Gustav heading for Louisiana, Hanna heading for the Bahamas, TD9 ready to form...

Gustav underwent rapid intensification Friday evening through Saturday afternoon.  In 24 hours ending 00Z Sunday, the central pressure fell 34mb, and in 23mb in 12 hours.  It strengthened from a 60kt tropical storm to a 130kt CAT4 hurricane in 27 hours.  Unfortunately, it accomplished this while heading for, and passing over, western Cuba, causing extensive damage.

Since exiting Cuba, it has had a hard time reorganizing, though still a 100kt CAT3 hurricane.  It is heading NW at 15kts, toward the central LA coast, and landfall is expected Monday morning as a major hurricane near Marsh Island.  However, there is still uncertainty, and a hurricane warning covers the LA and MS coasts.  As far as Katrina-ravaged New Orleans goes, so far about 15,000 people have evacuated, and evacuation orders are still in place for the city.  Lake Pontchartrain can expect a 15-20 foot storm surge on Labor Day, which will certainly re-test the levee system protecting the below-sea-level city.  Other parishes in coastal LA also have mandatory evacuation orders.  As of this writing, over 3/4 of oil production in the Gulf has ceased, as platforms and rigs are evacuated and shut down for the duration of the storm.

The latest intensity is 100kts and 962mb.  It is forecast the strengthen a bit more again, perhaps to CAT4 status, before landfall.  It's currently looking ragged on satellite, lacking a clear eye, showing signs of southerly vertical shear, and has dry air wrapping around west and south of it.  The main factor in its favor is deep, warm water under it.

You will be able to track its progress toward the coast via radar loops that I'm generating... a long and short range from New Orleans, and a short-range from Lake Charles (all are available at http://einstein.atmos.colostate.edu/~mcnoldy/tropics/atlantic/).

Hanna, still maintaining modest tropical storm intensity, is strongly sheared.  Latest intensity is 45kts and 999mb, and heading WNW at 9kts.  It's now a couple degrees north of the Turk islands, and it is expected to track slowly westward toward the Bahamas, then NW toward the southeast US coast as a hurricane.  Landfall could be sometime next weekend... however, the steering environment is incredibly complicated, and Hanna will just have to be watched for the next few days to figure out where it's going!

The easterly wave I mentioned 2 and 3 days ago near the Cape Verdes has gotten better organized and is now located near 16N 35W.  Development of this wave should be slow as it heads W at 12kts.  The next name on the list is Ike.

Please visit my tropical Atlantic headquarters.

Gustav exits Jamaica, Hanna gaining strength also...

First of all, today marks the 3-year anniversary of the final, historic, and infamous landfall of Hurricane Katrina.  Katrina was a Category 3 hurricane when it came ashore near the LA/MS border.  It was responsible for 1833 deaths, and $81 billion in damage.  Though not in the running for the deadliest landfall, it did set the record for the costliest landfall, and costliest natural disaster for that matter, in US history.

Another bit of history to point out as we look ahead to the holiday weekend is the infamous Labor Day Hurricane of 1935.  This storm mostly affected the Florida Keys, and was the most intense (by pressure) US landfall on record... Camille was #2, Katrina was #3, and Andrew was #4.  It was responsible for over 400 deaths and it basically obliterated Islamorada and other towns/keys in extreme southwest Florida.  Fortunately, residential air conditioning wasn't affordable or practical yet and Florida was barely populated compared to today (during the 1950's, the state's population grew by 79%, largely because of A/C!).

