Marine Weather and Tide Forecast for Westfield, NY

KEY MESSAGES
1) Showers return this afternoon and evening with a few storms that may be capable of producing gusty winds and hail.

2) Cool but relatively dry weather Sunday through Tuesday with frost potential Sunday and Monday night.

3) Unsettled weather returns by the middle of next week with periods of rain Wednesday through Thursday.

DISCUSSION
KEY MESSAGE 1...Showers return this afternoon and evening with a few storms that may be capable of producing gusty winds and hail.

A surface low centered over the UP, will continue to progress northeast into Ontario this afternoon, dragging its attendant cold front across Michigan and eventually into New York State tonight.
Ahead of the cold front, there is a line of showers and embedded thunderstorms currently crossing Michigan State, where this line of activity will spread across New York State this afternoon.

While it has taken most of the morning to begin to clear out across western New York, from the initial passing shortwave trough and low clouds cover, the few hours of clear skies during peak diurnal heating will allow for mid-level lapse rates to steepen enough to support a fair amount of instability (SBCAPE values of around 500 J/kg). This combined with around 30 knots of bulk shear should support any strong storms to become severe, and produce gusty winds and some hail. As this line of storms enters the Finger Lakes region and encounters a less favorable environment, due to the limited time of sunshine today from the abundance of cloud cover the line of storms will quickly weaken. This all being said, SPC has expanded the Marginal Risk for Severe Weather eastward into the Finger Lakes.

KEY MESSAGE 2...Cool but relatively dry weather Sunday through Tuesday with frost potential Monday night.

A longwave troughing pattern will remain overhead across the Great Lakes and into New England Sunday through Tuesday supporting a cool airmass to linger across the region, resulting in daily high temperatures to average around 10 degrees below average through the start of the week. Clear skies and light winds each night (Sunday and Monday) will support radiational cooling and result in temperatures to plummet into the 30s supporting the threat for frost and freeze conditions. Frost will likely form away from the lakeshores, with freeze conditions possible in the colder Southern Tier valleys and across Lewis County. Please note the remainder of the forecast area enters their growing seasons on May 11th.

KEY MESSAGE 3...Unsettled weather returns by the middle of next week with periods of rain Wednesday through Thursday.

A potent shortwave trough will dive and rotate through the longwave trough by Wednesday, likely evolving into a mid-level closed low settling in across the Great Lakes by the middle of the week. This being said, chances for rain will increase from west to east late Tuesday night through Wednesday as this system nears. Chances for precipitation will continue into the end of the week as the trough and closed low slowly departs east.

AVIATION /18Z SATURDAY THROUGH THURSDAY/
Quiet conditions begin the 18Z TAF period, but a cold front with storms upon it will be bearing down on our region.

Instability is marginal, though will include thunder within a PROB30 for a 3 to 4 hour period for the western 4 TAF sites as several broken line segments of convection are expected to reach far WNY around 23Z, and propagate eastward. Flight conditions are expected to lower to IFR/MVFR in heavier convection. A later arrival and limited instability, will likely taper off any thunder by time the line of convection reaches KART.

Any thunderstorm may bring locally higher wind gusts to the airfields this evening.

Behind the line of storms, and with a shortwave passage, light showers, generally with VFR visibilities, but MVFR ceiling heights will pass across our region through the mid-overnight hours. All together these showers will exit east of KART by 12Z.

Behind the cold front winds will veer to west to northwest late tonight...though within a light surface pressure gradient field lake breeze circulations will develop late in the period with SW winds northeast of the Lakes.

By the final hours of the TAF cycle a fairly substantial amount of cumulus clouds are expected to be bubbling up...with skies SCT - BKN...but VFR.

Outlook...

Sunday afternoon through Tuesday...Mainly VFR.

Wednesday.. MVFR/IFR with showers and a few thunderstorms.

Thursday...IFR/MVFR improving to MVFR/VFR with showers ending through the day.

MARINE
South to southwest flow will continue to strengthen this afternoon ahead of an approaching cold front, resulting in choppy conditions on the lakes this evening. Additionally, with the passing of the cold front, expect a line of showers with embedded thunderstorms to start to cross the lakes at 21Z into the evening hours. The cold front will work from west to east tonight supporting continued choppy conditions through Sunday, with potential for low end small craft advisory levels on the east end of Lake Ontario Sunday afternoon.

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