TC Bertha

[brunota2003]

Monday the 14th or Tuesday the 15th (about 10 days).

[HURAKAN]

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

----- Current Analysis -----
Date : 05 JUL 2008 Time : 191500 UTC
Lat : 16:49:34 N Lon : 38:36:12 W

CI# /Pressure/ Vmax
3.4 / 997.4mb/ 53.0kt

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

Latitude bias adjustment to MSLP : +2.2mb

Center Temp : -44.7C Cloud Region Temp : -46.0C

Scene Type : UNIFORM CDO CLOUD REGION

Positioning Method : FORECAST INTERPOLATION

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

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

[JonathanBelles]

I have a question....if she were to make landfall in the CONUS....what timeframe are we looking at? 7 days? 10 days? I know it depends on whether or not she slows down, etc. But, at this point, an estimation would suffice. Thanks.

Between the 11th and 14th.

[gatorcane]

Well folks I did call for the West movement about 2 days ago and it is finally here. I did not agree with the NHC about a WNW track. The ridge and heights north of Bertha are just too strong. You can see the pronounced ridge guiding Bertha through the WV loop:

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

Another thing I want to mention is that its rare for models about this time to show a west bend in the long-term. They almost always want to recurve or bend a system NW as it gets towards the CONUS. Part of the reason why is because of the more complex synoptic setup over the EC that typically exists.

I'm not buying a NC to New England area situation and I'm surprised anybody is considering how dead wrong the models have been for the life of Bertha. We can just monitor Bertha and anybody from the NE Leewards to Bermuda and the ENTIRE EC should be watching.

There is still plenty of time to watch Bertha. If she impacts the CONUS we are talking 8-10 days out. Alot can happen until now and then.

[CrazyC83]

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

----- Current Analysis -----
Date : 05 JUL 2008 Time : 191500 UTC
Lat : 16:49:34 N Lon : 38:36:12 W

CI# /Pressure/ Vmax
3.4 / 997.4mb/ 53.0kt

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

Latitude bias adjustment to MSLP : +2.2mb

Center Temp : -44.7C Cloud Region Temp : -46.0C

Scene Type : UNIFORM CDO CLOUD REGION

Positioning Method : FORECAST INTERPOLATION

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

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

Not enough of a change to warrant straying from the NHC and going up to 50 kt yet.

[deltadog03]

See, what I am trying to figure out is when it approches the bahamas from the E or SE there will be a H5 ridge. Now, most models are keeping this fairly weak and if that happens the low level flow will allow for an escape. But, if stronger...which IMO will be the case she should continue to drive atleast WNW or NW and well.....we shall see.

[CrazyC83]

http://manati.orbit.nesdis.noaa.gov/sto ... _at_0.html

Is this current? There is an unflagged barb of over 50 kt in that.

[boca]

I smell a NC threat on this one, and just a guess.Totally unrelated to Bertha of 1996.I do think its ironic though.

[gatorcane]

See, what I am trying to figure out is when it approches the bahamas from the E or SE there will be a H5 ridge. Now, most models are keeping this fairly weak and if that happens the low level flow will allow for an escape. But, if stronger...which IMO will be the case she should continue to drive atleast WNW or NW and well.....we shall see.

DeltaDog precisely. I'm a little concerned of some kind of H5 ridge that could situate itself off the EC in about 5-7 --- and which the models do not have a firm grasp on yet --- preventing Bertha from escaping. Miami NWS yesterday mentioned a building ridge in the long-term that would switch T-storm activity over South Florida to the west coast thus indicating a strong mid to low-level easterly flow.

I can think of many systems in July that tend to be less "pole" biased than in say October or June or even late September. Ridging is strong in July and weaknesses tend to fill quickly.

[wzrgirl1]

what does the H5 stand for?

[MiamiensisWx]

what does the H5 stand for?

Height 500 or 500 mb (upper level)

[wzrgirl1]

thanks....learning

[SouthFloridawx]

Do you think that the Upper Low and associated trough will affect Bertha's track and intensity?

A weaker Bertha means she moves west, vs a deeper Bertha moving farther north.

Atlantic Water Vapor Loop:
http://hadar.cira.colostate.edu/ramsdis/online/trop_ge_wv_ls_0.html
Atlantic Visible Loop:
http://hadar.cira.colostate.edu/ramsdis/online/trop_ge_vis_ls_0.html
http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/carib/gfs/12/images/gfs_500_120l.gif


THE ATLANTIC OCEAN...
THE UPPER PATTERN REMAINS DIFFLUENT OVER THE W ATLC IN
ASSOCIATION WITH BROAD TROUGHING OVER THE ERN CONUS AND AN UPPER
LOW CENTERED OVER SRN FLORIDA. SCATTERED SHOWERS AND TSTMS ARE E
OF THE UPPER LOW N OF CUBA ACROSS SRN FLORIDA...THE ERN STRAITS
OF FLORIDA AND THE NW BAHAMAS. E OF 75W A BROAD AMPLIFIED RIDGE
COVERS THE REST OF THE W ATLC IN THE UPPER LEVELS. FARTHER E...A
LARGE UPPER LOW IS SPINNING NORTH OF THE AREA NEAR 35N49W WITH
TROUGHING EXTENDING S TO NEAR 22N58W. LARGE SCALE RIDGING HOLDS
E OF THERE WITH AN UPPER HIGH POSITIONED NEAR 20N39W. OVERALL...
THIS PATTERN IS PRODUCING LITTLE SENSIBLE WEATHER.

