With a Bachelors Degree in Environmental Sciences (2009), began tracking tropical storms in 2002 and is now a private forecaster.
By: Cavin Rawlins , 10:39 AM GMT on August 15, 2009
Tropical Storm Ana (left), while Invest 90L (right)
Tropical Storm Ana has formed in the Atlantic, and it is understood that this is rather unexpected since 24 hrs ago it was a remnant low. The first named storm of the season is located near 14.6N 46.8W or 1630 KM east of the Leeward Islands. Estimated surface winds are near 40 mph with a minimum central pressure of 1005 mb. The satellite presentation of this small tropical storm greatly improved during the day on Friday and this was confirmed by a NOAA hurricane hunter plane, which found a well-define circulation and tropical depression winds. This system was re-designated around 12:30am EDT this morning. Currently the system is moving into much warmer waters and shear is 10 knots above the disturbance, unlike what nearly killed it on Thursday. Shear also remains favourable but not ideal and there is the issue of dry air ahead of the disturbance, but some further strengthening remains possible.
The storm is moving to the west but slightly south thereof. The storm will continue west but then turn more west northwest over the upcoming days under the influence of a high-pressure ridge. This system was expected to be a fish storm, now its heading right for the islands and Florida. Tropical Storm Ana should reach the islands in about 2 days then the Greater Antilles by 3 days and the Bahamas by 5 days. According to how close Tropical Storm Ana comes, tropical storm conditions are expected for the Leeward Islands, that is, heavy rains and gusty winds, then will likely spread to Puerto Rico 12 hrs later.
That’s just system number 1. Behind 90L is a more troubling system. Tropical Invest 90L is on the verge of becoming Tropical Depression 3 then Tropical Storm Bill later this weekend. Satellite imagery showed an organizing system with clusters of deep convection wrapping around the center of circulation. Dvorak estimates have climbed to 2.0, which is about 35 mph, which indicate a depression has form or is forming. QuikSCAT also revealed a very define circulation with alteast 30 knot winds. It is likely if this continues, we will have a new depression in the Atlantic today.
Invest 90L is moving west, just as Ana is doing but then will eventually curve more west northwest. In about 72 hrs or 3 days, the models are thinking 90L will be strong enough to feel more of weakness in the ridge and be pull north. The turn northwest is rather sudden on the 06Z runs and that’s why the official track remains south of the global models. This official track brings 90L over Anguilla in approximately 5 days as a hurricane. If 90L continues to track west, the forecast tracks will also shift just like the case with Tropical Storm Ana.
Official Guidance in black
I encourage all in the islands, Bahamas and Florida to monitor the progress of both Ana and 90L. Review your hurricane plan today and get your needed supplies. Those in the islands know it only takes a tropical wave to cause major flooding problems. In addition, listen to what your local mets are saying because it likely watches may go up today or on Sunday.
Comments will take a few seconds to appear.