Marine Weather and Tide Forecast for Mayville, NY

KEY MESSAGES
1) Increasing heat and humidity this week. Warmest heat indices could reach the mid to upper 90s Thursday and Friday.

2) Scattered showers and thunderstorms are expected through Friday evening.

DISCUSSION
KEY MESSAGE 1...Increasing heat and humidity this week. Warmest heat indices could reach the mid to upper 90s Thursday and Friday.

Increasing heat and humidity is expected Thursday and Friday as a ridge builds into the region. 850 mb temperatures will climb near +18C and the combination of heat and humidity will support heat index values in the lower to mid 90s, possibly even higher. Heat headlines are possible for some locations during this time period.

Cooler and more comfortable weather are expected across the region behind a cold front this weekend.

KEY MESSAGE 2...Scattered showers and thunderstorms are expected through Friday evening.

An anomalously moist airmass will remain over the region this morning. Showers and a few embedded thunderstorms will move east into western New York early this morning, with heavy downpours as the primary impact through this morning. Due to dry antecendant conditions, the flood risk is low tonight. Coverage will decrease form west to east through the day, as subsidence and dryer air builds into western New York. A westerly flow will also stabilize areas east of Lake Erie. Showers and a few thunderstorms may form along the convergence of lake breezes south of Lake Ontario this afternoon. Profiles indicated an uptick in shear with an isolated risk of strong/severe storms, mainly across the Finger Lakes and east of Lake Ontario this afternoon. Any heavy showers or thunderstorms will produce heavy rain. There is a non-zero threat of localized flooding if training storms materialize.

A very moist airmass will remain in place Thursday. Scattered convection expected during the morning, with heavy downpours as the primary impact. Impressive instability developing by afternoon will lead to additional convection, mainly on lake breeze or convergence boundaries inland from the lakes. Weak shear profiles gives lower confidence of severe potential.

A trough will deepen across the Great Lakes region Friday. A warm, moist airmass will reside ahead of an approaching strong cold front.
The combination of an increasing wind field and a unstable airmass will support the potential for strong thunderstorms across the region. Another risk from any heavy showers or thunderstorms will be heavy rain, as PWAT values are expected to exceed 1.5", which is above the 90th percentile for this time of year. Drier air is expected to move into the region for the start of the weekend.

AVIATION /06Z WEDNESDAY THROUGH SUNDAY/
A warm front will push east across the area early this morning bringing deteriorating flight conditions. Flight conditions should deteriorate to widespread MVFR/IFR (LIFR interior Southern Tier)
Cigs from west to east through 12z, with the worst conditions expected across the western NY terminals. An uptick in shower and isolated thunderstorm activity expected after 09z with brief periods of MVFR/IFR within any heavier showers/storms.

Widespread IFR/MVFR CIGS will remain in place through midday today, while scattered showers and storms persist as a mid level trough moves in from the west. As the mid level trough starts to exit the area this afternoon, so will the widespread shower and thunderstorm activity across western NY, with improvement back to VFR from KROC westward this afternoon. MVFR is expected to linger east of Lake Ontario through the end of the day.

Outlook...

Tonight through Friday...Mainly VFR with a chance of showers and thunderstorms. Localized lower flight CATs within any heavier showers or storms. Also, lower CIGS possible during the overnights (Wednesday night and Thursday night) across the higher terrain.

Saturday...Mainly VFR.

Sunday...VFR/MVFR with a chance of showers and thunderstorms.

MARINE
South winds will continue this morning at generally 10 knots or less. Winds will turn more southwest by this afternoon with a general southwest to west flow remaining through Thursday night. Wind speeds likely remaining 15 knots or less with only the expectation of some light chop with waves 2 feet or less.

The passage of a cold front Friday could bring a brief uptick to winds, but headlines are not anticipated.

The passage of several waves of low pressure will generate a few thunderstorms over the lakes at times through the end of the work week.

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