psu_met's Blog

Tropical Storm Dean
As of 11am, 8/14/07: Winds: 40mph G: 50mph
Movement: W 23mph
Pressure: 1004 mb (29.64in.)
Position: 1430 E of Lesser Antilles

Overview: TD #4 has improved only slightly since yesterday, but enough to be upgraded to Tropical Storm Dean.  The TS should continue to move in a general westward direction for the next fews days after which a curve to the north could occur. It is moving very fast at this hour but should slow down gradually over the next few days.  Wind Shear is still about 15-20 knots.
Track Forecast:  Several Models today develop Dean into a hurricane that will approach the N Lesser Antilles by Friday night or Saturday.  Two models don't develop Dean at all.  Given the current conditions this seems very unlikely to occur and these 2 models are pretty much being ignored.  In about 3 days a trough will move off the US East Coast.  If the trough is weak Dean will plow into the Gulf of Mexico.  If strong enough this might pull the storm further north than currently forecast.  If the storm does get pulled north one of two things are likely to happen. 1.) A ridge of high pressure moves in forcing Dean into Florida.  2.) An upper-lever low forms off the SE coast forcing Dean even farther north and threatening New England or the Mid-Atlantic Coast.  It is still way to early to predict which of these has the best chance to occur.
Intensity Forecast:  Most of the models don't show much strengthening until Wednesday.  After Wednesday steady strengthening is expected into a hurricane and possibly a major hurricane.  One model has Dean as a CAT 4 or 5 by the time it approaches Puerto Rico.  This is mostly likely over done but a CAT 3 major hurricane could be possible by that time (5 days from now).

My Thoughts:  I think Dean will hit the northern Lesser Antilles as a minimal hurricane around Friday night.  After that Dean will probably continue to strengthen but how much and where it goes are still big questions.  I know that is not necessarily what people want to hear but I'm just being honest.  After 3 days the models are not sure how the trough will affect Dean.

Invest 91L:  The disturbance in the Gulf of Mexico this afternoon has gotten better organized since yesterday.  Wind Shear is only 5-10 knots currently.  An Air Force Reserve reconnassiance plane should be investigating the system as I write this (1pm).  There is a decent chance that the system may already by a depression.  The disturbance will make landfall along the Texas/Mexico border tomorrow afternoon.  It could be a minimal TS.  The biggest impact will be heavy rain over an area that doesn't need any.  There could be serious flooding.  A TS watch or warning may need to be issued with little advance notice.

Hurricane Flossie: Flossie (110mph)  should pass 70-100 miles south of the Big Island of Hawaii today.  A tropical storm warning and hurricane watch remain in effect.  Tropical storm force winds extend out 150 miles from the center so some wind damage can be expected.  Rainfall amounts of 10-15 in. is the biggest concern.  Hawaii is in a drought and could use some rain, but obviously not this much, this fast.

Small update after midnight tonight with a full update tomorrow afternoon.