-- Discussion containing changed information from previous version are highlighted. --
580
FXUS61 KBGM 210009
AFDBGM

Area Forecast Discussion
National Weather Service Binghamton NY
809 PM EDT Thu Jun 20 2024

.SYNOPSIS...
Scattered thunderstorms are expected to continue through this
evening with potential for stronger storms to produce damaging winds
and torrential rainfall. Similar pattern continues tomorrow with the
convective threat shifting to northeast PA. Heat and humidity is
expected to continue through the weekend with relief coming Monday.

&&

.NEAR TERM /THROUGH FRIDAY NIGHT/...
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340 PM Update...

Similar pattern continues as strong high pressure aloft remains
just south of us placing us in the upper most portion of the
ridge. This allows weak perturbations to move through aloft
along with a boundary leading to thunderstorm development this
afternoon. Surface boundary expands across the middle of our CWA
oriented SW to NE. Modeled soundings show CAPE values up to
1,600 J/Kg, but with very weak shear present storms will be
pulse in nature. DCAPE values are also quite favorable
suggesting localized downburst/microburst winds. SPC has brought
us down from a slight risk to a marginal risk and has excluded
us from a watch.

Model soundings also showed favorable PWAT values, and warm cloud
depths. These features combined with the orientation of the boundary
being parallel to the upper flow suggests localized heavy
rainfall is also a threat. Convection will focus along the
stalled out boundary with potential for rain to fall in areas
that have already seen heavy rainfall in the past 48 hours.
Temperatures will again climb into the upper 80s to low 90s
across with region with slightly higher dew points in the upper
60s to mid 70s. Heat index values will still meet or exceed 95
in CNY and NEPA, therefore heat advisory still remains in effect
until 8PM this evening. Otherwise thunderstorms could provide
some relief this afternoon in places they develop.

Heavy rain threat continues tomorrow as the boundary shifts further
south over NEPA along with the possibility for severe storms in the
afternoon. Many of the same key players, high CAPE values, weak
shear aloft, high PWATs, favorable warm cloud layer, are all present
tomorrow suggesting similar threats. Some cooler air dips into
CNY but heat index values still appear to surpass 95 in the
southern finger Lakes and southern tier of NY. Heat advisory
still runs through tomorrow eyeing for south CNY and NEPA. Mild
lows are expected overnight with temperatures ranging in the mid
to upper 60s.
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&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
A quasi-stationary front draped over the region 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. Given the very humid airmass
heat index values of 95-105 are likely again across a good
portion of central New York and northeast Pennsylvania. Luzerne,
Wyoming and Lackawanna counties look to close to 105 for
maximum heat index values. So, the heat advisory was extended
through Saturday for portions of central New York along with a
excessive heat watch for the counties that could get to a 105
peak heat index values.

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.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Sunday has trended warmer with the latest model runs today.
Given the humid airmass many locations look to top out in the
95-105 range, so additional headlines may be needed.

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.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
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800 PM Update

VFR conditions are expected to persist for the rest of the
evening and most of the overnight hours. There could be some
patchy MVFR fog/mist around, mainly at RME, ITH and ELM between
06-11z. It is possible that if ELM sees clearing tonight a
short period of IFR fog could develop; used a tempo group in the
taf to indicate this, mainly between 07-11z early Friday morning.

All sites are expected to return to VFR conditions shortly after
daybreak and through the morning hours. There will be scattered
showers and thunderstorms around the region on Friday, mainly
during the afternoon and early evening hours. However, a stray,
isolated shower or storm cannot be ruled out in the morning
hours too; mainly across the CNY terminals of SYR/RME. Added in
PROB30 groups for possible thunderstorms in the afternoon and
early evening hours at ITH/ELM/BGM where probabilities were the
highest at this time.

Outlook...

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

VFR conditions possible on Tuesday with high pressure.
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&&

.BGM WATCHES/WARNINGS/ADVISORIES...
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PA...Heat Advisory until 8 PM EDT Saturday for PAZ038>040-048-072.
     Heat Advisory until 8 PM EDT Friday for PAZ043-044-047.
     Excessive Heat Watch from Saturday morning through Saturday
     evening for PAZ043-044-047.
NY...Heat Advisory until 8 PM EDT Saturday for NYZ022>025-055-056-
     062.
     Air Quality Alert until 11 PM EDT this evening for NYZ062.
     Air Quality Alert from 11 AM to 11 PM EDT Friday for NYZ062.
-- End Changed Discussion --

&&

$$

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