Bertha slowly intensifies, continues west-northwest

By: Dr. Jeff Masters , 12:22 PM GMT on July 04, 2008

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Tropical Storm Bertha has slowly intensified overnight, with new heavy thunderstorm activity building up around the center. Sea Surface Temperatures (SSTs) are now slightly below the threshold of 26°C considered beneficial for tropical storms, and this is limiting Bertha's intensification. This morning's 4:01am EDT QuikSCAT pass revealed top winds of about 30 mph, but the satellite was not able to reliably detect Bertha's strongest winds, since QuikSCAT does poorly in heavy rain. Bertha's current intensity is based mostly on satellite imagery of the cloud patterns. The storm is under about 10 knots of wind shear. Bertha should continue to slowly intensify today.


Figure 1. Track chart of all Atlantic tropical storms that have formed east of 40°W longitude since 1851.

The forecast
Not much has changed in the forecast, with all of the computer models foreseeing a west-northwest track into the mid-Atlantic over the next five days, with a possible recurvature to the north by the end of the period. Whether this recurvature takes place depends on how strong Bertha gets. A larger, stronger storm will be more likely to "feel" the approach of the trough of low pressure expected to recurve Bertha, which a shallower, weaker storm might be able to avoid recurvature and continue west-northwest. Wind shear is expected to remain below 10 knots the next three days, then increase to 30-40 knots by day five, according to the GFS model, when Bertha hits a branch of the Subtropical jet stream. The GFDL model does not go along with this high shear forecast, and makes Bertha a Category 2 hurricane that begins recurving to the east of Bermuda. In contrast, the HWRF model keeps Bertha a weak tropical storm for the next six days. Suffice to say, there is a lot uncertainty in the long range intensity forecast for Bertha!

The hurricane season of 2008 sets a new record
Bertha's at 25° West longitude is the farthest east a tropical storm has ever formed in the Atlantic so early in the season. Reliable records of Eastern Atlantic storms go back to 1967, the beginning of the geostationary satellite era. It's remarkable that no other early July storm even comes close to matching how far east Bertha formed (Figure 1).

Is the formation of Bertha a harbinger of an active hurricane season?
Probably. According the the Hurricane FAQ, "as shown in (Goldenberg 2000), if one looks only at the June-July Atlantic tropical storms and hurricanes occurring south of 22°N and east of 77°W (the eastern portion of the Main Development Region [MDR] for Atlantic hurricanes), there is a strong association with activity for the remainder of the year. According to the data from 1944-1999, total overall Atlantic activity for years that had a tropical storm or hurricane form in this region during JJ have been at least average and often times above average. So it could be said that a JJ storm in this region is pretty much a "sufficient" condition for a year to produce at least average activity."

Elsewhere in the tropics
A tropical wave (93L) that passed through the Lesser Antilles Islands Wednesday night is now in the central Caribbean and is very disorganized, thanks to high wind shear. This wave is not expected to develop, and no computer models are predicting development anywhere else in the Atlantic over the next seven days.

I'll post an update Saturday morning. Happy 4th of July weekend!
Jeff Masters

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1886. TropicalNonsense
2:42 PM GMT on July 06, 2008
hey everyone!
Member Since: July 3, 2007 Posts: 0 Comments: 524
1885. CATfour
6:19 PM GMT on July 05, 2008
Here's what Bertha looks like now...Link
1884. CATfour
3:08 PM GMT on July 05, 2008
National Hurricane Center has Bertha becoming a Hurricane by Tuesday.
1883. MZV
1:26 PM GMT on July 05, 2008
Models are notoriously unreliable when they initialize on a storm. They need at least a few days of data. The current convergences deserve more attention than what we were initially being presented with.
Member Since: July 3, 2008 Posts: 0 Comments: 227
1880. surfmom
12:49 PM GMT on July 05, 2008
is the accuracy of the models affected by the fact that Bertha is basically a total anomaly as she formed so early in the season
Member Since: July 18, 2007 Posts: 30 Comments: 26536
1879. TerraNova
12:48 PM GMT on July 05, 2008
New Blog!
Member Since: July 30, 2007 Posts: 76 Comments: 4062
1878. breald
12:48 PM GMT on July 05, 2008
I'm with surfmom this stuff can be addicting..LOL
Member Since: May 28, 2008 Posts: 38 Comments: 5303
1877. IKE
12:47 PM GMT on July 05, 2008
It is moving faster...almost due west....
Member Since: June 9, 2005 Posts: 23 Comments: 37858
1876. IcemanMC
12:47 PM GMT on July 05, 2008
I'll second that; I have more faith in StormW than the paid professionals
Member Since: August 19, 2007 Posts: 0 Comments: 275
1875. aquak9
12:45 PM GMT on July 05, 2008
G'morning to you as well breald...Lurking is good sometimes. Nice to have someone else here in Duval county. (northeast florida)
Member Since: August 13, 2005 Posts: 163 Comments: 25504
1874. surfmom
12:44 PM GMT on July 05, 2008
we ALL LISTEN to what you have to say StormW!! LOL :)
Member Since: July 18, 2007 Posts: 30 Comments: 26536
1873. wxpaladin
12:44 PM GMT on July 05, 2008
Also, just some background on me since I am fairly new to the blog...

