textproduct: Buffalo

WHAT HAS CHANGED

No significant changes with this update.

KEY MESSAGES

1) A mix of snow and rain east of Lake Ontario tonight.

2) Widespread rain Sunday, possibly ending as light snow Sunday night.

DISCUSSION

KEY MESSAGE 1...A mix of snow and rain east of Lake Ontario tonight.

Clipper low will track along a baroclinic zone orientated NW to SE across the Great Lakes, with the center of the low sliding from the upper Great Lakes tonight to northern New York Sunday. A period of warm advection snow will develop east of Lake Ontario tonight before changing to mainly rain by Sunday morning, as warmer air spreads northward. A brief mix with sleet/freezing rain is possible before the transition to all rain. Snow accumulation should be minor (<2") with latest HREF probabilities showing a 10% to 20% of amounts greater than 2 inches.

KEY MESSAGE 2...Widespread rain Sunday, possibly ending as light snow Sunday night.

Clipper low slides across New York State Sunday sending a cold front south through the area. This will bring a round of rain to areas south of Lake Ontario. Rainfall amounts generally a tenth to a quarter inch. Colder air filtering in Sunday night may bring a change to all snow, but any accumualations will be very light, with HREF probabilities showing only about 10% for amounts greater than an inch.

AVIATION /18Z SATURDAY THROUGH THURSDAY/

CIGS are expected to lift into the VFR range areawide as some low level dry air associated with high pressure passing by to the north works in this afternoon.

Tonight...Terminals south of Lake Ontario are expected to remain VFR through much of tonight south of a quasi-stationary boundary draped from southeast Ontario Province ESE across the eastern Lake Ontario. Deteriorating conditions (MVFR/possible IFR VSBY at times) are expected to re-develop north of this boundary across the North Country (KART) overnight as a weak wave of low pressure riding ESE along this boundary brings a period of light snow at the onset this evening, gradually changing over to light rain through the second half of tonight. A period of LLWS will be possible second half of tonight for areas south of Lake Ontario as a LL jet segment works ESE across the western NY.

Sunday...Conditions will gradually deteriorate region-wide as a Clipper system pushes through Sunday morning, followed by a trailing cold front Sunday afternoon...both bringing a period of rain to the area. Expect MVFR conditions to develop south of Lake Ontario during the morning hours, with IFR North Country. Conditions will worsen through the afternoon with widespread IFR conditions developing as the cold front slowly presses south through the region.

Outlook...

Sunday night...IFR improving to mainly MVFR with rain tapering off as light wet snow.

Monday...Mainly MVFR with scattered snow showers.

Tuesday...Mainly VFR.

Wednesday...VFR/MVFR with chances for rain or snow showers.

Thursday...IFR/MVFR with snow changing to rain.

MARINE

A clipper low approaching from the northwest will cause easterly winds to increase on Lake Ontario this evening. Northeasterly winds will briefly increase on Lake Erie as well, though small craft headlines are not anticipated.

Light to moderate onshore flow will develop on the lower Great Lakes Sunday, with northerly winds further strengthening Sunday night behind a cold front. This may result in a period small craft advisory conditions on Lake Ontario, particularly the eastern end of the lake. Winds become northwesterly and diminish to 15 knots or less Monday.

Calmer conditions are expected through mid week.

BUF WATCHES/WARNINGS/ADVISORIES

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