Good morning everyone visiting zoomradar, stormchasers, meteorology students, and professional meteorologists. My name is Brandon brady and I am installing my latest blog on Baroclinic vs Barotropic weather environments. This is my second to the last blog on this subject, essentially the third in the series. Today I am going to write about specific examples of weather systems that are associated with Baroclinic and Barotropic weather systems. The first part of the series covered what Baroclinic and Barotropic is, essentially defining each one. The second part went into the modeling of each weather system with one specific example in Baroclinicity. This installment covers all specific examples of both weather environments. Let’s begin.
I am going to touch on High Pressure Systems and Low Pressure Systems so I want to give you some brief insight on different levels upper and surface levels of each system.
1. UPPER LEVEL HIGHS – (Ridges) -Warm Core Highs or Weak Low Pressure. Thick layers in warm Regions, any maximum in Pressure (height) can be called a High pressure System.
2. UPPER LEVEL LOW – (Troughs) – Cold Core Lows or Weak High Pressure. Thinner Layers in cooler Regions, any minimum in Pressure (height) can be called a Low Pressure System.
3. Important Note – It is possible to have a Surface Low Pressure and a Upper level High Pressure just above it, in the upper troposphere. Also strong cold temps near the surface will likely lead to Low pressure or a trough in the upper parts of the troposphere. Conversely, if you could have an upper level High Pressure System a Warm Core High in the Upper levels and or a Warm Core Low pressure directly below it. This is a classic Tropical Low Pressure setup, such as, a tropical Storm or Hurricane.
I . BAROTROPIC WEATHER SYSTEMS – I know I stated in previous blogs that Barotropic weather conditions usually have no advections, fronts, etc. For the most part this is true, but that doesn’t mean they don’t have different weather systems with them. In this section you will be provided with specific weather systems in the genre.
1. Cold Core Barotropic Lows –
These Low Pressure have cold air throughout their systems, especially at the core. There is no strong differential in temperature within the Low Pressure System, essentially these are weak Low Pressures or in a state of weakening in a dissipation stage. The most Common type of Barotropic Low Pressure is Occlusion Lows. Occlusion Lows have the coldest Air at the center, north of the Polar Front Jetstream.
1b. Cut Off Lows –
The Low Pressure systems are isolated. These Upper level Lows usually occur south of the Polar Front Jetstream. They usually have a weak circulation associated with it and very difficult to identify at he surface. These Barotropic cut off lows are handled poorly by long range and short range computer forecast models.
This is a classic example of a cold core barotropic low pressure system. This is a cut off low pressure in the upper levels that has dug west and southwest of Baja California. This system is cold throughout the entire system. I wouldn’t be surprised if rain/t-storms with small hail was occurring in the highlands of the Baja.
2. Warm Core Barotropic Lows –
These Barotropic Lows are located in the Tropics or occur in Deserts of the world. They have warm air throughout their entire system. The have very low surface pressure, in fact, cyclonic circulation weakens with height and may become high pressure aloft. In essence, Strong Low Pressure at the surface and High Pressure sitting above it or aloft. These Low Pressure Systems are located South of the Polar Front Jet, and are caused by low level heating of air Masses or differential heating of Land/Water Bodies.
A. Thermal or Heat Lows – These Low Pressure Systems occur in the Deserts of the World usually the Hot Deserts of the World. For example, The Desert Southwest of the United States, The Sahara Desert in Northern Africa, The Kalahari and Namib in Southern Africa and the Great Victoria Desert in Australia are prime examples of Hot Deserts where Thermal Lows reside.
B. Tropical Cyclones – These Low Pressure Systems thrive on warm ocean temperatures above 80 degrees Fahrenheit. These Cyclones get fueled by adiabatic energy and differential heating. There are no fronts associated with these systems nor is there any advections of cold or warm air. These awesome systems get fueled by the release of Latent Heat of Condensation. These process is very dynamic as it involves three states of matter: Solid liquid and gas, actually liquid and gas. The energy released in the condensation process is phenomenal, for water to transform from a vapor or gaseous state to a liquid is an astounding 600 calories per gram of 80+ degree water. That’s incredible can you imagine an large amount of ocean basin at 80+ degree water temperature, Awesome. The power that these tropical systems have is unfathomable.
Latent Heat release within the Hurricane continues to feed or “FUEL” the Storm, making a WARM CORE BAROTROPIC SYSTEM.
3. Cold Core Barotropic Highs –
These High Pressure Systems usually occur in the “wake” of a cold front. When I mention “wake” in meteorological terms this refers to after or behind a main feature. Cold Core Barotropic Highs have weak circulation with gaining height, and usually are associated with Polar Air Masses, behind cold fronts associated with Mid-Latitude Cyclones. These features develop in High Latitudes, cover large spatial areas, produce synoptic scale subsidence and have Cold Air throughout their System, once again there are no fronts and weak circulation associated with them. As you can see folks this is a defining characteristic of Barotropic weather systems.