textproduct: Binghamton

WHAT HAS CHANGED

No significant changes made to the forecast at this time.

KEY MESSAGES

1) A broad upper level low moving southeastward into the area tonight into Sunday is expected to lead to unsettled weather into early next week.

2) High pressure builds in for a brief lull in wet weather Wednesday, then additional showers and thunderstorms are expected to return Thursday into Friday.

DISCUSSION

KEY MESSAGE 1...

A broad upper trough will be setting up across the eastern U.S. this weekend with an upper low dropping southeastward out of Canada and becoming a closed low over the Great Lakes on Sunday. A surface low is expected to develop over the eastern Great Lakes region as well Saturday night into Sunday. These features are expected to be the main drivers of our weather into early next week. There is also a surface low developing near the mid- Atlantic coast today that will be sliding northeastward but most of the moisture from this is expected to pass by off to our south and east.

Clouds will increase from south to north and there can be some isolated showers this afternoon and evening, but shower chances will increase later tonight into Sunday as an embedded upper shortwave rotates into the area and the upper trough becomes more neutral to slightly negatively tilted as it shifts east. Chances for thunder look to be pretty low this afternoon and evening with modest instability (500 to locally 1000 J/kg of MUCAPE), but little in the way of MLCAPE and bulk shear. Mid- level lapse rates are poor as well, so thunder was reduced to just a slight chance during this time.

The surface low over the eastern Great Lakes is expected to lift north-northeast, passing just north and west of the CWA Sunday. As it shifts north toward the Ontario/Quebec border, it will drag a surface cold front across the region Sunday (timing of the frontal boundary is a bit uncertain). The chance for thunder is a little better on Sunday as 0-6km shear noticeably increases to 35-50 knots across the CWA and mid-level lapse rates are a bit higher around 6- 6.5 C/km as well. MUCAPE still looks to average 500-1000 J/kg, but the NAM is a little more bullish east of I-81. In the wake of the frontal passage, model guidance suggests there can be a brief break in shower activity as a dry slot develops Sunday evening.

By Monday, the 500mb closed low moves overhead. This combined with with cooler air aloft moving over the Great Lakes with 850mb temps falling to +6C to +10C and a west to northwest flow in place, additional showers are expected to develop. As the upper low lifts NE Tuesday, there could be a few lingering showers downwind of Lake Ontario near and north of the NYS Thruway before drier conditions return. Near to slightly below average temperatures are expected this weekend before turning noticeably cooler Monday with the upper low overhead with highs in the 60s and low 70s.

KEY MESSAGE 2...

High pressure briefly builds in Tuesday night into Wednesday with dry conditions. Then Thursday into Friday, model guidance suggests a similar pattern to this weekend setting back up with a potential low moving up from the south and another upper trough pushing in from the west that would bring the chance for additional showers and thunderstorms. As of now these features appear to be more progressive and look to move out of the region by next weekend.

AVIATION /12Z SATURDAY THROUGH WEDNESDAY/

Valley fog will continue to impact ELM this morning, bringing LIFR restrictions through 13-14z, before quickly scattering out and improving back to VFR by around 1430Z. AVP has some sct to bkn MVFR stratus clouds in the vicinity, but these will begin to dissipate by mid morning. The other TAF sites are expected to remain VFR through the day today.

There is a slight chance for a stray shower or t'storm INVOF AVP or BGM by late afternoon or early evening, but confidence and coverage was too low to include in the TAF a this time.

Otherwise, lowering cloud bases and CIGs move in from the south later this evening, with MVFR conditions forecast to reach AVP after 23/02z, ELM 23/03z and BGM 23/04z. The MVFR and even IFR CIGs are forecast to continue spreading north over much of the forecast area late tonight and early Sunday morning. There will also be increasing chances for showers and isolated thunderstorms heading into tonight and Sunday morning as a frontal boundary approaches. These could bring occasional IFR visibility restrictions and gusty/erratic wind gusts at times.

Expected light east-southeast winds early this morning, less than 5 kts. The winds turn south-southeast and increase between 6-15 kts late morning into this afternoon and evening.

Outlook...

Sunday...Showers and potential thunderstorms with associated restrictions.

Monday...Scattered showers at the Central NY terminals with associated restrictions possible.

Tuesday and Wednesday...Mainly VFR.

BGM WATCHES/WARNINGS/ADVISORIES

PA...None. NY...None.