Now back to 2008.  Gustav has completed its trek over Jamaica, but has already caused at least 59 deaths across Haiti, Dominican Republic, Jamaica, and Cuba.  It is now over open, deep, warm water and poised to intensify to a powerful hurricane as it heads WNW toward western Cuba, then into the Gulf of Mexico.  As of 15Z today, the intensity is 55kts and 988mb and is located 165 miles from Grand Cayman.  It has sped up a little and is now moving WNW at 7kts (has been 3-4kts lately).  All conditions and current appearance suggest rapid intensification is primed to take place.  The latest satellite images indicate that an eyewall is forming already.
http://rammb.cira.colostate.edu/ramsdis/online/latest_image_640.asp?product=tropical_ge_1km_center_relative_vis_floater

So of course, the question is what about landfall?  The western tip of Cuba is the next target probably on Saturday evening as a strong hurricane.  Then the US gulf coast is next, probably Tuesday morning as a very strong and dangerous hurricane.  The current NHC forecast track is centered on the middle LA coast, but anywhere from Corpus Cristi, Houston, New Orleans, Panama City is within the 5-day average track error cone.  Coastal residents within this range should at least begin basic preparations.
http://www.nhc.noaa.gov/storm_graphics/AT07/refresh/AL0708W5_NL+gif/

Hanna is still a tropical storm as well, and like Gustav, is on an intensification trend.  TS Hanna is moving WNW at 10kts and intensity is estimated at 45kts and 1000mb.  It is forecast to continue strengthening, and slowing as it heads WNW... then by the end of the weekend, start turning SW toward the Bahamas.  A long-range model run, shown here, forecasts Hanna to then turn westward, enter the Gulf, and make landfall on LA late next week as a strong hurricane. This plot is valid Friday evening (Sept 5):  http://www.ecmwf.int/products/forecasts/d/getchart/catalog/products/forecasts/medium/deterministic/msl_uv850_z500!Wind 850 and mslp!192!North America!pop!od!oper!public_plots!2008082900!!chart.gif

Elsewhere, the easterly wave that exited the African coast yesterday is now just east of the Cape Verdes and still looks impressive on satellite.  Central pressure of the Low associated with the wave is estimated at 1007mb.  This will likely be the next named storm in a couple days: Ike.

Please visit my tropical Atlantic headquarters.

Gustav heading for Jamaica, Hanna forms...

After crawling across Haiti's southwestern peninsula and almost losing tropical storm status (it weakened to 40kts and 999mb yesterday), Gustav is now back over water, but made a remarkable turn in the last 12 hours or so.  Rather than the expected westward track which would have put it along the southern edge of Cuba, it turned southwest and is now east of Jamaica and should end up passing over or SOUTH of Jamaica!  From that point, the previous forecast track remains unchanged: clip the extreme western tip of Cuba (or miss it by a little), then enter the central Gulf, then head NW toward Louisiana.  The official forecast, which agrees with many models, is for a major landfall on Labor Day in/near Louisiana.

As of 15Z, Gustav was located on the eastern tip of Jamaica, with an intensity of 60kts and 983mb... nearly a hurricane again.  It appears to be forming another eye, but the mountains of Jamaica could disrupt that later today.

The HWRF forecast is shown at (surface winds and sea level pressure):
http://einstein.atmos.colostate.edu/~mcnoldy/tmp/gustav/gustav_wind_n.gif
It is forecasting an extremely intense hurricane in the Gulf and at US landfall... reaching it's peak intensity of 894mb and 137kts on Sunday evening.  If this verifies, it could rival the infamous Labor Day Hurricane of 1935.  As usual, do not focus on the exact track... the 3-5 day range has too many uncertainties, but should be used as a guideline for preparedness.  Certainly anyone in coastal LA, MS, AL should at least be preparing for this.

The disturbance that was near 20N 57W yesterday was upgraded to TD8 early this morning, then TS Hanna later this morning.  Latest intensity is 35kts and 1002mb and it's located near 20N 59W.  it is forecast to gradually intensify to hurricane status and head westward toward the US east coast in a week or so.  At its somewhat far north location, it would be easy for it get recurved by a mid-latitude trough though.

And, a new easterly wave has exited Africa (near 18W) and is already quite impressive.  It will be watched for further development.  The next name on the list is Ike.

Please visit my tropical Atlantic headquarters.