Mobile, Ala. (WKRG)- This is not what we want to hear after the events 2020 has already brought us. We are expecting an above average active tropical season thus upcoming Summer and Fall. Colorado State released their outlook and is forecasting 16 named storms, 8 named Hurricanes and 4 Major Hurricanes.
News 5 Meteorologist Colleen Peterson is breaking down 4 different parameters that goes into forecasting tropical cyclogenesis in the simplest way possible!
Lets start in the Indian Ocean. This is where the tropical waves originate. When we see hot sea surface temperatures it can contribute to creating the atmosphere above it unstable. That is the first parameter as we are expecting sea surface temperatures of 30 degrees Celsius or higher.
The second parameter is seeing rising motion and upper level divergence over the Indian ocean!
This is shown on the 200 mb velocity potential anomaly forecast model done by Tropical Tidbits. You can see the arrows moving away from the center point indicating divergence.
The third parameter is what type of ENSO period we are in.
With El Nino it helps inhibit the formation of tropical cyclones with a westerly flow that increases the wind shear. Tropical cyclone’s do not like wind shear which is the change of wind direction and strength with height. We are forecasting to stay in a neutral period and will not have that factor helping increase the wind shear.
The fourth parameter might be a little confusing but it is called down-welling of easterlies into the lower stratosphere.
Some models are indicating an easterly flow over the Indian Ocean that could result in multiple tropical waves off the coast of Africa.
We are also forecasting a wetter and stronger African monsoon this upcoming season as well.
From all of those combined we are forecasting a western extent of the easterly winds off the coast of Africa over above average Sea surface temperatures of the Atlantic where hurricanes and tropical cyclones are favorable to develop.
Those tropical waves off the coast of Africa end up in the Atlantic and that’s when things starts brewing and a tropical cyclone can be formed.
The ingredients are there to favor an active tropical season this upcoming summer and fall. Make sure to stay updated with the First Alert Storm Team. Meteorologist Colleen Peterson WKRG News 5.