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393
FXUS61 KBGM 200805
AFDBGM

Area Forecast Discussion
National Weather Service Binghamton NY
405 AM EDT Thu Jun 20 2024

.SYNOPSIS...
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Hot and humid conditions will persist today, with scattered
thunderstorms expected. Some stronger storms will produce
localized damaging winds and torrential rainfall which could
lead to spot flooding. Heat and humidity will shift slightly to
the south Friday, along with the main threat area for
thunderstorms. Temperatures finally look to cool into the 80s by
Saturday, with more relief coming early next week.
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&&

.NEAR TERM /THROUGH FRIDAY/...
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400 AM Update:

Strong showers and thunderstorms just west of the CWA boundary
mostly weakened as they moved into the Finger Lakes and Thruway
corridor overnight/this morning. Meanwhile, the MCS over
southern Ontario is about to cross the Niagara River.

Overall thoughts on the evolution of convection today remains
mostly unchanged. Weakening convection over the Finger Lakes has
likely left a boundary somewhere around the Southern Finger
Lakes arcing back up towards Syracuse, though it`s poorly
defined and not easily analyzed, especially at night. This
boundary is expected to be reinforced and pushed a little
southward as the MCS coming in from Ontario weakens and pushes
across the Lake Plain. Some scattered thunderstorms are possible
as the remnants push through this morning.

By afternoon, we`ll end up with a west-east oriented (or WNW to
ENE) boundary across the middle of the CWA, likely just north of
the Southern Tier near the southern end of the Finger Lakes,
arcing back up towards the Mohawk Valley. This boundary will
then become the focus for thunderstorm development later this
afternoon and evening as additional weak perturbations in the
westerly flow aloft roll through the area.

PWAT values of 1.75 to around 2 inches, and warm cloud depths
of 11,000 feet will promote localized torrential downpours. The
orientation of the boundary parallel to the upper flow,
somewhat weak steering flow will further enhance the risk of
localized heavy rainfall, potentially falling in areas which
have already seen heavy rainfall in the past 48 or so hours
(mainly west of I-81). Some localized flooding issues could
occur later today, though the spotty nature of the heaviest
precip, and lingering questions over the location of the stalled
boundary preclude issuing a watch at this point.

While the focus for convection will be along the stalled out
boundary, scattered thunderstorms will also extend further north
towards the Thruway corridor. Fairly high CAPE values (at "fat
CAPE" profiles per BUFKIT) could result in some localized
downburst/microburst winds despite the relatively weak flow
aloft. With weak shear, the storms will tend to be very pulsey.

Although some convective debris will be around this morning,
and temperatures will be a hair cooler than the past day or two,
dewpoints will be a little higher, and Heat Index values will
still meet or exceed 95 across much of Central NY, with
upper-90s in valley locations, and pushing 100 in lower
elevations in PA. Thunderstorms will provide some relief this
afternoon, at the cost of the aforementioned heavy rain and
strong wind threats.

Today`s convection will push the boundary further south for
Friday, with the Northern Tier of PA becoming the main focus for
stronger thunderstorms Friday afternoon, with a continued heavy
rain threat as low level moisture pools along the
boundary/front. Some "cooler" air will seep into north-central
NY, but Heat Index values still look to push 95 in the lower
elevations of the Southern Finger Lakes and Southern Tier of NY,
as well as Sullivan County. HI values will again push 100 in
NEPA, and the Heat Advisory has been extended through Friday
evening for south-central NY and all of NEPA.
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&&

.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
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400 AM Update...

A quasi-stationary front draped over the region Friday night into
Saturday combined with a few weak perturbations in the flow
aloft will lead to additional scattered showers and
thunderstorms. Convection will be most likely during the
afternoon and early evening on Saturday with PoPs around 50-60%.
These values were lowered a bit from NBM which loaded in
categorical PoPs greater than 75% or portions of the area, and
while it is likely for there to be showers and storms, given its
scattered nature it`s tricky to identify where those highest
PoPs may be at this point. Also, given the clouds, convection
and placement of the boundary, high temperatures Saturday will
be tricky as well. Highs are expected to be in the low to mid
80s across CNY while the Twin Tiers and NE PA can range from the
mid 80s to near 90 degrees in some valley locations.

The frontal boundary is expected to lift back northward Saturday
night into early Sunday and as the flow becomes more southwesterly,
it will lead to a very warm, muggy night with lows in the upper 60s
and low 70s.
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&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
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400 AM Update...

The strong upper-level ridge is expected finally begin breaking down
on Sunday as a shortwave trough and surface cold front approach from
the west and increase chances for showers and thunderstorms later
Sunday into Sunday night. Highs Sunday are generally expected to
range from the mid 80s to the low 90s. While there is some
uncertainty with the timing of the cold frontal passage between
Sunday night and early Monday, cooler, more refreshing air is
expected to filter in for Monday with highs mainly in the upper 70s
and low 80s and dew points retreat into the upper 50s and low 60s
during the afternoon. There is still a small chance of a shower or
thunderstorm as well on Monday with the upper level trough lagging
overhead. By Tuesday high pressure briefly builds in leading to a
dry day before another front looks to bring the chance for showers
and storms back into the area midweek. Temperatures are expected to
trend back up Tuesday but dew points stay relatively low in the
upper 50s and low 60s.
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&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
Convection that developed late this evening is now weakening as
it approaches SYR. Given the unstable environment that the
decaying convection is moving into, a short fused TEMPO for a
thunderstorm was added until 07Z in case it pulses back up one
more time. Outside of this, VFR conditions are expected through
this morning at all terminals. The potential for early morning
fog at ELM remains low with scattered high clouds in place and
rain passing by to the north and west.

Chances look better this afternoon and evening for thunderstorm
development across the area but given the scattered nature of
the convection, confidence remains low in terms of timing and
location. Although the CAMs in recent days have not be handling
pop up convection very well, there seems to be some agreement
that ITH, ELM and BGM may have the best chance of seeing storms,
so PROB30 groups were added to these locations for now starting
18-19Z, but this will continue to be monitored. If ELM does see
some rain later in the day and there is enough clearing, then
the potential for fog will be there near or shortly after the
end of the TAF period.

Outlook...

Thursday night through Monday...Spotty restrictions possible in
showers and thunderstorms.

&&

.BGM WATCHES/WARNINGS/ADVISORIES...
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PA...Heat Advisory until 8 PM EDT Friday for PAZ038>040-043-044-047-
     048-072.
NY...Heat Advisory until 8 PM EDT this evening for NYZ009-015>018-
     036-037-044>046-057.
     Heat Advisory until 8 PM EDT Friday for NYZ022>025-055-056-062.
     Air Quality Alert from 11 AM this morning to 11 PM EDT this
     evening for NYZ062.
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&&

$$

SYNOPSIS...MPH
NEAR TERM...MPH
SHORT TERM...DK
LONG TERM...DK
AVIATION...AJG/DK