TC Bertha

[KWT]

Really not all that surprising that its strength has been dropped down to 90kts given its starting to get more and more sheared as it heads NW, indeed this is only going to get worse probably. Shear does lower down again around 27N though so we may see a weaker secondary peak if heat content is good enough and the systems inner core isn't ruined by strong shear before then.

[tolakram]

The other wrench in the works is the steering.

If Bertha drops in strength rapidly might it start to head west again? Or is it assumed that once weaker it will continue in the same direction it's heading in now.

[KWT]

Hmmm actually thats a good question I would think now its on the weakness it should carry on to the NW but its something that I'm not sure about!

[Chacor]

90 kts is still a tad high imo. I think they're holding to 90 for Dvorak constraints (both SAB and TAFB down to T4.5/5.5).

[DESTRUCTION5]

She is being sheared bigtime right now...She also is slowing doen to a crawl..I would say 8kts or so at this point..

[Sjones]

I'm also wondering if she's slowing down will that have an impact on her direction?

[tolakram]

Eye is gone in the water vapor loop.

[cycloneye]

I think 75 kts is a better estimate right now.

[Chacor]

That's what I'm thinking as well, Luis. Doesn't look a 90 kt storm and I think the only basis for 90 kts was the T4.5, which might have been constrained within Dvorak rules.

[tolakram]

I keep forgetting to read the TA forum, Scott's forecast pretty much sums it up.

viewtopic.php?f=29&t=101644

http://nencweather.com/tropicalweather/2008/bertha.html

The eye of the storm is about to enter a threshold of 20kt deep layered shear; however, mid-level shear remains minimal. Still, if Bertha cannot maintain high, cold cloud tops and a deeply stacked circulation, it will not strengthen much beyond its current intensity. In fact, the intensity forecast continues the previous, and levels off intensity overnight, before weakening the storm slightly due to heavy shear


Apparently either the shear is worse that forecast or the storm is stronger than we think and just looks bad because of the shear.

[dixiebreeze]

The NHC discussion said to expect a couple ERC's in the next 12 hours or so. Could be why she's looking rather forlorn.

[Cyclone1]

Finally, a major hurricane that didn't bomb into a category 5.

[tolakram]

[Chacor]

That's a very shabby-looking hurricane.

[KWT]

That obviously looks like a pretty hefty dose of shear on the system, look at the way all the convection is becoming lo[-sided on the NE side again, certainly is weakening at a rapid rate as of now.

[sgr4000]

Hello everyone!

I just wanted to peek in and say hello. I found this site the other night and have been following this thread since page 72. Alot of interesting information on this topic. I will continue to follow along and learn some of the lingo you ppl are using. Have a good day!

[kpost]

if she decreases in intensity very fast (some have stated possible 75kts) will that have an effect on her steering, considering the models that have been on track have her more intense then that?
Just a question, i am trying to learn.

why are the steering winds not having an effect on her?
how do the cmc models normally perform?
they have her weak and far west, is this completely impossible now?

[wxman57]

The NHC discussion said to expect a couple ERC's in the next 12 hours or so. Could be why she's looking rather forlorn.

It's not an eyewall replacement cycle, more like an eye dissipation cycle. Shear is taking its toll on Bertha. I agree, 90 kts is on the high side for an estimate. 75-80kts would be more realistic.

[UpTheCreek]

Hello everyone!

I just wanted to peek in and say hello. I found this site the other night and have been following this thread since page 72. Alot of interesting information on this topic. I will continue to follow along and learn some of the lingo you ppl are using. Have a good day!

Welcome sgr4000! I've been following along and learning for years now, it's a GREAT forum!

[WmE]

Could there be a dry air intrusion due to the shear?