Marine Weather and Tide Forecast for Fredonia, NY

KEY MESSAGES
1) Seasonably warm with a few showers and thunderstorms, especially occuring Sunday.

2) Unsettled weather will return Monday and Tuesday with increasing coverage of showers and thunderstorms.

3) Upper level trough to bring chances for convection along with a cooler airmass Wednesday and through the end of the week.

DISCUSSION
Key Message 1...Seasonably warm with a few showers and thunderstorms, especially occuring Sunday.

Surface high pressure that has granted our region with several days of fine summer weather has shifted eastward to New England, with a southerly return flow now found over our region. This flow will begin to bring mid level moisture back into our region, favoring the southwestern portion of our region today. Hi-rez models try to develop a shower over the now warmer Lake Erie waters this morning, lifting any showery convection northward towards Buffalo. Given the dry airmass this activity will be entering, will just place a low chance to slight chance for a shower through midday for areas near Lake Erie.

As peak heating increases through the day and instability begins to build a few additional showers and thunderstorms will be possible along a Lake Erie lake breeze circulation for the hills east of Lake Erie. Poor mid level lapse rates of around 5 C/km and MUCAPE less than a 1K J/KG will likely lead to any thunderstorms being just garden variety.

Moisture pooling ahead of a shortwave trough tonight will build mid level moisture further for the day Sunday. Though the first shortwave will pass in the early morning hours of Sunday, a secondary shortwave trough will add additional lift for Sunday afternoon, that with the presence of deeper instability and increased spatial coverage of this instability we should see scattered showers and thunderstorms developing across WNY during the afternoon hours. Though this activity will likely develop higher cores owing to increase mid level lapse rates, the lack of much wind flow aloft will again likely keep any thunderstorms below severe thresholds.

Temperatures SUnday will be similar to Saturday, however what will be notable will be the increase in humidity, with dewpoints Sunday afternoon rising into the mid 60s.

Key Message 2...Unsettled weather will return Monday and Tuesday with increasing coverage of showers and thunderstorms.

Several additional shortwave troughs will dive southeastward over a burgeon ridge of high pressure over the Rockie Mountains next Monday and Tuesday. This pattern will allow for a long wave trough over Hudson Bay to expand southward, with its associated cooler airmass aloft settling southward.

A more humid airmass to start the week will fuel instability to become greater such that more widespread showers and thunderstorms will become likely. This activity will likely become taller with mid level lapse rates increasing to over 7 C/km, however the faster flow and longer 0-6 km bulk shear vectors are found just to our west and south over the Ohio Valley. Cannot rule out a few stronger storms Monday and Tuesday, especially towards SW NYS. Additional forcing ahead of a cold front Monday night and into Tuesday could make this an active period.

Key Message 3...Upper level trough to bring chances for convection along with a cooler airmass Wednesday and through the end of the week.

Following a cold front passage Tuesday, an upper level trough of low pressure will settle over the eastern Great Lakes. Dewpoints will be lower, making for a more comfortable end to the work week...even through air temperatures remain in the 70s and lower 80s. Steepening lapse rates with the associated cooler airmass aloft will lend to isolated to scattered afternoon convection blossoming. There are model differences on how fast this upper level trough and moisture exits our region, and while much of the time will be rainfree, there will be chances, especially towards the eastern zones for showers and thunderstorm through the remainder of the work week within the presence of this upper level trough.

AVIATION /12Z SATURDAY THROUGH WEDNESDAY/
For the 12Z TAFs, VFR flight conditions are found with a few patches of mid level clouds beginning to increase across SW NYS.

Mid level moisture increasing behind an area of surface high pressure will bring back the presence of not only a variable sky cover, but also chances for a few showers and afternoon thunderstorms. Initial showers this morning will favor near Lake Erie and northeastward where high res models depict a few showers developing over the warmer Lake Erie waters. Confidence is too low to include a precipitation qualifier into the KBUF and KIAG TAF at this time.

By afternoon and with increasing amounts of instability a few showers and thunderstorms will likely form along a Lake Erie lake breeze circulation. This convection may impact KJHW this afternoon.

By evening and with the setting sun all convection will begin to wane. Fog will become possible across the Southern Tier, especially in areas that received earlier rainfall.

Outlook...

Sunday...VFR/MVFR with a chance for showers/thunderstorms, mainly in the afternoon.

Monday through Wednesday...VFR/MVFR with showers and thunderstorms possible.

MARINE
Though surface high pressure has shifted eastward towards New England, a still weak pressure gradient will grant light winds and minimal waves this weekend and into the beginning of next week. By Tuesday, and ahead of a cold front, southwest winds will increase with choppy waters developing on the northeast ends of the lake.

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