Eastern Pacific Hurricane Watch -  In the Wake of Hurricane Dean

The remains of Hurricane Dean are forecast to turn up the west coast of Mexico and very closely follow the track of Debbie in 1988. What is curious is that in 1988, a majority of the storms formed far west in the Pacific, just like this year. In 1988 only two tropical depressions even threatened Baja. I can go with that.

The less positive analytic year is that of Dolly in 1996. That was the year as many of you may recall, that Hurricane Fausto pasted Baja California Sur.

Now, I don't have access to Sea Surface Temperatures in the Sea of Cortez in 1988 and 1996, but both of those storms that did make it across, did so at the end of August, first of September. Since our water temperatures are only slightly above normal throughout the basin, we can assume that we should have no greater chance of Dean reforming than did Debbie ad Dolly.

It is likely that crossing the mountains of Central Mexico will wring a majority of the water from Dean, but the water into which the storm will emerge will be able to replenish some of that and with luck we should receive some much needed rain in a much more gentle form that the Yucatan is receiving theirs today.

More below...
 

So, how will all this affect our basin? August 15th marks the REAL beginning of the Baja Hurricane Season. The earliest tropical cyclone to ever make Baja landfall was on Aug 15th and the latest, October 17th. So we are into it now, a time when we need to be aware of systems forming to the SE of us.

Well, contrary to what many fishermen in the Sea have been saying, the NHC says our Sea Surface Temperatures are seasonal normal or slightly higher than normal. This is true throughout our Hurricane Birthing zone. Normal or slightly above normal Sea surface Temperatures. As stated in past articles, this means the ocean temperature is contributing a normal amount of energy to the hurricane formation formula. There are of course, a significant number of other factors that lead to storm formation. High winds aloft, coming off mainland Mexico have thwarted the formation of several promising young systems already this year.

The ridge of High pressure that has defended Baja from humidity and also cyclones is retreating into the central Pacific. The 1012Mb isobar had extended south of Baja far later in the season than usual. Giving us very dry weather through the second week of August. Very soon the northern hemisphere will begin to cool, (well, at least for those up you a little further north than Baja) and the mid level winds will increase from the SW across Baja. These are the mid level winds that turn a naturally westward bent hurricane back to the NE and over Baja.

Hurricane Dean cleared a swath for us, free of tropical waves for a 72hr period. Usually, when the Atlantic basin, particularly in the Caribbean Sea, has an active hurricane the pacific Basin gets some time off. We won't see another tropical wave until late in the week. This isn't necessarily good, as it give time for moisture and energy to build up. There is another wave less than 36hrs behind the first – this could give the Pacific Basin two turns at bat for a tropical cyclone in the week ahead. And as has been proven by John in 2006 and Ignacio in 2003, we can get hit in the last week of August on quite easily.

The 26° thermo cline shown on the graphic left by a red arrow is another sign that we are entering the threat season for Baja. Water warmer than 26°C is an integral part of storm formation and growth. Once crossing into waters below that temperature storms degrade very quickly. The magic line now encompasses then entire tip of Baja, up as far north in the Pacific as Magdalena Bay. This is just about normal for this time of year.

By late weekend the forecast calls for a strong High to form over central Mexico which should continue to keep things dry in the eastern basin.

So now the fun part, my prognostications. I burned my Ouiji board and walked 7 times around the building to break my luck - I pulled perfect 0 last week. The system I had expected to move west like all it's predecessors and become a tropical storm angled NW and passed just west of Cabo San Lucas by a few hundred miles. We got a smattering of rain, not much more. It never deepened before entering sub 26°C waters and was a big nothing.

Ahead, I see rain toward the weekend as a result of the remains of Dean. The forecasts I am looking at now for dean were formulated while the hurricane was still over the Yucatan peninsula, so a lot may change. But the forecasts don't call for the system to even maintain tropical depression status. We have some warm water in the southern part of our basin and about the largest amount of thunderstorm activity in the ITCZ that we have seen in some time. But Dean is the wildcard and there will be significant disruption to the weather patterns following it's passage. I am going to look into my crystal ball and prognosticate that there will be a hurricane form inside of 110°W from the second tropical wave headed our way and we're going to have to keep an eye on this one I think. The time is right for them to head more to the NW.

But remember, what do I know...

Clear skies and fair winds!   Tomas

Our Eastern Pacific Hurricane Watch is an editorial/entertainment analysis of data from the National Hurricane Center, NASA and NOAA and is based on information provided by the same, but is an amateur endeavor. For actual storm information readers should refer to notices and warnings posted by the National Hurricane Center. or visit the Mexican Nation Metrological website for more information.