Marine Weather and Tide Forecast for University at Buffalo, NY

KEY MESSAGES
1) Periods of unsettled weather are expected through Friday.

2) The remnants of Hurricane Isaias will bring a soaking rain to the region Sunday into early Monday.

DISCUSSION
KEY MESSAGE 1...Periods of unsettled weather are expected through Friday.

Aloft, cyclonic WNW'erly flow and embedded shortwave troughs affect our region through Friday as a longwave trough axis moves from eastern NY and vicinity to near the western Canadian Maritimes by sunset Friday evening. At the surface, a weak trough lingers over the eastern Great Lakes and vicinity, including our CWA, through this early evening. During tonight through Friday, a high pressure ridge should build gradually from the western Great Lakes. Net low-level CAA on the synoptic-scale persists through Friday. Late afternoon highs should reach mainly the mid 50's to mid 60's today and the lower 50's to mid 60's on Friday amidst a primarily mainly clear to partly cloudy sky. In between, overnight lows should reach mainly the upper 30's to mid 40's around daybreak Friday.

Primarily fair weather is expected through nightfall Friday evening. However, periodic lake-effect rain showers should occur over/downwind of ~16C Lake America, especially this evening through Friday afternoon, amidst a W'erly to WNW'erly mean low-level flow of sufficiently-cold/moist air (e.g. 850 mb temperatures near 3C) and weak to moderate lake-induced CAPE. These lake-effect rain showers should be focused across Oswego County, the Tug Hill Plateau, and vicinity. Note: the low-level air mass should remain insufficiently-cold for lake-effect rain showers over/downwind of Lake Erie during this latest spell of cold weather. Outside the lake-effect precip, isolated rain showers are possible through this early evening, especially across the Niagara Frontier, Finger Lakes, and North- Central NY, and during Friday afternoon, especially across North-Central NY as weak boundary layer CAPE, stemming from daytime warming amidst sufficient low- level moisture, should be released by low-level convergence/moist ascent along surface trough axes attendant to shortwave troughs aloft. A few thunderstorms are possible across North-Central NY this afternoon through early evening, when weak surface-based MUCAPE profiles should exhibit MUCAPE of at least 200 J/kg in the primarily electrical charge separation zone (i.e. the portion of the MUCAPE profile that spans the cumuliform cloud temperature range of 0C to -20C). Precip should end by sunset Friday evening, as the boundary layer stabilizes via nocturnal cooling and lake-induced CAPE wanes via synoptic-scale low-level dry air advection and a lowering subsidence inversion that will accompany the aforementioned surface ridge.

KEY MESSAGE 2...The remnants of Hurricane Isaias will bring a soaking rain to the region Sunday into early Monday.

Dry weather is expected this Friday night through Saturday as the ridge at the surface and then aloft continues to build and then crests E'ward across our CWA and vicinity, and is accompanied by stabilizing subsidence. Despite the development of weak net low-level WAA on the backside of the surface ridge Friday night, mainly clear sky, weak surface winds, and low humidity should allow overnight lows to reach mainly the mid 30's to lower 40's around daybreak. The coldest lows are expected in Lewis County. Strengthening net low-level WAA and daytime heating should allow late afternoon highs to reach the upper 50's to upper 60's in North-Central NY and the mid 60's to mid 70's elsewhere in our CWA

During Saturday night, ridging at the surface and aloft should exit slowly E'ward from Western and Central NY as Isaias' remnant and vertically-stacked low at the surface and aloft, embedded in a trough aloft, wobbles NNE'ward across the western TN Valley and toward the Lower OH Valley. Isolated rain showers are possible, especially after midnight and across the Western Southern Tier, in response to moist isentropic ascent aloft generated by the low pressure system. Continued net low-level WAA and increasing cloud cover will limit nocturnal cooling.
Lows should reach mainly the upper 40's to upper 50's around daybreak Sunday. On Sunday, the ridge at the surface and aloft should continue to exit slowly E'ward from our CWA as the aforementioned and vertically-stacked low at the surface and aloft wobbles NE'ward from near the Lower OH Valley toward the central Appalachians and the trough axis aloft approaches our CWA from the western Great Lakes and vicinity. Widespread rain, steady to heavy at times, should overspread our CWA generally from south to north as isentropic ascent aloft continues over our region and taps into abundant moisture originating over the southern Gulf Stream. Daytime highs should reach the 60's amidst continued net low-level WAA.

