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 — the same data the big apps repackage, without the watering down. Every source is decoded in the table below, and every forecast we publish is scored against reality on the scoreboard, daily, misses included.
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 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.
Questions worth answering straight
How accurate are snow forecasts for New England ski resorts?
Good at the yes/no call a day out, rough on exact amounts — terrain amplifies small errors, and anyone quoting one confident number three days out is marketing. Our record is on the scoreboard, per resort, updated daily.
What's the most accurate snow forecast for New England?
No one can claim that title without publishing verification, and almost nobody does. upslope logs every forecast before the weather happens and publishes the scores after, misses included — the scoreboard and the storm receipts are the evidence.
Why do different apps show different snow totals for the same mountain?
A forecast is a distribution, and every app picks a different point on it — some the median, some the high end that gets clicks. We show the range.
What is upslope snow?
After a storm exits New England, northwest winds force moist air up the Green Mountain spine, wringing out snow for days on the high terrain while valleys see flurries. It's how Jay, Smuggs, and Stowe rack up totals the national apps never saw coming — and this site's namesake.
When does ski season start in New England?
First natural snow brushes the northern summits in late October, snowmaking spins up with November cold, and most mountains open between mid-November and mid-December. This site flips to snow mode at the first flakes.
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.