Model comparison & split view

Pit several weather models against each other at a single point, show two maps side by side, or scrub a multi-model hourly timeline, to gauge how trustworthy a forecast is before you commit to it.

Where to find it

• Model comparison (Models): Weather panel (wind icon on the map toolbar) › Models section, always visible at the bottom of the panel.
• Split View: map toolbar › Weather category › Split View button (two-columns icon).
• Multi-model timeline: Multi-model forecast button (wind-icon pill) centred at the bottom of the map.

Hierarchy

Map
├── Weather panel
│   └── Models (model comparison)
│       ├── Model selector (GFS, ECMWF IFS, ICON, Météo-France, GEM, UKMO)
│       ├── Divergence warning
│       ├── Wind speed (per-model values + mean + spread)
│       ├── Pressure (per-model values + mean + spread)
│       ├── Confidence (agreement bar)
│       ├── Wind 72h (sparkline)
│       ├── Pressure 72h (sparkline)
│       └── Refresh
├── Split View
│   ├── Primary map (left)
│   ├── Adjustable separator
│   │   ├── Sync / Unsync map position
│   │   └── Close split view
│   └── Secondary map (right)
│       └── Compare View (control panel)
│           ├── Copy settings from primary view
│           ├── Wind / Pressure / Waves
│           ├── Wave sub-modes (height, decomposition, cross sea)
│           └── Day / Hour sliders (or GRIB time step)
└── Multi-model timeline (bottom drawer)
    ├── Tabs: Wind · Waves · Currents
    ├── Draggable map point (+ back to boat position)
    ├── Model settings (check / drag to reorder)
    └── Colour-coded hourly table (Beaufort) · WMO emoji header

Model comparison

Models

What it's for: overlaying the forecasts of several global weather models at the same point (the map centre) so you can see whether they agree. When the models converge, confidence is high; when they diverge, the forecast is uncertain and you should stay cautious.

How to use it: 1. Open the Weather panel from the map toolbar. 2. Scroll down to the Models section. 3. Click at least two models in the button row to switch them on (the coloured dot lights up). 4. Centre the map on the area you care about: the comparison recomputes automatically at the map centre. 5. Read the per-model values, the mean and the spread, then the Confidence bar. 6. Scan the Wind 72h and Pressure 72h sparklines to see where the models part ways over time. 7. Set the forecast day and hour (Weather panel sliders): the dashed white cursor on the sparklines marks the selected moment.

Options & settings:

Tips & limits: - You need at least 2 models active, otherwise the message "Select at least 2 models to compare" appears and nothing is computed. - The calculation is done at the map centre. To compare a different point (a landfall, a transition zone), re-centre the map on it. - The sparklines cover 72 h; beyond that, rely on the instantaneous values and the Ensemble panel for the long range. - A wide grey band with lines crossing each other = uncertain scenario. A narrow band with tightly packed lines = high confidence. - Each model has a different reach (Météo-France ~4 d, ICON/UKMO ~7 d, ECMWF/GEM ~10 d, GFS ~16 d): at long lead times some models stop providing data. - Internet connection required (data fetched on the fly).

Split View

Primary map and secondary map

What it's for: showing two independent maps side by side. The left map is your usual primary map; the right one is a second map with its own weather settings. Ideal for comparing wind against waves, two different lead times (D+1 vs D+3), or pressure against wind at the same moment.

How to use it: 1. In the Weather category of the toolbar, switch on Split View. 2. The map splits in two; the Weather overlay switches on automatically if it wasn't already. 3. Set the right-hand map via its Compare View panel (top-left of the secondary map). 4. Drag the central separator to adjust the width of each map (between 25% and 75%). Double-click the separator to snap back to 50/50. 5. To close, click the cross (Close split view) in the middle of the separator.

Options & settings:

Tips & limits: - Both maps share the same base map and, where applicable, the same loaded GRIB file; only the mode and lead time differ on the right. - Classic trick: keep wind on the left and waves on the right at the same moment to spot rough-sea zones under strong wind, or compare D+1 and D+3 to watch a system evolve. - In pressure mode, isobars are drawn on the secondary map too. - The separator is limited to 25%–75%: neither map can be fully hidden.

Sync / Unsync map position

What it's for: linking the two maps' movement so they always show the same geographic area, or unlinking them to explore two different places.

How to use it: 1. Find the chain button in the middle of the separator. 2. Click to Sync map position (closed-link icon, highlighted): panning or zooming one map drives the other. 3. Click again to Unsync map position (open-link icon): each map pans freely.

Options & settings: - Sync map position: both maps stay locked to the same centre and zoom. - Unsync map position: independent panning on the left and the right.

Tips & limits: - Keep sync on to compare two weather parameters over the exact same area (the most common case). - Unsync to compare two distinct regions, for example the start and the end of a passage.

Multi-model timeline

Multi-model timeline ("Multi-model forecast")

What it's for: a bottom-of-screen drawer showing a colour-coded hourly table that compares several weather models side by side for a single point, over 7 days, hour by hour. One row per model, one column per hour (grouped by day). At a glance you see whether the models agree — the answer to "which model should I trust?".

How to use it: 1. Click the Multi-model forecast pill (wind icon) centred at the bottom of the map. The drawer opens. 2. Pick the parameter top-left: Wind, Waves or Currents. 3. Read the table: each cell is a colour-coded square (Beaufort scale) with the value and a direction arrow. Rows are models, columns are hours. 4. To change the point, drag the teal disc on the map: every model reloads for the new location. A lat/lng badge appears in the header, with a button to return to the boat / route position. 5. Click any cell to jump the app's time scrubber (and the animated boat on the route) to that exact hour. 6. Close the drawer with the chevron top-right.

Options & settings:

Tips & limits: - A position is required: a point dragged on the map, the boat's GPS/Signal K position, or the first waypoint of an active route. With none, the drawer prompts you to click the map to place a point. - Internet connection required: all data is fetched live (Open-Meteo). A "Loading…" message shows during fetching. - Horizon 7 days, hourly, in UTC. - Columns where the colours agree across models = high confidence; colours that diverge = uncertain forecast at that hour. - A perfect complement to the Models block: the timeline shows the hour-by-hour evolution, while the Models block gives the numeric snapshot and overall agreement.

See also

• Weather overlays
• Forecast controls
• GRIB files