Groupe Plein Air Terrebonne Snow Report

609 FXUS61 KBTV 290632 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 232 AM EDT Tue Sep 29 2026 .WHAT HAS CHANGED... As of 229 AM EDT Tuesday... No significant changes to the current forecast. && .KEY MESSAGES... As of 229 AM EDT Tuesday... 1. Showers finally clear the region this morning, though low level moisture persists with continued cloud cover and seasonably cool temperatures today. High pressure returns mid week, with rebounding temperatures. 2. Shower chances return late Thursday into Friday with localized breezy conditions, mainly in the St. Lawrence and Champlain Valleys. 3. Seasonable temperatures and additional chances for showers are expected for this weekend. && .DISCUSSION... As of 229 AM EDT Tuesday... KEY MESSAGE 1: Our coastal low, centered just off Cape Cod, MA as of 2AM, will finally begin to pull east as ridging over the Canadian Maritimes breaks down. Subsidence will begin to erode precipitation across the area toward this morning, with gradual drying in the mid to upper levels of the atmosphere. Low level moisture, however, will take a bit longer to depart due to continued easterly cyclonic flow. Low clouds will hang around the region, keeping mountains obscured, and temperatures on the seasonably cool side. Highs today as a result will be in the upper 50s to low 60s with weak diurnal heating. As clouds slowly erode from west to east, areas across the St. Lawrence Valley may be able to warm into the mid 60s, should clouds trend more sunny towards the latter portion of the day. Winds across the area today will be northerly and generally light. However, some continued channeled flow in the Champlain Valley will continue through this morning, before our pressure field becomes more broad this evening. An airmass change will take place into the rest of the mid week period, as tropical moisture from the SW CONUS begin to advect northeastward. Ridging will build in across the Mississippi Valley and extend into our neck of the woods leading to warming temperatures with southerly flow Wednesday. Highs will warm into the upper 60s to low 70s Wednesday. Aside from some mid to high clouds, Wednesday looks to be fairly tranquil. KEY MESSAGE 2: A brief pattern change will take place by the latter portion of the week as shower chances and warm temperatures return to the region, associated with Pacific tropical air. Zonal flow Thursday will turn more amplified to the southwest by Friday, advecting warm air and higher dewpoints in the region. 850-mb temperatures in the GFS and ECMWF are fairly consistent in the mid teens, supporting temperatures in the mid 70s for most locations. Complicating our maximum temperature potential Thursday will be the presence of advected low level moisture and potential shower activity. Decent isentropic lift along a boundary in the St. Lawrence Valley Thursday will spur shower chances by late Thursday into Friday. Model trends have hinted at delaying the arrival of shower chances towards Thursday night into Friday, keeping most of Thursday on the drier side. However, by Friday a cold front will push through the region with elevated PWs up to 1.5"; more reminiscent of a summer-time airmass. Thankfully, this front will be quite progressive, aided by a 40-50kt LLJ, and good stretching between a Bermuda high, and a building high across the Midwest. As a result, ensembles depict only a few tenths of an inch of rain, mainly across northern New York and northern Vermont. Only a 10-20% chance of exceeding 1" of rain exists in the GEFS, and is focused only over the St. Lawrence Valley. As our flow pattern turns more southwesterly on Thursday, our gradient flow will tighten with localized gusty winds. Soundings depict gusty channeled flow in the Champlain Valley winds with reasonable winds in the 25-30+ MPH range. Across northern New York, slightly stronger channeled flow is expected with winds approaching 40 MPH in a reasonable higher end scenario out ahead of the cold front during the day Thursday. Given climatology, sustained winds look marginally strong in this area but gusts will not be impactful. Mountain summits will likely remain gusty around 40 MPH Thursday through mid day Friday. Winds look to weaken through the day Friday with the arrival of better precipitation chances. KEY MESSAGE 3: A seasonable and dry start to the weekend is expected for Saturday as a brief period of high pressure builds into the region. The dry conditions look rather short lived, with precipitation chances increasing for Sunday as another low pressure system moves into the region. There is still some uncertainty regarding the low track at this point, which will influence how much precipitation we see, but additional rainfall chances look likely at this point. Temperatures this weekend look to be fairly seasonable, with daytime highs climbing into the upper 50s to mid 60s. Heading into next week, high pressure looks to build into the region again, bring dry weather and cooler temperatures. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... Through 06Z Wednesday...Low clouds, mist, and lingering rain showers across the region will continue to lead to reduced flight conditions, with most terminals experiencing IFR conditions or lower. Ceilings are the main driver of the low flight conditions, with ceilings generally between 200 and 1500 ft AGL, although some reduced visibilities generally 3-6SM due to rain and mist will continue for the next few hours. These conditions are expected to prevail for the next several hours, with gradually improvement not expected to begin until 15Z or so, with more rapid improvement towards 18Z. forecast period. Winds will generally be north to northwesterly throughout the forecast period, less than 10 knots. Outlook... Wednesday: VFR. Patchy BR. Wednesday Night: VFR. NO SIG WX. Thursday: VFR. NO SIG WX. Thursday Night: VFR. Chance SHRA. Friday: Mainly VFR, with local MVFR possible. Chance SHRA. Friday Night: Mainly VFR, with local IFR possible. Slight chance SHRA. Saturday: VFR. NO SIG WX. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ WHAT HAS CHANGED...Danzig DISCUSSION...Danzig/Kremer AVIATION...Kremer