Bertha strengthening again, after rapidly falling apart

By: Dr. Jeff Masters , 1:15 PM GMT on July 09, 2008

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Hurricane Bertha fell apart yesterday to a minimal Category 1 hurricane about as quickly as her meteoric rise to major hurricane status had come. At Bertha's peak--a Category 3 hurricane with 120 mph winds and 948 mb pressure--Bertha was the third strongest hurricane on record so early in the season. Increased wind shear of about 20 knots plus some dry Saharan air that got injected into the core caused Bertha's sudden demise.

The intensity forecast
Shear is on the wane again over Bertha, down to about 15 knots. The storm is beginning to get a more symmetric cloud pattern and better organization, as seen on visible satellite loops. An eye is reappearing, and with Bertha over warm 28°C water, further intensification is likely today. None of the models are predicting a return to Category 3 status again, but Bertha could become a Category 2 hurricane again before wind shear increases once more later this week.


Figure 1. Bertha at peak intensity: 21:15 GMT Monday July 7, 2008. At this time, satellite estimates of Bertha's strength were 115 kt (135 mph), making the storm a weak Category 4 hurricane. Bertha was the third strongest hurricane on record so early in the season.

The track forecast
Bertha is slowing down and turning northward as it "feels" the approach of a trough of low pressure to the north. All of the computer model turn Bertha northwards east of Bermuda, and it currently appears that the island will feel only peripheral effects of Bertha. However, the trough of low pressure turning Bertha to the north will not be strong enough to fully drag the storm into the far North Atlantic, so Bertha will wander close to Bermuda early next week while it waits for another trough of low pressure to finish the job. It is very unlikely Bertha will threaten the U.S., but it could eventually affect the Maritime Provinces of Canada.

Elsewhere in the tropics
There are no threat areas to discuss in the tropical Atlantic. The GFS model is predicting that a tropical depression may form off the coast of Africa on Monday.

Dramatic temperature difference in California
At 3pm PDT yesterday, the temperature at the Point Sur Light Station was 52°F. A shallow marine layer lay along the coast, keeping temperatures cool. Just 20 miles inland, the temperature was 111°F at Arroyo Seco RAWS! You can check out this remarkable contrast by viewing the Wundermap for the region. We just added a fire layer to the product yesterday, so you can see the smoke density in the region as well. It's another bad day in Big Sur!

I'll post an update Thursday morning.
Jeff Masters

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1501. Patrap
2:48 PM GMT on July 10, 2008
Latest from the Experts on Bertha Link
Member Since: July 3, 2005 Posts: 424 Comments: 128344
1500. TheCaneWhisperer
1:05 PM GMT on July 10, 2008
Reasoning for the EWRC is the westward wobble. Hurricanes tend to wobble more when a EWRC is underway. I do agree with the dry air as well.
1499. HurricaneKing
1:05 PM GMT on July 10, 2008
New blog.
Member Since: July 6, 2005 Posts: 71 Comments: 2481
1498. nrtiwlnvragn
1:04 PM GMT on July 10, 2008
7:45 AM

SAB 77 knots, 4.5 4.5
TAFB 77 knots, 4.0 4.5
Member Since: September 23, 2005 Posts: 14 Comments: 11179
1497. extreme236
1:04 PM GMT on July 10, 2008
Conditions should remain favorable for intensification today so she still has potential to become a major hurricane again. All hurricanes have fluctuations in intensity due to various reasons...usually EWRC's are the usual reason but I want to see if the NHC diagnoses that as the reason for her weakening, assuming they do drop her intensity at the next advisory.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
1496. HurricaneKing
1:01 PM GMT on July 10, 2008
Link

I think some dry air worked to her center. This has been happening her entire life cycle. She should start to fill back in soon.
Member Since: July 6, 2005 Posts: 71 Comments: 2481
1495. extreme236
12:58 PM GMT on July 10, 2008
Bertha is fluctuating in intensity. NHC is looking to decrease the intensity down to 80 knots unless something changes between now and 11am advisory (which has happened frequently). Maybe an EWRC could be in the works? I will be very interested in the NHC's discussion at the next advisory.

...INITIAL CONDITIONS...
LATCUR = 26.3N LONCUR = 59.8W DIRCUR = 315DEG SPDCUR = 8KT
LATM12 = 25.2N LONM12 = 58.6W DIRM12 = 316DEG SPDM12 = 8KT
LATM24 = 23.8N LONM24 = 57.0W
WNDCUR = 80KT RMAXWD = 10NM WNDM12 = 90KT
CENPRS = 977MB OUTPRS = 1014MB OUTRAD = 200NM SDEPTH = D
RD34NE = 120NM RD34SE = 75NM RD34SW = 60NM RD34NW = 90NM
Member Since: August 2, 2007 Posts: 19 Comments: 19234
1494. weathersp
12:55 PM GMT on July 10, 2008
Betha the Buzzsaw...
Member Since: January 14, 2007 Posts: 17 Comments: 4140
1492. extreme236
12:52 PM GMT on July 10, 2008
1490.

