Marine Weather and Tide Forecast for Chazy, NY

NEAR TERM /THROUGH SUNDAY/
As of 725 AM EDT Saturday...
**Heat Advisory in effect from 11 AM Sunday through 8 PM Sunday for high heat and humidity across the St. Lawrence Valley, southern Champlain Valley, and lower Connecticut River Valley.
Heat will continue to build, and a Extreme Heat Watch is also in effect Monday through Tuesday evening across the Champlain Valley and lower Connecticut River Valley

**Slight Risk Outlook (Level 2 of 5) tonight for scattered severe thunderstorms in St. Lawrence and Franklin Counties with the primary hazards being strong damaging winds, frequent lightning, and heavy rain.

Today's forecast features fantastic weather. Mid-level ridging will promote dry conditions with fair weather cumulus and a steady breeze in the afternoon as we mix in some of that dry air to the ground. Expect temperatures to climb in the upper 70s to mid 80s with comfortable dewpoints.

This evening, the ridge will slide east, allowing increasing southwesterly return flow. Warm, moist air will advect as a broad warm front moves northeastwards. An MCS is present over the Northern Plains and will race east parallel to that warm front and pass just north of Montreal towards midnight. Sustaining this complex of thunderstorms will be increasing 55-65 kt 850hPa flow driving instability quickly northeast across the Great Lakes region. There will also be a deep elevated mixed layer present, resulting in a tongue of high instability. The main forecast question is how much thunderstorm activity occurs south of the MCS, which will depend on the instability advecting into the region. Typically, it is best to have the high instability already in place, leading to some uncertainty in the coverage and intensity of activity. Ensemble clusters continue to depict modest spread in the speed of 850mb flow and available instability. A notable shift northward in several model scenarios could also result in the highest instability and moisture to be north of the international border given how high instability tapers off in its eastward extent.
The potential remains conditional and somewhat uncertain, with one scenario being some decaying nighttime thunderstorms and moderate rain, or strong to severe thunderstorms with the potential for damaging winds and a real lightning show. The Storm Prediction Center has maintained a Slight Risk outlook for northern New York with the primary hazard being damaging winds.
HRRR max gusts depict a few ensembles that highlight the potential for strong to severe thunderstorm wind gusts within the Slight Risk.

Some of this activity could bleed into Sunday morning depending on how quickly the MCS translates east-southeast. If the MCS lifts far enough north and convection south of it drives a cold pool southwards, then we may also have precipitation develop as southwesterly flow brings back that warmth and moisture back across Vermont and northern New York. Some high res guidance is sparking convection associated with that Sunday afternoon and evening.
Fortunately, the speed of deep-layer flow will have decreased substantially, but this potential for convective development in the midst of the elevated mixed layer and a forcing mechanism in isentropic lift could result in thunderstorms getting to tap into 2000-2500 J/kg of CAPE. Dry air should limit coverage, but the presence of a boundary could focus clusters if enough activity can get going. SPC has placed the forecast area in a Marginal Risk outlook (Level 1 of 5) across the region, and given this potential scenario, this seems reasonable. Temperatures climbing on Sunday, especially south given the mesoscale frontal boundary over the northern extent of our forecast area.
Temperatures will range from the mid 80s to lower 90s, and heat indices will creep up towards 87-97 across the region.

SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/
As of 321 AM EDT Saturday...
**Extreme Heat Watch in effect 11 AM Monday through 8 PM Tuesday

**Dangerously hot conditions with heat index values up to 105 possible for the Champlain and Connecticut River valleys Monday morning through Tuesday evening. Heat related illnesses increase significantly during extreme heat and high humidity events.

High pressure in the southeastern United States will advect mild and humid air into the forecast area on Sunday night with lows failing to fall below the mid 60s to mid 70s. Dew points will remain steadily in the mid 60s to lower 70s, resulting in uncomfortable sleeping weather. This will also act as a warm starting off point for temperatures to rise quickly Monday.

