discussion on 2024-02-22

000
FXUS61 KOKX 221211
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
711 AM EST Thu Feb 22 2024

.SYNOPSIS...
High pressure weakens Thursday morning. A frontal system and
associated low pressure will move across the area late Thursday
night into Friday. High pressure builds in for the start of the
weekend and remains in control through Sunday. A warm front passes
through Sunday night, followed by a weak cold front Monday. Another
warm front approaches Tuesday and Tuesday night, then passes through
on Wednesday.

&&

.NEAR TERM /THROUGH FRIDAY/...
Minor adjustments were made to temperatures and dewpoints to
account for current trends. Cloud cover was also increased
about 10-15% for most of the area based on current
observations. Otherwise, the forecast remains on track for this
update.

Increased cloud cover due to onshore flow has prevented most
radiational cooling in the overnight hours. Everyone in the area
will be waking up to temperatures much warmer than yesterday
morning.

High pressure that was nosing in from the northeast weakens today as
an offshore low nudges the high pressure centered northeast of the
Canadian Maritimes out into the far north Atlantic. At the same
time, a low pressure system along a front in the Ohio Valley will
approach the area, increasing overcast cloud cover west to east
throughout the day. Ahead of the frontal system, onshore flow will
lead to warmer temperatures with highs in the mid/low-40s today.

Thursday evening the first wave of rain from the frontal system
should arrive, overspreading across the area from west to east. This
frontal system arrives with a mid-level shortwave which could
provide waves of mid-level energy to bring more consistent rainfall.
Despite this, forcing does not look particularly strong, so it will
likely be light precipitation at the onset. Some light snow or a
rain-snow mix is possible Thursday evening and early Thursday night
for areas in the interior portions of Connecticut and the Lower
Hudson Valley. Some brief sleet or freezing rain may also be
possible. The impact from this is expected to be low as warm air
advection from a warm front ahead to the approaching low will lead
to temperatures warming both at the surface and in the low-mid
levels late Thursday night. In addition, surface temperatures will
only briefly reach touch freezing in interior sections before
rising, based on the latest model guidance.

Based on 00Z CAMs, it looks like the main shield of precipitation
ahead of the approaching low late Thursday night into early Friday
will fall along northern portions of the CWA with intermittent rain
for southern portions of the CWA during this time. Rain will pick up
again midday Friday into the afternoon as the low passes with a
frontal boundary by late afternoon/early evening. The forcing from
this boundary should lead to widespread light rain across the area
during midday to afternoon Friday. Rain will clear west to east with
the exit of the system late Friday afternoon/early evening.

Event QPF is currently forecasted to be between 0.25 to 0.35 inches.
Higher totals are possible for northern and eastern areas. 00Z HREF
shows probabilities for >=0.5" around 50% for Long Island, S CT and
the Lower Hudson Valley. This drops down to 0% for >=0.75" for most
of the area with only a 15-25% probability in the interior sections
of the Lower Hudson Valley. PWATs during the event max out midday
Friday around 0.7-0.8" which lies around the 90th percentile per
SPC`s Sounding Climatology page.

Its also worth noting, highs on Friday with be in the mid/upper-40s
with areas of NE NJ topping off around 50 degrees thanks to warm air
advection from the warm front.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
A secondary cold front arrives Friday night behind the exiting
system reinforcing cold, dry air in the region. This leads to
decreasing clouds through Friday night with lows in the low-30s to
mid-20s. Following the frontal passage, breezy northwest winds are
expected throughout Friday night and much of Saturday before
gradually easing Saturday evening, becoming light by Sunday morning.

