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ARGold · 02-07-2009, 17:54

Now in SF and the Skipper has just arrived from Alaska. We went over the to-do list and have a week or so work before our shakedown cruise.

I'm doing daily weather forecasting and checking the long range forecasts taken days ago against the current conditions so I can get a good idea of the quality of the forecasts. So far we have not have an offshore low come in and there are none in the forseeable future so I realize the test of quality is limited.

My prediction process goes like this: First I use LINKS to NATIONAL WEATHER SERVICE MARINE FORECAST OFFICES
to get the current conditions.

Next I study the U.W. MM5 Mesoscale 36km surface analysis loops: NAM-Initialized Pacific Northwest MM5 Weather Forecasts
This gives me a good idea of model driving the weather on the coast for the next 96 hours. I also look at the 12km loop but under these conditions (no lows coming in) they are not any more informative than the 36km model (they should be more informative under low pressure conditions)

I compare the MM5 loop against the Radiofax surface analysis charts for the current and 24, 48 and 96 hour forecasts: Radiofax Charts - Pt. Reyes, CA

Next, I look at the wind/wave analysis and prediction loops from: NWW3 Product Viewer
Unfortunalty this does not give me period and I know that period is very important. As a rule of thumb, I would not want to get into a squared or better period where the period in seconds is equal or less than the wave height in feet (Thanks Gordy Cole for that advice). If anyone has a good wave analysis site, let me know.

02-07-2009, 17:54	#66
ARGold Registered User Join Date: Dec 2008 Location: Seattle, WA Boat: C&C 34 Posts: 30	Weather prediction Now in SF and the Skipper has just arrived from Alaska. We went over the to-do list and have a week or so work before our shakedown cruise. I'm doing daily weather forecasting and checking the long range forecasts taken days ago against the current conditions so I can get a good idea of the quality of the forecasts. So far we have not have an offshore low come in and there are none in the forseeable future so I realize the test of quality is limited. My prediction process goes like this: First I use LINKS to NATIONAL WEATHER SERVICE MARINE FORECAST OFFICES to get the current conditions. Next I study the U.W. MM5 Mesoscale 36km surface analysis loops: NAM-Initialized Pacific Northwest MM5 Weather Forecasts This gives me a good idea of model driving the weather on the coast for the next 96 hours. I also look at the 12km loop but under these conditions (no lows coming in) they are not any more informative than the 36km model (they should be more informative under low pressure conditions) I compare the MM5 loop against the Radiofax surface analysis charts for the current and 24, 48 and 96 hour forecasts: Radiofax Charts - Pt. Reyes, CA Next, I look at the wind/wave analysis and prediction loops from: NWW3 Product Viewer Unfortunalty this does not give me period and I know that period is very important. As a rule of thumb, I would not want to get into a squared or better period where the period in seconds is equal or less than the wave height in feet (Thanks Gordy Cole for that advice). If anyone has a good wave analysis site, let me know.