Marine Weather and Tide Forecast for Waterloo, NY

KEY MESSAGES
1) A strong cold front will bring gusty heavy rain showers this afternoon and evening.

2) There will be a rapid drop in temperatures with the passage of the cold front tonight, with rain changing to a quick burst of snow and possibly a flash freeze as temperatures fall into the 20s to upper teens by early Tuesday.

3) Accumulating lake effect snow is likely for Oneida County Tuesday afternoon through Tuesday night.

DISCUSSION

KEY MESSAGE 1...

Cloud cover today has significantly limited instability and thus the severe thunderstorm threat has decreased. However, a strong line of rain showers with embedded thunderstorms will still be possible this afternoon and evening. The strongest winds will likely be associated with FROPA this evening and the cold air advection behind the front overnight. A wind advisory for the Finger Lakes and a portion of the Twin Tiers has been extended until 8am tomorrow morning. Gusty winds will also get close to advisory criteria across the Poconos and a wind advisory remains in effect there until midnight tonight. Rainfall totals are also looking less than previous forecasts, however there will still be some potential for minor flooding, but no major flooding impacts are expected at this time.

KEY MESSAGE 2...

Behind the cold front, a very cold airmass for this time of year will move in quickly and cause surface temperatures to drop 25-30 degrees in a 6 hour window (between 6PM and midnight).
Rain will change to sleet and snow this evening and some of the higher elevations across Steuben County could exceed 4 inches of snow. A winter weather advisory has been issued for there due to the snow and the potential for a flash freeze in this situation, given how quickly the air temperatures drop behind a rain- producing front.

Elsewhere, 1 to 3 inches of a snow and sleet mix will be possible across higher elevation areas and valleys will likely see little to no accumulations. The flash freeze potential is area-wide, but the limiting factor will be the warm ground temperatures overall, which are much warmer than even a couple weeks ago. Also, remaining gusty winds tonight into Tuesday morning may also help to dry out the wet roads before the cold air really settles in.

KEY MESSAGE 3...

On Tuesday, strong cold air advection takes hold and 850mb temperatures will drop to -16 to -18C. The wind orientation will initially be westerly, or even west- southwesterly Tuesday morning, which will allow for most of the lake effect snow showers to initially be located north of Oneida County/closer to Lake Ontario. However as the primary upper trough shifts eastward, the flow will become more west-northwesterly, which will favor an upstream lake connection and allow for the lake effect snow to shift southward Tuesday afternoon, first into Oneida County, then towards the NY Thruway corridor Tuesday evening. A fairly organized lake effect band will likely be present late in the afternoon into Tuesday night (rather than mid-day Tuesday during the strong mid-March sun angle). Due to the timing, several inches of snow will be likely over Oneida County and a Winter Storm Watch for lake effect snow has been issued. Heavy snow may snow may also push south into Northern Onondaga and Madison Counties, but confidence was too low at this time to include them in any headlines at this point.

AVIATION /18Z MONDAY THROUGH SATURDAY/
A mix of VFR and MVFR/Fuel-Alt conditions are expected over the next few hours as showers stream northward ahead of an approaching strong cold front. There can be brief visby drops to IFR, but most obs so far have been around 3-4 miles with these showers, and a rumble of thunder cannot be ruled out, especially around AVP. A convective line of showers and possible embedded thunderstorms with the actual cold front will move from west to east across the terminals between 20Z and 02Z with strong winds and a wind shift out of the west. This convective line can produce 35 to 45 knot wind gusts as the front moves through.

In the wake of the front temperatures drop rapidly with precipitation transitioning from rain to snow quickly. The snow won't last long as the precipitation begins to move out of the region by around 06-07Z for all terminals. Some lake effect snow showers off of Lake Ontario are expected to develop near the end of the TAF period around RME and SYR. Snow showers off of Lake Erie could potentially reach ELM and BGM as well. Lingering LLWS at AVP and BGM is expected to diminish this evening.

Outlook:

Tuesday afternoon through Tuesday Night...Snow showers become more localized as lake effect snow over SYR and RME late on Tuesday. With winds staying gusty, blowing snow will also be possible.

Wednesday...Mainly VFR.

Thursday and Friday...Mainly VFR; a low chance for spotty rain/snow showers.

Friday night into Saturday...A chance for additional rain/snow showers as a clipper moves through the region; low confidence on timing.

BGM WATCHES/WARNINGS/ADVISORIES
PA...Wind Advisory until 8 AM EDT Tuesday for PAZ038.
Wind Advisory until midnight EDT tonight for PAZ043-044-047- 048-072.
NY...Winter Storm Watch from Tuesday afternoon through Wednesday morning for NYZ009-037.
Wind Advisory until 8 AM EDT Tuesday for NYZ015>018-022>025- 036-044-055.
Winter Weather Advisory from 8 PM this evening to 4 AM EDT Tuesday for NYZ022.