Cold dry air behind the front with high pressure building back into
the area and a deep trough aloft will lead to sunny skies and highs
in the mid/low-30s Saturday afternoon, lows in the mid-teens to low-
20s Saturday night.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
High pressure over the area shifts offshore Sunday afternoon. Winds
shift SW with a warming trend through the rest of the long term
forecast period. Highs on Sunday close to normal at mostly 40-45. A
warm front passes through Sunday night. Moisture is limited, but
combined with isentropic lift, slight chances of a rain/snow mix
north of the city. Thermal profiles are marginally cold enough for
the potential for all snow, but in any case, overall chances for
precip are low with very little liquid equivalent potential. A weak
cold front follows during Monday. High temperatures still manage to
reach the upper 40s to lower 50s in spite of this.

Low pressure over the Northern Plains on Tuesday shifts east,
reaching the Great Lakes Region on Wednesday as it gains some
strength. An associated warm front will approach us on Tuesday.
Overrunning light rainfall may occur during the day. PoPs capped at
chance for this period. Given the progged position and strength of
the parent low center and low level jet development/strength, not
expecting this warm front to move through the area during Tuesday
night as it is not climatologically favored this time of the year.
Isentropic lift and moisture will both increase however, and rain
becomes likely across the area Tuesday night. Better chances for the
warm front to push north through the forecast area during Wednesday,
but this is still not a given. Would like to see better agreement of
the low in the Great Lakes being progged stronger and farther east
to have more confidence. For now, will go with the idea that it
shifts through during the day with a transition of rain to a chance
of showers. Temperatures above normal for both Tuesday and
Wednesday.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --High pressure weakens into tonight as low pressure approaches,
passing through during Friday.

VFR during the rest of the morning push. Terminals starting with
MVFR should have prevailing VFR by early afternoon. VFR then
prevails during the afternoon into early evening before flight
categories lower with rain. Mostly MVFR overnight, but IFR north
of the city.

Southerly winds around 10kt or less today, backing toward SE
this evening, then veering SW for the Friday morning push.

 ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...

TEMPO MVFR possible before 13z. MVFR may redevelop a few hours
later than indicated in TAFs tonight.

OUTLOOK FOR 12Z FRIDAY THROUGH MONDAY...

Friday: MVFR/IFR conds in rain, improving to VFR in the
afternoon.

Friday night: Becoming VFR early. NW winds G15-20kt.

Saturday: VFR. NW winds G20-25kt.

Sunday - Monday: VFR.

Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --

&&

.MARINE...
Small craft conditions arrive on the ocean waters due to increasing
seas beginning Thursday morning as a 8 second period SE swell
increases to around 10-11 second period during Thursday. Small craft
seas are likely to last through the remainder of the week. The winds
will be mainly out of the SE and S late Thursday and Thursday night
as high pressure departs and low pressure approaches the waters. The
winds will switch around to the NW by Friday evening falling short
of small craft gusts until Friday night.

5-6 foot seas from a southeasterly swell will likely be ongoing at
the start of Friday night. At the same time, low pressure will be
exiting the area and a northwest wind will be increasing, likely
reaching 25 kt gusts late Friday night and dropping below SCA
criteria gusts midday Saturday.

With the exception of seas lingering above 5 ft at times on the
eastern ocean waters, Sunday will feature sub-advisory conditions.
Winds pick up Sunday night and subside on Monday, but will be strong
enough with some swell to build ocean seas to advisory levels Sunday
night and maintain elevated seas through at least during the daytime
Monday.

&&

.HYDROLOGY...
No hydrologic impacts are expected throughout the entire forecast
period.

&&

.TIDES/COASTAL FLOODING...
With the approach of a full moon late this week with astronomical
tides increasing, minor coastal flood benchmarks will be approached
for the south shore back bays of Nassau County for the Friday
morning high tide cycle. At this time it appears that other
locations will fall short of minor benchmarks.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 7 PM EST Friday for ANZ350-353-355.

&&

$$

SYNOPSIS...JC/BR
NEAR TERM...BR
SHORT TERM...BR
LONG TERM...JC
AVIATION...JC
MARINE...JC/BR
HYDROLOGY...JC/BR
TIDES/COASTAL FLOODING...