TC Bertha

Matt-hurricanewatcher · #2881 Postby **Matt-hurricanewatcher** » Tue Jul 08, 2008 1:39 am

Centered at 21.3/52.9 it appears, also has holded on to a very well defined eye. Yes the cdo is smaller, but I would say it's still near 100 knots.

WOW this was the 03z location->20.8N 52.8W. OK I just updated my thing.. It is above 21 north, but its moving pretty slow..

The ace should move close to 7 points at 5am.

Matt-hurricanewatcher · #2882 Postby **Matt-hurricanewatcher** » Tue Jul 08, 2008 1:58 am

The system is clearly turning to the northwest, with even some hints of a west-northwest the last frame. Interesting! Also, I see clouds shooting back out like they did last night, so it is not impossible this could go through another round of strengthing.

Matt-hurricanewatcher · #2883 Postby **Matt-hurricanewatcher** » Tue Jul 08, 2008 2:07 am

000

WHXX01 KWBC 080630

CHGHUR

TROPICAL CYCLONE GUIDANCE MESSAGE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0630 UTC TUE JUL 8 2008

DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.
PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE
AND SUBTROPICAL CYCLONE INFORMATION.

ATLANTIC OBJECTIVE AIDS FOR

TROPICAL CYCLONE BERTHA (AL022008) 20080708 0600 UTC

...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
080708 0600 080708 1800 080709 0600 080709 1800

LAT LON LAT LON LAT LON LAT LON
BAMS 21.1N 52.9W 22.3N 55.1W 23.3N 56.8W 24.4N 58.5W
BAMD 21.1N 52.9W 22.2N 54.2W 23.3N 55.5W 24.6N 56.7W
BAMM 21.1N 52.9W 22.0N 54.7W 22.9N 56.3W 23.9N 57.8W
LBAR 21.1N 52.9W 22.0N 54.0W 23.1N 55.4W 24.1N 56.7W
SHIP 105KTS 96KTS 87KTS 82KTS
DSHP 105KTS 96KTS 87KTS 82KTS

...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
080710 0600 080711 0600 080712 0600 080713 0600

LAT LON LAT LON LAT LON LAT LON
BAMS 25.5N 59.8W 27.1N 61.7W 27.7N 62.5W 27.9N 62.8W
BAMD 26.0N 57.5W 28.5N 58.2W 30.2N 58.6W 31.2N 59.3W
BAMM 24.9N 58.9W 26.6N 60.3W 27.2N 60.8W 27.9N 61.3W
LBAR 25.1N 57.5W 26.4N 57.9W 26.8N 57.3W 28.6N 56.4W
SHIP 75KTS 64KTS 60KTS 59KTS
DSHP 75KTS 64KTS 60KTS 59KTS

...INITIAL CONDITIONS...
LATCUR = 21.1N LONCUR = 52.9W DIRCUR = 310DEG SPDCUR = 8KT
LATM12 = 19.9N LONM12 = 51.6W DIRM12 = 311DEG SPDM12 = 9KT
LATM24 = 19.1N LONM24 = 49.4W
WNDCUR = 105KT RMAXWD = 15NM WNDM12 = 100KT
CENPRS = 955MB OUTPRS = 1013MB OUTRAD = 200NM SDEPTH = D
RD34NE = 100NM RD34SE = 60NM RD34SW = 40NM RD34NW = 100NM

$$
NNNN

#2884 Postby **TheEuropean** » Tue Jul 08, 2008 3:13 am

08/0545 UTC 21.2N 53.0W T5.0/6.0 BERTHA -- Atlantic Ocean
http://www.ssd.noaa.gov/PS/TROP/positions.html

UW-CIMSS Automated Satellite-Based
Advanced Dvorak Technique (ADT)
Version 7.2
Tropical Cyclone Intensity Estimation Algorithm

Current Intensity Analysis

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

----- Current Analysis -----
Date : 08 JUL 2008 Time : 064500 UTC
Lat : 21:16:41 N Lon : 53:01:34 W

CI# /Pressure/ Vmax
5.8 / 953.7mb/109.8kt

Final T# Adj T# Raw T#
(3hr avg)
5.1 5.1 5.1

Latitude bias adjustment to MSLP : +0.9mb

Estimated radius of max. wind based on IR : 16 km

Center Temp : +6.9C Cloud Region Temp : -52.7C

Scene Type : EYE

Positioning Method : RING/SPIRAL COMBINATION

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

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

****************************************************

Chacor · #2885 Postby **Chacor** » Tue Jul 08, 2008 3:31 am

WTNT32 KNHC 080831
TCPAT2
BULLETIN
HURRICANE BERTHA ADVISORY NUMBER 21
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL022008
500 AM AST TUE JUL 08 2008

...POWERFUL BERTHA MAINTAINING MAJOR HURRICANE STATUS...

AT 500 AM AST...0900Z...THE CENTER OF HURRICANE BERTHA WAS LOCATED
NEAR LATITUDE 21.4 NORTH...LONGITUDE 53.3 WEST OR ABOUT 675 MILES...
1085 KM...EAST-NORTHEAST OF THE NORTHERN LEEWARD ISLANDS AND ABOUT
1035 MILES...1660 KM...SOUTHEAST OF BERMUDA.

BERTHA IS MOVING TOWARD THE NORTHWEST NEAR 10 MPH...17 KM/HR...AND
THIS GENERAL MOTION IS EXPECTED TO CONTINUE FOR THE NEXT 48 HOURS.

MAXIMUM SUSTAINED WINDS ARE NEAR 120 MPH...195 KM/HR...WITH HIGHER
GUSTS. BERTHA IS A CATEGORY THREE HURRICANE ON THE SAFFIR-SIMPSON
HURRICANE SCALE. SOME FLUCTUATIONS IN INTENSITY MAY OCCUR TODAY...
BUT A GRADUAL WEAKENING TREND IS EXPECTED TO BEGIN WITHIN THE NEXT
COUPLE OF DAYS.

