Marine Weather and Tide Forecast for Hammondsport, NY

NEAR TERM /THROUGH SUNDAY NIGHT/
Widespread light snow is expected across much of Central NY later this afternoon through tonight. Isentropic lift out ahead of a warm front and a weak upper level short wave will produce light snow over much of the area. The best chance for accumulating snow will be from the Finger Lakes region and north/east into Central NY, with very light accumulations also possible in the Southern Tier. The best lift/forcing likely will set up north of the NYS Thruway Corridor. Accumulations across most of the area will be less than an inch, but north of the NYS Thruway, 2 to 5 inches will be possible as this system pushes through tonight.

Light to moderate snow continues overnight as the surface low associated with the front moves east across southern Ontario.
Warm air advection will start raising temperatures late tonight and that can allow for some rain to possibly mix in around the Syracuse Metro early Sunday morning as temperatures reach the mid 30s. A mix of rain and snow showers will taper off Sunday morning as the surface low progresses into southern Quebec.
While 850mb temperatures won't be nearly as cold in the wake of the low (generally -3 to -4C), with a west- northwest flow developing off the lakes, additional lake enhanced rain and snow showers are possible through the afternoon north of the Southern Tier. Highs Sunday range from the mid 30s to the low 40s with the Wyoming Valley reaching the mid 40s in the afternoon.

There were no changes to winter weather headlines with this afternoon update and the winter storm warning remains in effect for Northern Oneida and an advisory is still in effect for Southern Oneida County.

SHORT TERM /MONDAY THROUGH TUESDAY/
300 PM Update

A shortwave lifting into the Ohio River Valley will push a warm front into the region Monday morning. Widespread rain showers are expected to develop along and behind the front across the region starting mid to late morning. Most of the area will be above freezing, but there is a chance for sheltered valleys and higher elevations to remain at or a degree below freezing along and just behind the warm front for a few hours at precipitation onset. This would bring pockets of freezing rain across the Twin Tiers and east of I-81 in NY. Guidance has trended slightly warmer from the previous run, backing off on the freezing rain coverage. Amounts look to be light, with a trace to a couple hundreths of an inch possible. Confidence in freezing rain amounts and location is low given our colder surface temperatures are right around 32 and duration of freezing rain looks to be short.

Rain will continue through the day, pushing east of the region by late afternoon/early evening. Temperatures Monday will climb into the upper 30s to low 40s.

Southerly flow will continue through Monday night, continuing to advect warm and moist air into the region. A few weak shortwaves will ripple through the overall SW flow pattern, kicking off some scattered rain showers through the night. Temperatures won't fall too far from afternoon highs, only dipping into the mid to upper 30s. Rainfall totals from onset Monday morning thru Monday night look to be between 0.25 and 0.5 inches.

The pattern does not change much on Tuesday as SW flow continues across the region as a large upper trough digs into the central US. WAA and upslope flow will bring chances for scattered rain showers, but widespread rain is not expected during the day. Temps will be very warm thanks to the aforementioned WAA, climbing into the mid 40s at higher elevations to low 50s in the normally warmer valleys.



LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/
320 PM Update

The pattern remains very active through the rest of the work week, with a deep upper level trough driving the weather.

A deep, positively tilted trough will slide through the central US Tuesday night. Over our region, this trough will generate multiple surface lows that will ride a baroclinic zone that will slowly move through the area from west to east as the trough tilts from positive Wednesday morning to slightly negative Wednesday night. The first low will move from S to N west of our CWA Tuesday night. The second low looks to develop over central PA Wednesday morning and track right over CNY through the day.
The last low impacting our area will develop over NJ in the afternoon hours and skirt us to the east. We look to be in the warm sector of this trough Tuesday night through early Wednesday afternoon, and thus, all precip will be rain. A strong cold front will slowly push through Wednesday afternoon as the upper trough tilts from neutral to negative. The changeover to snow should begin from west to east Wed afternoon, with all snow falling by the mid evening hours.

Very cold air is expected to fill into the region Thursday and Friday. mb temps fall from 4C Wednesday to -16z by Thursday.
This should kick off a strong lake response with snow showers from Lake Erie and Lake Ontario impacting parts of the CWA early Thursday morning into the late overnight hours. Guidance is showing wind direction to be west to slightly SW, which would put the Lake Erie band into the Finger Lakes and western Twin Tiers while areas north of the Mohawk Valley would see snow off Lake Ontario. Confidence in snow location is low given the variance in direction and strength from guidance, but it will definitely be cold enough for lake effect showers to develop.

High pressure looks to build into the area Friday night through Saturday, cutting off the lake effect engine and bringing quiet conditions.

AVIATION /20Z SATURDAY THROUGH THURSDAY/
More widespread snow will be pushing into the region late this afternoon and tonight. This will lead to mainly MVFR restrictions for the CNY terminals with periods of IFR or worse visby restrictions possible as well. Confidence is highest at SYR and RME for potential IFR conditions with lower confidence at ELM, ITH and BGM.

As the warm front with this system lifts north, low level winds will increase just above the surface. Low level vertical profiles show some borderline wind shear at most terminals, Sunday morning, but for now, have added LLWS to only Central NY terminals and exclude BGM and AVP, but it may be added with later forecast or amendments as confidence increases.

Outlook...

Sunday...Mainly VFR. Some restrictions may linger at KSYR and KRME as rain/snow showers depart the area.

Monday through Wednesday...Periods of rain and mixed rain/snow likely.
Restrictions possible.

BGM WATCHES/WARNINGS/ADVISORIES
PA...None.
NY...Winter Storm Warning until 10 AM EST Sunday for NYZ009.
Winter Weather Advisory until 10 AM EST Sunday for NYZ037.