Six weeks and counting

Six weeks and counting, too long for allatsea to be playing at this nautical malarkey. Oh to  be home. Sadly the great weather God is calling the shots as always.

Significant wave Summary from FNMOC WW3 Model (Periods discussed are PEAK periods).

Data period from 12:00 UTC on 06 September 2014 to 12:00 UTC 12 September 2014.

The WW3 model predicts significant wave heights of around 1.0m this evening, rising to around 1.7m tomorrow and then gradually falling through Monday to be around 1.0m again by Tuesday morning. From Tuesday afternoon the significant wave height is predicted to rise to be 2.5-3.0m by Wednesday morning and then to fall to be 1.5-2.0m by Thursday and to remain so through Thursday and Friday.

The dominant wave direction is predicted to be NNW through tonight and tomorrow and to become W’ly by Tuesday and to remain W’ly throughout the remainder of the forecast period. The peak period is expected to be around 5-6s tonight, and gradually increase to be 7s by early Tuesday morning. Through Tuesday afternoon the period is expected to shorten to 5s again for a time and from Wednesday increase to be 10s on Friday.

 

Significant Wave height

The significant wave height is predicted to be around 1.0-1.5m this evening, rise to 2.3-2.8m by tomorrow afternoon and then falling back to around 1.5m by Monday morning. The significant wave height is predicted to continue falling through Monday and Tuesday to be around 1.0m by late Tuesday evening but then to rise to around 1.5m again through Wednesday. Through Thursday afternoon it is predicted to increase further to be around 3.5-4.0m by Thursday night and then fall through Friday to be 2.5-3.0m by the evening. The dominant wave direction is expected to be NW this evening, become N’ly tomorrow, W’ly on Monday and is then expected to remain W’ly for the remainder of the forecast period.

Spectral analysis

1. Short period sea and swell (<8 seconds). The predicted energy in this period band yields an equivalent wave height of around 1.0m at first but then increases overnight and through tomorrow morning to given an equivalent wave height of around 2.5m by tomorrow afternoon. Through tomorrow afternoon and Monday the equivalent wave height falls to be around 1.0m by Monday evening and then is predicted to remains around this level for the remainder of the forecast period.

2. Middle period swell (>8-14 seconds). The forecast energy in this band yields an equivalent wave height which is almost negligible this evening but through tomorrow increases, yielding equivalent wave heights of around 1.0m by the afternoon. The equivalent wave height remains around 1.0m through into Tuesday and then is predicted to gradually fall to be around 0.5m by Wednesday. Through Wednesday it is expected to rise to around 1.0m, and on Thursday to rise to 3.0-3.5m by the evening. Through Friday the predicted equivalent wave height falls to be around 2.5m by the evening and remains so into Saturday.

3. Longer period swell (>14-22 seconds). The forecast energy in this band gives an equivalent wave height which is less than 0.1m through until Thursday, when it increases to be around 1.4m by Friday but then is predicted to fall to be around 0.4m by Saturday.

Comments

The observed wave height is 1.4m through a mix of wind wave and W’ly and NW’ly swell train with the peak period around 8.0s and is a little higher than that predicted by the Spectral model. The Spectral Model appears to have recovered from its earlier issues and now gives a sensible output with swell energies reintroduced. The trends shown by both models are similar with wave heights rising for a time tomorrow, slowly falling through the first half of next week followed by a sharp increase from mid week. However, there some differences in magnitude and timings between the models. The FWW3 model has decreased the predicted wave height for tomorrow when compared to the previous run, which has more in common with the Spectral Model for tomorrow’s increase.

Confidence for an increase in wave heights to around 2.5m tomorrow is fairly high, as is that for the gradual drop off through Monday and Tuesday but beyond Wednesday is Low as there remain wide variations in outputs from both models at this time..

Yawn yawn yawn…………….help

About allatsea

Sixty year old master-mariner. Absolutely gorgeous. Well wedged.....when compared to a Nairobi street urchin. Sorted, in that I haven't been in court recently. Hopelessly optimistic, terminally disappointed. Good with cats and other fluffy things. No musical talent. Generous to a fault provided it's someone else's round. Political centreist with far right and left viewpoints. A green activist from the hydrocarbon position with nuclear leanings. Averse to avarice but always happy to receive lottery wins, gifts, windfalls, legacies, prizes and wet sloppy kisses.
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