upslope / about
What this is
One page that answers the morning question: where's the snow, and how sure are we? Every lift-served mountain in New England, the week at a glance, probability ranges instead of a single hyped number, and powder alerts that buzz your phone when the odds clear a bar you set.
Where the data comes from
Straight from the National Weather Service. It's the same data the big apps repackage, without the watering down. The 7-day numbers are the NWS forecaster-adjusted grids, hand-tuned for this terrain by the meteorologists at the Burlington, Gray, Boston, and Albany offices. The probability ranges come from the National Blend of Models, which is roughly thirty models agreeing and disagreeing. That's why we can tell you "4 to 14 inches, most likely 8" instead of pretending to know. The hourly storm view is the HRRR, the 3km model that resolves the rain/snow line. The forecast discussions are the forecasters' own words, unedited.
Who forecasts what
Four National Weather Service offices split New England ski country, and the borders follow radar coverage and geography, not state lines. Burlington VT covers the Green Mountain spine from Jay Peak to Killington. Gray ME covers New Hampshire and western Maine. Boston covers the Massachusetts hills. And southern Vermont (Stratton, Magic, Mount Snow, Bromley) belongs to Albany NY, because Albany's radar sees those mountains from close range while Burlington's view is blocked by a hundred miles of Green Mountains. On a powder day at Magic, the person who forecast it was sitting in New York.
The acronyms, decoded
| name | what it is on this site |
|---|---|
| NWS | The National Weather Service. Taxpayer-funded, everything public. The source of nearly everything here. |
| NDFD | The National Digital Forecast Database: the 7-day numbers in the table. Forecaster-adjusted grids, hand-tuned by the local offices. Amounts are committed about 3 days out; beyond that we show outlook instead. |
| NBM | The National Blend of Models, roughly thirty forecasts run side by side. Where our ranges, odds, and outlook days come from. |
| HRRR | The The High-Resolution Rapid Refresh model: 3km detail, updated hourly, next 18 hours. Powers the hourly strips and sees the rain/snow line. |
| AFD | Area Forecast Discussion: the forecasters explaining their own reasoning, several times a day. Shown under "the forecasters' own words." |
| CoCoRaHS | The Community Collaborative Rain, Hail and Snow Network: volunteers who measure precipitation every morning with standardized gauges. They are the referee our scoreboard grades against. |
How to read the numbers
The forecast is run about thirty times with slightly different starting points. The range we show is the 10th to 90th percentile of those runs: "1.5 to 5.7 inches" means one run in ten got less than 1.5 and one in ten got more than 5.7. The single number is the median. The odds ("2″+ 99%") are the share of runs that delivered at least that much. A wide range means the models genuinely disagree; a narrow one means trust it. In the 7-day table, days 1 to 3 are amounts the forecasters commit to; the hollow-bar days beyond are model-median outlook, shown lighter because they will change. Off-season the same table tracks rain to keep the pipeline honest and the scoreboard grading; snow takes over automatically at the first flakes. In winter, a thin green underbar (or the word "rain") on a day means rain or mix also falls that day. That is the classic New England trap, and we flag it so a snow number never hides a base-wrecker.
Why trust it
You shouldn't, not on our say-so. Every forecast this site publishes is logged the moment it goes up, then scored against what volunteer weather observers actually measured near each mountain. The results live on the scoreboard, updated daily. Cherry-picking is impossible by construction. When we're wrong, that page says so before we do.
Who makes it
One New England skier and software engineer who got tired of paying more every year for forecasts built on free public data. The site is independent. No resort money, no pass-company money. If it ever charges for anything, it will be the alerts, it will be cheap, and this page will say so plainly.
The name
When a storm departs New England and the wind swings northwest, moist air gets forced up the spine of the Greens. It snows on the high terrain for days while the valleys see flurries. Upslope snow is the refill the national apps miss, the powder day nobody drove north for. That's the gap this site exists to close.