LRandyB's Tropical Weather Discussion 

Quoting JPCSTORM:
Thank you for the update. Does anyone refer to the eastern Caribbean as the Hurricane graveyard anymore?

I remember this being mentioned often in the past anf I haven't heard that reference for some time.

Thank you again,

John

Hi John,

Actually, now that you mention it, I haven't heard that term used in a while. But the phenomenon still exists.

In essence, the "hurricane graveyard" is caused by low level divergence in the atmosphere in the eastern Caribbean. The specific causes and variability of this divergence is still a subject of much research but what is known is that the Caribbean Low Level Jet that exists year round in the central Caribbean is strongest in the early part of the hurricane season and is strengthened further by El Nino. This low level jet produces speed divergence in the eastern Caribbean. And low level divergence produces subsidence, or descending air, in the column above the divergence. And subsidence inhibits convection. So as a result, there is a marked decrease in the genesis of tropical storms in the eastern Caribbean early in the season and tropical depressions, tropical storms, and weak hurricanes that traverse the region from the Atlantic might lose intensity in an environment that is otherwise favorable for intensification. The effect is too weak to have a major impact on stronger storms.

This phenomenon is normally limited to the eastern Caribbean and is only a significant factor in the early part of the Atlantic hurricane season (June-July).

Thanks for the question,

Randy

Quoting BahaHurican:
Hi Randy,

I assume u have been pretty busy w/ Ernesto lately, but I hope u will b around later to talk about it and upcoming storms.

Meanwhile, I leave 1 qtn that bloggers in Doc Masters' blog have been curious about. Aside from Biloxi and St. Croix, is there any other location from which the HHers regularly fly missions? Some were disputing even that Biloxi was a mission start point....

Hi Baha,


That's a good question. The Hurricane Hunters are based out of Keesler AFB in Biloxi MS. Whenever it is practical, they do fly out of Biloxi. For example, the mission currently in the air this morning (Tuesday morning at 8:00am CDT) took off from Biloxi and will return there. It's simply more cost effective to fly from here whenever they can. The Hurricane Hunters area of operation, as defined by the National Hurricane Operations Plan, includes storms from 55W in the mid-Atlantic to about 155W in the eastern Pacific. As a storm approaches 55W in the Atlantic, NHC will task the Hurricane Hunters to begin flying. St. Croix is considered a forward opoerating location for storms in the mid-Atlantic. If a storm threatens St. Croix while they are operating there, they often evacuate to either Barbados or Homestead, FL. For Pacific storms, believe it or not, most often they will fly out of Biloxi. A storm on the west coast of Mexico can be flown pretty easily from Biloxi. For storms threatening Hawaii, they fly out of Hickam AFB in Hawaii.

I hope that answers your question. I will be posting an update later today on the tropics.

Randy