Dennis strengthens to Category 4...

At 00Z today, Dennis was upgraded to 115kts, making it a CAT4 hurricane.  
Since then, it had leveled off at 115kts as it scrapes the southern Cuba 
coast.  It nipped Cabo Cruz, Cuba last night as a CAT4.  At 15Z this 
morning, it was upgraded further to 130kts and 938mb based on aircraft 
recon data.  In the past 24 hours, the central pressure has fallen 30mb 
and the winds have increased by 40kts.  The latest position is 21.4N 
79.9W and motion is NW at 13kts.  It is only 6kts from being the first 
Atlantic July CAT5 in recorded history.

Hurricane Warnings are in place for most of Cuba and the Florida Keys, 
and the northern Gulf coast is still very much in danger of a major 
landfall late Sunday into early Monday.  As the time draws near and the 
track forecast errors are slimmed down, the strip between New Orleans 
and Apalachicola still looks like the target, with even higher 
likelihood between Mobile and Pensacola.  If you're in these areas, you 
should certainly be moving along with plans to evacuate and protect your 
house (a Hurricane Watch should be issued later today for you).  
Likewise in the Florida Keys... although you may not experience a direct 
hit, the eyewall or near-eyewall could reach that area Saturday morning 
and cause significant damage.

The forecast takes Dennis over western Cuba as a CAT4, weakening a bit 
as it crosses the island, then reintensifying as it makes its way across 
the Gulf toward the US.  This has the potential to hit the same area 
that Ivan hit last year, but perhaps even stronger.

As an aside, the NTC (Net Tropical Cyclone activity) for 2005 is already 
24.1%.  According to Phil Klotzbach here at CSU, this is only behind the 
seasons of 1996 (28.9%) and 1966 (42.6%) for June-July activity.  So 
although this season is freakishly active so early, it is not 
unprecedented.

Please visit my tropical Atlantic headquarters.