Marine Weather and Tide Forecast for Chateaugay, NY

NEAR TERM /THROUGH FRIDAY NIGHT/
As of 200 PM EDT Thursday...Scattered showers and some thunderstorms have begun to bubble up across the area, with some containing frequent lightning. Some of these cells may have damaging winds, a brief weak tornado or 2 and localized heavy rains over the course of the afternoon/evening. As a result the Storm Prediction Center has issued a Severe Thunderstorm Watch for Clinton County New York, and all of central and northern Vermont. A prefrontal trough has moved into the area based on the latest satellite images and radar reflectivity axis across St. Lawrence County New York. This will be the main focus for any potential severe weather heading into the remainder of the afternoon. With current temperatures running a few degrees above forecast, where showers have not impacted observation stations, current thermodynamic profiles indicate 1000-1500 J/kg of SBCAPE across northern New York with pockets of 2000 J/kg just north of the border. Furthermore, dewpoints are generally near 70 with Pwats around 2" which is ample moisture and energy for cell development today. The good news, is that unlike recent events, these cells are moving so the flash flooding threat is low.
Dynamically speaking, the low responsible will be close to the international border which will help effective shear to increase toward 30-40 kts as the nose of a strong low-level jet enters the region. These high shear values are currently across eastern Ontario where the cold front resides. Lastly, surface- levels in the hodographs suggest the potential for a weak brief tornado or two with SRH around 150-200 m^2/s^2 by this afternoon. Cells will likely start off in a multi-cellular cluster and then continue into upscale growth by this evening to more of a broken squall- line. A few discrete supercells out ahead of this line cannot be ruled out which would be the best chance of any tornado potential. From a broad view, the ingredients for severe weather are present, however, there remains the question of whether they will interact in tangent still. If the shear and instability can align themselves any cells that develop have an easy path to becoming strong to severe. This is in line with the current SPC Slight Risk Outlook for severe storms across northeastern New York and north/central Vermont. The main threats for today will be damaging winds, and localized heavy rain. Best timing for any severe storms across Vermont will be between 5-8 PM.

The front looks to pass through beyond 8-10 PM tonight with strong winds remaining overnight. Winds at 925mb will be around 40-50kts which should mix down to the surface, particularly in the Champlain Valley for gusts up to 30 kts. With the strong front, northwest winds will usher noticeably cooler air and much lower humidity values. Dewpoints this evening will be in the lower 70s, but by Friday morning they will fall to the upper 40s to low 50s.
Temperatures will also take a dive from the upper 80s to the mid 70s for highs tomorrow. Friday will be a spectacular day with calming winds, seasonable temperatures, and clearing skies. Overnight relief will also be present Friday night with good raditional cooling looking to take place. Lows Friday night across the higher terrain could drop into the low to mid 40s with mid 50s across the valley floors.

SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/
As of 200 PM EDT Thursday...Saturday looks to maintain the trend set on Friday with seasonable weather for much of the day. Temperatures will be in the upper 70s to low 80s with dewpoints near 60. Clear skies in the morning will transition to increasing clouds throughout the day as a broad shortwave approaches from the west. While there is a general chance for showers Saturday afternoon into the evening, trends have been pushing the shortwave axis further to the south out of the region. Broad energy may lead to an isolated shower late Saturday afternoon however most of the activity should remain in southern Vermont and the lower Adirondacks. Given the timing of the system as well primarily Saturday evening and overnight, the threat of any strong to severe thunderstorms looks low attm. Overnight lows on Saturday will remain seasonable in the upper 50s to low 60s.

LONG TERM /SUNDAY THROUGH THURSDAY/
As of 200 PM EDT Thursday...Showers will be departing Sunday with some lingering chances mainly in northeastern Vermont before drier conditions return by late Sunday. The replacement airmass will be out of the Canadian plains and is strongly favored to be drier given its continental origin. As such, pleasant conditions, highs in the 70s/low 80s through Tuesday, are anticipated with a slow warming trend as the high's center tracks slowly eastward and becomes absorbed by the semi-permanent Bermuda Ridge over the western Atlantic. Mid-late week, southwesterly flow is more likely to return possibly resulting in a sharper warming trend back above seasonal averages becoming more favored. Ensembles and blended guidance favor a flattening of the upper level pattern which could allow for a few showers or a thunderstorm to for over the North Country by Wednesday/Thursday. Cloud cover and showers may be at odds with projected highs which are projected back into the upper 80s/around 90, but these details will be teased out as we get closer.

AVIATION /18Z THURSDAY THROUGH TUESDAY/
Through 18z Friday...Widely scattered showers will become more numerous this afternoon with increasing chances of thunderstorms through 00Z as a trough sweeps west to east across the North Country. Some storms will be strong to severe.
Cloud layers will be lower than "usual" given LCLs below 3Kft and higher likelihood of heavier rain elements. IFR is plausible in showers/storms today and VLIFR possible should a storm pass directly over a terminal. LLjet strength could product a few areas of LLWS, but best shot of that lies at SLK; otherwise, deep mixing will promote southerly gusts 20-30kts through 00z, becoming westerly/northwesterly overnight and decreasing in general. Most terminals will stand a good chance of MVFR CIGs overnight before skies begin to clear in earnest after 12Z Friday.

Outlook...

Friday Night: VFR. NO SIG WX.
Saturday: VFR. Slight chance SHRA.
Saturday Night: Mainly VFR, with local MVFR possible. Chance SHRA, Slight chance TSRA.
Sunday: Mainly VFR, with areas MVFR possible. Slight chance SHRA, Slight chance TSRA.
Sunday Night: Mainly VFR, with local MVFR possible. NO SIG WX.
Monday: VFR. NO SIG WX.
Monday Night: VFR. NO SIG WX.
Tuesday: VFR. NO SIG WX.

BTV WATCHES/WARNINGS/ADVISORIES
VT...None.
NY...None.