Rapid Intensification Threat from Karl, Erosion of Igor's Eyewall

By: 1900hurricane , 12:18 AM GMT on September 17, 2010

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Hurricane Karl held his structure together amazingly well while crossing the Yucatan, and now that he is over open water, intensification has resumed. However, the big question is how much stronger Karl will get before landfall. The NHC is calling for a Category 2 Hurricane by landfall. I'm predicting slightly higher, a Category 3 Major Hurricane. Here's why:

Karl has a well defined core.

As I mentioned earlier, Karl had very good structure coming off of the Yucatan, and it has only improved since then. The latest Microwave pass reveals that Karl has developed a very well defined and tight core, and with the favorable conditions that Karl is currently experiencing, steady and possible rapid intensification should continue up to the point of landfall. Recently, the small eye has started to become decreeable on visible imagery, which is another possible sign of rapid intensification. 

A small eye is now being seen.

The only limiting factor that can be seen in Karl's future at the moment is landfall. From an academic standpoint, it will be quite interesting to see how strong Karl can manage to get before landfall.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The same story cannot be said about Major Hurricane Igor. After completing a pretty radical Eyewall Replacement Cycle and reaching a tertiary peak intensity at 125 kt (145 mph), the behemoth has begun to encounter some southwesterly wind shear, which has caused a portion of the eyewall to erode and subsequently weakened the giant. Below will be a time series of Igor's eyewall erosion as seen by 85GHz Microwave imagery:

ERC completed

By 0255Z September 16th, Igor completes his ERC. His very large eye then begins to clear out and once again, he begins to strengthen.

Peak 3

By 0928Z, Igor reaches his tertiary peak intensity of 125 kts. At this point, wind shear starts to impact him and strengthening ends. The effects of the shear can be seen in Igor's southwest quadrant, where the brightness returns are much weaker than in the rest of the eyewall.

SW eyewall eroded

A couple of hours later, at 1224Z, the shear/dry air combo continues to take its toll on Igor, and it can easily be seen that the SW eyewall has been eroded away. By this time, Igor has begun to weaken again and is down to 120 kt (140 mph) by the time of this pass. Since then, Igor has weakened even more, down to a 110 kt (125 mph) category 3 hurricane. However, the National Hurricane Center states this in their forecast discussion:

HURRICANE IGOR DISCUSSION NUMBER 35
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL112010
500 PM AST THU SEP 16 2010

AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT REACHED THE CENTER OF
IGOR AROUND 1600 UTC. THE HURRICANE HUNTERS MEASURED A MINIMUM
PRESSURE OF 940 MB AND MAXIMUM FLIGHT-LEVEL AND SFMR WINDS OF 130
AND 98 KT...RESPECTIVELY. SINCE THAT TIME..THE CLOUD PATTERN
ASSOCIATED WITH IGOR HAS CHANGED LITTLE IN ORGANIZATION...AND
DVORAK T-NUMBERS REMAIN AT 5.5 FROM SAB AND TAFB. BASED UPON THE
AIRCRAFT DATA AND THE LOWER SATELLITE INTENSITY ESTIMATES...THE
INITIAL INTENSITY IS REDUCED TO 110 KT. THE EXTENSION OF AN
UPPER-LEVEL TROUGH PASSING NORTH OF IGOR IS STILL PRODUCING ABOUT
15 KT OF WESTERLY SHEAR OVER THE CYCLONE...ACCORDING TO THE LATEST
UW-CIMSS ANALYSES. THE SHIPS MODEL OUTPUT SHOWS A REDUCTION IN THE
SHEAR WITHIN THE NEXT 12 HOURS AS THIS FEATURE MOVES AWAY...WHICH
COULD ALLOW AN OPPORTUNITY FOR SOME RE-INTENSIFICATION IN THE
SHORT-TERM.


Despite weakening, Igor remains an intense and very, very large hurricane. To illustrate this point, here is one of the last visible images of the day, showing the sun setting over Igor over the right side of the frame. Compare his size to the state of Texas:

Igor is a behemoth

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

***UPDATE***

Karl continues to show signs of organization with his eye tightening even more the before:

Karl Strengthens

This is further reflected in the IR imagry, which shows his eye becoming more apparent and surrounded by a very cold and symmetric CDO:

Karl IR

Also, as mentioned in the NHC Discussion for Igor above, it appears that the shear may be relaxing over him, as much of the eroded portion of his eyewall has redeveloped according to a fairly recent microwave pass:

Igor restrengthening?

Although he still looks somewhat ragged on IR, if this trend continues, he may be able to strengthen again, hitting a quaternary peak intensity and achieving category 4 once agian.

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21. surfmom
4:51 PM GMT on December 31, 2010
Happy New Year!!!! better be NO Canes in your forecast!!!
Member Since: July 18, 2007 Posts: 30 Comments: 26536
20. weatheringpoints
2:54 PM GMT on December 25, 2010
Member Since: February 26, 2008 Posts: 13 Comments: 2028
19. EmmyRose
3:25 PM GMT on December 24, 2010
Thanks for being THE BEST MET on the DECK

Here's to 2011 - could it be another swirl o'fun?
Merry Christmas to you and yours
GIG EM

vintage christmas Pictures, Images and Photos
Member Since: July 15, 2005 Posts: 347 Comments: 76405
18. Barefootontherocks
4:28 AM GMT on December 24, 2010
Enjoy your school vacation!

To you and your family...
Member Since: April 29, 2006 Posts: 159 Comments: 19393
17. EmmyRose
8:29 PM GMT on November 01, 2010
Igor? Karl? I thought we were on Tomas
Get with it Norris.....
Member Since: July 15, 2005 Posts: 347 Comments: 76405
16. ChuckNorris
8:06 PM GMT on November 01, 2010
Cool Blog Bro.
Member Since: October 31, 2010 Posts: 0 Comments: 20
14. 1900hurricane
4:28 AM GMT on September 18, 2010
Igor is sure one strange tiger!



