INTERPRETING FORECASTS Refer to weather booklet - YM7 1.
Look at the shipping forecast issued on the 7th August.
a) What time was it issued? b) What time period does it cover?
2. 3.
Using the synoptic charts for the 7th August, what weather feature is expected to pass over the sea area, Bridge between 0900 and 1200?
A vessel in the Northern Territories on the 7th August has access to synoptic charts, a GFS based weather app, and the shipping forecast.
a) How does the shipping forecast describe the sea state for the Bridge sea area, between 0900 and 1800?
b) What wave height does that equate to in meters? c) Is that the maximum wave height you could expect to encounter? Explain your answer? d) Using the live observations for the ODAS buoy off Stubbington, what actual wave height was observed between 1200 and 1800? e) Using the Analysis MSLP Synoptic chart, what is the measured wind speed in this area? f ) Using the GFS model, at 1200 on 7th August, what is the predicted: i) Wind speed? ii) Gust speed?
g) Using the live observations for the ODAS buoy off Stubbington, what was the highest gust recorded between 1200 and 1800? h) Why might you expect a live wind observation to differ from the forecast? i ) Based on the data extracted above, and using the Beaufort Scale; a) Does the wave height fall within the range for the actual wind speed? b) What could be the reason for any differences?
4.
Consider the following sources of weather information. In each case comment on: a) How might each source be accessed? b) How suitable is each source for: Short, medium or long-term planning Navigational decisions for short local passages Navigational decisions for extended offshore passages
i) GRIB files ii) Shipping forecasts iii) Inshore waters forecast iv) Synoptic charts v) Maritime Safety Information Broadcasts
5. Looking at the GFS model based data for the 7th August:
a) At what time does the wind begin to decrease? b) Would you expect it to reduce at that exact time? Explain your answer.
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