Katrina a Category 1, still incredibly destructive

Katrina continues to move northwards and accelerate through Mississippi. Katrina is now a Category 1 hurricane with 95 mph winds, but still causing massive storm surge flooding, tornadoes, wind damage, and rain water flooding. Numerous tornadoes continue to be spawned out of Katrina's spiral bands, and the National Weather Service is also issuing tornado warnings for "destructive winds near 110 mph in the eyewall and inner rain bands of Hurricane Katrina." This is a new warning technique that is used to trigger the emergency response needed for a tornado-like threat. There are not actually tornadoes occurring for these tornado warnings.

Storm surge and rainfall
According to NHC and NWS sources, peak storm surge values were 22 feet in Bay Saint Louis, MS, and 20 feet along many areas of eastern Louisiana. Southwest Lake Pontchartrain received a 10-12 foot storm surge. Mobile Bay received a 9-12 foot storm surge, and Biloxi at least 10 feet. Exact surge heights have been difficult to measure since most of the tide gauges were destroyed by the hurricane. Peak rainfall from Katrina was over the central coast of Mississippi, where radar estimated 8-12 inches fell.

Six weather radars fail
As of 11am EDT, communications with six National Weather Service radar sites failed. No radar information is available from the New Orleans, Lake Charles, and Fort Polk stations in Louisiana, Jackson and Columbus AFB stations in Mississippi, and the Red Bay station in the Florida Panhandle. The NWS offices are still able to send out warnings and forecasts.

What's behind Katrina?
Tropical Depression 13 died early this morning, the victim of wind shear. The remains of TD 13, located about 700 miles east-northeast of the Lesser Antilles, do have the potential to re-develop into a depression later in the week as they move northwest over the open ocean.

A new tropical wave near 10N 35W is large, well-organized, and has developed a circulation. I expect this wave will become a tropical depression in the next day or two as it moves west-northwest towards the Leeward Islands.

Dr. Jeff Masters