Tropical Storm Bertha Model Runs

[cycloneye]

12z UKMET vanishes Bertha by 3 days.

TROPICAL STORM BERTHA ANALYSED POSITION : 13.2N 23.9W



ATCF IDENTIFIER : AL022008



VERIFYING TIME POSITION STRENGTH TENDENCY

-------------- -------- -------- --------

12UTC 03.07.2008 13.2N 23.9W WEAK

00UTC 04.07.2008 14.4N 26.3W WEAK LITTLE CHANGE

12UTC 04.07.2008 14.7N 29.6W WEAK INTENSIFYING SLIGHTLY

00UTC 05.07.2008 14.6N 33.4W WEAK WEAKENING SLIGHTLY

12UTC 05.07.2008 16.0N 37.5W WEAK LITTLE CHANGE

00UTC 06.07.2008 BELOW TROPICAL STORM STRENGTH

[Aric Dunn]

wow look at the hwrf it shifted way west with no turn,..

http://www.nco.ncep.noaa.gov/pmb/nwprod ... loop.shtml

thats a large shift

[Derek Ortt]

as a wave though

[cycloneye]

12z Canadian tracks to 20n-55w and then goes more north as a hurricane.

http://moe.met.fsu.edu/cgi-bin/cmctc2.c ... =Animation

[Aric Dunn]

as a wave though

as a wave?

look again
http://www.nco.ncep.noaa.gov/pmb/nwprod ... loop.shtml

here is the nested..

[Derek Ortt]

thanks for posting the nested run

[KWT]

True it does take a more westward path but at times its barely a closed system, for most that jounrey its a TD at most Aric, thats probably why its shifted westwards because its progging a pretty weak system.

[Aric Dunn]

thanks for posting the nested run

no problem. i mean breifly it looks like the Hwrf opened it up .. but then no ..

[Aric Dunn]

True it does take a more westward path but at times its barely a closed system, for most that jounrey its a TD at most Aric, thats probably why its shifted westwards because its progging a pretty weak system.

exactly.. but it strengthens it towards the end of the run

[Aric Dunn]

more interesting the ukmet barely keeps the system and drives it wnw then west into the norther carribean..

http://moe.met.fsu.edu/cgi-bin/ukmtc2.c ... =Animation

[Derek Ortt]

I think it's more interesting that the models are backing off of development quite a bit

maybe we'll get lucky and have a short lived cyclone

[cycloneye]

502
WHXX01 KWBC 031831
CHGHUR
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1831 UTC THU JUL 3 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) 20080703 1800 UTC

...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
080703 1800 080704 0600 080704 1800 080705 0600

LAT LON LAT LON LAT LON LAT LON
BAMS 13.4N 25.0W 14.2N 28.5W 14.9N 32.0W 15.5N 35.0W
BAMD 13.4N 25.0W 14.5N 27.5W 16.0N 30.3W 17.5N 33.4W
BAMM 13.4N 25.0W 14.4N 28.0W 15.7N 31.2W 16.8N 34.5W
LBAR 13.4N 25.0W 13.9N 27.5W 15.1N 30.4W 16.4N 33.6W
SHIP 35KTS 43KTS 50KTS 57KTS
DSHP 35KTS 43KTS 50KTS 57KTS

...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
080705 1800 080706 1800 080707 1800 080708 1800

LAT LON LAT LON LAT LON LAT LON
BAMS 16.5N 37.6W 19.5N 43.8W 21.7N 48.8W 22.4N 52.0W
BAMD 19.0N 36.5W 21.8N 42.6W 25.4N 45.5W 28.0N 45.0W
BAMM 17.9N 37.8W 19.7N 44.5W 21.7N 48.3W 23.2N 49.5W
LBAR 17.7N 37.0W 20.8N 43.1W 22.2N 47.2W 24.0N 48.8W
SHIP 61KTS 68KTS 66KTS 59KTS
DSHP 61KTS 68KTS 66KTS 59KTS

...INITIAL CONDITIONS...
LATCUR = 13.4N LONCUR = 25.0W DIRCUR = 285DEG SPDCUR = 10KT
LATM12 = 12.7N LONM12 = 22.9W DIRM12 = 291DEG SPDM12 = 11KT
LATM24 = 12.0N LONM24 = 20.8W
WNDCUR = 35KT RMAXWD = 30NM WNDM12 = 30KT
CENPRS = 1006MB OUTPRS = 1012MB OUTRAD = 170NM SDEPTH = M
RD34NE = 30NM RD34SE = 30NM RD34SW = 0NM RD34NW = 30NM

$$
NNNN

[KWT]

Yep it also weakens Bertha very soon, the only reason I can see is its responding lower heat content but right now its wrapping around nicely and there is low shear and I remember Boris getting stronger in heat content as low as what is progged so don't quite believe that quite yet.