[ekal]

http://manati.orbit.nesdis.noaa.gov/storm_at_image21/latest_at_0.html

Is this current? There is an unflagged barb of over 50 kt in that.

That pass is from 20:31 yesterday, almost 24 hours ago. However, it is not the first to show unflagged 50-knot barbs.

[MiamiensisWx]

Do you think that the Upper Low and associated trough will affect Bertha's track and intensity?

A weaker Bertha means she moves west, vs a deeper Bertha moving farther north.

Atlantic Water Vapor Loop:
http://hadar.cira.colostate.edu/ramsdis/online/trop_ge_wv_ls_0.html
Atlantic Visible Loop:
http://hadar.cira.colostate.edu/ramsdis/online/trop_ge_vis_ls_0.html
http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/carib/gfs/12/images/gfs_500_120l.gif


THE ATLANTIC OCEAN...
THE UPPER PATTERN REMAINS DIFFLUENT OVER THE W ATLC IN
ASSOCIATION WITH BROAD TROUGHING OVER THE ERN CONUS AND AN UPPER
LOW CENTERED OVER SRN FLORIDA. SCATTERED SHOWERS AND TSTMS ARE E
OF THE UPPER LOW N OF CUBA ACROSS SRN FLORIDA...THE ERN STRAITS
OF FLORIDA AND THE NW BAHAMAS. E OF 75W A BROAD AMPLIFIED RIDGE
COVERS THE REST OF THE W ATLC IN THE UPPER LEVELS. FARTHER E...A
LARGE UPPER LOW IS SPINNING NORTH OF THE AREA NEAR 35N49W WITH
TROUGHING EXTENDING S TO NEAR 22N58W. LARGE SCALE RIDGING HOLDS
E OF THERE WITH AN UPPER HIGH POSITIONED NEAR 20N39W. OVERALL...
THIS PATTERN IS PRODUCING LITTLE SENSIBLE WEATHER.

The bolded portion is referring to the TUTT. I believe my analysis (in the link) a few pages back addresses most of your queries on Bertha.

http://www.storm2k.org/phpbb2/viewtopic.php?p=1728870#p1728870

[gatorcane]

Here is the NWS Miami discussion about a deeping ridge for the long-term. So what I am wondering is...is this not the same ridge that would keep Bertha from escaping?

.LONG TERM...TUESDAY THROUGH SATURDAY...A SIGNIFICANT CHANGE IN
THE WX PATTERN IS EXPECTED DURING THIS PERIOD. MOST MDLS SHOW THE
DEEP LAYER ATLC RIDGE BUILDING WESTWARD ACROSS NORTHERN PENINSULA
PUTTING MAINLAND SOUTH FLORIDA UNDER DEEPER EASTERLIES (ESE FLOW
ACTUALLY). GFS FORECAST SOUNDINGS ALSO SHOW A SIGNIFICANT
DECREASE IN PW VALUES DURING THIS PERIOD. ALTHOUGH ISOLD TO SCT
AFTERNOON ACTIVITY MAY STILL BE EXPECTED, THE FOCUS OF AFTERNOON
CONVECTION WILL BE MAINLY INTERIOR AND WEST

[Steve]

A couple of related things: here's the color WV showing the environment out front of Bertha:

http://twister.sbs.ohio-state.edu/sat/G ... atl_wv.gif

Here is the eastern sector (Africa) IR showing a little curvature SE of Bertha. Some may recall some of the models bringing a second system on a more southerly track. Here is the beginnnigs of a second system if anything does get better organized:

http://www.nrlmry.navy.mil/archdat/medi ... LATEST.jpg

Early cycle guidance for 18z (including tropical models). Note the NHC is most similar to the bam-shallow track which they have more or less been following for a couple of runs:

http://euler.atmos.colostate.edu/~vigh/ ... early1.png



Steve

[cycloneye]

http://manati.orbit.nesdis.noaa.gov/storm_at_image21/latest_at_0.html

Is this current? There is an unflagged barb of over 50 kt in that.

That pass was at 347 AM EDT.

[MiamiensisWx]

It will be interesting to observe the movement of the cone at 5 p.m. EDT. The ongoing rapid movement of the LLC just N of due west may spawn the impetus for a slight west adjustment.

[gatorcane]

It will be interesting to observe the movement of the cone at 5 p.m. EDT. The ongoing rapid movement of the LLC just N of due west may spawn the impetus for a slight west adjustment.

I'm anxiously awaiting also. It's hard to believe the model guidance at its current position which all show a WNW movement when Bertha has been racing almost due W now for at least 12 hours. A speed of 21mph is awfully fast for a tropical system.