FXUS61 KBGM 280027

Area Forecast Discussion
National Weather Service Binghamton NY
827 PM EDT Thu Apr 27 2017

A passing cold front, will bring the chance for showers and
thunderstorms tonight, especially west of Interstate 81. Friday
looks rain-free and warm, under the influence of weak high
pressure. Over the weekend, although it won't be a complete
washout, some showers should return, as a frontal boundary
wavers over our region.


830 pm update...
Low level capping inversion in place much of the day across
central PA/NY has begun to erode as a line of convection
approaches from the w/sw. The convection on the leading edge of
a nwd rotating upper trough should be allowed to persist and
possibly pulse up and down through the rest of the evening with
brief periods of heavier showers/storms...mainly west of I-81
through n-central PA and central NY. Primary concerns continue
to be gusty winds and heavy downpours...with a secondary concern
of small hail. The storms should exit the region to the NE late
tonight/early Friday morning.

Previous discussion...
Lower stratus clouds have dissipated across the area this
afternoon allowing for some sunshine and temperature climbing
well into the 70s in most areas with some lower 80s over the
lake plain where south-southeast is flow is downsloping off of
higher terrain to the south. Dew points have risen into upper
50s and lower 60s and mixed layer CAPE values are up around 500
J/kg. Low level flow remains backed from the southeast resulting
in anticyclonically curved low-level hodographs and 0-1 km
shear values increasing to around 20 kts.

Main concern today will be the impact of a cold front
approaching the area from the Ohio Valley. The upper support
associated with this front is forecast to remain mostly north
and west of our area this evening with 500 mb height falls only
around 30-50 m. However low-level convergence along the front
looks pretty strong and we are expecting a band of showers with
scattered thunderstorms along or just ahead of the front as it
passes across the area. A ribbon of precipitable water values
over 1.5 inches will accompany MLCAPE values of 500 to 1000 J/kg
with the passage of the front along with a band of 30-35 kt
low-level shear. High resolution models are showing a band of
showers with some embedded storms this evening, strongest over
the Finger Lakes then weakening and lifting north as they
approach the I-81 corridor. The combination of convection and
strong low- level wind shear will result in a few storms
probably approaching severe limits with gusty winds and small
hail, and in fact a few severe storms and even an isolated small
tornado cannot be ruled out given the strong low-level wind
field. The storms will be east of the area by around midnight
with some clearing overnight.

Friday will be a quiet day with dryer air building in behind the
front. Dew points will fall through the 40s and temperatures
will recover back into the 70s to near 80.


245 pm update... Friday night, the proximity of short-wave
energy aloft in the broad SW flow pattern, along with the
approach of a surface boundary in the pre-dawn hours, will bring
the chance of showers back into the region. The best chance for
shower activity should be after midnight, with the evening hours
expected to be mainly dry.

On Saturday, the above mentioned front should slide southward
across CNY/NEPA, with continued chances for showers and
thunderstorms. The best chance of thunder will be over NY's
southern tier and NEPA.

Saturday night-Sunday, the just referenced surface boundary is
expected to stall out somewhere near the southern border of PA,
before coming back north again as a warm front by later Sunday.
The continued passage of short-energy in the mid-levels, along
with the resurgence of warm advection by late Sunday, will
probably keep at least some showers in the vicinity, with
thunder again possible with daytime heating by Sunday afternoon.

Highs should range from the upper 60s-upper 70s both Saturday
and Sunday.


250 pm update... Hit and miss showers are expected Sunday night,
within a warm advection regime. A better chance of showers and
thunderstorms are anticipated Monday afternoon and evening,
ahead of a fairly strong cold front. If adequate destabilization
can develop Monday, some stronger storms are not out of the
question, given a healthy low-level wind field. Temperatures
Monday afternoon should be back into the 70s.

Tuesday-Wednesday look cooler, post frontal passage. Some
lingering light showers are possible, with an upper trough in
the vicinity, but overall things look drier this period. Highs
mainly in the 60s Tuesday, should drop mostly into the 50s by


730 pm update...

Some 4k ft VFR cigs approaching from south into AVP well ahead
of a cold front in Ohio. Showers and scattered thunderstorms
still a few hours away in western NY and central/western PA.
Have a tempo for MVFR thunderstorms in NY mostly between 2 and
7z. AVP just VFR showers. Ceilings expected to fall to MVFR
after the cold front and precipitation late tonight. Probably
will only last a few hours and be above fuel alternate. Chance
of ITH/BGM going to fuel alternate with northwest flow off of
Lake Cayuga. SYR/ELM will be MVFR the shortest between 7 and
10Z. For rest back to VFR around 12z.

Southerly winds at 10 with gusts to 20 kt ahead of the front.
Winds shift to west at 4 to 8 kts with front. west winds Friday
at 5 to 10 kts.


Friday night through Tuesday...Although VFR is likely the
majority of the time, rounds of showers or thunderstorms could
bring occasional restrictions.




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