-- Discussion containing changed information from previous version are highlighted. --
589
FXUS61 KBGM 200619
AFDBGM

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

.SYNOPSIS...
Hot and humid conditions with scattered afternoon and evening
thunderstorms are expected through the entire week. A break in
the heat may not come until after the weekend into early next week.

&&

.NEAR TERM /THROUGH TODAY/...
1130 PM Update:

Strong to severe thunderstorms have popped up along an apparent
surface boundary extending from SW NY to just north of the
Finger Lakes. Surface analysis suggests this boundary may extend
further east than the current area of convection, north of
Skaneateles and Syracuse to somewhere in northern Oneida County.
The storms have fired up in an area of weaker steering flow, and
have been nearly stationary, staying just barely west of the CWA
boundary so far. SPC mesoanalysis also indicates low level
moisture pooling along the lake plain, roughly coincident with
the boundary.

CAMS not really handling things too well, though a few did
produce some convection further east than reality, and the ones
that did suggest additional storms will fire up along the
boundary near the Thruway in the next hour or two, but otherwise
not move further east. But outflow boundaries from these storms,
too far away to pick up on radar just yet, will propagate east,
and could kick up additional isolated thunderstorms across the
Finger Lakes and areas N and W of BGM overnight.

PoP grids have been increased in the far west, and along the
apparent boundary near the Thruway over the next couple hours.
PoPs tapering off to the east in time considering the
possibility of additional initiation off outflow boundaries as
previously mentioned.

Outflow boundaries from this mess will almost certainly impact
convection initiation later on Thursday.


955 PM Update:

Thunderstorms are now initiating along a convergence zone just
west of our forecast area, across NW PA and SW NY. These storms
are tapping into 2200 J/Kg of MLCAPE, with mid level lapse rates
around 6.5C/Km.DCAPE values are still around 1100 J/kg out in
this region. The CAMs are not handling this convective
initiation well at this time. Forecast grids grids were updated
to show a chance for thunderstorms redeveloping (along outflow)
further east into portions of our CWA; especially Steuben,
Yates and Seneca counties over the next several hours. Main
threat with these slow moving storms will be for isolated
strong, gusty outflow winds and heavy rainfall.

745 PM Update:

Just a few, isolated thunderstorms on the radar early this
evening. The majority of the activity has been across eastern
Delaware and Otsego counties thus far. There is abundant instability
out there, with MLCAPE over 2500 J/kg, and LIs of -8. Effective
layer shear is rather weak around 20 kts over the western
portion of the area. Looking at the latest water vapor and IR
satellite loops, there are no real triggers for added lift to
get organized convection going at this time. The CAMs,
especially the latest 22z HRRR develop some scattered
thunderstorm activity over the next few hours across Central NY.
So far the storms have been unable to push higher reflectivity
cores up above the -20C (~25k ft agl) level...however we will
continue to monitor any storms that can develop very closely
considering the high amounts of instability, and DCAPE values of
1000+ J/KG, which is highly conducive to downbursts and
localized strong winds.

Otherwise, tonight will be another muggy night with lows in the
upper 60s to 70s over the region. Just like last night, downtown
Syracuse may struggle to fall below 80 degrees. Thursday is
another hot and humid day, and heat advisories remain in effect
areawide. Scattered thunderstorms develop in the afternoon and
there is a Slight Risk for severe storms.

230 PM Update:

Isolated convection will continue at times into tonight mainly
extending from the western Finger Lakes to the Upper Mohawk
Valley where lingering boundaries exist amongst better broad
scale lift south of the prevailing westerlies. Diurnal
stabilization should end best chances, but persistent high
dewpoints will still provide fuel for any rogue meso convective
system that rides the ridge later on. Not seeing any indications
of this to be confident, but a primed atmosphere will do what
it wants.

Ridge flattens further on Thursday with stronger westerlies
expected to dip across northern NY. Once again, hot and humid
conditions will prevail, however, confidence is higher that
thunderstorms may be a little more intense and numerous than
the past several days. Strong low level lapse rates will exist
with max CAPE values likely nearing 2500 to 3000 J/kg. With the
stronger flow aloft moving in, 0-6 km bulk shear will increase
to around 20 to 25 knots, which should be enough to support a
better organization of convection than today. Locally damaging
winds will be the main threat. Also, PWATs will again be in the
99th percentile range and short Corfidi vectors of less than 10
knots suggest heavy down pours and back building thunderstorms
will be possible, with a threat for localized flash flooding.

A continuation of warm and muggy conditions at night will
continue Thursday night and with a weak stationary front in the
area, shower and thunderstorm chances will linger into the
evening.

Lows in the 70s and highs in the upper 80s to mid 90s will
persist.

&&

.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
250 PM Update...

High pressure recedes to the southwest with an upper level ridge
resting over our region. Along this ridge a few disturbances move
through with a weak stalled frontal system. This leads to the
possibility for showers and thunderstorms to develop especially
during peak heating hours. Although models are trending drier
Friday morning, so pulled back on pops. Instability parameters
show CAPE values up to 1,700 J/Kg with marginal wind shear. This
suggests strong to severe storms are possible with isolated
damaging wind being the primary threat. However, any slower-
moving storms can produce heavy rainfall with PWAT values
anywhere from 1.5 to nearly 2.0 inches across the area.
Placement of the frontal system, cloud cover and shower
development will lead to a challenging temperature forecast for
Friday. Highs are expected to range in the mid 80s to lower 90s
in northeast PA and the Southern Tier of NY. Lows will follow
this same pattern with overnight temperatures ranging in the mid
60s to low 70s across the area.

Quasi-stationary front lingers over the region on Saturday before
lifting Saturday night. This allows additional showers and
thunderstorms to develop especially during peak heating hours.
Depending on the timing of when the front lifts will impact the
temperature forecast. As of now temperatures are forecasted to range
higher in the mid to upper 80s west of I-81, with highs ranging
in the low to mid 80s east.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
250 PM Update...

Upper level ridge begins to break down on Sunday as an upper level
trough starts to nudge into the region along with a surface cold
front. This brings potential for additional showers and
thunderstorms to develop ahead of the system as moisture gets
advected into our region. There is uncertainty in the timing of
the frontal passage, it appears to move through Sunday night
into Monday morning. Regardless cooler air will begin to filter
in early next week providing relief to the region. Upper trough
slowly tracks east Monday allowing another opportunity for
shower and thunderstorms to develop under this pattern. Brief
ridge along with surface high pressure builds in on Tuesday with
dry conditions anticipated at this time. Models begin to diverge
towards the end of the period, but another system could creep in
by Wednesday.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --
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.
-- End Changed Discussion --

&&

.BGM WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
PA...Heat Advisory until 8 PM EDT this evening for PAZ038>040-043-
     044-047-048-072.
NY...Heat Advisory until 8 PM EDT this evening for NYZ009-015>018-
     022>025-036-037-044>046-055>057-062.
     Air Quality Alert from 11 AM this morning to 11 PM EDT this
     evening for NYZ062.
-- End Changed Discussion --

&&

$$

SYNOPSIS...JAB
NEAR TERM...JAB/MJM/MPH
SHORT TERM...ES
LONG TERM...ES
AVIATION...AJG/DK