Gusts stronger than forecast
On Saturday 17 October in El Prat de Llobregat, the models forecast gusts of 27 km/h and gusts of 80 km/h were measured
With what we measure, we cannot tell why.
Port de Barcelona - Bocana Sud station (Meteocat), 6 km from El Prat de Llobregat and 2 more stations in the area.
What happened
- No model saw it coming: the closest, the ICON, gave 32 km/h.
- It happened at 3 stations in the area.
- This station usually measures gusts 10 km/h stronger than forecast; that day they were 53 km/h stronger.
- With what we measure, we cannot tell why.
- The Atlas Forecast missed too: 11.3 km/h average error each hour (the median of the models, 10.6 km/h).
What each model gave
| Model | For that day (0–24 h) | A day earlier (24–48 h) |
|---|---|---|
| ECMWF IFS | 26 km/h | — |
| GFS | 22 km/h | 25 km/h |
| ICON | 32 km/h | 30 km/h |
| UKMO | 27 km/h | 29 km/h |
| Median | 27 km/h | 29 km/h |
| Measured | 80 km/h | |
Hour by hour
Maximum gust at the Port de Barcelona - Bocana Sud station, with each model's forecast for that same day (0–24 h). Spanish mainland time.
- Measured
- Median of the models
- Each of the other models
Show the data in a table
| Time | Measured | ECMWF IFS | ECMWF AIFS | GFS | ICON | ARPEGE | UKMO |
|---|---|---|---|---|---|---|---|
| 03:00 | 10.1 | 10.8 | — | 4.3 | 6.8 | — | 6.5 |
| 04:00 | 7.6 | 10.8 | — | 2.9 | 6.8 | — | 5.8 |
| 05:00 | 10.4 | 10.4 | — | 3.6 | 6.5 | — | 4.7 |
| 06:00 | 10.1 | 10.4 | — | 4 | 6.5 | — | 4 |
| 07:00 | 11.2 | 10.8 | — | 4 | 6.8 | — | 5.4 |
| 08:00 | 9.7 | 10.8 | — | 4 | 8.3 | — | 6.5 |
| 09:00 | 11.2 | 10.1 | — | 4.3 | 8.6 | — | 7.6 |
| 10:00 | 23.4 | 9 | — | 3.2 | 8.6 | — | 7.6 |
| 11:00 | 24.5 | 10.1 | — | 4.3 | 8.6 | — | 7.6 |
| 12:00 | 21.2 | 14.8 | — | 6.1 | 7.2 | — | 7.6 |
| 13:00 | 10.4 | 21.6 | — | 7.9 | 15.8 | — | 7.6 |
| 14:00 | 15.5 | 25.9 | — | 8.6 | 20.5 | — | 13.7 |
| 15:00 | 21.6 | 26.3 | — | 8.6 | 20.2 | — | 19.4 |
| 16:00 | 23.8 | 24.1 | — | 7.9 | 24.5 | — | 26.3 |
| 17:00 | 23.8 | 22 | — | 8.3 | 25.6 | — | 27 |
| 18:00 | 22 | 20.2 | — | 7.6 | 23.8 | — | 25.6 |
| 19:00 | 20.9 | 18.4 | — | 6.5 | 17.3 | — | 26.3 |
| 20:00 | 19.1 | 16.9 | — | 9 | 10.4 | — | 19.8 |
| 21:00 | 13 | 16.2 | — | 8.3 | 12.6 | — | 23.4 |
| 22:00 | 36.7 | 16.2 | — | 16.6 | 24.8 | — | 24.8 |
| 23:00 | 79.9 | 15.8 | — | 20.2 | 31.3 | — | 20.9 |
| 00:00 | 42.5 | 15.5 | — | 18.4 | 30.6 | — | 19.1 |
| 01:00 | 33.8 | 15.5 | — | 21.2 | 32 | — | 17.3 |
| 02:00 | 35.6 | 15.1 | — | 22 | 31 | — | 14.4 |
The stations in this episode
- Port de Barcelona - Bocana Sud: 80 km/h (forecast 27 km/h)
- Cabrils: 70 km/h (forecast 26 km/h)
- Port de Barcelona - ZAL Prat: 68 km/h (forecast 27 km/h)
Weather in El Prat de Llobregat · Model accuracy · The model league · Other misses
How we spot them
Every day we compare what the Meteocat (in Catalonia) and AEMET weather stations measured the day before with what each model had forecast for that same day (0–24 h ahead). It counts as a notable miss if 15 mm or more fell and the median of the models gave less than 3; if it gave 15 mm or more and less than 1 fell; if the high was off by 4 °C or more (and by at least 4 °C more than that station usually is); or if a gust went over 60 km/h and was 25 km/h or more above the forecast. Stations within 40 km with the same miss count as one episode, and we show at most 5 per day.
The explanations come from the same data: which model saw it, whether the rain came earlier or later, whether it fell (or was forecast) a few kilometres away, whether it was very concentrated… When none of that fits, we say so. Days run from midnight to midnight UTC (2 am to 2 am in summer and 1 am to 1 am in winter, Spanish mainland time).
Missing now and then is unavoidable: the weather is chaotic and every model has its days. How often each one gets it right, on average, is in Accuracy and in the model league.