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PAOS Weather Discussion

Hurricane Katrina

Katrina’s Landfalls

• Florida– Landfall at 6:30PM EDT Thursday August 25th on the Miami /

Broward County line– Maximum winds 90 mph

• Louisiana– Landfall at 6:10AM CDT Monday August 29th near Buras, LA– Maximum winds 140 mph

• Louisiana / Mississippi– Landfall at 10AM CDT Monday August 29th near LA/MS

border– Maximum winds 125 mph

Florida• TD 12 - 5PM August 23rd• Tropical Storm Katrina - 11AM August 24th

– Moving over warm SSTs (31 deg C)– Weak wind shear– Some dry air

• Hurricane Katrina - 5PM August 25th– Cat 1, 75 mph winds– Landfall north of Miami at 630PM August 25th– Tracks further south than forecast– Only 7h over S. FL (mostly over the Everglades)– Emerges into Gulf of Mexico at 130AM August 26th

Florida• Images

– IR Satellite Loop– Visible Satellite

Loop– Radar loop– Surface Observations

• Impacts– 11 people killed– 1.45 million households without power

• Expect 90% of power to be restored by Tuesday

– Highway overpass collapsed in Miami

Gulf of Mexico• Crossed into Gulf of Mexico at 130AM August

26th as a Category 1 hurricane (75 mph, 984 mb)• Forecast track not well handled initially

– Loop of NHC forecasts

– Forecasts until 11AM Friday had Katrina making landfall in the Florida panhandle

– Forecasts over next 12 h shifted the forecast track to near New Orleans

– Little changes in forecast track after this

• Friday 11:30AM– Category 2 hurricane (98 mph, 971 mb)

Gulf of Mexico• Saturday 5AM

– Category 3 hurricane (115 mph, 971 mb)– Katrina was located in an environment that “cannot get

much more conducive for strengthening” - NHC Forecast Discussion

– Warm SST (near 90F)– Weak wind shear

• Saturday 11AM– NHC discussion mentions possibility of Katrina

becoming a Cat 5 hurricane

• Sunday 2AM– Category 4 hurricane (144 mph, 935 mb)

Gulf of Mexico• Sunday 8AM

– Category 5 hurricane (161 mph, 908 mb)– Intensity difficult to forecast due to eyewall replacement cycles

• Sunday 11AM– Maximum winds 178 mph

• Sunday 5PM– Central pressure drops to 902 mb – 4th lowest pressure observed in the Atlantic Basin– Hurricane Gilbert, 1935 Labor Day hurricane, and hurricane Allen

• Monday 5AM– Category 4 hurricane (150 mph, 915 mb)– Dry air entrained on west side– Erodes eyewall on south and southwest sides of hurricane

Gulf of Mexico• Monday 6:10AM CDT

– Landfall near Buras, LA– Maximum winds 140 mph

• Monday 10AM CDT– Landfall near LA/MS border– Maximum winds 125 mph

• Images– IR Satellite Image– Visible Satellite Image– Mobile, AL radar– Surface observations

New Orleans

Gulf PortBiloxi

Mobile

Impacts• Mobile, AL

– Peak winds 80 mph– Downtown Mobile under several feet of water– Dusk to dawn curfew in effect for Mobile– Oil rig broke free from mooring and crashed into US Hwy 98

bridge

• Biloxi, MS / Gulfport, MS– 25+ foot storm surge– Coastal flooding up to 6 miles inland– 54 people killed in MS– I-10 impassable between Gulfport and Biloxi– Casinos along coast were destroyed (some moved 500 feet inland)

• Loss of $500k / day in tax revenues to MS

Impacts• New Orleans, LA

– Levee on Lake Pontchartrain has been breeched (200 feet long)

– Water levels are still rising in the city– ~80% of city is flooded with water up to 20 feet deep– Both airports are underwater– NWS reported total structural failure in New Orleans– Roof of Superdome damaged– Bridge on I-10 over lake

was destroyed– Oil tanker grounded and

leaking oil

Impacts• New Orleans, LA

– 50” Water main severed– Numerous gas leaks in the city– Repairs to water and electric could take 3-4 weeks

– “City of New Orleans is in a state of devastation” - Mayor Ray Nagin

– We expect “a significant amount of loss of life in the city” Mayor Ray Nagin

– New Orleans evacuees “should stay away for at least a week to avoid a wilderness without power or drinking water that will be infested with poisonous snakes and fire ants” - CNN

Impacts• General

– 1.7 million households without power– Tens of thousands of people may be displaced

for months– Early damage estimates of $10 to $25 billion– Disruption of oil production / supply

• Price of oil rose to $70/barrel on Monday