I'm a PT dual degree student at LSU...Religious Studies(BA) and Geography of Science(BS)...basically a Climate degree...my specialties in GEOGS are in Desertification, Forecasting....working on trying to get more classes on the tropics but they only show up every other year. Most of the classes are on the basics like climate, meteorology, mapping, etc..

But I like the tropics the most.
Member Since: June 29, 2008 Posts: 0 Comments: 19
1872. TerraNova
12:44 PM GMT on July 05, 2008
1871. Weather456 7:42 AM EST on July 05, 2008

Sometimes I can't help but thinking that some of the models have a northward bias for systems in the Central and Eastern Atlantic. Remember Dean? That map you posted pretty much looked the same as Dean emerged off the African coast.
Member Since: July 30, 2007 Posts: 76 Comments: 4062
1871. Cavin Rawlins
12:42 PM GMT on July 05, 2008
1862. JFV 8:36 AM AST on July 05, 2008
You appear to be stunned this morning Weather, what's up bud?


July 02 2008



Its the steering this year that gots me spooked.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
1870. severstorm
12:41 PM GMT on July 05, 2008
mourning StormW, had some exciting weather here outside z-hills last night a funnel cloud hanging really low but never touching.
Member Since: November 25, 2007 Posts: 0 Comments: 956
1869. Cavin Rawlins
12:40 PM GMT on July 05, 2008
1860. JFV 8:35 AM AST on July 05, 2008
I'm absolutely floored beyond words, thank you so much for your heartfelt compliment StormW! Good morning 456! So guys, what's your take on Bertha this morning?


She is interesting. She continues to struggle over 25C waters and dry air that would of killed some tropical cyclones but she remains defined. Her track is also interesting. It seems as though, Bertha may affect some landmass down the road. A very big change from when she was born, and I think it will change maybe more in the upcoming days.



I am also watching the wave behind Bertha, GFS still wants to develop this one.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
1868. surfmom
12:39 PM GMT on July 05, 2008
Good morning StormW --- look at all these early risers checking things out -- I think I am going to have to add weather addiction to my life's addiction basket --- I have a few
Member Since: July 18, 2007 Posts: 30 Comments: 26536
1867. TerraNova
12:39 PM GMT on July 05, 2008
The NWS in Puerto Rico has already begun to mention Bertha in their Area Forecast Discussion:

