296
FXUS61 KOKX 010915
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
515 AM EDT Thu May 1 2025
.SYNOPSIS...
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High pressure remains in control today as the center shifts off the
New England coast. A warm front approaches tonight and lifts through
the region into Friday morning. A cold front then slowly approaches
Saturday into Saturday night, with a wave of low pressure
developing along it. This frontal system may linger near the area
through early next week, as a cutoff upper low develops to the
southwest.-- End Changed Discussion --
&&
.NEAR TERM /THROUGH TONIGHT/...
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Upper ridge axis shifts overhead today as surface high pressure
drifts off Cape Cod.
Dry conditions expected thru the day. Winds veer SE into the
afternoon as the high moves offshore, and the resultant onshore flow
limits temperatures along the coast with SSTs still in the low 50s.
Highs here top out in the upper 50s to mid 60s, with lower 70s
expected away from the marine influence in the LoHud Valley and NE
NJ.
As the high shifts further east tonight, low pressure tracks into
the Great Lakes with the associated warm front approaching the local
region. This introduces increased cloud cover, along with the chance
for showers late tonight into Friday morning. Can`t rule out a
spotty thunderstorm with this activity either, but coverage overall
appears limited, and some locales may not see precipitation. The
front lifts through toward daybreak, and could see areas of fog
break out in its wake into Friday morning as the shower activity
exits.-- End Changed Discussion --
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
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A more active pattern looks to develop in this period, with an
increasing likelihood of unsettled conditions persisting thru at
least early next week.
Behind the warm fropa early Fri AM, a much warmer air mass advects
in on deep SW flow. Any fog around in the morning burns off and S/SW
flow and deep mixing allow temps west of the Hudson to rise into the
80s, or a good 15 degrees above climo for early May, while coastal
areas remain in the 60s to around 70.
As the East Coast ridging shifts farther offshore, several northern
stream shortwaves dig a trough from the Canadian Plains into the
Mississippi River Valley Friday into Saturday. The pre-frontal
trough approaches western portions of the area Friday aft/eve,
bringing the potential for scattered showers and thunderstorms,
mainly for NYC and points N&W in a weakly forced, but marginally
unstable/modest shear environment. A more stable airmass along the
coast will likely have any convection dissipating as it overspreads
the coast and encounters this environment. Conversely, could be
dealing with stratus/fog development for southern and eastern
coastal areas late Friday into Sat with moist onshore flow over cold
waters (lower 50 SSTs). CSU MLP still indicates a marginal severe
threat, which seems conditionally possible.
Perhaps a better chance for organization of scattered shower and
thunderstorm activity ahead of the approaching cold front Saturday
afternoon and evening for NYC and points NW once again with approach
of northern shortwave in a marginally unstable and strong deep layer
shear environment. Although airmass is similar on Friday to
Saturday, potential for more in the way of convective debris on
Saturday limiting full insolation.
Better agreement amongst global guidance relative to this time
yesterday, with most ensemble members now signaling a cutoff low
closes off to the SW of the region this weekend thru early next
week as an omega blocking pattern develops across the Eastern
US into Western Atlantic. The result being the aforementioned
cold front stalling to the west of the region and strong
Canadian maritime high to the NE leading to a persistent Atlantic
subtropical moisture flow into next week.-- End Changed Discussion --
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
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The combo of a cutoff upper low developing over the Ohio Valley and
an amplifying upper high over the western Atlantic will be the main
drivers of sensible wx for the area. A feed of subtropical Atlantic
moisture into the area between these two systems will keep us
unsettled through the period and offer the likelihood of some
periods of heavier showers, whose exact timing and rainfall amts are
still uncertain. Latest guidance suggests best time frames for
heavier rainfall may be Sunday night into Mon morning and more so
Tue into Tue night. Latest ECMWF ensemble is focusing in more on
Tue, showing higher probabilities of 1-2 inches in 24 hours in that
time frame, and 90th percentile QPF of over 3 inches.-- End Changed Discussion --
&&
.AVIATION /09Z THURSDAY THROUGH MONDAY/...
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High pressure passing to the north will move off the coast this
afternoon. A warm front will approach tonight.
VFR for most of the period, with generally light N-NE winds becoming
E this morning and then SE around 10 kt this afternoon. With the
approach of the warm front, some MVFR cigs should move into the NYC
metro area and across Long Island after midnight.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
No unscheduled AMD expected.
.OUTLOOK FOR 06Z FRIDAY THROUGH MONDAY...
Late tonight: IFR cond likely/LIFR possible with the approach of the
warm front. Scattered/numerous showers and an isolated tstm
possible.
Friday: MVFR or lower cond to start should improve to VFR by late
morning after warm fropa, then showers/tstms possible in the
afternoon and at night. S winds G15-20 kt in the afternoon.
Saturday: MVFR or lower cond possible with chance of showers/tstms.
thunderstorms. S winds G15-20kt.
Sunday: MVFR or lower cond possible with chance of showers/tstms.
Monday: MVFR or lower cond possible with chance of showers. E-NE
winds G15-20kt.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
0-- End Changed Discussion --
&&
.MARINE...
-- Changed Discussion --
Winds and seas remain low through tonight with high pressure near
the region.
Marginal S/SW SCA gusts possible on the ocean Fri aft/eve and then
once again Sat aft/eve with approach of cold front. More confidence
in ocean seas building to 5 ft during this time, lingering into
Sunday based on persistent S/SW flow.
Residual 5-ft ocean seas Sunday morning should subside by afternoon.
Increasing E flow on Mon may bring minimal SCA cond to the ocean
waters, with E winds gusting to 20-25 kt and seas building to 5
ft.-- End Changed Discussion --
&&
.FIRE WEATHER...
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Light southeasterly flow 5 to 10 mph develops by late morning or
early afternoon today. RH values drop to 25 to 35 percent by late
morning, increasing above 40 percent along the coast by the
afternoon with strengthening onshore flow. A wetting rain is
possible overnight into Friday.-- End Changed Discussion --
&&
.HYDROLOGY...
-- Changed Discussion --
There is potential for heavy rain of over 2 inches next week, but
timing/duration of any heavier periods of rain and exact amounts
remain uncertain.-- End Changed Discussion --
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...BG/DR
NEAR TERM...DR
SHORT TERM...DR
LONG TERM...BG
AVIATION...BG
MARINE...BG/DR
FIRE WEATHER...DR
HYDROLOGY...BG/DR