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000 
FXUS61 KBGM 171902
AFDBGM

Area Forecast Discussion
National Weather Service Binghamton NY
302 PM EDT Thu Aug 17 2017

.SYNOPSIS...
Clouds will increase and rain showers will begin tonight.
Conditions will remain humid with showers and scattered 
thunderstorms through Friday evening. Locally heavy rain is
possible tonight and a few storms may produce hail and gusty 
winds Friday afternoon. Cooler, but still somewhat unsettled 
weather continues on Saturday.

&&

.NEAR TERM /THROUGH FRIDAY/...
300 pm update...
Main concern in the near term is focused around the developing
showers and isolated storms tonight...with a brief respite late 
Friday morning, and another round of convection Friday 
afternoon/evening.

Low pressure system in the Great Lakes moving newd into ern
Canada will be the driving force behind the potential for
showers and storms across central NY and ne PA tonight through
Friday. The surface low currently situated in nrn WI with a warm
front extending sewd into wrn PA and far wrn NY. The warm front
will be the initial forcing mechanism behind developing showers
and isolated thunderstorms this evening. A strong surge of deep
moisture and a layer of WAA in the mid levels combined with a
weak lead upper level s/w will produce a broad area of weakly
forced showers/storms tonight. 

The most favorable time for the strongest forcing with the warm
front appears to be just after midnight tonight through 8-10am 
Friday morning. Elevated CAPE values around 500 J/kg may be
sufficient for embedded convection/t-storms...however weak mid
level lapse rates may hinder the extent of the convection that
does initiate. Either way, the presence of an abundant amt of 
moisture throughout the column, and a slow moving warm front 
should create favorable conditions for locally heavy rainfall. 
Antecedent ground conditions being relatively dry should inhibit
any real chance of flooding...but will need to keep an eye on 
this batch of rain.

Most of the model guidance shows a dry slot developing on the
back side of the warm front as it exits to the ne late Friday
morning. If this does occur and most of the cloud cover does
scatter out, there may be rapid destabilization across central
NY...enough to trigger strong to possibly severe convection. The
potential is there for 1500-2000 J/kg of ML CAPE, and 30-35kt of
deep layer shear, along with steep low level lapse rates.
Shallow mid level lapse rates may inhibit things a bit. A
surface cold front will drop in from the nw, and where the
convection does develop will depend on the timing of the fropa 
and the clearing of clouds in the dry slot. Best forecast right
now is for storms to develop from Utica to Cortland to Elmira,
and track to the se through the afternoon and early evening. A
lowering wet bulb zero height, and dry air getting entrained in
the mid levels may lead to a few storms producing large hail 
and damaging winds...along with brief heavy rain. Although if
conditions remain stable and the clouds/rain linger longer than
expected, fropa may end up being quite benign. 

Conditions will become more stable after sunset Friday evening
with lingering light rain showers tapering off west to east.
Weak ridging ahead of the next upper trough swinging through
Saturday may suppress any precip late Friday night and Saturday
morning.

Lows tonight will be very mild with muggy conditions...into the
mid to upper 60s. Highs on Friday will top out in the upper 70s
and lower to mid 80s. Temps remain mild Fri night, only into the
60s.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
A mid-level short wave will track east across the area during
the day on Saturday. Moisture and instability will be lacking 
with this feature, having moved east with the eastward passage 
of the system on Friday. Still this system looks strong enough 
to generate at least scattered showers and maybe an isolated 
thunderstorm during the afternoon Saturday. After this system 
passes east a quiet mild period is in store as high pressure 
builds toward the area. There may be enough dry air coming in 
behind the system on Saturday so that fog will be limited Sunday
morning, then Sunday will be dry and sunny with near to 
slightly below normal temperatures in the mid 70s to lower 80s.

&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
The long-range period will start out dry and seasonably warm on
Monday with highs from the upper 70s to mid 80s. High pressure
will drift off the east coast on Tuesday as a cold front
associated with a digging short wave moving southeast from the
Great Lakes approaches the area. That will set the stage for
rather warm and humid weather on Tuesday with temperatures
mainly in the 80s. The cold front will pass across the area late
Tuesday through Wednesday along with a chance of showers and
thunderstorms. Cooler and dryer weather will return later
Wednesday through the second half of next week.

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
VFR conditions generally expected through 06Z tonight. High thin
cirrus and a scattered strato-cu deck around 5-8k ft will
prevail the rest of the afternoon...becoming thicker while 
lowering this evening as a warm front approaches. Showers will 
start to spread across the area 04Z-09Z Friday, with ceilings 
eventually lowering into fuel alternate required levels. Light 
and variable winds, will become generally southeast or south 
5-10 knots this evening with gusts 10 to 20 kt not out of the
question through 18Z Friday. Rain showers expected tonight with
conditions potentially breaking up by the mid to late morning
hours Friday. This may destabilize conditions enough for
scattered thunderstorms...impacting mainly KBGM and KAVP. 

Outlook...

Friday night...Periodic restrictions from showers/thunder as a
system moves through area.

Saturday through Monday...Mainly VFR, though a few showers and
brief restrictions still possible Saturday.

Tuesday...The next chance of showers and storms with associated
restrictions possible.

&&

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

&&

$$
SYNOPSIS...BJT

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