TC Bertha

[artist]

Hurricane Frances had an eye of 80 miles.

[cycloneye]

[artist]

I am wondering if it will start revving up once that eye clears out.

[Cyclenall]

This has got to be one of the oddest TC's ive watched. a roller coaster of intensity, shear, dry air, and cool SSTs all take their whack but all fail to prevent a cat 3, annular (pretty much), tiny eye, huge eye. All I have to say, I wish I could be sitting in the middle of Bertha's eye right now.

That pretty much sums up my thoughts thus far on Bertha. The debris in her large eye are still not gone yet, the inner eye wall must be yelling to stay in there!

Someone should make a 200 hour loop of Bertha, that would be neat to see.

[Ed Mahmoud]

So, what say the pro-mets on the "A" word?

[wxman57]

6-hr movement - 335 deg. at a little over 6 kts

3-hr movement - 356 deg. at a little over 7 kts

Appears to be moving northward now.

[RL3AO]

This has got to be one of the oddest TC's ive watched. a roller coaster of intensity, shear, dry air, and cool SSTs all take their whack but all fail to prevent a cat 3, annular (pretty much), tiny eye, huge eye. All I have to say, I wish I could be sitting in the middle of Bertha's eye right now.

That pretty much sums up my thoughts thus far on Bertha. The debris in her large eye are still not gone yet, the inner eye wall must be yelling to stay in there!

Someone should make a 200 hour loop of Bertha, that would be neat to see.

Make your loop as long as you wish.

http://rammb.cira.colostate.edu/products/tc_realtime/4kmirimg_archive.asp?storm_identifier=AL022008

[tolakram]

The loop is pretty to look at:

http://www.ssd.noaa.gov/goes/east/nwatl/loop-vis.html

[wxman57]

So, what say the pro-mets on the "A" word?

Aardvark?

[Ed Mahmoud]

So, what say the pro-mets on the "A" word?

Aardvark?

Annular-ish...

[wxman57]

So, what say the pro-mets on the "A" word?

Aardvark?

Annular-ish...

Sort of. It does have some banding, though.

[AnnularCane]

Maybe I just have a short-term memory, but I don't know if I've ever seen so many feathery clouds on one hurricane before.

[KWT]

That eye just won't clear out, stubborningly the SE side of the old inner eyewall still seems to be sticking out and until thats gone then the eye is always going to look messy IMO. The overall structure still looks pretty good however!

All good to see the system is still moving at 6-7kts, I sure hope it doesn't stall or does a loop!

[cheezyWXguy]

So, what say the pro-mets on the "A" word?

Aardvark?

Annular-ish...

I think its annular...it fits practically every requirement, does it not? Big eye, no major bands, proper latitude, fairly deep convection.

[RL3AO]

Up to 80kts

ESTIMATED MINIMUM CENTRAL PRESSURE 976 MB
EYE DIAMETER 40 NM
MAX SUSTAINED WINDS 80 KT WITH GUSTS TO 100 KT.
64 KT....... 30NE 30SE 15SW 30NW.
50 KT....... 60NE 50SE 50SW 60NW.
34 KT.......120NE 110SE 100SW 120NW.
12 FT SEAS..210NE 150SE 120SW 210NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

[KWT]

I don't think its quite annular yet because it still does have some bands but it does have the big eye and its not too hard to think that it could become annular very soon and expect NHC to mention that again.

[Ed Mahmoud]

Are those bands or outflow channels?

[gatorcane]

well the NHC officially mentions the loop possibility that I thought might happen from my analysis several days ago.....

indeed maybe she'll loop a couple of times? Maybe three times? lol

Got to love Bertha.

[MiamiensisWx]

The following post is NOT an official prognosis.

Bertha is still situated over +28 C SSTs (with small areas near ~29 C) and sufficient oceanic heat content, which is contributing to a more unstable boundary layer and rapid ascent of parcels, especially along the eastern semicircle. The signs are evident: note the initiation and development of additional thunderstorms east of the center. Since a new larger eye has developed (as I expected) overnight, there is no contrast between the sinking subsidence in the remnant inner eye and the subsidence that is contributing to the formation of the current larger eye. The small and ephermal inner eyewall is currently dissipating, while the large outer eyewall is starting to gradually contract, so I anticipate a brief period of re-intensification as the TC moves slowly and remains over substantial SSTs/OHC. Consequently, I believe Bertha may approach Category 2 intensity for a period as it slows and briefly stalls near Bermuda. Bertha is clearly exhibiting a very large eye near ~69 mi in diameter; when the structure of the TC is considered, it is probable that Bertha may eventually evolve to an annular hurricane, especially as the slow forward movement contributes to upwelling and the TC eventually moves over lower OHC/SSTs beyond the next ~24-36 hours. Since Bertha will eventually encounter decreasing OHC and SSTs, the strongest winds (again) will likely not mix to the surface; in light of all available data, I do not believe Bertha will exceed strong Category 1 intensity (~80 kt). However, residents in Bermuda (like all other regions) should be prepared for stronger winds and any category on the Saffir-Simpson Hurricane Scale; with the trends in the track, it is becoming increasingly plausible that the island will experience 1-min winds of at least TS intensity, and the probabilities of brief sustained hurricane force winds (or at least gusts) are increasing. This will be explained in the next paragraph.

Although the short term movement is nearly due north, the long term movement continues to indicate a NW track. A shortwave trough to the west of Bertha will likely remain largely in place, leaving the TC under weak upper level steering currents (per 400-850 mb streamline analysis) within the short to medium term. The problems resulting from this movement are manifold. The larger wind radii (which I mentioned yesterday) will likely contribute to greater chances of sustained TS force winds (<34 kt) on Bermuda, especially when it is corrobated with Bertha's current close proximity to Bermuda and its long term NW movement. This also increases the probabilities of hurricane force gusts, and there is a chance that sustained winds of hurricane intensity (<64 kt) could briefly occur over isolated portions of Bermuda and the immediate offshore waters. However, it is more likely that the vast majority of the island will experience 1-min winds of TS force with hurricane force gusts. The long duration of Bertha's impact (because of its slow drift) over the next few days will likely result in an enhanced threat for large waves and erosion along the island, especially on the northern, eastern, and southern portions which are exposed.

Bermudians should be prepared (in terms of supplies and protection of vulnerable oceanfront/beach structures) for a lengthy erosion, wave, and wind threat. Erosion and large waves will be a much more significant threat than the wind, since structures are very staunch and well constructed to withstand winds, though winds will still cause damages to trees and vegetation. Overall, Bermuda residents should be ready for the extended erosion/wave threat over the next few days. A loop is becoming more plausible, which could prolong Bertha's presence near Bermuda over the extended period (next several days), though the wind/wave/erosion threat should subside beyond Sunday and Monday as Bertha moves further from the island.

http://www.ssd.noaa.gov/goes/flt/t1/loop-avn.html

Edit: I believe the possible stall will be very brief and temporary.

[MiamiensisWx]

...LARGE EYE OF BERTHA LEISURELY MOVING NORTH-NORTHWESTWARD...

Lixion Avila is probably making a vain attempt to reduce his stress. Undoubtedly, Bertha has been perplexing even for the NHC's forecasting, including the forecasters involved.