OF PARTICULAR INTEREST...TROPICAL STORM BERTHA CONTINUES TO CHURN
OUT IN THE TROPICAL ATLANTIC OCEAN...POSING ONLY A THREAT TO
SHIPPING LANES AT THIS TIME. THE SYSTEM SHOULD MAINTAIN A WESTWARD
TRACK FOR THE NEXT DAY AS IT PROPAGATES AROUND THE PERIPHERY OF
THE ATLANTIC SURFACE HIGH. GUIDANCE SUGGESTS AN EVENTUAL WEST-
NORTHWESTERLY TRACK WITH TIME...WHICH NOW PLACES THE FEATURE
MUCH CLOSER TO THE LOCAL ISLANDS BY WEDNESDAY OF NEXT WEEK. WILL
DEFER TO FUTURE FORECAST PACKAGES BEFORE INCREASING THE
PRECIPITATION ON WEDNESDAY UNTIL THE TRACK OF BERTHA IS MORE
CERTAIN.
Member Since: July 30, 2007 Posts: 76 Comments: 4062
1865. breald
12:39 PM GMT on July 05, 2008
Hey Aquka, I am sitting and reading all thr intersting info as well. I hope you had a great 4th!
Member Since: May 28, 2008 Posts: 38 Comments: 5303
1863. weathersp
12:37 PM GMT on July 05, 2008
Yeah 456 I just about fell out of bed when I saw that this morning... I was up till 2 AM and wehen I saw that.. I ain't goin back to sleep now! LOL
Member Since: January 14, 2007 Posts: 17 Comments: 4140
1861. weathersp
12:36 PM GMT on July 05, 2008
blog a litle slow this morning?
Member Since: January 14, 2007 Posts: 17 Comments: 4140
1859. Cavin Rawlins
12:34 PM GMT on July 05, 2008
Huh????




Member Since: July 24, 2005 Posts: 407 Comments: 19076
1858. IKE
12:34 PM GMT on July 05, 2008
1843...Dean didn't get to 16.5N until it was near 74W....Bertha is there at 36.5W.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
1857. weathersp
12:34 PM GMT on July 05, 2008
Wow di everyone just wake up at the same time? LOL!
Member Since: January 14, 2007 Posts: 17 Comments: 4140
1856. Cavin Rawlins
12:33 PM GMT on July 05, 2008
5-10 percent chance I will be affected by tropical storm force winds




Member Since: July 24, 2005 Posts: 407 Comments: 19076
1855. morningmisty
12:33 PM GMT on July 05, 2008
Good Morning all,

To nrtwinvragn, Thanks again for the link on African dust. I'm still learning to use it. Do you think the African dust in magenta to the NNW of Bertha will affect it?



http://oiswww.eumetsat.org/SDDI/cgi/listImages.pl?m=prod,a=1,sa=9,pr=RGB,f=1,c=DUST,se=0,n=24,d=1,v =200,pp=0,t=200807041200#controls
Member Since: September 29, 2007 Posts: 0 Comments: 13
1854. surfmom
12:33 PM GMT on July 05, 2008
Good Morning Compadre's!!! sigh of relief NO barn today, young teen bucks are sleeping off the the 4th. Checking in before I dash out for my run (running to coldplay's new album is divine)so I can eat my ice cream tonight. Happy to see Bertha alive and well.

Back to business at hand --OK guys, is it still quiet in Kman's territory??? --looked like there was some potential there last night --wouldn't mind something running up through the shoot into the GOM. And as far as Bertha.....looks like I might get what I wished for (although now my mate is wagging his finger at me saying it'll be my fault if a cane hits FL & totals the house, cause I have been hoping for a 'cane to keep my mom up north...so far tickets have NOT been purchased)Still think I'd rather have interaction w/Bertha..then watch my mom & mate duel it out.

Been without SURF all of June ..now into July, don't want to spend $ on gas/hotel to cross over to the east coast of Florida --so as I always say, no "storm of mass destruction" - just a buoy rocker so I can get out and play in the waves.
Member Since: July 18, 2007 Posts: 30 Comments: 26536
1853. Cavin Rawlins
12:32 PM GMT on July 05, 2008
Good Morning SW
Member Since: July 24, 2005 Posts: 407 Comments: 19076
1852. aquak9
12:32 PM GMT on July 05, 2008
Thanks, JFV. I thought for some reason, you were in the islands.

you often ask a lot of questions, the same questions I would have. So thank you.

(aqua sits in corner quietly, listening to the discussion)
Member Since: August 13, 2005 Posts: 163 Comments: 25504
1850. weathersp
12:32 PM GMT on July 05, 2008
6z GFDL is back on the N route and stronger..

Link
Member Since: January 14, 2007 Posts: 17 Comments: 4140
1848. Cavin Rawlins
12:31 PM GMT on July 05, 2008
Good Morning All
Member Since: July 24, 2005 Posts: 407 Comments: 19076
1846. trunkmonkey
12:31 PM GMT on July 05, 2008
I know this is a day late, but I think its worth putting on here, folks after reading this, lets all reflect as americans!
appy 4th

Happy 4th everyone and remember, Those who went before us paid one Hell of a price... So that we could live in freedom!


