Tuesday, August 31, 2021

Tropical Depression Ida, Tropical Storm Kate, and the Atlantic Blob: 30 August, Update A

And more importantly, Goodbye Ida!! She is now a Tropical Depression, last seen over central Mississippi at around 33.3N, 89.5W, heading NE at 10mph. Winds have decreased to 35 mph, central pressure is around 998mb, so she is fairly weak but still has quite a bit of rain which you can see is falling over a number of states in the US:

The full extent of damages is still not known yet of course, and it is extensive, but clean up and recovery has slowly started.
Some of you wondered how unusual this hurricane was in keeping her eye for many hours after landfall. It is not the first time we have seen this. Strong storms that come ashore over any swampy water (such as in southern Louisiana) have the same behaviour because they are going over an area with warm water (a 'brown ocean'). Another notable example was Hurricane Andrew in 1992 which made landfall in Miami as a cat 5 storm and crossed the southern Everglades, maintaining a solid eye, and emerging back in the Gulf of Mexico as a cat 4 storm. 

In many ways, this storm was really not unusual - it's the time of year for strong storms and we know that they reach this part of the Gulf. It also crossed that Loop Current Eddy (deep warm water) so, because the conditions in the atmosphere were 'good', it was inevitable that she would intensify. 

The only unusual aspect that I noticed was that we don't normally see such strong storms at this time of year get named so close to landfall - usually we see the August/September/October storms coming across the Atlantic and they become hurricanes or named Tropical Storms much earlier in their track. We did see this Atlantic Blobette coming across the Atlantic (like TD10 - now Tropical Storm Kate), but it wasn't upgraded to a Tropical Depression until Thursday afternoon in the western Caribbean. We normally see Caribbean and Gulf of Mexico storms pop up early and late in the season - when the storms are not so strong.

In this case, there was a lot of dry air - that Saharan Air Layer - which kept her convection and development in check. However, she did have considerable circulation so as soon as she got away from that, she was over very warm water and blossomed quickly.

This is my last note on Ida. 

Tropical Storm Kate
This was TD10 yesterday and was named this morning. She is barely a Tropical Storm with winds of 40mph, central pressure 1003mb. There isn't a lot of convection, but what little there is you can see in the satellite imagery above. She is at 22.7N, 50.9N. and is moving N at 6mph:

The forecast is that she will be a TD tomorrow. She is under some wind shear and dry air, and has very little circulation in the mid-troposphere, so I would say she is actually already a Tropical Depression. 

There is one more Atlantic Blob that just emerged from Africa - it does have some circulation in the lower half of the troposphere (more than Kate) but it isn't quite developed enough to be a Tropical Depression.

Oh, and in case you were wondering what happened to Tropical Storm Julian - well he became post-tropical today as expected and went away too. Just like that. 

That's all for today! 

Toodle pip, 

Blogs archived at http://jyotikastorms.blogspot.com/

Twitter @JyovianStorm



These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and local weather service announcements. This is not an official forecast. If I "run away, run away" (Monty Python), I'll let you know.

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