Katrina modestly intensifying

Katrina continues to intensify at a modest pace, and if present trends continue will hit Florida near Fort Lauderdale tonight as a minimal Category 1 hurricane with 75 - 80 mph winds. The northwest side of the storm continues to suffer from dry air intrusions, and the primary intense thunderstorms and strongest winds are on the south side. Thus, the usual rule about the right front quadrant (north side) of the storm being the most dangerous is not neccesarily the case with Katrina. The highest storm surge will still be to the north of where the center comes ashore, but wind damage may be equally distributed on both sides of the storm.

The Miami radar loop continues to show an increase in low-level banding, and an eye-like feature trying to form. Upper level outflow is improving and slowing expanding.

As I discussed in the previous blog entry, the major threat to South Florida from Katrina is freshwater flooding from her rains. Rainfall amounts of 6 - 10 inches are expected from this slow-moving storm. For comparison, Hurricane Irene of 1999, which hit South Florida as a Category 1 hurricane, dumped 10 - 20 inches of rain. Damage from Irene was over $800 million in Florida. Damage from Katrina will probably be much lower, in the $30 - $100 million range, since Katrina's rainfall will be half of what Irene's was.

Katrina's path once she makes landfall and crosses over the Florida Peninsula is highly uncertain, and the various computer models project a landfall anywhere between Pensacola (GFDL model) and Tampa (UKMET model). If her path in the Gulf allows her to remain over water for at least a day, Katrina could easily strengthen to a Category 1 or 2 hurricane before making her second landfall in the Florida Panhandle. If Katrina tracks right up the west coast of Florida, she would likely remain a tropical storm due to the interference of land.

What's that behind Katrina?
A large area of disturbed weather even bigger than Katrina lies to her east, just north of Hispanolia. This disturbance lies in an area of high wind shear of 25 - 35 knots, and is not a threat to develop into a tropical depression in the next few days.

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

turtlehurricane (Weston, Broward County)

sngalla (Fort Lauderdale)

MrJ76 (Okeechobee)

Zeenster (Cape Coral, SW Florida)

evolution (Charlotte Harbor, SW Florida)

Dr. Jeff Masters