During Sunday night through nightfall Monday evening, the trough axis aloft should move from the central Great Lakes and central Appalachians toward the Canadian Maritimes and Atlantic waters east of the Delmarva Peninsula. The vertically-stacked surface low should dissipate in vicinity of the Mid OH Valley Sunday night. As the Sunday night through Monday period elapses, the low aloft should move generally E'ward toward Atlantic waters east of the Delmarva Peninsula and a new surface low should develop, deepen, and wobble NE'ward from the Mid-Atlantic states toward Atlantic waters south of Nova Scotia, amidst mid/upper- level divergence and attendant large-scale tropospheric ascent/MSLP falls ahead of the trough axis aloft. Simultaneously, another ridge at the surface and aloft should build into our CWA from the western Great Lakes and vicinity. Accordingly, the moist isentropic ascent over our region should weaken and the related rain should taper and then end generally from west to east across our area Sunday night through Monday morning.
Current odds then favor dry weather the rest of Monday as stabilizing subsidence accompanies the ridge. Late afternoon highs should reach the 60's to lower 70's as an unusually-warm air mass lingers across our region and a cold front extending from the Upper Midwest to central QC approaches Western and Central NY from the northwest. Note: the potential for flooding from this upcoming soaking rainfall appears to be minimal because soils are abnormally-dry across most of our region per the latest U.S. Drought Monitor and our latest official forecast calls for rainfall totals near 0.25" to 0.75". Stay tuned for forecast updates.

AVIATION /18Z THURSDAY THROUGH TUESDAY/
VFR conditions currently across western NY terminals with FEW-SCT low-level cumulus development early this afternoon. West winds will continue gusting around 20-25 kt through the afternoon with mostly dry conditions. However, lake effect/enhanced rain showers may develop east of the lower Great Lakes late this afternoon into this evening. Showers should be fairly isolated, with the best chance of seeing brief reductions to MVFR conditions in the north country near KART. Isolated light rain showers may linger into Friday morning across the north country, but otherwise VFR conditions should persist through the forecast period. Breezy west winds will build back up again by late morning on Friday.

Outlook...

Friday Night through Saturday...Mainly VFR.

Sunday through Tuesday.. MVFR/VFR with rain showers possible.

MARINE
A trough lingers over our eastern Great Lakes waters before a ridge begins to build from the western Great Lakes tonight through Friday. Mainly W'erly to NW'erly winds initially around 15 to 22 knots over both eastern Great Lakes ease to around 10 to 20 knots tonight and then ease further to around 5 to 15 knots on Friday. As for waves, initial wave heights of 3 to 6 feet on Lake Erie should subside to 3 feet or less by this late evening and waves should then remain 3 feet or less through Friday. On Lake America, waves as large as 3 to 7 feet should persist through early Friday afternoon and then abate to 3 feet or less by sunset Friday evening. Here are the latest Small Craft Advisories:

- Until 11 PM EDT today from Ripley to Buffalo - Until 2 AM Friday from the Niagara River outlet to Hamlin Beach - Until 8 PM Friday from Hamlin Beach to the St. Lawrence River

Note: waterspouts are possible on Lake America this evening through the very early evening hours of Friday.

During Friday night through Sunday, the aforementioned ridge should exit slowly E'ward. Variable winds Friday night should be followed by winds varying between E'erly and S'erly on Saturday through Sunday. During Sunday night through Monday morning, an inverted trough axis should sweep E'ward across our eastern Great Lakes waters and be followed quickly by the E'ward passage of a narrow ridge axis. Accordingly, SE'erly winds should back quickly to W'erly. During the remainder of Monday, the ridge should begin to exit E'ward and be accompanied by SW'erly to W'erly winds. Wind speeds around 5 to 15 knots and waves of 3 feet or less are expected Friday night through Monday.

The ridge should continue to exit E'ward Monday night and be followed by the SE'ward passage of a cold front across eastern Lake Erie and Lake America on Tuesday. SW'erly winds around 10 to 20 knots should veer to NW'erly with the cold front passage.
Waves should build to as large as 3 to 6 feet and another Small Craft Advisory will probably be needed.

BUF WATCHES/WARNINGS/ADVISORIES
NY...None.
MARINE...Small Craft Advisory until 11 PM EDT this evening for LEZ040- 041.
Small Craft Advisory until 2 AM EDT Friday for LOZ042.
Small Craft Advisory until 8 PM EDT Friday for LOZ043>045.