Marine Weather and Tide Forecast for Ontario, NY

NEAR TERM /THROUGH WEDNESDAY/
High pressure will drift to our east tonight while continuing to provide dry weather and mainly clear skies. It will be a warm night with lows ranging from the 60s across the interior Southern Tier and North Country to the lower 70s across the lake plains.

Heat and humidity build Wednesday. Temperatures along the Lake Ontario plain, Genesee Valley and northern Finger Lakes around 90F or bit higher, combined with increased humidity should get maximum heat indices into the mid to possibly upper 90s. A Heat Advisory has been issued for these areas. Shortwave advancing into the region will increase the potential for convection, especially during peak heating. Severe threat looks to be limited in an unfavorable shear environment, with the main threat being the potential for locally heavy rainfall with precipitable water values nearing 2 inches.

Rainfall will be very uneven Wednesday afternoon, with some areas remaining completely dry. The greatest coverage of rain will likely be from the western Southern Tier into the Genesee Valley and Finger Lakes along the southeastern edge of the Lake Erie lake breeze. A lower chance of rain will be found northeast of Lake Erie and Lake Ontario where stable lake shadows will inhibit deep moist convection.

SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/
Convection lingering into Wednesday night, but coverage should lessen through the night. It will be muggy with most overnight temperatures remaining in the 70s.

Cold front advances into the region Thursday. Another round convection expected, especially during the afternoon/evening.
Main threat looks to be the potential for locally heavy rainfall in a very moist environment ahead of the front. Front shifts southeast of the area Thursday night, lessening chances for showers and thunderstorms.

Friday should be quite a bit cooler with comfortable humidity levels. Some morning cloud cover possible, but overall should have a good amount of sunshine. Temperatures should be some 10-15 degree cooler with highs mainly in the 70s. High pressure builds overhead Friday night with clear skies and lows in the 50s, with lower 60s closer to the lakes.

LONG TERM /SATURDAY THROUGH TUESDAY/
Surface high pressure overhead Saturday is advertised to gradually exits off to our east but will continue to provide dry weather across the Lower Lakes. Zonal flow aloft will then direct the next shortwave east towards the Lower Lakes on Sunday, with increasing chances for showers and thunderstorms. High pressure returns for the start the new work week promoting largely dry weather.

AVIATION /00Z WEDNESDAY THROUGH SUNDAY/
Mainly clear skies and VFR will prevail overnight through Wednesday morning. A few areas may see some minor MVFR VSBY in haze, but increasing southerly flow just off the deck should prevent any meaningful fog formation.

Scattered showers and thunderstorms will develop Wednesday afternoon with diurnal heating, and as a mid level shortwave approaches and increases large scale ascent. The greatest chance of rain and thunder will likely be from the western Southern Tier into the Genesee Valley and Finger Lakes (KJHW, KROC) along the southeastern edge of the Lake Erie lake breeze. The relative lowest chance of rain and thunder will be northeast of Lake Erie and Lake Ontario (KBUF, KIAG, KART) where stable lake shadows will inhibit storms.

Outlook...

Wednesday night through Thursday...Local/brief restrictions with scattered showers and thunderstorms.

Friday through Saturday...Mainly VFR. Local IFR possible in fog each late night and early morning.

Sunday...Mainly VFR with a chance of showers and thunderstorms and associated brief restrictions.

MARINE
Quiet conditions will continue across the lower Great Lakes through tonight with light/variable winds.

A modest southerly flow will then develop following the passage of a warm front Wednesday, but wind speeds should remain at or below 10 knots. Scattered thunderstorms will develop in the afternoon, with locally higher winds and waves possible near storms.

A cold front will approach the area Thursday, then cross the eastern Great Lakes Thursday night and early Friday. Southwest winds will increase ahead of the cold front Thursday, then become northwest following the passage of the front Thursday night and Friday. Small Craft Advisory conditions are likely on Lake Erie and Lake Ontario Thursday through Thursday night.

BUF WATCHES/WARNINGS/ADVISORIES
NY...Air Quality Alert until 11 PM EDT this evening for NYZ001>007- 010>012-019-020-085.
Heat Advisory from 11 AM to 8 PM EDT Wednesday for NYZ001>007- 013-014.
Air Quality Alert until midnight EDT tonight for NYZ008-013- 014-021.
MARINE...None.