psu_met's Blog

Hurricane Dean
As of 11pm, 8/16/07: Winds: 95mph G: 120mph
Movement: W 25mph
Pressure: 976 mb (28.81in.)
Position: 160 ESE of Martinique

Numerous Hurricane/Tropical Storm watches and warning have been issued for the Lesser Antilles. A Tropical Storm Warning is in effect for the US Virgin Islands and Puerto Rico.  A Tropical Storm Watch is now in effect for portions of the Dominican Republic.

Overview: Hurricane Dean is continuing to plow toward the Lesser Antilles and has now developed an eye. Wind Shear is down to 5 knots and the only thing slowing Dean from rapid intensification is dry air surrounding the storm. However, Dean is well on it's way to becoming a major hurricane.
Track Forecast: The computer models are very similar to yesterday's runs. They bring Dean through the Caribbean and into the Yucatan Peninsula. The GFDL is the outlier pulling Dean across the extreme western tip of Cuba and into the Gulf of Mexico.
Intensity Forecast: Steady strengthening should continue as Dean pushes westward. The western Caribbean has a very deep layer of warm water, which could really make him a very dangerous storm. Cat 4 is likely and CAT 5 status is not out the question. Of course this is very hard to predict, especially when a well-organized Dean starts going through eye-wall replacement cycles.
My Thoughts: I think Dean will cross the Lesser Antilles as a CAT 2 hurricane. On the islands where Dean's center crosses, severe wind damage may occur. Due to his very quick speed, 2-7in. of rain may fall, but nothing extreme. Wind damage is the biggest concern for the islands. After that the Yucatan Peninsula and the Texas/Mexico border continue to look like the best bets for landfall. We'll have to continue watching the models though. If some others move farther north like the GFDL then an adjustment to the forecast will be needed. A Hurricane Hunter mission into Dean will be flown this afternoon. This will give us a better idea of how strong he really is.

Tropical Depression Erin: Tropical Depression Erin made landfall early this morning over South Texas. She never strengthened above a 40mph TS and the last advisory on her was issued at 11am. Flooding is still a concern in parts of Texas though.

2pm Update: The Hurricane Hunter plane just reached Dean. In it's first pass through the storm they measured 90mph winds and estimated the pressure at 970mb, 7mb lower then 11am's estimate. Considering they most likely didn't hit the strongest part of the storm in their first pass though and with the lower pressure, I expect to see the 5pm advisory upgrade Dean to a CAT 2.

5pm Update: Dean is now indeed a CAT 2 hurricane. An eye-wall is still forming but due to dry air it has a gap on the the west side. Once it is completely formed expect him to reach CAT 3 status. Dean will cross the Lesser Antilles late tomorrow morning or early afternoon.

11pm Update: The appearance of Dean has deteriorated over the past several hours.  There is no longer an eye visible on satellite but don't let this fool you.  Dean will still continue to strengthen over the next couple of days.  He will be crossing the Lesser Antilles in 6-12hrs.  There are now signs that upper air conditions could be a little less favorable when Dean reaches the W Caribbean.  We'll see what the models show overnight and adjust the forecast as needed.  Either way Dean will still be a very dangerous hurricane racing through the Caribbean.