Predicting Hurricane Tracks - Rock Solid Prediction and on the beach

[TacomaSailor]

I wanted to present a case study about the problems with predicting an East Pacific Hurricane track and the difficulty one has of deciding to go or stay and if the answer is go - GO WHERE?

As others have mentioned – I was asking myself exactly this question on September 20 – 21, 2003 as Hurricane Marty was heading on exactly the track now being followed by Blanca. We were in the north Sea of Cortez and had six-days to try to figure out what Marty was going to do. The current cyclogenesis and track of Blanca is almost identical to the first four days of Hurricane Blanca.

I made what I thought was a very well reasoned and carefully considered decision based on 50-years of East Pacific hurricane and tropical storm tracks and data. I listened very carefully to all the NWS predictions. Five boats then chose to stay well anchored in a cove that had never been hit by a hurricane. My buddy boat was a professional mariner with a lot of experience and he made the same choice – to stay in what we thought was a very safe and secure anchorage. Seventeen other experienced cruisers left to sail 55 NM directly toward the storm to seek shelter in a near perfect hurricane hole.

Monday evening at sunset, we were sitting in our cockpit drinking beer and playing cards secure in the knowledge that NHC forecast the storm to go ashore over 100 NM SE of us. They had been predicting that track for 48-hours. The consistent forecast was for no more than 24-knots of wind at our "secure" location.

At 4 AM Tuesday, September 22 my boat was on the beach in 60-knot winds and 10’ breaking seas. We were on a remote desert island 60 miles from the closest road. We were within 5 NM of the storm core, which just 12-hours earlier was reporting heading into the desert mountains 125 NM to our SE with 35-knot winds only extending only 75 miles from it’s core.

I have written a long and detailed analysis of the decision making process. You can read the post action report I wrote six years after the event at:

TWO FAVORITE QUESTIONS ANSWERED

It provides pages of detailed charts and describes our reasoning process. It also contains many details about the enormous errors that occurred in the tracking, reporting, and predicting of the hurricane’s path.

Two details about reporting and tracking of Hurricane Marty:

-The storm was reported moving at 348 degrees during the 24-hours prior to making a direct hit on us. Subsequent analysis showed it actually moved, very-very consistently at 309 degrees. That meant it was moving directly toward us rather than angling away from us.

- NHC “repositioned” the storm center 79 NM west and north just 6-hours before it hit us. That meant it was staying over 90 degree water and would stay over that hot water for another 24-hours rather than going ashore in desert mountains.

I've attached charts of the reported track and actual track. The B&W chart is from NWS and the dotted lines show predictions, the solid actual, and the Puerto Refugio note on the top center is where we decided to stay "securely anchored."

You can read the message I posted about our decision making PRIOR to the storm hitting us at:

Here Comes Marty!

Hurricanes are unpredictable, particularly in the Baja California region where there are so many confounding factors affecting the path:

- the 70 NM mile wide Sea of Cortez with 85 degree water sandwiched between
- 7,000 foot desert mountains running from NW to SE on the Baja Penninsula
- 6,000 foot desert mountains running the length of the Mexican Mainland
- 60 degree Pacific Ocean water just 40 NM west of the hot Sea of Cortez water

[JPA Cate]

Tacoma sailor,

Yes. Jim and I had the experience of being informed by a fellow cruiser with a sat phone that a cyclone was headed our way. I wanted to leave that night, but there were so many reefs around we didn't leave till morning. But, as the prediction became available on HF radio, we started to plot on our paper charts, both the predicted positions, and also the positions attained. NOT EVEN ONCE were they the same.

We weren't hit, but we made the effort to find the hurricane hole, got there "first", and nothing happened.

My advice is this: plot for yourself the course the "furycame" is taking. The current one, Blanca, I just noticed is going to bring strong winds to Zeehag on Monday; others are trying to hide out from it. Some suggestion it may attain Cat. 5. Not good news.

At the moment, inside the Golfo de California, the water is hot. Outside, as you go north, it is getting cooler, or rather, has not yet warmed so much.

I think your sea surface temperatures are a very good indicator of whether or not the waters at your location can support a hurricane.

Ann