Area Forecast Discussion

WHAT HAS CHANGED

No significant changes with this forecast package.

KEY MESSAGES

1) Scattered showers with isolated thunderstorms are possible from tonight through Thursday night.

2) Temperatures on Friday night will be cool behind a front with lows near 40 degrees for portions of the Tug Hill.

3) Moisture returns over the weekend with another chance of showers and thunderstorms Saturday afternoon through Sunday with lower chances continuing into Monday.

DISCUSSION

KEY MESSAGE 1...Strong high pressure overhead this morning will move off the New England Coast by tonight. Mid and high level moistre will overspread the area today with increasing cloud cover while low level dry air is slow to overcome. The upper level ridge axis will expand into western New York today but will be suppressed slightly to the south tonight as a trough swings across northern Ontario into Quebec. Expect to see scattered light showers develop tonight. Can not rule out a thunderstorm or two but instability is limited and mainly confined to areas east of Lake Erie.

Surface low pressure tracks from near Hudson Bay to northern Quebec with the trailing frontal boundary settling south into the area on Wednesday. High temperatures are expected to reach the upper 70s but may be impacted by coverage of showers. CAPE values peak in the 500- 1000 J/kg range across the southern tier and a few thunderstorms may try to develop late afternoon. Pops are generally in the chance range as placement could end up just a little farther south into PA.

Models do show some spread by Thursday morning with regards to where this boundary may be located. It very well could lift back north during the day on Thursday with additional showers before strong high pressure builds south out of Ontario with the airmass drying out for Friday.

KEY MESSAGE 2...Strong high pressure will build south out of Canada on Friday night. Light wind conditions are expected towards the Adirondacks while better chances for clouds are focused in SW New York. While most of the area can expect lows in the upper 40s to near 50 degrees, portions of the Tug Hill may see lows fall to near 40 degrees with a few cooler spots if ideal radiational cooling conditions develop.

KEY MESSAGE 3...Low pressure will track out of the Plains across the Central and Eastern Great Lakes on Saturday. This will bring a little more focused potential for showers and possibly thunderstorms, Saturday night into Sunday. Probabilities of half inch of rain or more are generally in the 50-60 percent range.

AVIATION /06Z TUESDAY THROUGH SATURDAY/

VFR conditions will continue for the bulk of the TAF period. Some low VFR clouds have developed off the lake and into the Tug Hill region, including near KART. These will maintain through daybreak and will stave off any non-VFR conditions. Meanwhile, in the Southern Tier, calm and clear conditions may allow for some pre-dawn fog and mist and have introduced some MVFR into KJHW.

High pressure will continue east of the region with a warm front lifting through the eastern Great Lakes. Winds on the warm sector of this front will be generally southerly. Some gusts in the 20 to 30 kt range will be possible this morning and afternoon, especially in the typical downslope areas. A weakening cold front will approach from the west toward the end of the TAF period, bringing lowering ceilings along with some rain chances. With a slowing and weakening front and unfavorable timing, rain will be fairly scattered and any TS activity should be west of the airspace, holding off until Wednesday.

Outlook...

Late Tuesday night through Wednesday...VFR/MVFR with scattered showers possible. Slight chance of a thunderstorm.

Wednesday night through Thursday...MVFR/IFR with showers likely at times along with a chance of a few thunderstorms.

Friday...MVFR CIGS early, improving to VFR.

Saturday...VFR.

MARINE

Southerly flow will be favored on the lake today with high pressure departing the region to the east and the area in the warm sector of a system moving through the Great Lakes. A weakening cold front will move across the lake tonight into Wednesday and shift winds to the west then north then east through Wednesday night. Any onshore flow on Wednesday and Wednesday night will remain in the 5 to 10 kt range and resultant waves should be minor. The former cold front will settle south of the lake and a weak low will move along the boundary for Thursday, allowing for north to northeast winds to return to the basin. High pressure will build from the northwest starting on Thursday night through Saturday. Northwest to north winds of 10 to 15 kts will be favored on Thursday night through Friday night and 1 to 3 ft waves will be possible along the southern shores of the lake. As the system departs to the east, easterly flow will be favored on Saturday. Overall, no marine headlines are expected through the forecast period.

BUF WATCHES / WARNINGS / ADVISORIES

NY...None. MARINE...None.