922 
FXUS61 KBGM 311806
AFDBGM

Area Forecast Discussion
National Weather Service Binghamton NY
206 PM EDT Thu Aug 31 2017

.SYNOPSIS...
A cold front will drop through the region today bringing 
showers to the southern tier and northeast Pennsylvania into the
early afternoon. Friday and Saturday will be primarily dry but 
cool, followed by a wet Saturday night into Sunday morning.

&&

.NEAR TERM /THROUGH FRIDAY/...
1020 am update...
Local radars show widespread showers across the southern tier
and the western Catskills which is immediately behind the cold
front. Raised pops into the likely category for the next couple
of hours in the southern tier and northern tier of Pennsylvania
and this boundary continues dropping south. The activity is 
over for the northern forecast area and will end in the southern
tier during the early afternoon. Due to extensive cloud cover 
and lack of any instability removed the mention of thunder.

6 am update...
Update to speed up the cloud cover and reduce the pops. Most of
the light showers will stay in the western half of the NY
counties. Temperatures already showing a response to the
increased winds and rising into the 60s. 

3 AM Update... 
Showers already moving into central NY well ahead of a cold 
front. These isolated showers will stay mostly in the northeast 
CWA and weaken. Cloudy skies are also pushing south into the 
region. Further south is river valley fog in south central NY 
and northeast PA. Behind the cold front over Lake Ontario is a 
band of mainly light showers. This will move south into the 
Finger Lakes around sunrise. By afternoon it will be in 
northeast PA then out of there by 5 PM. The band of showers will
become less numerous as it moves south. Weak heating in NEPA 
and the Catskills could be enough to cause an isolated 
thunderstorm. Models not showing much instability and only weak 
forcing. Rainfall amounts will be mostly under a quarter of an 
inch. Behind the front is good cold air advection. Temperatures 
will not recover much in the far north despite some sunshine. 
Mid 60s north to low 70s far south. 

This evening skies become partly cloudy. Airmass will continue
to dry and cool with 850mb temps falling to 0C. Lows will drop
to the upper 30s far east and northeast to low and mid 40s
elsewhere. Not seeing much fog with the dry advection. 

Friday high pressure centered over the Great Lakes will keep it
mostly sunny. With the cold Canadian airmass highs only in the
low and mid 60s.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY/...
200 PM UPDATE...
The remnants of Harvey will be approaching the region from the 
Tennessee Valley on Saturday, however, there will be a rather 
dry Canadian high pressure system over CNY and NEPA. This dry 
air will eat away at the leading edge of the tropical remnants 
and much of Saturday looks to be dry with increasing cloudiness 
across most of the forecast area. Do have a low chance of rain 
working into mainly NEPA by early evening (00Z). The tropical 
remnants get swept up in a northern branch trof pushing through 
the Great Lakes region and should be a quick hit of high 
confidence rainfall moving through on Saturday night and the 
first part of Sunday. Timing in the models is pretty good on the
beginning phase of the event, but there is some discrepancy as 
to exactly when rain moves out. Have made some adjustments to 
the PoP timing, but even with the downward adjustment during the
afternoon period, Sunday may trend drier faster than the 
current forecast. 

Nudged temperatures up a tad on Saturday with anticipation of
less rainfall, and also kept overnight lows up higher than 
guidance given clouds and rain moving into the area. Close to 
guidance on Sunday, but still cooler than normal.

&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
200 PM UPDATE...
High amplitude mid level trof begins to develop during this 
time frame and will move over the area by Wednesday. 
Interactions with tropical system Irma closing in on the western
Atlantic may help to beef up the downstream ridge. Models 
already showing trends of slowing down the cold front 
approaching us from the Great Lakes region for Tuesday. Have 
pushed PoPs back into Monday night and lowered slightly, 
especially in the southeastern zones. Front should be bringing 
showers and a chance of thunderstorms for Tuesday. Models then 
diverge further into the week with placement of the front and 
where it may stall, or drift back west. Most medium range models
push the front through our area with the GFS most progressive 
through Thursday morning. ECMWF and Canadian Global are also to 
our east, but are showing hints of developing low pressure aloft
within the high amplitude trof and lifting it north. Will have 
to see what the trends offer up, but stalling the front further 
westward across the Eastern CONUS may turn out to be the answer 
going forward as Irma moves closer to the U.S. by next weekend. 
The short answer is we continue to mention chance PoPs across 
the forecast area (especially east half) from Wednesday through 
Thursday.

Overall, temperatures below normal next week with a small surge
of near normal temperatures on Tuesday ahead of the cold front.



&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
Cold front has cleared the terminals ending the possibility of
any more showers. Conditions through this afternoon will be
primarily low VFR with ceiling around 4K feet but at
KITH/KBGM/KAVP, MVFR/Alternate required conditions will persist
until 21Z. This evening skies will be primarily clear except for
a some scattered lake clouds at KSYR/KITH/KBGM. High pressure
on Friday will give the area clear skies. Fog is not expected
overnight due to dry air advection and boundary layer mixing. 

Northwest winds 8-12 knots with gusts 15-20 knots decreasing
early this evening to 5 knots or less. Northwest winds on Friday
at 7-10 knots.
 
Outlook...

Friday night through Saturday...VFR.

Saturday night through Sunday...Showers/rain with MVFR/IFR
restrictions.

Monday...Primarily VFR.

Tuesday...Showers with restrictions possible.

&&

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

&&

$$
SYNOPSIS...TAC
NEAR TERM...RRM/TAC
SHORT TERM...JAB
LONG TERM...JAB
AVIATION...RRM