TC Bertha

[gatorcane]

she may not look great but finally we see the decrease in convection. I actually see Bertha starting to move more West today than WNW. Here is loop that shows this. She is now under full control of the Azore High ridge that has firmly built in to the north.

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

[Category 5]

[cycloneye]

The low center is SW of the ball of convection.

[Blown Away]

Maybe the LLC rapidly accelerating and the convection is trying to keep up.

[GeneratorPower]

Great video discussion by James Spann on the future track of Bertha. From 10:50am this morning:

http://www.alabamawx.com/?p=7648

[cheezyWXguy]

You know, while none of you think that it looks very good right now, and I agree, it has certainly improved since yesterday. In fact, I believe that this is the first time it has actually produced deep convection during the day. That, IMO, proves that it is at least maintaining strength.

[Extremeweatherguy]

Impressive ball of convection on the north end of the circulation...

[Tampa Bay Hurricane]

That burst of convection should allow for slow intensification of the storm.

[HURAKAN]

Bertha is at least holding itself at the moment.

[GeneratorPower]

She's doing fine. Leave her alone. She'll ebb and flow, but in the end, she'll do just fine. What is it with you people anyway?!? A 1mb shift one way or the other doesn't mean the difference between bombing out and fizzling. The trend is your friend.

[Chacor]

AL, 02, 2008070418, , BEST, 0, 153N, 308W, 45, 1000, TS, 34, NEQ, 75, 30, 0, 75, 1012, 180, 30, 0, 0, L, 0, , 0, 0, BERTHA, D,

[Sanibel]

The cooler water and SAL combined with the storm's strength could make it more subtropical as it encounters that cooler pocket.

[Blown Away]

I think Bertha looks great considering the marginal SST's and it's July 4. She seems to be moving just S of the NHC track and picking up speed. Bertha has finally hooked up and is on the accelerating ride across the pond. I think we will see a moderate TS moving WNW between 18-21mph for the next few days.

[Aric Dunn]

The center is clearly at 15n....as of a couple hours ago..

[gatorcane]

Bertha is heading nearly due West now this afternoon (I'd estimate 275 or so) and as some have mentioned as finally hooked up with the ridge to the north. The ball of convection is north of the center and is probably what is allowing her to move more W instead of WNW.....so I suspect now that models will initialize her moving more west that the recrurve scenario at 55W is less and another track shift left could be in store....

We really need Bertha to just go poof is the bottom-line. I think with the TUTT stretched across the Western Atlantic and some other pockets of high upper-level winds before the TUTT, she may just be a naked swirl in the end.

[ekal]

I don't see the westward motion. The 15z advisory position was 14.9N, 29.7W. The 18z best track has the center at 15.3N, 30.8W. That's WNW.

It might appear to be moving westward on visible, as convection is building SW, but that is not the motion of the center.

[cycloneye]

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 7.2.3
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 04 JUL 2008 Time : 184500 UTC
Lat : 15:11:48 N Lon : 30:38:43 W


CI# /Pressure/ Vmax
3.3 / 999.1mb/ 51.0kt


Final T# Adj T# Raw T#
(3hr avg)
2.8 3.4 3.4

Latitude bias adjustment to MSLP : +2.7mb

Center Temp : -23.0C Cloud Region Temp : -39.4C

Scene Type : SHEAR (0.04^ TO DG)

Positioning Method : FORECAST INTERPOLATION

Ocean Basin : ATLANTIC
Dvorak CI > MSLP Conversion Used : ATLANTIC

Tno/CI Rules : Constraint Limits : NO LIMIT
Weakening Flag : ON
Rapid Dissipation Flag : OFF

[gatorcane]

Bertha at 72 hours by TAFB. Notice the ridge axis above Bertha (squiggly line aross the top of the picture).....is there enough of a weakness is the question:

[ekal]

Does anyone know if "Positioning Method : FORECAST INTERPOLATION" means that the center position was estimated based upon where it was forecasted to be at 18:45z?

[Gustywind]

000
FXCA62 TJSJ 041952
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
352 PM AST FRI JUL 4 2008



TROPICAL STORM BERTHA...CONTINUED ACROSS THE FAR EASTERN
ATLANTIC...WEST OF THE CAPE VERDE ISLANDS THIS AFTERNOON. LATEST
MODELS GUIDANCES INDICATED THAT THE SYSTEM SHOULD MAINTAIN A
WEST-NORTHWEST TRACK DURING THE NEXT SEVERAL DAYS THEN MEANDERING
ABOUT 700 MILES TO THE NORTHEAST OF PUERTO RICO BY THE END OF THE
WEEK...REPRESENTING A CONCERN ONLY FOR THE MARINE COMMUNITY AT
THIS MOMENT. HOWEVER...DUE TO LONG TERM TRACK ERRORS IT IS
IMPERATIVE THAT MARINERS...RESIDENTS...AND TOURISTS MAINTAIN A
WEATHER WATCH AND STAY TUNED TO THE LATEST UPDATES FROM THE
NATIONAL WEATHER SERVICE.

LOOKING WELL AHEAD...GFS MODEL GUIDANCE SUGGESTS THAT A TROPICAL
WAVE WILL DEVELOPS INTO A LOW PRESSURE SYSTEM ACROSS THE WINDWARD
ISLANDS BY THE END OF THE UPCOMING WEEK. THE DEVELOPED LOW
PRESSURE CENTER WILL MOVE THEN WEST NORTHWESTWARD ACROSS THE LOCAL
ISLANDS. STAY TUNED. Hey Hey... looking suspcious hope that GFS will be wrong, and the others models too, but we have time in case of, but once again, "no time out " , . At this rate, it was as if we were approaching the peak of the season, and we are only july 4th!!!