JERSEY WEATHER CHAT LIVE OPS

WHERE THE DATA COMES FROM: the box in the top-left corner of the map shows the model (NOAA’s American GFS), which run it is — runs start at 00, 06, 12 and 18 UTC (“Z”) and take a few hours to compute — and roughly when the next one will reach this map. Each new run can shift a storm’s track and strength, so it is worth checking back after an update.
HOW TO READ THIS MAP: the map is fixed on the area that matters to Jersey — Ireland and the Western Approaches across to the Low Countries, Biscay up to Scotland. The colours are NOAA's forecast wind at 10 metres above the ground at the chosen time (gusts or average wind, key below the map), and the thin white lines are isobars — equal sea-level pressure every 2 hPa, bolder every 10 — the closer together they are, the stronger the wind. Each glowing line is the forecast path of a storm centre (a low) over the next 10 days: the dots are every 12 hours, the number beside each is its pressure in hPa (the lower, the stronger), and the larger marker is where the centre is at the chosen time. Tap a number in the row of hours to jump to that time — it is the same NOAA GFS run as the big charts on Wetterzentrale and elsewhere, so the hours match. Tap or click anywhere on the map for the gust, average wind, direction and pressure at that spot. The map is NOAA's 15-mile grid, so it shows the broad pattern; gusts on exposed headlands can be stronger.
THE BOX BELOW THE MAP: Jersey's own wind forecast from several models at once, shown as a range — when the models agree the range is narrow, and when they are more than 15 mph apart the box says so. “Strongest spell” is the best 3-hour spell in each model, not a single hour, so one freak hour in one model cannot become the headline.
NAMES: every storm gets a number. When the UK Met Office, Met Éireann, KNMI (Netherlands), Météo-France and partners, or the German weather service give a storm an official name, the page picks it up automatically from the news and the name replaces the number. A storm keeps the same number from one update to the next. If an automatic name is wrong or late, tap RENAME on its card (changes only your own view) — or ask Matt to set it for everyone.
Worked out by computer from NOAA's GFS forecast and refreshed every 6 hours. The further ahead, the less certain the position and depth — always check Jersey Met warnings for what is actually expected here.