Bill weakens, waves dont as storm heads to Nova Scotia
August 21, 2009
The latest guidance from the NHC shows Bill has weakened slightly to a strong Cat-2 hurricane after encountering some moderate shear. There is a good chance the system will reorganize as shear diminishes and hits warmer waters Friday. However the forecast shows Bill slowing to a weak Cat-2/strong Cat-1 as Saturday progresses.
The forecast models are in good agreement on the track, taking Bill due North Friday night, before making a NE turn into Sunday.
The greatest threat to the US will be in the form of coastal erosion as high seas will affect the eastern seaboard from Florida to Maine. The highest expected seas will occur near Cape Cod, which could experience 20′ waves. The threat from rip currents is moderate and expected to increase as Bill travels North.
We will continue to monitor the system and provide updates as necessary.
Bill Makes the Turn as a Strong Cat-3
August 20, 2009
Hurricane Bill is forecasted to track NW over the next 24 hours (early Friday morning), with a slight northward turn in the next 48 hours while maintaining sustained winds in excess of 111 mph (Cat-3).
The current National Hurricane Center’s 3-day forecast has Bill approximately 360 miles due-East of Delaware by early Sunday morning. However the system is forecasted to remain a category 3 storm through until Sunday where it will weaken due to cooler waters and increased shear velocity.
The forecast models are showing disagreement on where Bill will track in the coming days. Though most agree that Cape Cod will experience weak-to-tropical storm force (35+ mph) sustained winds over the weekend. Significant wave activity is also expected all along the Eastern Seaboard due to Bill’s immense size and strength.
The image below shows the AOML satellite-derived wind speeds as of 930 EST this morning. The HU strength wind radius has shrunk slightly, but should increase again today as the surrounding air warms.
AOML 8/20/09 1330 UTC Satellite Derived Winds
We will continue to monitor the situation and provide updates as necessary.
Claudette lands softly; Bill still Looming
August 17, 2009
Tropical Storm Claudette made landfall overnight with little affect on the Florida panhandle and Alabama coast. Sustained winds of 48 mph were recorded, with slightly higher gusts. The National Weather Service has not reported any major damage or flooding.
Meanwhile, Hurricane Bill continues to spin in the Atlantic just east of the Antilles. The NHC is forecasting winds to reach 110 knots (SS-3) by Thursday night. The forecast models have shifted the expected track slightly W/NW from yesterday’s runs.
Bill will be closely observed over the next few days to monitor forecast track and intensification.
Three’s Company; Ana, Bill, and Claudette
August 16, 2009
After a slow start, the 2009 Atlantic hurricane season has begun, and in grand fashion. On Saturday the 15th, the first and second tropical systems of the season, Ana and Bill, developed. By early Sunday morning, Claudette had strengthened from a depression to a tropical storm, and is making landfall along the Florida panhandle and Alabama coast.
The main threat from Claudette will be inland flooding, as 3 – 5 inches of precipitation are forecast with areas of heavier precip possible. Sustained winds around 6o mph are expected, with higher gusts also present.
Ana is weakening due to a strong influence from dry Saharan air. Organization is fading quickly and forecasters do not expect the storm to redevelop at this time.
Last, but far from least, is Tropical Storm Bill. Bill is likely to strengthen to a hurricane overnight, and reach “intense” status by Friday afternoon. The models are in good agreement over the next 3 days, but then diverge. A developing low pressure system over the US is expected to develop, and may steer Bill away from land. Model plot from Colorado State below shows the predicted tracks. These are used for guidance only and can quickly change with each run.
Atlantic Forecast Accuracy
July 2, 2009
Status Update
It’s been quiet thus far after 1 month in the Atlantic. Maybe due to the onset of El Nino? The latest from the Climate Prediction Center indicates that we are moving that direction.
The latest report from researcher Dr. Amato Evan indicates that the Saharan Air Layer (SAL) isn’t to blame. The predicted dust levels over the African Sahel region from his experimental methods are below average due to plentiful precipitation and subsequent vegetation. Values predicted are similar to those observed last year. Record lows of dust were reported in the extemely active 2005 Season.
Forecast Accuracy
Now that the major forecasts are out, the next question is “Who should we listen to”? Each forecasting group has experienced varied success in recent years. The image below indicates the actual number of observed named storms, and the May/June predictions from Klotzbach-Gray, Tropical Storm Risk, and NOAA.
These forecasts are indicative of the pure number of tropical cyclone formations, and are not indicative of landfall counts.
Forecasted and Observed Atlantic Named Storms from Klotzbach-Gray, Tropical Storm Risk, and NOAA
UK Met Office Issues 2009 North Atlantic Forecast
June 18, 2009
The UK Met Office has released their 2009 July–November North Atlantic Tropical Storm Forecast, calling for 3 – 8 storms, with 6 being the most likely count. The M.O. was highly accurate last year, predicting between 10 and 20 named storms, with 15 being most likely.
For the first time, they have also released an ACE forecast (Accumulated Cyclone Energy) for the North Atlantic. ACE values are predicted to be between 40 and 80, with the most likely value of 60. The long term ACE average is 131.
You can find a full description of the 2009 forecast values, past forecast verification, and documented methodology at:
http://www.metoffice.gov.uk/weather/tropicalcyclone/northatlantic.html
The Met Office is U.K.’s equivalent of NOAA; providing weather and climate information to the public and private sector.
- Zack Schmiesing – Towers Perrin
Welcome, and a look back
May 29, 2009
With the effects of the 2008 Atlantic hurricane season still fresh on many minds, the 2009 season is already upon us.
Last year brought the Atlantic Basin 16 named storms, eight of which reached hurricane status and five that were classified as major hurricanes. Property Claim Services (PCS) estimated personal, commercial and auto insured losses due to tropical activity at $14.5 billion, driven notably by Hurricane Ike, which made landfall in Galveston, Texas, early in the morning on September 13.
The damage in Texas and Louisiana, coupled with unusual damaging winds in the Midwest associated with Ike’s remnants, resulted in an estimated $11.7 billion in insured losses. Total loss estimates of the costliest U.S. hurricanes on record place Ike at number 4 of all time.
To help you better understand the risk to tropical activity and provide real-time information and educational insight, Towers Perrin has expanded our hurricane Web site for the 2009 season. Towers Perrin’s Hurricane Center gives you one site to gather vital storm information to help make effective decisions as the systems approach. Additionally, we provide links to expert analysis and opinion on developing systems to enhance your knowledge of hurricane science.
We welcome your comments and questions!
- Zack Schmiesing, Towers Perrin
