Marine Weather and Tide Forecast for Macedon, NY

KEY MESSAGES
1) Showers and thunderstorm develop this afternoon and evening. A low end severe and flooding risk.

2) Below average temperatures return late in the weekend, however more seasonal temperatures will arrive by Tuesday.

DISCUSSION
KEY MESSAGE 1...Showers and thunderstorm develop this afternoon and evening. A low end severe and flooding risk.

A narrow ribbon of moisture (PWATs of 1.25-1.5") will surge into the region ahead of an inbound cold front late this afternoon and evening. This will lead to a round of showers and embedded thunderstorms. Lastest SPC Day 1 Outlook continues with a Slight Risk area covering most of WNY south of I-90. Instability in place ahead of the cold front will be very limited, but favorable shear profiles and dry air in mid and lower levels could bring stronger winds down to the surface with evaporative cooling with some potential for isolated damaging wind gusts. While hydro concerns remain low at this time, locally heavy rainfall is possible. Main concerns stem from sensitive antecedent conditons in areas of more complex terrain, such as in the Southern Tier, Finger Lakes, and perhaps the Tug Hill region.

KEY MESSAGE 2...Below average temperatures return late in the weekend, however more seasonal temperatures will arrive by Tuesday.

A pattern change is expected late this weekend as a deep upper level trough moves across the Great Lakes region and the Northeast. A return to well below normal temperatures and the chance for snow showers will begin this Sunday.

A west-northwest flow is expected across the region Sunday. Cold air advection and daytime heating will strengthen low-level lapse rates through the day. An increase in PVA and large scale ascent will move across the region. A mix of rain and snow showers is expected to develop across western NY with a focus of showers along a convergence zone from the Buffalo Metro to the Finger Lakes region.
Showers are also possible across the Saint Lawrence Valley through Sunday afternoon. A secondary cold front is expected to move through the region Sunday night with 850mb temperatures falling to -12C Monday. Snow showers are possible at times Sunday night through Monday. Little to no accumulation is expected.

A strong upper level ridge will build into the Plains and Mid-West through mid-week before moving into the Great Lakes region late in the week. Day-to-day warming is expected across the region.

AVIATION /18Z SATURDAY THROUGH THURSDAY/
For the 18Z TAFS, active weather with dry and breezy conditions yielding to showers and thunderstorms as a strong cold front pushes eastward across the region. Flight conditions will briefly lower to IFR to MVFR, especially visibilities, within heavier shower and storm activity as the front passes through the TAF region later this afternoon and early evening. Any thunderstorm will produce locally brief period of stronger wind gusts.

A more prolonged period of IFR and MVFR post cold front this evening and thorugh the overnight time period along with scattered rain showers mixing with and changing to snow.

Winds behind the cold front will veer to northwesterly tonight and into Sunday...with daytime increased mixing heights promoting gusts into the low to mid 20 knot range by late morning.

Outlook...

Sunday night...A mix of MVFR/IFR with upslope/lake effect rain showers mixing with and changing to snow showers.

Monday...Improvement to VFR with leftover scattered lake effect/upslope snow showers ending.

Tuesday...Mainly VFR with a chance of rain showers.

Wednesday and Thursday...Mainly VFR.

MARINE
Southerly winds will continue at 15-20 knots this afternoon with the more significant wave action directed into Canadian waters. A cold front will approach the region this afternoon, showers and embedded thunderstorms will overspread the waters from west to east. Some of these thunderstorms may produce brief high wind gusts and wave action. Special Marine Warnings may need to be issued.

Winds will shift westerly and diminish some behind the front this evening. Elevated winds will continue with higher wave heights turning more onshore, before winds subside to 10 knots or less late.

Cold air deepening across the lakes and an increasing pressure gradient will cause westerly winds to freshen Sunday. Winds will turn northwesterly Sunday night and remain elevated into Monday morning with speeds near 20 knots. This may support a period of small craft headlines on Lake Ontario and possibly Lake Erie.

BUF WATCHES/WARNINGS/ADVISORIES
NY...None.
MARINE...None.