Historical look at Hurricanes in Baja

(Click on images in this article to expand)

The Eastern Pacific Hurricane Season begins May 15th, but residents of Baja will scoff about any threat so early in the season. I've heard tribal knowledge like, "Hurricanes never come up the Sea of Cortez before September 1st." Well, right off the bat, my first hurricane, Ignacio proved that one wrong in 2003.

So we did a little research and here's the scientific straight scoop. We went to the NHC's Historical Hurricane Plotter which has data on tropical weather compiled from 1948 to 2003. We looked at plots of tropical storms though Category 5 hurricanes that passed within 250 miles of Baja. To confirm our data, it was checked against the Unisys data complied independently. Our plots and data do not include 2003's direct hits by Ignacio and Marty.

Anyone who has spent the summer in Baja knows, about August 15th the days become still and humid, and this is in addition to near 100 degree heat every day. Thunderstorms appear regularly over the mountains between Cabo San Lucas and La Paz. The saving grace is the jet stream. The jet stream can steer the hurricanes east, in opposition to their natural desire to head west. These strong high level winds usually drop down the west coast of Baja and turn eastward north of Turtle Bay.

The warm water of the Sea can be in the upper 80°'s by late August and this becomes a very strong hurricane magnet. Storms that generate NW of Acapulco can sometimes get stuck  'inside' and travel up the Sea. Hurricane Ignacio did exactly that on August 26, 2003.

The good news is August hurricanes in Baja are still rare. The upper atmosphere steering winds are still moving eastward far north of the hurricane track and a majority of the storms move off into the colder waters of the Pacific and spin apart.

August can spawn monster storms too, like Kiko in 1989. Kiko made it to Category 3 has it churned up the Sea of Cortez and  made landfall on the East Cape with winds in excess of 120 MPH.

August Storms

There is a map for each month of the season, click on the map for an enlarged view of storms tracked during that month. Each table shows the year of the storm, the first date of it's highest wind speed and the highest Saffir-Simpson Scale Category rating the storm achieved. The storms are sorted by the day they achieved maximum strength, showing what part of the month is most prone to storms.

Let's Start with May, that's an easy one. Since 1951 not a single tropical storm or hurricane has passed within 250 miles of Baja.

In June the Eastern Pacific is starting to really warm up and the storm activity increases. By mid June hurricanes become a possibility in Baja, although still pretty remote. The last time a June hurricane hit Baja was in 1958. The early season storm packed winds of 85 mph as it passed within 25 miles of Cabo San Lucas, which wasn't much more than a few fishing huts at the time.

June Storms

In July the water in the Sea of Cortez is warmer. But hurricanes in our hemisphere want to go to the west because of their rotation. The jet stream usually doesn't drop southward across Baja until late August. Historically speaking, July is a safe month too, as the storms move harmlessly out into the Pacific and dissipate. There has been one Category 2 hurricane brush past Magdalena Bay and make landfall north of San Ignacio back in July of 1954. Tropical storm Calvin hit East Cape in 1993 and another tropical storm Calvin hit Todos Santos in 1981. (yes, the same day twelve years apart!) Ok, we can make it though July without a hurricane.

July Storms

Well, dream on if you think the luck will hold though August. I heard it said just days before hurricane Ignacio last year that "...it was no concern, storms never come up the Sea until after September 1st." That is nothing but an old wives tale. By the end of August we can start to get into some serious hurricane weather.

September is the month to be a storm watcher in Baja. More than 150 tropical storms have passed within 250 miles of Cabo San Lucas since 1950. Many of them were just tropical storms, but September is the peak of the storm season.

By mid September the jet stream has dropped well down into Baja Sur before it makes a dramatic turn to the east. Last year while I was plotting hurricane Marty the computer models forecast a continued NW progress harmlessly into the Pacific. Friday afternoon I noticed a drop to the south in the jet stream on the US Navy plots. These high speed upper air currents came almost as far as Magdalena Bay, then turn 90° east. That Friday night the LosCabosInsider predicted that Marty would not continue into the Pacific but would turn and cross the peninsula south of Magdalena Bay. Marty hit the eastward winds south of the jet stream and banked against it's spin, progressively to the east. Marty arrived in La Paz on Monday morning. (thanks to my amateur weather tutor, Jim from Sea Witch!)

The jet stream can make a hurricane turn and it can tear it apart. The central column of convection is the engine that drives a hurricane. Hard turns or strong high altitude winds can disrupt the column and spin the storm apart. As the northern hemisphere cools these upper atmosphere steering winds drop further down Baja before turning east. The combination of these winds and energy still built up in the tropical regions are what make the period from September 15th to October 15th the peak of our storm season.

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Source Data:
National Hurricane Center Historical Hurricane Plots
Unisys Hurricane Archives
 

More Reading on Baja Hurricanes

Offsite:
Baja Hurricanes in Perspective - by Gene Kira