Union, New York 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

393
FXUS61 KBGM 191700
AFDBGM

Area Forecast Discussion
National Weather Service Binghamton NY
100 PM EDT Thu Jun 19 2025

.SYNOPSIS...
A surface trough will move through the afternoon hours, bringing a
chance for isolated to scattered severe thunderstorms possible.
Conditions stay warm and humid today before being followed by a
brief cool down to finish out the week. Temperatures then surge
much warm early next week. There will be chances for showers
and thunderstorms through the weekend followed by a few dry days
to start next week.

&&

.NEAR TERM /THROUGH FRIDAY NIGHT/...
950 Am Update...

After a mostly clear morning allowing temperatures to climb into
the 70s, clouds are starting to stream into the region from the
SW. This will really put a damper on widespread thunderstorm
chances across areas west of I-81 along the pre-frontal trough
early this afternoon. CAM guidance is showing CAPE values around
500 j/kg in this area during the early to mid-afternoon hours,
with 0-6km bulk shear around 30-35kts. This is enough to get
convection going, especially where more sunshine is able to
break through. Areas east of I-81 continue to look the best for
severe storm development this afternoon, although the forcing to
kick the storms off should be from the pre-frontal trough. The
stronger forcing from the cold front will not occur until late
this afternoon/early evening and after peak heating. A line of
showers and storms should develop along the front as it transits
the CWA from west to east, with the best chance for stronger
storms over the Finger Lakes region. CAM guidance has it
weakening as it progresses eastward, which could be the case if
we get earlier storms in this region that have already worked
the atmosphere over.


335 AM Update...

Today will be an active day with isolated to scattered strong to
severe storms possible. Our area will be well within the warm
sector, allowing for a very moist and warm environment with
increased instability, and temperatures reaching the mid to
upper 80s effectively removing any convective inhibition. The
areas most prime for severe development will likely be along
I-81 and eastward, with CAPE values of 1000-1500 J/kg and 0-6
km bulk shear around 40 knots, which can favor development of
organized lines of storms or clusters of storms. Though east of
I-81 has the highest likelihood, severe storm development is
possible across all areas in Central NY and NE PA. With a prime
environment in place, storm development will kick off as a
boundary approaches from the west, acting as the main mechanism
for broader storm initiation, with development of a QLCS-type
line segment that brings the increased isolated tornado threat.
However, more discrete storm cells could develop ahead of the
boundary in the late morning/early afternoon hours. As the main
boundary approaches, the development of a more organized line
segment is more likely later in the mid- to late-afternoon,
progressing west to east. Overall potential threats across the
entire area are gusty to damaging winds, severe hail (greater
than 1 inch diameter), and isolated tornadoes. The tornado
threat is primarily for areas along I-81 and eastward.
Additionally, with this moist of an environment and PWAT values
of around 1.5 inches, localized flash flooding cannot be ruled
out.

After the passing of the frontal boundary, leftover scattered
rain showers are possible for northern Central NY, and
temperatures will cool a little bit into the mid 70s to low 80s
for Friday. A much weaker and smaller shortwave will attempt to
bring some afternoon showers and storms, but are not expected to
become severe.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
100 PM Update

Will be watching shower and thunderstorm potential in this period,
along with developing hot and humid conditions by Sunday.

Saturday features rising heights aloft as an upper level ridge
begins to build over the region. A strong shortwave disturbance is
modeled to ride over the top of the ridge heading into Saturday
night and Sunday morning. Therefore, most of Saturday looks dry with
just an isolated late day pop up t`storm possible across Central NY.
It will be partly sunny, a bit more humid and warm with highs in the
80s areawide. As the above mentioned shortwave rolls across southern
Canada Saturday night, a strong warm front will push through at the
surface for our area. Mixed layer instability increases markedly
overnight as a strong Elevated Mixed Layer (EML) arrives; mid level
lapse rates approach or perhaps exceed 8.0C/Km with the northwest
flow over the top of the building ridge. This is a classic setup for
fast moving complexes of thunderstorms, so this will be something to
watch closely (especially CNY) Saturday night into Sunday morning.
By Sunday afternoon any lingering morning convection or clouds
dissipate...giving way to sunshine, high humidity and hot
temperatures. Latest model data is trending up with temperatures and
heat indices for Sunday. 13z NBM now shows highs ranging from the
upper 80s to mid-90s Sunday afternoon, with dew points 70-75...this
gives peak heat indices in the low 90s to low 100s. This upward
trend is likely due to the 500mb ridge building in faster, with
heights reaching 595dm by early evening. Upper level high moves
directly overhead Sunday night, giving clear skies, light winds and
muggy conditions with lows in the upper 60s to low 70s.

&&

.LONG TERM /MONDAY THROUGH WEDNESDAY/...
100 PM Update

Main story in this period will be the extremely hot and humid
conditions, with possible record high temperatures earl in the week.
Very warm to hot conditions continue midweek, with increasing shower
and thunderstorm potential.

Latest guidance, including the 13z NBM continues to trend higher
with the temperatures Monday and Tuesday. Our official forecast
follows this trend, and is even on the lower side of guidance near
the 25th percentile NBM. The deterministic NBM may be suffering
feedback from climatology and/or previous forecast, considering it
is now below the 10th percentile on Monday. Did not want to go too
much higher, but again, went close to the 25th percentile NBM which
put Monday in the top 5 of observed all time high temperatures in
June at many of our Climate data sites. This matches up well with
the ECMWF extreme forecast index, which is in the 95-99th percentile
across most of the area. 850mb temperatures around 20-21C also
support highs well into the 90s both Monday and Tuesday afternoon.
It`s possible a few of the deeper valley locations may even hit 100
degrees. Also factoring in surface dew points in the upper 60s to
lower 70s during the afternoon, and peak heat indices will be
downright oppressive between the upper 90s to low 100s both days.
Monday will be rain free and sunny under the extensive upper ridge,
while Tuesday could see a stray pop up late day thunderstorms as the
upper high shifts slightly south. Overnight lows only dip into the
70s. These hot daytime and muggy nighttime temperatures will lead to
major/locally extreme HeatRisk over the region. As confidence
continues to increase Extreme Heat Watches may eventually be needed.

The center of the upper level ridge/high drops south Wednesday into
Thursday. This will open the door for showers and thunderstorms to
move through our area on the norther periphery of this feature.
Temperatures gradually decrease, but it will still be very warm to
hot on Wednesday with mid-80s to low 90s expected, with generally
80s expected for highs by next Thursday.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
VFR conditions expected until later in the afternoon, where we
will see another round of showers and storms, but timing and
location are still uncertain. TEMPO groups have replaced last
TAF package`s PROB30 groups, with TS potential from 18Z to 22Z
at all terminals for chances of discrete storm cells ahead of an
incoming cold front. Winds are expected to pick up this morning,
with 10-15kts gusting up to 25kts out of the SW possible by the
afternoon.

Outlook...

Thursday afternoon...Coverage of showers and thunderstorms
increase, especially in the afternoon. Occasional restrictions
likely.

Thursday night through Monday...Mainly VFR, but isolated to
scattered afternoon showers and possibly a thunderstorm may
result in brief restrictions; chances somewhat better for NY
terminals versus KAVP which may stay dry.

&&

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

&&

$$

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