Area Forecast Discussion
Issued by NWS Upton, NY

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS61 KOKX 270225
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
1025 PM EDT Sun Mar 26 2017

.SYNOPSIS...
A warm front will approach overnight and then waver near the
Tri-State region Monday into Monday night. Weak low pressure
passes through on Tuesday followed by a cold front moving
through during Tuesday night. High pressure then builds in for
Wednesday and Thursday, and shifts offshore Thursday night. A
low pressure system then potentially impacts the region Friday
and Saturday.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Widespread drizzle and fog has overspread the NYC metro, LI,
and the souther portions of the Lower Hudson Valley and will
continue work across the remainder of the area through the
overnight. Minor updates were made to account for latest
observations.

Isentropic lift is increasing from south to north over the area
ahead of an approaching warm front. More widespread rain
development expected across W/NW portions of the Tri-State late
tonight into Mon Morning with approach of the shortwave energy
aloft and 40-45kt llj overrunning a +2-3 stds PWAT airmass over
an approaching warm front.

Additionally...moistening easterly flow and a strengthening low-
level flow ahead of the approaching warm front point towards
an increasing probability for fog to become more widespread
during the late night hours.

Temps will run slightly above seasonable with cloud cover and
onshore flow.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
Shortwave energy pivots through Northern NY into Northern New
England on Monday...with surface warm front likely struggling to
lift north of the area as low pressure weakens over Southern
Ontario. With a weak wave development along the front...and a
45kt llj bringing in PWATS 2-3 stds above normal ahead of
it...would expect a band of overrunning rain to work w to e
across the area in the morning into early afternoon. The exact
location of the warm front/surface low will determine where the
heaviest overrunning rain axis will occur on Monday...with
highest probs across interior closer to shortwave forcing.
Stratus and fog are expected to hold tough to the north of the
warm front in the morning...and possibly into the afternoon for
parts of the area.

There are some hints of weak elevated instability across NW zones
Monday afternoon in the wake of the surface low as the shortwave
energy is coming through. This should support some residual shower
activity...and cant rule out an isolated tstm across NE NJ/Lower
Hudson River Valley if warm front can work north.

Temps forecast is tricky on Monday...conditional on warm frontal
progress. Potential for temps to get into the lower 60s across NE NJ
and surrounding if warm front moves north...while temps across
interior CT could remain in the 40s if warm front hangs to the
south. Coastal areas will likely see temps rise to around 50 degrees
with onshore flow.

Any rain/shower activity should taper off from w to e late Monday
afternoon into early Monday Evening as the shortwave moves off to
the east.

The weak stationary front will likely hang near the region Monday
night. With weak pressure gradient and abundant low-level
moisture...stratus/fog are likely once again. Otherwise...region
looks to be in between shortwaves...so not expecting much in the way
of any organized rain activity.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Models are coming into better agreement regarding a weak area of low
pressure passing through or just south of the area Tuesday into
Tuesday night. An associated warm front might push north into the
southern zones, but with a lack of low level jet this time of the
year, thinking is that the warm front won`t push through the entire
area. Associated lift and moisture will however bring increasing
chances of light rain as Tuesday progresses with best overall
chances occurring during the late-day/evening hours and focused over
the southern zones where best convergence and lift exist. A cold
front quickly follows during the late night hours with additional
chances of rain across the entire area. Temperatures through this
period are expected to be above normal.

High pressure builds in on Wednesday and shifts through the region
Thursday into Thursday night. This period will be dry with above
normal high temps on Wednesday as the strongest cold advection gets
delayed until late in the day or evening. Thursday`s highs will be
closer to normal.

Models are also coming into better agreement regarding a late-week
storm. Right now it appears that low pressure moving in from the
west during Friday redevelops off the coast to our south on Saturday
and heads out to sea into Saturday night. Rain would become
increasingly possible as Friday progresses with a decent chance for
rain Friday night and Saturday. There would also be a chance of
mixed PCPN early Friday morning for some of the interior sections.
Have PoPs capped at 50% for now with this being primarily a day 6-7
event.

Weak high pressure returns for Sunday with dry weather and highs in
the 50s.

&&

.AVIATION /02Z MONDAY THROUGH FRIDAY/...
Low-level ridge will gradually weaken overnight and give way to
an approaching warm front to the south. This front will lift
slowly through during the late morning/early afternoon hours,
possibly washing out across or just north of the area.

Lower ceilings, drizzle, and fog continue to work in from the
SW tonight. Conditions will continue to lower through the overnight
with widespread LIFR toward daybreak, if not sooner based on
current trends.

IFR conditions could last through much of the period, especially
to the north and east of the NYC terminals due to the
uncertainty with the timing of the warm front.

.OUTLOOK FOR 03Z TUESDAY THROUGH FRIDAY...
.Monday night-Tue night...IFR likely, LIFR possible with rain/low
clouds/fog.
.Wednesday...VFR. NW winds G20KT.
.Thursday...VFR.
.Friday...Chance of rain with MVFR or lower conditions,
especially at night. E winds G20KT along the coast.

&&

.MARINE...
Marginal SCA gusts are expected on the ocean waters through tonight.
The resultant easterly fetch should maintain ocean seas at 4 to 7
ft. Winds are expected to weaken and veer se/s on Monday as a warm
front works into the waters...but e/se swells will likely keep seas
at SCA levels into the evening. Ocean seas likely gradually
fall just below SCA late Monday Night.

Weak low pressure shifts through the waters on Tuesday, then a cold
front moves through Tuesday night, followed by high pressure
building in on Wednesday. Although the pressure gradient tightens as
high pressure builds in, it appears that winds probably remain below
25 KT during this period. In spite of an offshore flow, a lingering
swell is expected to keep seas up to 4 ft on the ocean waters into
Thursday morning. A high pressure ridge then shifts through Thursday
into Thursday night with tranquil conditions. An onshore flow then
increases on Friday with the approach of low pressure. SCA conds
will be possible on the ocean by late in the day.

&&

.HYDROLOGY...
Generally one quarter to one half of an inch of rainfall is expected
through Monday...with locally higher amounts possible across the
interior.

No hydrologic concerns are anticipated with any periods of rain that
occur within the rest of the forecast period.

&&

.TIDES/COASTAL FLOODING...
Latest surge guidance indicating that water levels will stay
safely below minor flood thresholds for tonight and Monday
Morning high tide.

As astronomical tides rise through the week...water levels may
come close to minor levels during high tides in the most
vulnerable spots on Tue/Tue Night ahead of approaching low
pressure.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 2 AM EDT Tuesday for ANZ350-353-355.

&&

$$
SYNOPSIS...JC/NV
NEAR TERM...NV/DW
SHORT TERM...NV
LONG TERM...JC
AVIATION...DW
MARINE...JC/NV
HYDROLOGY...JC/NV
TIDES/COASTAL FLOODING...



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.