The purpose of this page is to explain some weather terms and conditions. It is in alphabetical order.
This is a phrase used for the trip northward on the outside of the Baja. March & April are worst months as the NW winds tend to be strongest. They begin to lighten up and in May, June & July there are short periods of relatively calm weather (windows consisting of NW winds < 20 knots). In August & September, when the winds are the lightest, there are windows of up to two weeks.
Catalina Eddy is the name given to a cutoff Low that develops during the summer months over Catalina Island off southern California. The season generally runs from April to September, peaking in June. It is the cause of the persistent marine layer in southern California during this period and is also called “Stratus Season” or “June Gloom”.
Coupled Ocean/Atmospheric Mesoscale Prediction System (COAMPS) is a high-resolution regional weather model that is used for predictions out to 48 hours. It has proven to be particularly valuable for forecasting weather in highly complex coastal areas. It is the primary model I use for short term forecasts and is the only one that shows sufficient detail of the Sea of Cortez to make an educated guess. It is available via SailDocs.
A Chubasco is just another name for a thunderstorm in the Sea of Cortez. It is primarily a summer-time phenomenon, strongest June – August, when storms move off the mountaintops where they form into the sea. 9 out of 10 Chubascos that affect the Sea of Cortez come from the Sierra Madre mountain range on mainland Mexico. Those that come from the mainland obviously move to the west though they can come off the Baja and move North or East. Ahead of the Chubasco you will experience strong winds, up to 60 knots, for an hour or so and very heavy rainfall. Within 2 hours it has normally passed. Chubascos cannot be predicted in advance. You can only see them after they develop using real-time satellite loops. These can allow you to see if the convection is moving, expanding in place or dissipating. This will give you some idea of the potential for chubascos in your area in the next 3 – 6 hours.
These are winds that change one time per day and blow from cooler areas to warmer areas. They are diurnal in that they change once per day. Offshore one typically feels the effects between 5 – 10 miles off the coast. The two types of diurnal winds are: 1) Land breeze is a diurnal coastal breeze that blows offshore, from the land to the sea. It is caused by the temperature difference when the sea surface is warmer than the adjacent land. Predominate during the night, it reaches its maximum about dawn. 2) Sea Breeze is a coastal breeze that blows onshore, from the sea to the land. It is caused by the temperature difference when the surface of the land is warmer than the adjacent body of water. Predominate during the day, it reaches its maximum early to mid afternoon.
A localized katabatic wind that is created in certain parts of the northern Sea of Cortez when cool wind from the mountain tops begins to flow down the slope and outward across the water extending 25 – 40 miles offshore. The air heats up as it is compressed during the flow and the wind is very warm and dry. It is sometimes characterized by a cloud that looks kind of like an elephant trunk. They can occur at any time, but predominantly occur early evening and at night when there is no pressure gradient and the land heating has ended for the day. The areas prone to these katabatic winds include; Gonzaga Bay, Bahia de Los Angeles, Punta Trinidad and the stretch north of Santa Rosalia.
Gap winds are those winds that increase as they blow through gaps. Most notable are the Tehuantepec and Papagayo winds. You can also get gap winds in the Cerralvo Channel outside of La Paz and the winds are always strongest on the exit side of the gap.
The official season runs from 15 May to 30 November with the peak between late August to early September.
Average number of Tropical Storms per year is: 16.5
Maximum number of Tropical Storms in a year is: 23
Least number of Tropical Storms in a year: 18
These are gap winds that shriek across Lake Nicaragua and extend at least 400 miles out into the Pacific Ocean. They originate from the trade winds off the north coast of Venezuela.
Pineapple Express is the name given to a plume of cloudiness that comes from the Intertropical Convergence Zone (ITCZ) and extends northeast towards Baja or the west coast of Mexico. Once the Pineapple Express is established it tends to slide southward until it dissipates normally in about 4 - 5 days.
This is the name given to the increase in winds due to a point of land that juts out. The wind off of these areas can often be double the nearby windspeed. A great example is Cabo Corrientes where the afternoon winds are quite higher than the winds just north or south of it.
A term used when one is not completely certain as to the exact direction of the winds. It describes a cone that extends 45 degrees either side of the direction stated. For example if a forecast called for north quadrant winds, one should expect the winds to be anywhere between NW and NE.
An area of compressed isobars between two or more areas of different pressure such as between a high and a low in close proximity.
Normal surface pressure is 1013.25 millibars. Anything above is considered High Pressure and anything below is considered Low Pressure.
The Gulf of Tehuantepec averages 16 wind events that are of gale intensity or stronger each winter season (Cobb et al., 2003). They occur during the “cool season” which is defined as the period from 1 October through 30 April, peaking during January and February. They develop when a strong high pressure center builds over the eastern US and the Gulf of Mexico. As the high pressure builds over the Gulf of Mexico a strong pressure gradient is concentrated along the NE coast of the Sierra Madre mountains. The gradient is allowed to be released through the Chivela pass, as cold dense air is funneled through the pass into the Gulf of Tehuantepec. As the winds pass over the Gulf of Tehauntepec they veer NE and can extend several hundred kilometers downwind. The pass is 220 kilometers long, 40 kilometers wide and the highest point is only 200 meters above sea level.