Corrections:

-Wind shear is light and should remain light for a couple days via most models.
-Convection in the southern quadrant has increased
-Bertha wasn't downgraded to a Cat 2...she remained a Cat 2.

Thats all I saw incorrect.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
1491. extreme236
12:50 PM GMT on July 10, 2008
12;15 image shows a fairly circular eye and deepening convection in the southern and southeastern quadrants of the cyclone. If/when that eye clears out she will look very impressive.


Member Since: August 2, 2007 Posts: 19 Comments: 19234
1489. pottery
12:42 PM GMT on July 10, 2008
This is NICE. An inch and three quarters rain since 5:00 am. Still coming down, but not as heavy. In Trinidad. Its 8:45.am
BBL
Member Since: October 24, 2005 Posts: 0 Comments: 24314
1488. cybergrump
12:36 PM GMT on July 10, 2008
Looks like a west movement again in the last 2 frames.
Member Since: September 17, 2007 Posts: 0 Comments: 434
1487. Thundercloud01221991
12:37 PM GMT on July 10, 2008
raw numbers continue to rise CI# still falling
Member Since: August 1, 2006 Posts: 28 Comments: 3716
1486. TampaSpin
12:35 PM GMT on July 10, 2008
Member Since: September 2, 2007 Posts: 178 Comments: 20439
1485. Thundercloud01221991
12:27 PM GMT on July 10, 2008
Bertha looks amazing right now
Member Since: August 1, 2006 Posts: 28 Comments: 3716
1484. extreme236
12:26 PM GMT on July 10, 2008
the 12:15 infrared image shows the eye starting to clear out again.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
1483. TheCaneWhisperer
12:25 PM GMT on July 10, 2008
Looks like an EWRC Thundercloud.

Seems like Bertha may get close and comfortable with Bermuda.
1482. extreme236
12:24 PM GMT on July 10, 2008
1481.

That happens sometimes. It was doing that yesterday afternoon before the 5pm advisory. The next frame will probably show it gradually becoming more visible.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
1481. Thundercloud01221991
12:21 PM GMT on July 10, 2008
Quoting extreme236:
1471.

I dont think so. Although I haven't looked at microwave images to check...usually you can tell on the infrared imagery and I see no evidence of that yet. The eye has only been around for less than 24 hours so we shouldn't see one till maybe later today/tonight


then why is it filled in or is it a pin hole eye right now
Member Since: August 1, 2006 Posts: 28 Comments: 3716
1480. IKE
12:21 PM GMT on July 10, 2008
Quoting WPBHurricane05:
We're here.......you-tube-ing it..........

Be careful what you youtube.


Just music.......
Member Since: June 9, 2005 Posts: 23 Comments: 37858
1479. TampaSpin
12:20 PM GMT on July 10, 2008
Member Since: September 2, 2007 Posts: 178 Comments: 20439
1477. Patrap
12:18 PM GMT on July 10, 2008
WW3,Bertha,sig wave heights.Link
Member Since: July 3, 2005 Posts: 424 Comments: 128344
1476. WPBHurricane05
12:17 PM GMT on July 10, 2008
We're here.......you-tube-ing it..........

Be careful what you youtube.
Member Since: July 31, 2006 Posts: 56 Comments: 8112
1475. Patrap
12:16 PM GMT on July 10, 2008
wunderground Bermuda site with range and winds on the forecast days.

Civil Air Terminal, Bermuda Link

Bermudans are VERY Hurricane Savvy folks..
Member Since: July 3, 2005 Posts: 424 Comments: 128344
1474. extreme236
12:16 PM GMT on July 10, 2008
1471.

I dont think so. Although I haven't looked at microwave images to check...usually you can tell on the infrared imagery and I see no evidence of that yet. The eye has only been around for less than 24 hours so we shouldn't see one till maybe later today/tonight
Member Since: August 2, 2007 Posts: 19 Comments: 19234
1473. NC0WX0Man
12:16 PM GMT on July 10, 2008
Good Morning All,

What happened to the model that forecasted a cut-off low forming off the Carolina coast and spinning up? Has the model dropped this or is it still showing up?
1472. Patrap
12:15 PM GMT on July 10, 2008
UNCLASSIFIED

FNMOC WW3 Model: COAMPS Area: West Atlantic
Significant Wave Height (ft.) and Direction,BerthaLink
Member Since: July 3, 2005 Posts: 424 Comments: 128344
1471. Thundercloud01221991
12:14 PM GMT on July 10, 2008
is Bertha going through EWR right now
Member Since: August 1, 2006 Posts: 28 Comments: 3716
1470. Thundercloud01221991
12:14 PM GMT on July 10, 2008
They have got to issue a watch today for that island if they don't then they are leaving them too little time to get ready
Member Since: August 1, 2006 Posts: 28 Comments: 3716
1469. cajunkid
12:11 PM GMT on July 10, 2008
this has got to be vexing for people in Bermuda
Member Since: July 10, 2005 Posts: 3 Comments: 1279
1468. IKE
12:10 PM GMT on July 10, 2008
1466....could be. I notice the high on that ECMWF run is strengthening westward...if something forms, doubtful it's a fish-storm.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
1467. biff4ugo
12:09 PM GMT on July 10, 2008
Wow, it is 5am in Cali. and still the temperature is in the mid 90's near Big Sur. The fires and smoke must be trapping the heat somehow. Yuck.
Member Since: December 28, 2006 Posts: 114 Comments: 1571
1466. TheCaneWhisperer
12:08 PM GMT on July 10, 2008
Quoting IKE:
Good morning....good coffee....


