Tropical Cyclone Five-A moving away from the coast of India

A new tropical cyclone over the Arabian Sea is causing havoc to portions of South India tonight. The cyclone has already caused three fishermen to go missing, as well as about 1500 homes in Sri Lanka being damaged. This system means business! Right now, the Joint Typhoon Warning Center is classifying this system as a tropical storm, however the India Meteorological Department is assessing this as a deep depression. This is why 05A has not gained a name yet. However, they continue to insist that this system will become a cyclonic storm thus gaining the name Thane. The JTWC also continues to insist that conditions will only be marginal for development, thus making strengthening difficult for the system. They only expect 05A to reach a peak of about 60mph.

An area of broad low pressure in the Southwest Indian Ocean continues to be stationary and struggle to develop. This system, designated 96S by the JTWC, has not moved in the past 12 hours. With vertical wind shear of about 30 knots impacting the system, mostly from the outflow of Tropical Cyclone 05A, any strengthening will be difficult. However, this system has shown signs of fighting for survival. The first name on the list is Alenga if it were to in fact to strengthen enough into such a storm.

Figure 1: Tropical Cyclone Five-A is shown to the west of India, and 96S is shown to the northeast of Madagascar.

That's all for today!

Matt

Possible late season activity for both basins?

Computer models are continuing to insist that we will have tropical storms in both basins by the end of the month. An area of disturbed weather (Invest 90E) has been designated in the Eastern Pacific and the National Hurricane Center is currently giving this system a low chance (10%) of developing in the next 48 hours. Tropical Storms this late in the season is very rare and there have only been 3 on record to have formed this late in the Eastern Pacific Hurricane Season: an unnamed tropical storm on November 27, 1951, Tropical Storm Sharon on November 27, 1971, and Hurricane Winnie on December 5, 1983. None of these storms affected land, and our potential Eastern Pacific Tropical Storm's track is uncertain.

Figure 1: My graphic on our newly formed Invest 90E.

In the Atlantic, the models are back on board with tropical/subtropical development northeast of the Atlantic. The origins would likely be non-tropical and the system would likely meander for a couple of days. This is similar to how Tropical Storm Sean developed.

So it's extremely possible that we get both Tropical Storm Kenneth (EPAC) and Tropical Storm Tammy (ATL) between now and next week. It's even possible that Kenneth could become a hurricane, if conditions improve for development.

Our first tropical disturbance of the 2011-12 South Pacific Season formed the other day and was extremely large in nature, almost monsoonal. This storm dumped a lot of rainfall on the island of Fiji. The Joint Typhoon Warning Center, at one time, gave this a Medium chance of development. However, the system was just too large, and wind shear was just too strong for this system to actually gain a name. We are in a La Niña event which typically means a more active season for both the South Pacific and the Australian Region. Activity is usually suppressed in the Southwest Indian Ocean during this event.

I'll have more updates as we learn more about our possible developments.

Matt

Sean merges with a front

Sean is now post-tropical as he has merged with a cold front. The National Hurricane Center has written their last advisory on the system. Bermuda did in fact get tropical storm force winds from Sean. Top winds were estimated to be around 45mph on the island. Sean indirectly caused one death in Florida due to rip currents.

Figure 1: Sean as it merged with a front.

There are no other areas to talk about currently, but the computer models are picking up on possible tropical development in the mid-Atlantic in about a week or so. They suspect a non-tropical low may gain some subtropical or tropical characteristics, similar to what happened with Sean. If any non-tropical low were to become subtropical, they name they would gain would be Tammy.

The other basins are quiet!

Matt

Sean has peaked

Our only area of interest in the tropics today is Tropical Storm Sean. Sean has reached his peak as a 65mph tropical storm and should not be able to strengthen to a hurricane due to cooler waters. Bermuda is still under a Tropical Storm Warning due to Sean's wind field being extremely large. The forecast shows that Sean will become extratropical sometime in the next day or two.

Figure 1: Rainbow IR picture of Sean.

Figure 2: Projected Path of Sean

Some of the computer models are showing development in two different places. The GFS (American) Model has been off and on with subtropical development in the mid-Atlantic in about a week or so. Other models, like the NOGAPS and CMC, are forecasting development in the Southwestern Caribbean. These are typical hotspots for November, so I wouldn't completely write off the 2011 Atlantic Hurricane Season just yet.

The Eastern, Central, Western, and Southern Pacific Basins are quiet.

The North and Southwest Indian Ocean basins are quiet.

The Australian Region is quiet as well.

A short post for a boring day!

Matt

Sean almost a hurricane

Tropical Storm Sean has gradually gotten better organized today. Infrared and Visible Imagery show that an eye may be trying to form. This may be a sign that Sean may be close to hurricane strength. Winds are already close to it and only 9mph shy of becoming a Category 1 hurricane. We'll see what the next few days hold.

The projected path for Sean continues the motion to the north with a turn to the northeast sometime tomorrow. During that time, the National Hurricane Center thinks that Sean could reach minimal Category 1 strength but quickly weaken. Due to the large wind field of the system and the proximity to Bermuda, the Bermuda Weather Service has issued a Tropical Storm Warning for the island. If Sean becomes a stronger hurricane than expected, it wouldn't be out of the question that a Hurricane Watch or Warning be issued. However this seems highly unlikely at the moment.

Tropical Cyclone Four-A lost organization today and the Joint Typhoon Warning Center wrote their last advisory on the system.

The Australian Region and South Pacific basins are quiet today and there are no areas of concern.

The Southwest Indian Ocean Cyclone Season starts November 15.

That's all for today.

Matt

Tropical Storm Sean; Rare Mediterranean cyclone; Four-A churning

Tropical Storm Sean is the main topic for the tropics today. Since it's November, the tropics really wind down. Every now and then we'll get a tropical system such as Tropical Storm Sean, the nineteenth tropical cyclone of the 2011 tropical season. The formation of Sean brings us in 6th place for the most active season on record. The origins of Sean can be tracked back from a non-tropical low that moved off the Carolina coastline. After meandering and moving southward, the low acquired subtropical characteristics and become Subtropical Storm Sean. Sean acquired tropical characteristics and became fully tropical this afternoon.

Sean is currently meandering to the southwest of Bermuda. There may be a slow drift to the west or west-northwest, but Sean (as of the 7pm EST advisory) is currently stationary. Sean is not expected to stay there for long. A trough that brought severe weather and tornadoes to Oklahoma yesterday, is expected to come a long and pick Sean up and scoot him very quickly out to sea. When the trough does come and pick Sean up, the island of Bermuda may be directly impacted. As a result, the National Weather Service in Bermuda has issued a Tropical Storm Watch for the island.

A hybrid low pressure system was dubbed 99L on the Navy Site for Tropical Cyclones yesterday in the Mediterranean Sea. Named "Rolf" by the German Weather Service, this system had acquired tropical characteristics. This marked the first time in history a tropical system had formed and been named in the sea. Other such happenings have occurred such as in 1995 where a hurricane like storm formed between Greece and Italy. It is highly likely that this basin along with other unusual formation spots (i.e. the South Atlantic Ocean) will see an increased number of activity of tropical systems.

Another tropical cyclone has formed in the Arabian Sea. November is a secondary peak of the North Indian Ocean and it has made itself known over the past week. This is the second system to form in the Arabian Sea this month. Tropical Cyclone Four-A is currently drifting northward, however a westerly and southwesterly component is expected.

Until the next post,

See ya!

Matt