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000
FXUS61 KBGM 221534
AFDBGM

Area Forecast Discussion
National Weather Service Binghamton NY
1134 AM EDT Thu Jun 22 2017

.SYNOPSIS...
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High pressure will keep conditions mainly dry and mild through
this afternoon. Tonight through Friday night more showers and
thunderstorms are expected as fronts pass through the area.
Locally heavy rain is possible. Seasonal temperatures are
expected into the weekend with decreasing chances for
precipitation.
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&&

.NEAR TERM /THROUGH FRIDAY/...
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1130 AM update...Forecast in good shape just minor adjustments
to near term temperatures and pops. Area of convection across
southern Ontario may brush the western and northern portion of
the forecast area later this afternoon. This convection is being
forced by an area of isentropic lift which will move into the
above mentioned area this afternoon. Dry low levels will limited
much of the activity to isolated coverage.

415 am update...
Main concerns in the near term are focused around patchy valley fog
this morning, the onset of showers and storms this evening with an
increase in coverage and intensity on Friday, along with warmer
temperatures, a more humid air mass, and gusty s/sw winds.

High pressure at the surface and weak ridging aloft across the
region this morning has allowed for mostly clear skies and calm
winds...which is favorable for areas of valley fog through srn NY
and nrn PA. GOES16 satellite and area observations picking up on fog
development early this morning. Fog will likely lift and mix out
between 7-9 am this morning.

Most of the day will be pleasant today with mostly sunny skies this
morning and increasing clouds in the afternoon. A warm front will
lift n/newd from the srn Great Lakes into nrn NY. As this front
moves across the region, the abundance of dry air in place will need
to be overcome to allow precip to form and reach the ground. It
appears this will take longer than previously thought...so a delay
in the precip onset was performed with the morning forecast. Now
have the best chance of showers and storms along the warm front not
impacting the Finger Lakes and Mohawk valley area until after sunset
tonight.

Precipitation efficiency will really start to ramp up Friday morning
and last through the as a very warm and moist swly flow sets up
ahead of an incoming upper s/w. The deep moisture streaming into the
area will be associated with remnants of tropical storm Cindy. PWATs
will range from 1.5 to as much as 2 inches at times Friday. Model
guidance is not in strong agreement with the placement, timing or
intensity of the precipitation during the day. There will likely be
a convective component as the boundary warms/destabilizes during the
day, but there is also some indication of a Predecessor Rainfall
Event (PRE). Portions of NY/PA may be situated in an environment
favorable for this type of heavy rain event. This type of
environment consists of being in the right entrance region of an
upper jet, ahead of a synoptic trough, within a plume of deep
tropical moisture, and near a low level theta-e axis...and all of
these conditions may end up being met. At this point, we are not
ready to nail down a location or rainfall amounts, but the potential
for heavy rain somewhere in the area is looking more favorable. Some
times these types of events can be very localized and not well
handled by model guidance, so we`ll need to be diligent in looking
for signals as today progresses. The most favorable time for heavy
rain appears to be during the day Friday. A Flash Flood Watch may be
needed at some point.

Will also need to concerned with the possibility of severe
storms on Friday...with the main threat being damaging winds.
Wet bulb zero heights will likely be too high to develop severe
hail. Low level shear will be elevated...around 30 kt of 0-1km
bulk shear...so the potential for a few tornadoes is not out of
the question.

High temperatures today will top out in the upper 70s and lower 80s.
Lows tonight will remain very mild, only dropping into the 60s and
lower 70s. These mild morning temps and a strong influx of
warm/moist air from the s/sw will set the stage for a hot and humid
day Friday...into the 80s, with dew points in the 60s and possibly
lower 70s.
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&&

.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY/...
4 am update...
Showers and thunderstorms continue into Friday night. Models
show the cold front moving a little slower. Passage late evening
to around midnight. Further northward progress of tropical
moisture from remnants of Cindy but most keep it south of PA.
Despite this PWATs will be around 2 inches. Storm motion this
period will be moving faster so only issue with flash flooding
will be training. Average rainfall amounts will be under an inch
this period. A "marginal" chance of severe weather the entire
area Friday afternoon and evening. During the evening the
biggest threat will be in northeast PA and the Catskills.
Moderate instability and shear Friday evening. The instability
will be mostly low level. Biggest severe threat damaging winds.
Friday night lows in the 60s with the moist humid air.

Slow drying behind the front Saturday. Cooler air takes its time so
highs near average mostly in the upper 70s. Rainfall Saturday less
than a tenth of an inch with chance pops.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
4 am update...
Little change to the forecast here. Unsettled and cooler than
normal with an upper level trough over the area Monday and
Tuesday. Some improvement Wednesday to Thursday as heights
slowly build and surface high pressure sets up across the middle
Atlantic states.

previous discussion...
The second half of the weekend into early and mid next week
still looks to feature a cool and overall unsettled pattern as
the next upper level trough and associated surface features move
through the Great Lakes region. Sunday looks to be the
relatively driest day in the long range with only isolated to
scattered afternoon showers. A pair of stronger waves moving
through Monday and again Tuesday afternoon will bring a better
chance for more widespread showers and storms. Temperatures
through the long range will be generally below average with
highs mainly in the low 70s.

&&

.AVIATION /16Z THURSDAY THROUGH MONDAY/...
High pressure will continue to dominate today with VFR
conditions after the valley fog lifts and mixes out after 13Z.
A warm front will moves in from the w/sw this evening and bring
mid lvl clouds to the region, along with a few rain showers to
KSYR and KRME after 03Z. The front is expected to lift to the
north after 06Z, with much of the region in a dry slot with
precipitation holding off until after 12Z Friday. Light and
variable winds this morning will become S/SW around 5 to 10
knots later today and persist tonight.

Outlook...

Thursday through Friday night...Showers and thunderstorms,
especially Friday, with associated restrictions.

Saturday - Monday...Mostly VFR, but shower/storm and brief
restriction possible.

&&

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

&&

$$
SYNOPSIS...BJT
NEAR TERM...BJT/RRM
SHORT TERM...TAC
LONG TERM...RRM/TAC
AVIATION...BJT/KAH/RRM