Gusts, Rain, and Early Mountain Snow — Weekend Adventure Outlook for Southern Maine & New Hampshire

October 31, 2025

A compact but dynamic low works northeast from the Mid‑Atlantic across New England tonight into Friday. For anyone planning outdoor time across southern Maine or coastal and interior New Hampshire, treat tonight as the first trip‑breaker of the week: widespread soaking rain and a period of gusty winds will be the headline, with mountain snow setting up by Friday night at the highest summits. Read this as a planning memo — where to push a trip, where to wait, and what to pack if you go.

The synoptic setup is straightforward and energetic. A strengthening low and a sharp short‑wave aloft ride into the right‑entrance region of an upper‑jet, producing strong ascent through the night. That pulls a solid axis of moderate to heavy rain across the region, with model soundings and precipitable water values near 1.25 inches. Forecast totals tonight and into Friday still cluster around 1–2 inches across the area, with the greatest totals expected on southeast‑facing mountain slopes where orographic lift adds extra rain. Expect locally poor drainage, ponding on roadways, and nuisance flooding in low spots — not widespread river flooding, but enough to make low‑lying parking lots and trailheads sloppy.

Wind is the other practical hazard. A robust ESE low‑level jet (LLJ) — 60 kts in a 2–4 kft layer aloft in models — will try to mix to the surface between about midnight and the pre‑dawn hours. Mesoscale guidance (HRRR and similar runs) are persistent in indicating a few short‑duration surface gusts over 45 mph in exposed locations, especially along the coast and across downwind ridges. A modest surface inversion may limit how well the strongest winds mix down, so gusts will be spatially spotty and short‑lived. The NWS has held off a Wind Advisory for now, but be prepared for tree‑limb damage and localized power outages if you’re in wooded, exposed trailheads or campsite areas.

Marine and coastal boaters: the pattern is elevated to hazardous. The watch was upgraded to a Gale Warning — expect gale‑force gusts offshore tonight into Friday night, with a lull Friday morning before winds shift to the southwest and pick back up into gale territory Friday afternoon into Saturday as the low deepens into the Canadian Maritimes. If you plan to launch, move to well‑sheltered harbors, delay until Sunday when conditions ease, or pick an alternate activity.

By Friday night the low lifts north into the St. Lawrence Valley and colder air wraps into the backside. Upslope showers will persist across and north of the mountains with a transition to rain/snow showers possible in the White Mountains by evening. The NWS expects a few inches possible on the highest summits through Friday night — not a deep snowpack, but enough for icy rocks and slippery approaches. Gusty southwest to west winds (around 30–35 mph gusting higher) will remain through Friday night, keeping valleys milder and the ridgelines raw and windy.

The weekend is a transition to high pressure building from the west while the low stalls out and deepens in the Maritimes. That brings gusty westerlies Saturday and scattered upslope rain/snow showers in the mountains — especially on the White Mountain western slopes — with highs generally cooler: low‑40s north to mid‑50s confined to immediate coastline. Coverage of mountain showers decreases Sunday as the airmass dries and winds ease. Next week the northern jet becomes active — expect a series of shortwaves and fronts Monday night, Thursday, and again toward next weekend. Each front brings a brief warm up ahead, rain or showers with the passage, and another cool shot behind it. Overall, a cool, unsettled mid‑week pattern with periodic mountain snow showers is the likely outcome.

What that means for adventures: tonight and Friday morning are poor choices for exposed hikes, backcountry paddling, or small‑boat outings. Driveed routes along sheltered coasts and short, low‑elevation walks in urban parks or protected estuaries are doable—just plan for heavy rain and wind gusts, and avoid gullies and stream crossings that can rise quickly. Friday afternoon through Saturday will be the most complicated window: winds shift west and gusts remain strong, making ridge traverses and exposed summits uninviting unless you have high wind experience and a conservative turnaround plan. Saturday could also bring the first meaningful snow on the highest White Mountain summits — use microspikes or traction if you’re heading above treeline. Sunday looks like the most comfortable day for local hiking and trail running at lower elevations as winds ease and the airmass dries.

Aviation and access notes to translate into trip plans: low ceilings and IFR/LIFR conditions overnight into early Friday will limit mountain flying and make early departure flights or scenic flights choppy. Expect temporary MVFR conditions at mountain airports into the weekend when upslope flow persists.

Bottom line operational guidance: delay open‑water trips tonight and Friday; move coastal launches to well‑protected harbors and watch the marine forecast; keep high ridgeline plans flexible and carry traction and a warm dry kit for sudden snow or wind chill above treeline. Expect a cool, unsettled week where short windows of better weather will appear between fronts — plan day trips, not multi‑day exposed pushes, until the pattern dries out later next week.