textproduct: Binghamton

WHAT HAS CHANGED

PoPs were increased and brought farther south Monday afternoon into the Twin Tiers and portions of NE PA as coverage of lake effect/lake enhanced showers is often underdone by the NBM.

KEY MESSAGES

1) A broad upper level low moving over the region is expected produce scattered showers and isolated thunderstorms early this week before moving away from the area Tuesday.

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 surface low centered near Georgian Bay early this morning will be gradually lifting northward toward the Ontario/Quebec border. As it does so, it will continue to drag a frontal boundary east-northeast across the CWA through the morning hours with a round of showers and perhaps a rumble of thunder before reaching the Hudson Valley region by the early afternoon. As the winds become more westerly in the wake of the frontal passage and an upper level low drops south over the eastern Great Lakes this afternoon, additional isolated to scattered showers and thunderstorms can pop up, especially across CNY and toward the Finger Lakes. 0-6km shear increases late this morning into the afternoon ranging from 30 to 45 knots with about 500 to 1000 J/kg of MUCAPE and about 300 J/kg of MLCAPE. Steep low-level lapse rates will be accompanied by mid- level lapse rates of 6-6.5 C/km. All of this combined with afternoon daytime heating means there is an isolated strong to severe thunderstorm risk where a few storms popping up could produce hail and locally damaging winds. SPC has a Marginal Risk (Level 1 out of 5) across the entire area for today.

Model guidance does show that a brief break in shower activity is expected this evening as a dry slot develops, then as the upper low settles overhead tonight, some spotty showers can make a return late. The upper low will be bringing in some noticeably cooler air with it as 850mb temps fall as low as +7 to +10C Monday morning. With the cool air aloft and a west to northwest flow in place, additional lake effect/lake enhanced rain showers are expected to develop Monday, especially during the afternoon. The NBM tends to be underdone with coverage of showers in this set up, so shower chances were added farther south through the Twin Tiers in the afternoon.

As the upper low lifts NE Tuesday, some spotty showers can still linger, especially downwind of Lake Ontario, before dry conditions return. Highs today will be in the 70s areawide before cooling down into the 60s and low 70s tomorrow. Lows tonight will be in the upper 40s to mid 50s.

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. Some model guidance and ensemble members lean toward the activity moving in more toward the afternoon hours on Thursday, so this is something to monitor in the coming days. As of now these features appear to be more progressive and look to move out of the region by next weekend.

AVIATION /06Z SUNDAY THROUGH THURSDAY/

A line of showers, with associated CIG/VSBY restrictions will press slowly through the area from west to east during the early morning hours. This could bring occasional MVFR/MVFR Fuel Alt restrictions as it moves through. RME and BGM may see a period of IFR CIGs around daybreak ( approx 09-13z) and into the early morning hours.

After the initial trough passage, more scattered showers and isolated thunderstorms are expected to develop late morning and into the afternoon hours. Included PROB30 groups for a chance of tsra at our NY TAF sites (mainly 16-21z today). Outside of the showers and isolated thunderstorms, CIGs are expected to rise and scatter, back to generally VFR by 17/18z as some drier mid level air works into the region. VFR conditions are then expected to prevail over the area this evening into tonight, as the lake effect rain bands stay just north.

southeast winds 5 to 15 kts early this morning are forecast to turn west-southwest later today and increase between 8-20 kts over the area. Winds then diminish below 10 kts heading into this evening.

Outlook...

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

Tuesday through Thursday...Mainly VFR.

BGM WATCHES/WARNINGS/ADVISORIES

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