Officially, the “ghost” has been tagged as Invest 90L by the National Hurricane Center. Is tropical trouble brewing close to home? In a nutshell: “I think not”! In fact, this old low pressure spinning over the Gulf States won’t even get a name as we go through the week.
Let me lay out my case for you with four exhibits:
- Sea Surface Temps are lower and lowering as a result of recent upwelling from Hurricane Isaac and the massive amounts of rain falling over the Gulf last week.
Gulf of Mexico SSTs
- The cyclonic spin with the ghost of Isaac, at this point, is all mid-level rotation. There is absolutely nothing surface based this morning.
500mb Analysis Chart
- SHIPS model guidance first “initialized” a location and wind speeds for Invest 90L. It has winds initialized at almost 30 mph, but on the surface charts, no area readings are above 20. The end-result is a chart that is skewed to higher wind speeds over time as the storm moves out over the Gulf. This is called a bias.
- Climatology says little to anything in recent history has formed this close to the Gulf coastline in the month of September. 2007 was the most recent, AND ONLY example in the 2000′s, of a depression forming.
September Tropical Cyclone Climatology for Invest 90L
Given all the data I have shown you, and the impending weather change on Friday with an approaching cold front, I see little reason to believe Invest 90L will attain tropical cyclone status. It will certainly bring some rain, some surf and a gusty breeze…but nothing for us to be concerned about at this juncture.