Models predict Weather

SUMMARY -- 1) A model predicted gale accurately 48 hour in advance. 2) We confirmed the prediction by following the system in. 3) But October weather is fairly predictable anyway as the Pacific high pressure area moves south and Aleutian low settles in.

1) Here is the US military site which predicted Sunday October 18ths wind and rain 48 hours in advance. Nice going.--- 

Site has changed--- Here is East Pacific model prediction page at a framed site

16 Oct -- high seas in Gulf

48 hour prediction = reach us

2) Tracking (and predicting) incoming weather systems across Dixon Entrance and Hecate Straits.

By using the US site one gets the last 24 hours data (Currently not working). I have plotted the system that came in on October 18th here. While we received rain and some wind, it was not even gale force. Still the model was accurate. And the data shows how to "watch a system come in" and thus calibrate our predictions for next time.

As a rule the winds will peak from South East (and the seas get the highest) when the "bottom of the low" pressure (see arrow) passes through as on the following three graphs.

Note -- These American automated buoys presently not working 1/2/02

3AM

West Dixon Entrance 46205

Primary and secondary axis reversed on this graph of farthest west.
And in contrast to next 2 graphs this one has wind speed in knots rather than wave height
Note Wave and Wind are usually correlated.

6AM

Central Dixon Entrance 46145

Because of the location, though the wind peaked while barometer at lowest, the wave height continued to increase when the direction went WSW. That is 13 foot seas with a 16 knot wind

7:30 AM

North Hecate Straits 46183

The winds got highest at this location gusting 30, but the seas were not very high (8 feet is nothing in Hecate) under this system's conditions.

Seeing the Bigger picture-- or face off between the Pacific high and the Aleutian low

3) Here is from northern hemisphere sea level pressures. While not shown here most these fields can be seen all the way across the pacific to central Asia.

By the 17th both the low and high had intensified
 What is happening becomes more obvious when we look at the effect of this face off on the jetstream. To the South of BC the Pacific high is still strong. The face off is spawning weather systems that track onto the central coast (for now). The 2 week prediction (lower right) shows this pattern will only intensify.

 

Whatever the correctness of this interpretation the mechanism is clear:
as the sun's warmth moves south below the equator the cooling ocean controls our weather.

 

 

Unfortunately the same models that generated the two week jetstream predictions above say the NW is going to get wetter than usual even for October

Last Updated--September 06, 2003

So is this a La Niņa year?

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