Found this interesting info from this mornings San Juan discussion.........

"Latest GFS model guidance continues to
suggests that an active tropical wave will approach to the local
islands next Tuesday...producing a general increase in shower
activity across the region. Looking well ahead...the model
guidances also suggests that a well defined low pressure system
will move very close to the forecast area by July 20-21.

Apparently the Tropic will continue very active. Stay tuned.".............


That's the one the ECMWF has on it's latest run....Cristobal?????




Amen to the good coffee.

Seen that on the GFS yesterday. Well defined low pressure with a well defined high pressure above. Looks to be a busy July indeed.
1465. IKE
12:07 PM GMT on July 10, 2008
Quoting Thundercloud01221991:
good morning is anyone still online


We're here.......you-tube-ing it..........
Member Since: June 9, 2005 Posts: 23 Comments: 37858
1464. TampaSpin
12:05 PM GMT on July 10, 2008
I think we maybe seeing signs of a West move alittle.
Member Since: September 2, 2007 Posts: 178 Comments: 20439
1463. extreme236
12:05 PM GMT on July 10, 2008
1462.

I am still online but I'm not sure who else is
Member Since: August 2, 2007 Posts: 19 Comments: 19234
1462. Thundercloud01221991
12:04 PM GMT on July 10, 2008
good morning is anyone still online
Member Since: August 1, 2006 Posts: 28 Comments: 3716
1461. extreme236
11:48 AM GMT on July 10, 2008
1458.

Isn't because of Bertha since her outflow isn't down that far.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
1460. IKE
11:47 AM GMT on July 10, 2008
00Z ECMWF shows that system that the San Juan met talks about starting around 10N and 40W...next Tuesday....you can see it here on the north hemisphere run....on July 15th...then cruising WNW and strengthening....

Link
Member Since: June 9, 2005 Posts: 23 Comments: 37858
1459. juniormeteorologist
11:47 AM GMT on July 10, 2008
im going to bed.

take a look at my blog..

be back in like 3 hours with an update!

LATER!
1457. TampaSpin
11:44 AM GMT on July 10, 2008
Twin ULL to the West of Bertha and the BAM Tracks....
Member Since: September 2, 2007 Posts: 178 Comments: 20439
1456. HurricaneKing
11:43 AM GMT on July 10, 2008
Quoting IKE:
Quoting HurricaneKing:

Quoting extreme236:
In fact...if you look at the NASA imagery...deep convection is strongest in the SW eyewall.


Last night after the 11:00pm advisory she hardly had convection in her southern side. She looks alot better this morning.


Maybe she had a facial while we snored.


Hahahaha. She needed it.
Member Since: July 6, 2005 Posts: 71 Comments: 2481
1455. extreme236
11:42 AM GMT on July 10, 2008
I'd almost bet to you all that the ADT numbers would be 100-115 knots if that eye was in the positive temperature range.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
1454. IKE
11:41 AM GMT on July 10, 2008
Quoting HurricaneKing:
Quoting extreme236:
In fact...if you look at the NASA imagery...deep convection is strongest in the SW eyewall.


Last night after the 11:00pm advisory she hardly had convection in her southern side. She looks alot better this morning.


Maybe she had a facial while we snored.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
1453. IKE
11:39 AM GMT on July 10, 2008
Good morning....good coffee....


Found this interesting info from this mornings San Juan discussion.........

"Latest GFS model guidance continues to
suggests that an active tropical wave will approach to the local
islands next Tuesday...producing a general increase in shower
activity across the region. Looking well ahead...the model
guidances also suggests that a well defined low pressure system
will move very close to the forecast area by July 20-21.

Apparently the Tropic will continue very active. Stay tuned.".............


That's the one the ECMWF has on it's latest run....Cristobal?????


Member Since: June 9, 2005 Posts: 23 Comments: 37858
1452. extreme236
11:38 AM GMT on July 10, 2008
I think the biggest reason why the ADT shows weakening and is so low right now is probably because of the eye temperature...which it registers at -24.6 degrees C
Member Since: August 2, 2007 Posts: 19 Comments: 19234
1451. HurricaneKing
11:36 AM GMT on July 10, 2008
Quoting extreme236:
In fact...if you look at the NASA imagery...deep convection is strongest in the SW eyewall.


Last night after the 11:00pm advisory she hardly had convection in her southern side. She looks alot better this morning.
Member Since: July 6, 2005 Posts: 71 Comments: 2481

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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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