13 June 2006

Alberto makes landfall...

At around 16Z today, Alberto came ashore near Dekle Beach, FL as a 45kt tropical storm.  The MSLP was 996mb -- coastal locations to the east of the landfall point are experiencing 5-7' storm surges due to the shape and bathymetry of this portion of Florida (very easy to get big surges).
You can view a radar loop of the entire approach and landfall at
http://einstein.atmos.colostate.edu/~mcnoldy/tropics/alberto06/Alberto_12-13Jun06.gif
Of note is the burst of deep convection near the circulation center as it comes inland, indicating enhanced frictional inflow.  This is a fairly common, though ephemeral, last gasp of a tropical cyclone.

So far, 4 tornadoes have been reported in association with Alberto, and that threat remains high today in northern FL and eastern GA and SC.  The other significant threat is flash flooding.  It is forecast to zip off to the northeast as it merges with a mid-latitude trough, losing tropical characteristics as it does so.

Elsewhere, an easterly wave that exited the African coast on June 7 is now located near the Windward Islands.  It's been moving west at 15kts and still disorganized, but will be watched!  There is also a wave exiting Africa today, which had its root in the Ethiopian Highlands back on June 7.  You can track waves' progress across the tropical Atlantic and Africa at http://einstein.atmos.colostate.edu/~mcnoldy/tropics/hovmoller/atlantic/

Please visit my tropical Atlantic headquarters.

12 June 2006

Alberto heads for the Florida coast and strengthens...

Alberto has recently intensified quite notably, and now has sustained winds of 60kts and a central pressure of 997mb.  It is forecast to briefly achieve minimal hurricane status prior to landfall.  The forecast track is centered on Piney Point, west of Gainesville, but keep in mind forecast uncertainty... anyone from Tampa to Apalachicola should be prepared for severe tropical weather, which includes strong winds, flash floods, storm surge, and tornadoes.

The storm has slowed down a bit, and landfall isn't expected until Tuesday afternoon now.  This slower motion increases intensification potential, HOWEVER, the oceanic heat content will be lower and vertical shear should be higher, so the net effect might be maintaining intensity or minimal strengthening.

At 15Z today, TS Alberto is located at 27.1N 85.9W and crawling NNE at 6kts.  This puts it 220 miles southwest of Cedar Key, FL and about 36 hours from landfall.
Alberto's circulation is visible from Tampa's radar:
http://radar.weather.gov/radar.php?rid=TBW&product=N0Z&overlay=11101111&loop=no
and will be from Tallahassee's radar later today:
http://radar.weather.gov/radar.php?rid=tlh&product=N0Z&overlay=11101111&loop=no

Hurricane Warnings and Tropical Storm Warnings are now in effect for much of western Florida -- please visit http://www.nhc.noaa.gov/refresh/graphics_at1+shtml/144536.shtml?3day for the latest warnings.  The biggest threats from this landfall will be storm surge and tornadoes in the spiral rainbands.  Tornadoes have already been reported in western FL, and it's still 36 hours from landfall.

Please visit my tropical Atlantic headquarters.

11 June 2006

TD1 upgraded to TS Alberto...

At 15Z today, the season's first named storm formed in the southern Gulf of Mexico, Tropical Storm Alberto.  This upgrade was based on an aircraft recon flight into the storm this morning and a nearby ship report.  An active microwave scatterometer also observed 35-40kt surface winds on the north and east quadrants of the storm center.  Alberto is located at 23.9N 88.1W,  and tracking NW at 8kts.  Measured intensity is 40kts and 1004mb, and is narrowly holding onto TS status.

The satellite presentation is not as impressive today, as the entire bulk of deep convection is located east of the low-level center, indicating respectable westerly wind shear. However, there is a strong rain band on the east side, and a weaker one to its east that is already making its presence felt in the western FL peninsula.  SSTs are around 28C, and the storm is passing over the Loop Current in the Gulf, which means slightly higher SSTs and noticeably higher heat content during the next day or so.
http://radar.weather.gov/radar.php?rid=byx&product=N0Z&overlay=11101111&loop=no

The NW motion should soon become more northerly, then northeasterly by Monday morning.  It is still expected to make landfall north of Tampa late Monday night as a moderate TS.  Computer model guidance is fairly consistent with the track... practically all solutions lie between Tampa and Tallassee.

Please visit my tropical Atlantic headquarters.

10 June 2006

Tropical Depression 1 forms in the northwest Caribbean...

After over a week of crawling and festering, an area of disturbed weather in the western Caribbean finally developed a closed surface circulation, and was upgraded to TD1 at 13Z today.  It has a very impressive satellite presentation, and is nearly a Tropical Storm.  There is a very robust and cold CDO, or Central Dense Overcast, a sign of healthy intensification seen in the early stages of development.

At 13Z, TD1 was located at 21.1N 85.3W and moving NNW at 10kts.  Maximum sustained winds are 30kts and the minimum sea level pressure (MSLP) is 1003mb.  It is expected to strengthen to a TS later today as it heads into the southern Gulf of Mexico.  If this intensifies to 35kts, it will be upgraded to Tropical Storm Alberto, the first named storm of the season (as an aside, the first named storm of 2005 formed on June 8).  Tropical Storm Warnings are in effect for western Cuba.  The forecast track will also make this our first landfalling storm of the year too, probably north of Tampa, FL late Monday night (the first named storm of 2005 made landfall on the FL/AL border on June 11 as a 50kt TS).  After crossing the FL peninsula, it's predicted to travel northeast along the east coast of the US as it speeds up and merges with a mid-latitude trough.

Please visit my tropical Atlantic headquarters.