Marine Weather and Tide Forecast for Akron, NY

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

Increasing heat and humidity will move into our region Thursday and Friday as a mid and upper level ridge amplifies over the lower Great Lakes and Northeast. 850 mb temperatures will climb to near +18/+19C and the combination of heat and humidity will support heat index values in the lower to mid 90s. With this in mind, have gone ahead and issued a Heat Advisory for Thursday across portions of the Finger Lakes and the counties lining the south shore of Lake Ontario where confidence is medium to high of heat indices reaching the mid 90s.

Though similar conditions will be possible to end the work week, model consensus continues to struggle with the timing of a strong cold front poised to cross the area sometime Friday. If the faster timing comes to fruition, heat headline possibilities would lessen, especially further west. However, a slowing of the frontal passage would allow for the same or possibly even more areas to be impacted by dangerous heat and humidity levels. Stay tuned.

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 in place over the region through the end of the work week. Axis of a mid level trough driving the bulk of the convection this afternoon is currently moving through the Genesee Valley/Finger Lakes region, thus coverage of shower activity continues to dwindle west of the Genesee Valley as subsidence and dryer air builds into western New York in the wake of the trough. A westerly flow will also stabilize areas east of Lake Erie, although showers and a few thunderstorms may form along the convergence of lake breezes south of Lake Ontario later this afternoon. Sounding profiles continue to indicate an uptick in shear with an isolated risk of strong/severe storms, mainly across the Finger Lakes and east of Lake Ontario along and ahead of the aforementioned mid level trough through the remainder of the afternoon and early evening. Strong wind gusts are the primary threat with any stronger storms. Any stronger 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. However, amplifying ridging aloft trying to build in from the west aiding already relatively weak shear profiles in place by Thursday afternoon 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 with the primary risks being damaging winds and large hail.
There continues to be discrepancies amongst guidance as to the exact timing of the cold front. This will play a key role in exactly where the best potential for severe weather will be. An earlier frontal passage would likely keep most of the strong to severe convection confined to our eastern areas, while a slower moving front could place much of western and northcentral NY under a higher severe weather threat. Another risk from any stronger showers or thunderstorms will again 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 /00Z THURSDAY THROUGH MONDAY/
For the 00Z TAFS mainly VFR flight conditions are found. A very moist airmass will linger through the period, with opportunities for showers and thunderstorms as well as lower ceiling heights and or fog formation within the very moist boundary layer.

Fog formation, with IFR or lower flight conditions, is possible for KBUF and KART between 03Z and 12Z, on a light southwest flow over the still cool lake waters.

Additional showers and thunderstorms overnight, will become a bit more in numbers through the peak heating of the day tomorrow. Given the very moist atmosphere any shower or thunderstorm may contain heavy downpours, lowering visibility for a brief time to IFR or lower.

Outlook...

Thursday night 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 Thursday night across the higher terrain.

Saturday...Mainly VFR.

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

Monday...Mainly VFR, though there is a slight chance for a few showers.

MARINE
Southwest to west flow will remain through Thursday night. Wind speeds likely remaining 15 knots or less with only the expectation of a light chop with waves 2 feet or less.

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

The passage of a cold front Friday could bring a brief uptick to winds, but headlines are not anticipated. Drier air behind the cold front will end the thunderstorm threat.

BUF WATCHES/WARNINGS/ADVISORIES
NY...Heat Advisory from noon to 8 PM EDT Thursday for NYZ001>005- 013-014.
MARINE...None.