We shall see, if it stays weak like progged then there is a chance it will miss the weakness or at least not end up as far north as progged by other models. We shall see what happens!

[Aric Dunn]

I think it's more interesting that the models are backing off of development quite a bit

maybe we'll get lucky and have a short lived cyclone

well there is one problem .. ... a weaker system mean a more westward track. and although the models keep it weak the whole run once the bertha heads over warmer ssts and at that point shear is still forecast to low ( as long as it does not gain latitude) the models dont do well with intensity anyway so given the potential for re strengthening as it moves back over warmer ssts i would not be so jumpy on complete dissipation

[Aric Dunn]

502
WHXX01 KWBC 031831
CHGHUR
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1831 UTC THU JUL 3 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) 20080703 1800 UTC

...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
080703 1800 080704 0600 080704 1800 080705 0600

LAT LON LAT LON LAT LON LAT LON
BAMS 13.4N 25.0W 14.2N 28.5W 14.9N 32.0W 15.5N 35.0W
BAMD 13.4N 25.0W 14.5N 27.5W 16.0N 30.3W 17.5N 33.4W
BAMM 13.4N 25.0W 14.4N 28.0W 15.7N 31.2W 16.8N 34.5W
LBAR 13.4N 25.0W 13.9N 27.5W 15.1N 30.4W 16.4N 33.6W
SHIP 35KTS 43KTS 50KTS 57KTS
DSHP 35KTS 43KTS 50KTS 57KTS

...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
080705 1800 080706 1800 080707 1800 080708 1800

LAT LON LAT LON LAT LON LAT LON
BAMS 16.5N 37.6W 19.5N 43.8W 21.7N 48.8W 22.4N 52.0W
BAMD 19.0N 36.5W 21.8N 42.6W 25.4N 45.5W 28.0N 45.0W
BAMM 17.9N 37.8W 19.7N 44.5W 21.7N 48.3W 23.2N 49.5W
LBAR 17.7N 37.0W 20.8N 43.1W 22.2N 47.2W 24.0N 48.8W
SHIP 61KTS 68KTS 66KTS 59KTS
DSHP 61KTS 68KTS 66KTS 59KTS

...INITIAL CONDITIONS...
LATCUR = 13.4N LONCUR = 25.0W DIRCUR = 285DEG SPDCUR = 10KT
LATM12 = 12.7N LONM12 = 22.9W DIRM12 = 291DEG SPDM12 = 11KT
LATM24 = 12.0N LONM24 = 20.8W
WNDCUR = 35KT RMAXWD = 30NM WNDM12 = 30KT
CENPRS = 1006MB OUTPRS = 1012MB OUTRAD = 170NM SDEPTH = M
RD34NE = 30NM RD34SE = 30NM RD34SW = 0NM RD34NW = 30NM

$$
NNNN

interesting the models are trending more westward .. they are all past the nhc which for the most part was already more left then the majority of them ..
they will follow suit in the next package.

[cycloneye]

12z GFDL animation shows a 85kt hurricane.

http://moe.met.fsu.edu/cgi-bin/gfdltc2. ... =Animation

[Aric Dunn]

as a courtesy i am going to make animations of the model trends for everyone ..

so far just these two.

[Aric Dunn]

i mean that is only like a 600 mile shift .. lol

[txwatcher91]

I am hoping it will stay a weak TS and hit NC as a depression or storm because we REALLY need the rain.

[KWT]

What I see is the right most models now coming in line with the other model guidence, kindeed the models are in good agreement on a WNW track out to 50W. UKMO and nogaps which don't do much with this system still obn the southern side of the guidence.

If I was in Bermuda I'd be keeping a close eye just in case on this system given there is less of a chance of a major recurve now.

Also strong system on the GFDL as well as has been mentioned.