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713
FXUS61 KBGM 290455
AFDBGM

Area Forecast Discussion
National Weather Service Binghamton NY
1255 AM EDT Mon Apr 29 2024

.SYNOPSIS...
A frontal wave will bring showers and isolated thunderstorms to
the area this evening. Lingering clouds and areas of fog are
expected overnight into early Monday morning. A warm front will
bisect the area on Monday, with partly sunny and very warm
conditions from the Twin Tiers south across NE PA. The next
front arrives Tuesday with a better chance for more widespread
showers and scattered thunderstorms. Remaining very warm, with
well above average temperatures through the end of the work week.

&&

.NEAR TERM /THROUGH TODAY/...

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Only minor updates with the midnight update, previous
discussions below.


625 PM Update...

No major changes to the near-term forecast. The only change was
expanding the areas of fog development overnight through the
majority of Central NY and NE PA. We are currently monitoring
for any thunderstorm development in NE PA now through the next
few hours; these storms are not expected to become severe. Otherwise,
forecast remains on track.


340 PM Update

Main concern in the near term are the potential for scattered
thunderstorms this evening across the Southern Tier and NE PA.

MLCAPE values are being held in check by mostly cloudy skies and
limited daytime heating from the northern tier of PA northward
across all of CNY at this time. Current analysis shows only up to
250 J/kg, with sfc based LIs of 0 to -2 over the southern half of
the forecast area. Bulk effective layer shear is between 25-35 kts
out there this afternoon. With more clearing and temperatures in the
upper 70s to lower 80s now from Towanda south to Avoca and
Hazleton...this will be the most likely area to watch for scattered
thunderstorm development over the next several hours. Latest CAMs
such as the 18z HRRR show t`storm development by 4-5 PM over the NY
Southern Tier , with a line of storms then dropping south toward the
Wyoming Valley & Poconos between 5 to 9 PM this evening. There
remains an outside chance for a stray stronger storm to develop,
with a possible isolated instance of small hail or gusty winds.
Guidance continues to show MLCAPE reaching 300-500 J/kg over this
region before the storms move in.

Further north the rest of the evening will be dominated by clouds
and occasional rain showers, with thunderstorms being unlikely due
to limited/ non-existent instability. The main concern up this way
across Central NY will be the front sagging south overnight,
bringing a relatively cooler air mass, which combined with light
winds to produce areas of fog. Overnight lows dip into the 50s.

On Monday, the latest guidance has finally come into better
agreement on where the quasi-stationary warm front will set up.
Based on some of the hi-res guidance the front looks to be located
right along the US-20 corridor for much of the day. Along and north
of this front low clouds and stratus linger most of the day and
temperatures only reach the 60s to low 70s. South of the front, the
clouds scatter out by late morning, with partly sunny and very warm
conditions expected. With the upper level heights building overhead
any shower or t`storm development will be isolated. There will be
plenty of instability (1000 J/kg SBCAPE) but no lifting mechanism to
get the storms initiated. Highs range from the upper 70s to mid-80s
south of the front across the Twin Tiers and all of NE PA.

Generally quiet and warm weather Monday night, with perhaps just a
few showers riding across the top of the ridge. Muggy for late April
with lows in the mid-50s to lower 60s expected.
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&&

.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
300 PM Update...

Tuesday remains a tricky forecast at this time. The ridge
sitting overhead should break down Monday night, allowing a
trough to move into the region from the west and bring SW flow
across the area. Warm and moist air should move into the region,
with morning temperatures rising into the 60s to low 70s with
dewpoints in the low 60s. The big question here is will sky
cover be too thick to allow sufficient surface heating to break
a modeled cap between 700-600mb. Showers are expected to ride
the western edge of the ridge, west of our region Monday night
into Tuesday morning, which should pump clouds into the area.
Guidance is still unsure on how the event evolves, with some
incorporating more clouds and less instability, while others are
showing less clouds and more instability. Temperatures are
currently forecast to reach the mid to upper 70s, but a few
degrees difference either higher or lower makes a large impact
on the severe weather chances. Sifting through it all, leaning
on the lower values of 500-1000j/kg of CAPE and 0-6km bulk shear
between 25-35kts seems reasonable at this time, stretching from
NEPA into Delaware/Otsego counties. This should be sufficient
to generate scattered severe thunderstorms ahead of the
approaching front, but timing of the trough and front arrival is
still uncertain, with the longer range CAMs showing a quicker,
late morning arrival vs. global models which show a slower,
wetter solution.

Hydrologically, PWATs of 1-1.30in(2-3 standard deviations higher
than normal) imply enough moisture for heavy downpours and
corfidi vectors show training potential in the afternoon.
Warm cloud depths of 7-8k ft are not optimal for heavy rain
production, but tall enough that heavy downpours are possible.
All of these point to a chance for localized flooding under
heavy rain. Adding confidence to this is WPC has put us in a
marginal outlook for excessive rainfall.

Rain chances linger, especially east of I-81 Tuesday night into
Wednesday as the upper level trough slowly moves eastward.
Temperatures Tuesday night will be in the mid to upper 50s.

A ridge will quickly follow the departing front/trough on
Wednesday, building in from the SW and keeping warm air in the
region. Skies will clear from SW to NE, allowing highs to climb
into the upper 60s to mid 70s. High pressure remains in control
Wednesday night, keeping lows in the upper 40s to low 50s.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
330 PM Update...

Thursday and most of Friday should be quiet and warm, with temps
climbing into the 70s. The next system will arrive during the
weekend as a low pressure center over the north central US
climbs north into Canada and pushes a frontal boundary through
the region, bringing another round of rain showers and
isolated thunderstorms Sat and Sun. Guidance remains unsure on
the timing and strength of this feature so the NBM solution was
relied upon.

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...

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Variable conditions likely till about 14Z at all TAF sites.
Uncertainity is still present overnight on which sites will
mainly LIFR/IFR fog and IFR/MVFR stratus. Played a middle of the
road approach at almost every site with the exception of KELM
where confidence is higher in fog through the overnight.
Restrictions should lift between 13-20Z Monday from south to
north then VFR.

Outlook...

Monday Night...Mainly VFR.

Tuesday...Restrictions likely in rain showers and
thunderstorms, especially in the afternoon and evening.

Wednesday...Lingering morning clouds and restrictions possible,
becoming VFR in the afternoon.

Thursday...VFR Likely.

Friday..Mainly VFR, but late day showers/t`storms possible.
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&&

.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...None.

&&

$$

SYNOPSIS...MJM
NEAR TERM...KL/MJM/MWG
SHORT TERM...JTC
LONG TERM...JTC
AVIATION...MJM/MPH/MWG