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 30 MILES...45 KM...FROM
THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 115
MILES...185 KM.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 955 MB...28.20 INCHES.

REPEATING THE 500 AM AST POSITION...21.4 N...53.3 W. MOVEMENT
TOWARD...NORTHWEST NEAR 10 MPH. MAXIMUM SUSTAINED WINDS...120 MPH.
MINIMUM CENTRAL PRESSURE...955 MB.

THE NEXT ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE CENTER AT
1100 AM AST.

$$
FORECASTER PASCH

KWT · #2886 Postby **KWT** » Tue Jul 08, 2008 4:21 am

Wow so it may have been a category-4?!
Very impressive, still a major hurricane as well know I think its now starting to weaken again and may drop below major strength soon.

#2887 Postby **arkestra** » Tue Jul 08, 2008 4:23 am

Will they upgrade to cat4 in the postanalysis?

Nimbus · #2888 Postby **Nimbus** » Tue Jul 08, 2008 4:24 am

The TUTT between Bertha and the US appears to be drifting WSW which would allow enough room for the ridge to build back in a little.

As a Hurricane approaches 25 N you would expect it to really try to start turning poleward and recurve. Unless Bertha stalls early there is not much time for the ridge to build. We have not seen any stair stepping wobble that would indicate that she is getting ready to change course. The 5 am update sounded like they expect a track change to NW 315 soon.

KWT · #2889 Postby **KWT** » Tue Jul 08, 2008 4:26 am

As it happens I think its stair-steeping right now, it took a slightly more westerly path about 3-5hrs ago but now its swang back to an almost NNW motion again. I'm starting to also think there may not be enough time for the ridge to build back in but we will have to wait and see.

#2890 Postby **TheEuropean** » Tue Jul 08, 2008 4:45 am

And Bertha is getting weaker, the eyewall is eroding in the northwestern part, reflecting in the lower numbers:

UW-CIMSS Automated Satellite-Based
Advanced Dvorak Technique (ADT)
Version 7.2
Tropical Cyclone Intensity Estimation Algorithm

Current Intensity Analysis

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

----- Current Analysis -----
Date : 08 JUL 2008 Time : 084500 UTC
Lat : 21:25:32 N Lon : 53:12:49 W

CI# /Pressure/ Vmax
5.3 / 964.9mb/ 97.2kt

Final T# Adj T# Raw T#
(3hr avg)
5.0 4.8 4.8

Latitude bias adjustment to MSLP : +0.9mb
Estimated radius of max. wind based on IR : 16 km
Center Temp : +1.1C Cloud Region Temp : -49.7C

Scene Type : EYE
Positioning Method : RING/SPIRAL COMBINATION

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

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

****************************************************

KWT · #2891 Postby **KWT** » Tue Jul 08, 2008 4:50 am

Yeah I wonder if the shear is starting to weaken Bertha now, certainly is looking like Bertha has peaked for good. Probably back down to cat-2 next advisory I think, 95kts would be my guess.

#2892 Postby **wxman57** » Tue Jul 08, 2008 5:01 am

Bertha appears to be following the GFDL forecast of yesterday in recurving early, well east of Bermuda. It may slow down a bit this weekend, but should be carried safely out to sea early next week.

#2893 Postby **HURAKAN** » Tue Jul 08, 2008 5:05 am

Code: Select all

ACE (104kt²) (Source) — Storm: 
1 6.10 Bertha 2 0.37 Arthur 
Total: 6.47

Link: http://en.wikipedia.org/wiki/2008_Atlan ... ane_Season

KWT · #2894 Postby **KWT** » Tue Jul 08, 2008 5:13 am

Indeed wxman57, as I said last night the GFDL really did well this system, also it did forecast cat-3/4 which looks to have been a very good call by the model.

Thunder44 · #2895 Postby **Thunder44** » Tue Jul 08, 2008 5:14 am

wxman57 wrote:Bertha appears to be following the GFDL forecast of yesterday in recurving early, well east of Bermuda. It may slow down a bit this weekend, but should be carried safely out to sea early next week.

Yeah, and the latest run doesn't have it making it past 60W.

KWT · #2896 Postby **KWT** » Tue Jul 08, 2008 5:17 am

To be fair Thunder its still pulling off to the NW so thaty seems to be a reasonable call now. The only question has to be now how fast Bertha weakens as it heads towards the higher level of shear, already showing signs IMO.

#2897 Postby **HURAKAN** » Tue Jul 08, 2008 5:19 am

KWT · #2898 Postby **KWT** » Tue Jul 08, 2008 5:22 am

Not looking nearly as good as it did yesterday, eye has clouded over now so it probably is weakening steadily.

Thunder44 · #2899 Postby **Thunder44** » Tue Jul 08, 2008 5:23 am

KWT wrote:To be fair Thunder its still pulling off to the NW so thaty seems to be a reasonable call now. The only question has to be now how fast Bertha weakens as it heads towards the higher level of shear, already showing signs IMO.

I don't think shear has increased too much yet. I think it's running into to an area of subsidence to the west, that's causing the convection to diminish on the western eyewall.

KWT · #2900 Postby **KWT** » Tue Jul 08, 2008 5:25 am

I think its showing signs of shear though thunder, I don't think its the main reason behind the weakening mind you but there is signs, esp on the northern side of the system.

TC Bertha

Re: Hurricane Bertha in Central Atlantic

Re: Hurricane Bertha in Central Atlantic

Re: Hurricane Bertha in Central Atlantic

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Re: Hurricane Bertha in Central Atlantic

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