Marine Weather and Tide Forecast for Sandy Creek, NY

KEY MESSAGES
1) The remnants of post tropical cyclone Isaias will bring gusty downsloping winds off the Chautauqua Ridge and then a soaking rain to the region tonight through Monday morning.

2) The next round of rain showers arrives late Monday night into Tuesday with a cold frontal passage across western NY.

DISCUSSION
KEY MESSAGE 1...The remnants of post tropical cyclone Isaias will bring gusty downsloping winds off the Chautauqua Ridge and then a soaking rain to the region tonight through Monday morning.

Current nighttime microphysics satellite imagery and a mosaic of radar imagery across the Ohio Valley, shows the northern edge of the remnants of post tropical cyclone Isaias, with the northern edge of the precipitation crossing the NY/PA state line. Due to the abundance of dry air in place across the region from exiting surface high pressure (per the 00Z guidance) is acting to erode the moisture, limiting the entering rain to a few sprinkles. With the surface high exiting, a tight surface pressure gradient across the region this evening with southeast flow, is supporting some gusty winds downwind of the Chautauqua Ridge with gusts of up to 35mph.
High pressure will exit and allow the pressure gradient to relax as rainfall arrives in a few hours (around 4AM) which will cause winds lessen by 7AM.

As alluded to previously, the steadier rain will arrive by 8 AM across western New York as synoptic scale forcing overspreads the region today from the post-tropical low, widespread rain will persist throughout much of the day. Rainfall amounts will range between a quarter to a half of an inch today, with the higher amounts focusing across the southern portions of the region across the Finger Lakes region. Rainfall will begin to taper off from west to east overnight into early Monday morning as the upper level disturbance begins to shift east across the Mid-Atlantic.

KEY MESSAGE 2...The next round of rain showers arrives late Monday night into Tuesday with a cold frontal passage across western NY.

The next low pressure system will pass east across the Great Lakes late Monday and into Tuesday, pushing a cold front southeast across the region Tuesday. Ahead of the front and aligned with a leading shortwave, expect another round of rain showers. A few isolated embedded thunderstorms can't be ruled out as mid -level lapse rates approach 7 degrees Celsius per kilometer. This being said, storms will likely remain elevated due to poor low-level lapse rates.

There remains quite a bit of uncertainty with high temperatures across the region Tuesday, mainly tied to the timing of precipitation and the frontal passage. While the NBM shows afternoon highs now in the mid to upper 70s across western New York, the 25th and 75th percentile values from input guidance provides a range between the low 70s to upper 70s for much of western NY and Genesee Valley.

AVIATION /06Z SUNDAY THROUGH THURSDAY/
VFR conditions prevail across the region this morning despite a blanket of cirrus level clouds. Mid level ceilings will approach the region from the south after 06Z as the remnants of post tropical cyclone Isaias approaches the Ohio Valley.

Rain associated with the remnants of the aforementioned post tropical system will spread across the region around 12Z this morning. Conditions will deteriorated to MVFR and IFR between 12Z and 18Z today. While showers will taper off from west to east today and this evening, light winds and low level moisture will keep flight conditions MVFR to IFR.

Outlook...

Monday.. MVFR/IFR as rain exits east from the remnants of post tropical cyclone Isaias.

Monday Night and Tuesday.. MVFR/VFR with rain showers possible.

Wednesday and Thursday...Mainly VFR.

MARINE
As remnants of Hurricane Isaias continues to move north, an increasing pressure gradient will see southeast winds increasing over the lower Great Lakes early this morning, especially on Lake Erie off the Chautauqua Ridge. Gusts around 25-30 kt for the nearshore waters will result in Small Craft Advisory conditions, despite being offshore winds. Rain showers are expected through much of the day today before moving off to the east headed into Monday morning. Winds will be variable Monday ahead of the next cold frontal passage Monday night into Tuesday across the lower Great Lakes. Rain showers and southwest winds 10-20 kt will turn northwesterly Tuesday evening behind the front. Waves will be 3 to 6 feet Tuesday which may bring another round of Small Craft Advisory conditions.

BUF WATCHES/WARNINGS/ADVISORIES
NY...None.
MARINE...Small Craft Advisory until 8 AM EDT this morning for LEZ040- 041.