17 September 2010

Igor, Julia, and Karl still all hurricanes, Karl becomes 5th major hurricane...

Igor is still holding onto major hurricane status (it's been 5 days now) with winds of 105kts and a 945mb central pressure.  It's an extremely large storm, with tropical storm force winds extending 250 miles from the center on the front-left quadrant, and hurricane-force winds extending 90 miles out in the same quadrant.  It continues to slowly make it way toward Bermuda, and a closest approach is still forecast to take place Sunday night into Monday morning... Bermuda now has a hurricane watch in effect. You can monitor weather conditions at Bermuda here: http://www.ndbc.noaa.gov/show_plot.php?station=bepb6&meas=wdpr&uom=E&time_diff=-4&time_label=EDT and there's a radar loop available here: http://einstein.atmos.colostate.edu/~mcnoldy/tropics/igor10/Igor_19-20Sep10.gif

Julia has been slow to weaken, but is now estimated to be 75kts and 981mb.  It's been moving quite a bit further west than expected, and the relatively tiny storm is only about 800 miles due east of Igor and it's huge circulation.  The forecast is for continued weakening and a turn to the NW then recurving by 55W.

2010 is shaping up to be quite a historic season... during the overnight hours, Karl rapidly intensified to 105kts, making it the fifth major hurricane of the season, and the furthest south a major hurricane has ever existed in the Gulf of Mexico.  It also made a turn to the WSW, steering it directly into the city of Vera Cruz (Mexico's oldest and largest port with a population of ~ 700,000 and 490 years of history).  The city has never experienced a major hurricane, so this will probably be quite destructive and worthy of retiring the name Karl (which has been in rotation since the beginning of naming hurricanes)!  Only 3 other "K" storms have been retired: Klaus '90, Keith '00, and Katrina '05.  As I type this message, Karl is making landfall with an intensity of 105kts and a central pressure of 967mb.  Not only will the powerful winds be destructive, but flooding rains (up to 15" forecast) and a significant 12-15' storm surge.  There is a radar loop of Karl here: http://einstein.atmos.colostate.edu/~mcnoldy/tropics/karl10/Karl_16-17Sep10.gif showing an eyewall replacement cycle, subsequent eyewall contraction, and landfall.

An educational tidbit can be gathered from Igor and Karl: they are both 105kt storms (as verified by aircraft) yet Igor is about 4 times larger than Karl.  With tropical cyclones, it's important to realize that size and intensity are not related.  Another contrast is Katrina '05 and Andrew '92... at landfall, Andrew was quite a bit stronger than Katrina (Cat5 vs Cat3), but was a fraction of the size.  I cannot resist the opportunity to use a memorable quote from Yoda in Star Wars (Empire Strikes Back): "
Size matters not. Look at me. Judge me by my size, do you? And well you should not, for my ally is the Force, and a powerful ally it is."

The area I described yesterday with a surge of southwesterlies continues to look interesting, and more global models are beginning to pick up on possible tropical cyclone formation from it.  This area is at about 10-15N and 35-40W.

There's also a potent easterly wave that recently exited the African coast and is now located near the Cape Verde islands.  This will be watched closely in the coming days for development as well.  The next names on the list are Lisa and Matthew.

Please visit my tropical Atlantic headquarters.

No comments:

Post a Comment