Marine Weather and Tide Forecast for Waterloo, NY

KEY MESSAGES
1) Lake effect snow showers continue over Central NY today and into Thursday.

2) A shortwave brings some additional snow showers Friday night into Saturday. Continuing to monitor another system Sunday into Monday.

DISCUSSION
KEY MESSAGE 1...
Lake effect snow continues downwind of Lake Ontario this evening.
This really is a lake enhanced event with synoptic moisture that is wrapping all the way around an upper level low over norther Maine. The synoptic moisture combined with cold air low- level air (-12C or so at 850 mb) moving across Lake Ontario and riding upslope into the highlands of central NY continues to cause fairly widespread light to occasionally moderate snowfall.
Decided to add Chenango and Otsego into the winter weather advisory as per radar signatures and the flow pattern. The snow is enhancing in the higher terrain as expected. Colder and drier air is expected to work south later tonight and shut down the snows east of I-81 as per some of the CAM models but the persistent northwest low-level flow across Lake Ontario looks to prolong the lake effect snow east of I-81 and north of BGM.
We may have to continue the advisory longer or up amounts and potentially go to a lake effect snow warning in these areas. We will be looking into this as new guidance comes in. In the mean time, a widespread 3 to 7 inches snowfall expected mainly north and east of a BGM to ITH line.

Previous Discussion below...
Lake effect snow showers will continue across Central NY, with the most numerous snow showers downstream of Lake Ontario this afternoon. These snow showers will be aided by a weak mid- level disturbance and some instability, which could help produce a gusty snow shower or a few smaller snow squalls for northern Central NY this evening. As flow becomes more prominently northwest tonight, lake effect snow showers will likely develop off of the Finger Lakes, as well as Lake Ontario, continuing snowfall for areas south and east of the Finger Lakes. Some of these showers could possibly extend into portions of the Southern Tier as well. These showers are expected to last until at least Thursday early afternoon, and the Winter Weather Advisories for Onondaga- Southern Cayuga- Tompkins- Cortland have been extended in time to 1pm Thursday to account for these showers off of the Finger Lakes and Lake Ontario. Snow showers should diminish going into Thursday late afternoon with high pressure beginning to build in.

KEY MESSAGE 2...

Model guidance is starting to key in another shortwave moving through Friday night into Saturday with another round of snow showers and some light accumulations. This feature has trended stronger so we will continue to monitor.

Looking into the late weekend, another system looks to track through the Southern United States Sunday into Monday. The latest run of the ECWMF is the latest update that has our area under any impact, which would bring some mixed rain/snow into the area. Even though very few scenarios exist with impacts from this system, we've maintained some rain and snow showers in the forecast.

Confidence is increasing temperatures will get into the 40s for highs early next week. This would suggest a slower instead of sudden thaw process which would be helpful in terms of lowering the risk of any potential ice jams.

AVIATION /00Z THURSDAY THROUGH MONDAY/
Current snow showers will continue through the afternoon with those associate restrictions remaining at those terminals.
Another cold front drops through and brings some heavier snow showers across the area this evening, and will spread from north to south starting in the late afternoon into the mid evening hours. This should bring IFR conditions to ITH and BGM along with the already expected IFR at SYR and RME through the day. Lake effect snow is expected to last into tomorrow, but confidence in band placement and intensity for this evening into the overnight is low. Currently, ITH seems to have the best chance at remaining IFR through the night, with SYR/BGM/RME at MVFR. These terminals could see IFR as there are some signals for it, but confidence is not high enough at this time to include it in the TAFs.

ELM will see snow later this morning into the evening hours with MVFR restrictions. Like the other terminals, IFR could be possible but confidence is not high. AVP is expected to remain VFR through the day as snow is not expected to reach the terminal.

Outlook...

Thursday... Some IFR/MVFR restrictions possible from lingering snow showers in CNY.

Friday and Saturday... High pressure returns with VFR conditions expected at this time.

Sunday...Restrictions possible with the potential for a system to move into the area.

BGM WATCHES/WARNINGS/ADVISORIES
PA...None.
NY...Winter Weather Advisory until 8 AM EST Thursday for NYZ009-036- 037-045-046.
Winter Weather Advisory until 1 PM EST Thursday for NYZ017-018- 025-044.