Liberty has a price...

Have you ever wondered what happened to the 56 men who signed the Declaration of Independence?

Five signers were captured by the British as traitors, and tortured before they died. Twelve had their homes ransacked and burned. Two lost their sons serving in the Revolutionary Army, another had two sons captured. Nine of the 56 fought and died from wounds or hardships of the Revolutionary War. They signed and they pledged their lives, their fortunes, and their sacred honor.

What kind of men were they? Twenty-four were lawyers and jurists. Eleven were merchants, nine were farmers and large plantation owners; men of means, well educated. But they signed the Declaration of Independence knowing full well that the penalty would be death if they were captured. Carter Braxton of Virginia, a wealthy planter and trader, saw his ships swept from the seas by the British Navy. He sold his home and properties to pay his debts, and died in rags.

Thomas McKeam was so hounded by the British that he was forced to move his family almost constantly. He served in the Congress without pay, and his family was kept in hiding. His possessions were taken from him, and poverty was his reward. Vandals or soldiers looted the properties of Dillery, Hall, Clymer, Walton, Gwinnett, Heyward, Ruttledge, and Middleton. At the battle of Yorktown, Thomas Nelson, Jr., noted that the British General Cornwallis had taken over the Nelson home for his headquarters. He quietly urged General George Washington to open fire. The home was destroyed, and Nelson died bankrupt.

Francis Lewis had his home and properties destroyed. The enemy jailed his wife, and she died within a few months. John Hart was driven from his wife's bedside as she was dying. Their 13 children fled for their lives. His fields and his gristmill were laid to waste. For more than a year he lived in forests and caves, returning home to find his wife dead and his children vanished. A few weeks later he died from exhaustion and a broken heart. Norris and Livingston suffered similar fates.

Such were the stories and sacrifices of the American Revolution. These were not wild-eyed, rabble-rousing ruffians. They were soft-spoken men of means and education. They had security, but they valued liberty more. Standing tall, straight, and unwavering, they pledged:

"For the support of this declaration, with firm reliance on the protection of the divine providence, we mutually pledge to each other, our lives, our fortunes, and our sacred honor."

They gave you and me a free and independent America. The history books never told you a lot of what happened in the Revolutionary War. We didn't just fight the British. We were British subjects at that time and we fought our own government! Some of us take these liberties so much for granted...We shouldn't.

So, take a couple of minutes and silently thank these patriots. It's not much to ask for the price they paid
Member Since: August 18, 2007 Posts: 0 Comments: 557
1845. NC0WX0Man
12:30 PM GMT on July 05, 2008
Good Morning all!

So what is the latest going on with Bertha? Is she a fish storm yet as I keep constantly hearing on tv and seeing in other wx blogs?
1843. MZV
12:28 PM GMT on July 05, 2008
I'm surprised that anyone who has been on this blog more than a few years would pay any attention to models more than 3 or at most 4 days out. We have seen them move so many times.

I will admit though that there have been a few times the long term projections had a perfect lead on a storm (Dean comes to mind).
Member Since: July 3, 2008 Posts: 0 Comments: 227
1842. wxpaladin
12:27 PM GMT on July 05, 2008
But the high is weakening on it's trailing edge and building on it's leading edge over the Lesser Antilles....This in combination with the BH and the ULL/Trough should stear it NWrdly or atleast that is what I think it will do.
Member Since: June 29, 2008 Posts: 0 Comments: 19
1840. weathersp
12:26 PM GMT on July 05, 2008
Good Morning All!

I just about fell out of bedlooking at the GFS when I woke up at 2 am to see the 00z model runs.
Member Since: January 14, 2007 Posts: 17 Comments: 4140
1839. wxpaladin
12:24 PM GMT on July 05, 2008
<<< been talking about the high...but i'm relatively new so I don't get looked at

...I use the esl.lsu.edu site Nova. I know the Prof over that research model (Dr. Hsu).
Member Since: June 29, 2008 Posts: 0 Comments: 19

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About JeffMasters

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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