front stalls to
the south. The front will lift back toward the area as a warm
front late today into tonight as the high pulls away. 

Still seeing IFR conds at KJFK/KEWR/KGON and MVFR elsewhere. Drier 
air should start moving into the area, early this morning, with
conds improving to VFR at about the same time sfc winds shift
from WSW to WNW. 

Light rain with ocnl MVFR cigs may be possible late this afternoon, 
but more widespread MVFR conds appear more likely after 00Z. 

.OUTLOOK FOR 06Z SUNDAY THROUGH WEDNESDAY...
.Late tonight and Sunday...Rain with IFR conds. E-SE winds 10-15kt 
with G20-25kt. 
.Sunday night...Chance of rain with MVFR conds mainly KISP/KGON, 
otherwise VFR. 
.Monday through Wednesday...VFR.

&&

.MARINE...
Sub-SCA conditions are expected through this evening with weak
high pressure moving across the region.

Easterly winds will increase late tonight into Sunday morning, 
with widespread SCA conditions expected. Potential for a period 
of marginal gale gusts during this time on the ocean, with seas 
building to 6 to 10 ft.

Winds subside Sun Night with high pressure building in, but SCA 
ocean seas will likely take till Monday to subside. 

Sub SCA conds thereafter with high pressure building from the
west.

&&

.HYDROLOGY...
Rainfall late today through Sunday is expected to produce 
around 1 to 1 1/2 inches of rain, much of it on Sunday. There 
could be some locally higher amounts, especially in any areas 
of orographic lift. 

With saturated grounds, minor poor drainage flooding is 
possible on Sunday.

&&

.TIDES/COASTAL FLOODING...
Easterly SCA winds will likely result in 1 to 1 1/2 ft surge and
3 to 4 ft waves into Western LI Sound, which may result in some
localized minor flood/wave splashover in vulnerable areas with 
Sunday morning high tide.

&&

.EQUIPMENT...
NYC NOAA Weather Radio Station KWO-35 (162.55 MHz) is off the 
air for an extended period of time.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory from 1 AM to 6 PM EST Sunday for ANZ330-
     335-338-340-345.
     Gale Watch from late tonight through Sunday afternoon for 
     ANZ350-353.
     Small Craft Advisory from 1 AM Sunday to 7 AM EST Monday for 
     ANZ355.

&&

$$
SYNOPSIS...NV
NEAR TERM...NV
SHORT TERM...NV
LONG TERM...24
AVIATION...Goodman

National Weather Service Glossary of Abbreviations