Katrina batters Miami, and is back to hurricane status

Katrina is a hurricane again, after spending just seven hours over land, and briefly (for a four hour stretch) weakening to a 70 mph tropical storm. The unexpected southwestward path taken by Katrina (but hinted at for a long time by the GFDL model) put Miami in the bullseye for Katrina's strongest winds and heaviest rains. The eye passed directly over the National Hurricane Center and the Miami radar site, and Doppler Radar estimates of rainfall amounts show over ten inches of rain in a narrow band extending over the Hurricane Center. Some modest wind and flooding damage was reported by the media, consistent with typical Category 1 hurricane conditions. Four deaths, three from falling trees have been reported so far. Overall, Miami is extremely lucky--had Katrina had an additional 12 - 24 hours over water, she may have some ashore as a Category 3 hurricane.

Katrina has those 12 - 24 hours now, and more. The Miami radar loop continues to a well-organized storm, with a plainly visible eye. Upper level outflow is improving and slowing expanding. Katrina is in an almost ideal environment for intensification--31 to 32C waters, light shear, and no dry air. Katrina will likely be a Category 3 hurricane by Saturday night, and possibly a Category 4.

Although Katrina is currently moving just south of due west, the computer track models unanimously agree that a trough moving across the central U.S. this weekend will "pick up" Katrina and force it on a northward path towards the Florida Panhandle. These model predictions are high-confidence predictions, as the upper air environment around the hurricane is well-characterized thanks to the NOAA jet dropsonde mission flown last night. The NOAA jet is scheduled to fly another mission tonight. While New Orleans centainly needs to keep a wary eye on Katrina, it seems that the Florida Panhandle has its usual hurricane magnet in place, and the same piece of coast punished by Ivan and Dennis is destined for another strike by a major hurricane.

What's behind Katrina?
A large area of disturbed weather north of Hispanolia has diminished since yesterday. This disturbance lies in an area of high wind shear of 20 - 25 knots, and is not a threat to develop into a tropical depression in the next few days. The tropical wave spinning 900 miles east of the Leeward Islands is still experiencing wind shear, but still has the potential to develop into a tropical depression this weekend.

Katrina blogs
For observations of what's happening now in Southwest Florida, we have several bloggers writing today:

labsr4me (Naples, SW Florida)

Zeenster (Cape Coral, SW Florida)

evolution (Charlotte Harbor, SW Florida)

Dr. Jeff Masters