High pressure will shift north and east for the start of the work week, resulting in potentially the hottest day of the week as highs soar into the 90s by noon with the highest temperatures occurring in wider valleys, particularly the Champlain and Connecticut River valleys. Record high maximum and minimum temperatures for several climate sites are likely to be broken, with more details in the Climate section below. One possible limiting factor to heat risk concerns will be the ability for the atmosphere to mix drier air aloft down to the surface, especially east and northeast of the Greens where the mountains may act as a barrier between areas of high humidity and relatively lower humidity.

Still, heat indices in the 90s and 100+ are likely, especially for the Champlain and Connecticut River valleys, putting our HeatRisk into the major category across the entire region. This is expected to be the hottest weather of year so far, and Monday night's lows in the upper 60s to mid 70s will provide little relief overnight. The heat will be enough to affect anyone without effective cooling and/or adequate hydration. Be sure to stay hydrated and check on those more vulnerable to heat impacts.

Tuesday will be our second hot day with highs in the upper 80s to mid 90s and similar atmospheric mixing conditions to Monday. Because of the slightly lower temperatures and dew points in the mid 60s to lower 70s, heat indices are anticipated to reach the upper 80s and 90s in the afternoon, though 100+ indices are still possible in the broad valleys. A cold front is forecast to move through on Tuesday evening, bringing and end to the extreme heat with increasing cloud cover and some precipitation (20-50% chance of measurable precip).

LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/
As of 321 AM EDT Saturday...The cold front mentioned in the Short Term discussion above is expected to stall over southern New York and southern New England mid week with waves moving across it bringing chances of isolated to scattered showers or thunderstorms and generally unsettled weather for the second half of the week.
Temperatures moderate into the late week, dropping to the mid and upper 70s during the day and the mid 50s to lower 60s at night.
Deterministic models indicate the best next chance of appreciable precipitation occurs Friday as surface low pressure crosses the Great Lakes west to east.

AVIATION /12Z SATURDAY THROUGH WEDNESDAY/
Through 12Z Sunday...Winds are currently light or terrain driven at 5 knots or less. Fog has dissipated, leaving clear skies. Limited fair weather cumulus is expected, with mainly FEW070 and some high clouds at or above 15000 ft agl. After 20z, winds will trend south to southwesterly with increasing clouds from the northwest. Showers and thunderstorms are likely to slide southeast between 04-10z. The highest chances will be along the international border with activity decaying as it slides south. Fast 45-55 knot winds at 2000 ft agl will develop along and ahead of thunderstorms, as well as increasing surface wind speeds to 9 to 15 knots with gusts 18 to 25 knots. Although showers and storms will move south and east beyond 10z, LLWS will remain for a little longer and ceilings will drop towards MVFR behind the front. Conditions will generally improve beyond 12z.

Outlook...

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

CLIMATE
Record high maximum and minimum temperatures are likely during an upcoming hot spell. Below are the current daily records that could be broken:

Max Temp Records for 06-23 Site Forecast - Current Record KBTV 98 (Break) - 96|2020 KMPV 93 (Break) - 90|1975 KMSS 94 (Break) - 92|2020 KPBG 96 (Break) - 95|1983 KSLK 92 (Break) - 89|1964

Max Temp Records for 06-24 Site Forecast - Current Record KBTV 96 (Tie) - 96|2003 KMPV 93 (Break) - 89|2003 KMSS 92 (Break) - 91|1957 KPBG 94 (Break) - 93|1975 KSLK 90 (Tie) - 90|2003

High Min Temp Records Date KBTV KMPV KMSS KPBG KSLK 06-22 71|1976 67|1953 66|1976 68|1976 63|1976 06-23 75|1894 65|1985 71|1975 70|1975 64|1921

BTV WATCHES/WARNINGS/ADVISORIES
VT...Heat Advisory from 11 AM to 8 PM EDT Sunday for VTZ009-011-021.
Extreme Heat Watch from Monday morning through Tuesday evening for VTZ001-002-005-009-021.
NY...Heat Advisory from 11 AM to 8 PM EDT Sunday for NYZ026-035-087.
Extreme Heat Watch from Monday morning through Tuesday evening for NYZ028-035.