A very uncommon event occurred just east of Spain in the Mediterranean sea early this week. An area of low pressure has acquired tropical characteristics. This rarely occurs.
Meteorologists posted remarks about the system in the Mediterranean Sea:
H. REMARKS…DT= 2.5 BASED ON .5 BANDING ON LOG10 SPIRAL. PT=2.5. MET=2.0. FT IS BASED ON DT. DEEP CONVECTION HAS PERSISTED LONG ENOUGH AROUND THE LOW LEVEL CENTER FOR A TROPICAL CLASSIFICATION.
In the Atlantic, tropical storm Sean became our 18th named storm of the 2011 Atlantic hurricane season. The life of this system is rather interesting. Remember the heavy snow across the state of Colorado last week? The same system that caused the heavy snow across Colorado is now tropical storm Sean. It pushed into the United States as a mid-latitude cyclone and emerged off the southeast coast of the United States. It has been mainly stationary across this area for the past few days, and it began to acquire tropical characteristics and started to become a warm-core low. The National Hurricane Center (NHC) classified this as subtropical storm Sean on November 8, 2011. As of today, Sean has acquired all the elements to become fully tropical. As of now, Sean is 455 miles (735 Kilometers) southwest of Bermuda with sustain winds of 65 mph and a barometric pressure of 991 mb. A tropical storm warning is in effect for Bermuda. Bermuda can expect rough surf as this system will be quickly picked up by a trough as it accelerates to the northeast. This is the same trough, or extended area of low pressure, that caused the tornadoes across Texas, Oklahoma, and Louisiana on November 7-8, 2011.
Convection is increasing around the center of the storm, and appears to be organizing fairly well. I would give this system a 70% chance to become a hurricane. The NHC latest forecast agrees with this idea, as the system continues to show an eyewall forming around the center of the storm (image below). The pressure reading and increased convection around the storm makes me think this system has a chance to become a minimum hurricane before it pushes west of Bermuda. Rainfall rates will be rather low with this storm across Bermuda, and the NHC is only forecasting one to three inches. The center of Sean will be far away from Bermuda, so direct impacts are not expected with this storm. Sean will likely survive another two days before it is picked up and absorbed by the trough currently across the eastern United States. The Atlantic hurricane season officially ends on November 30, 2011.
Bottom line: A rare “medicane” – or storm with tropical characteristics – formed in the Mediterranean Sea and is producing strong winds and rain across southeast France. Medicanes in the Mediterranean are uncommon, but they have formed in the past. Tropical storm Sean could become a hurricane later tonight or tomorrow morning, but it should quickly drift to the northeast. Bermuda will likely see the outer bands of this system, but a direct hit is highly unlikely. For more information regarding Sean, please visit the National Hurricane Center.
Matt Daniel is Meteorologist for WBRC in Birmingham, Alabama. A self-described "big weather and music geek," Matt has a passion for helping to keep people safe when severe weather strikes and says if you don't have a NOAA Weather Radio ... you should get one.