Member Since: August 2, 2006 Posts: 47 Comments: 11709
13. surfmom
12:05 PM GMT on September 17, 2010
Goood Morning 1900 - I've been awake for hours & stalling from viewing the maps.....I think I'm afraid to see the truth - LOL

I am under the impression there is a Nuclear Plant in Karl's path - NOT GOOD -
Laguna Verde Nuclear Power Station
Mexico
Laguna Verde is a nuclear power plant, located in the municipality of Alto Lucero, Veracruz, Mexico. The plant, Mexico's only such facility, produces about 4.2 percent of the country's electrical generating capacity. The plant consists of two General Electric Boiling Water Reactors (BWR-5) which produce 682.5 MWe each. The plant is owned and operated by Comisi�n Federal de Electricidad (CFE)
Member Since: July 18, 2007 Posts: 30 Comments: 26536
12. stormwatcherCI
11:49 AM GMT on September 17, 2010
Good morning Ryan. As of this time Karl is now a category 3 expected to reach category 4 status before landfall later today. Great job on your analysis. Thanks.
Member Since: October 9, 2008 Posts: 0 Comments: 8436
11. 1900hurricane
4:03 AM GMT on September 17, 2010
Rapid Intensification to follow? Karl's structure is excellent!

Member Since: August 2, 2006 Posts: 47 Comments: 11709
10. 1900hurricane
2:46 AM GMT on September 17, 2010
000
WTNT43 KNHC 170240
TCDAT3
HURRICANE KARL DISCUSSION NUMBER 11
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL132010
1000 PM CDT THU SEP 16 2010

THE CLOUD PATTERN HAS CONTINUED TO BECOME BETTER ORGANIZED DURING
THE PAST FEW HOURS AND SATELLITE ESTIMATES FROM BOTH TAFB AND SAB
HAVE REACHED T-NUMBERS OF 5.0 ON THE DVORAK SCALE OR 90 KNOTS AT
0000 UTC. SINCE THEN THE EYE HAS BECOME A LITTLE MORE DISTINCT...
SURROUNDED BY A RING OF VERY DEEP CONVECTION. A RECONNAISSANCE
PLANE CROSSED THE EYE A FEW TIMES THIS EVENING. THE CENTRAL
PRESSURE DROPPED TO 968 MB AND THE FLIGHT LEVEL WINDS REACHED 90
KNOTS IN THE NORTHWEST QUADRANT ACCOMPANIED BY SFMR MEASUREMENTS OF
85 KNOTS. BASED ON THIS...THE INITIAL INTENSITY HAS BEEN INCREASED
TO 85 KNOTS. THIS ESTIMATE COULD BE ON THE LOW SIDE GIVEN THAT THE
SATELLITE PRESENTATION CONTINUES TO IMPROVE AS WE SPEAK.
KARL HAS
LESS THAN A DAY BEFORE LANDFALL...BUT GIVEN THE VERY FAVORABLE
ENVIRONMENT...THE FORECAST NOW CALLS FOR KARL TO BE A CATEGORY
THREE HURRICANE AT LANDFALL.
WEAKENING IS EXPECTED AFTER LANDFALL
OVER THE VERY HIGH TERRAIN OF MEXICO...BUT KARL WILL LIKELY PRODUCE
TORRENTIAL RAINS.

KARL IS MOVING TOWARD THE WEST OR 270 DEGREES AT 8 KNOTS...TRAPPED
SOUTH OF A PERSISTENT HIGH PRESSURE SYSTEM OVER THE NORTHERN GULF OF
MEXICO. THIS GENERAL TRACK IS NOT EXPECTED TO CHANGE THROUGH THE
ENTIRE FORECAST PERIOD. DESPITE SOME DIFFERENCES IN SPEED AMONG
MODELS...THE OVERALL MODEL TREND IS TO KEEP KARL ON A STRAIGHT
WESTWARD PATH OVER THE BAY OF CAMPECHE FOLLOWED BY A LANDFALL OVER
THE COAST OF MEXICO WITHIN THE HURRICANE WARNING AREA LATE FRIDAY.
THIS IS REFLECTED IN THE OFFICIAL FORECAST.


FORECAST POSITIONS AND MAX WINDS

INITIAL 17/0300Z 19.7N 94.5W 85 KT
12HR VT 17/1200Z 19.7N 95.6W 100 KT
24HR VT 18/0000Z 19.7N 96.8W 65 KT...INLAND
36HR VT 18/1200Z 19.5N 98.5W 30 KT...INLAND
48HR VT 19/0000Z 19.5N 100.0W 20 KT...INLAND
72HR VT 20/0000Z...DISSIPATING INLAND

$$
FORECASTER AVILA
Member Since: August 2, 2006 Posts: 47 Comments: 11709
9. DocNDswamp
2:39 AM GMT on September 17, 2010
Hiya 1900,
Excellent points!

Looking at Karl's compact size with a tight eye forming, I'm starting to believe it could become a major also (after being in denial earlier on the chance, lol)... Sorta reminiscent of a Charley...

Will be interesting to see the 10 PM NHC advisory in a few minutes... 95-100 mph maybe?
Member Since: September 21, 2005 Posts: 94 Comments: 4803
8. 1900hurricane
2:04 AM GMT on September 17, 2010
Quoting EmmyRose:
Igor is taking up the whole Atlantic.


Pretty much! As I've stated multiple times before, Igor is a behemoth!
Member Since: August 2, 2006 Posts: 47 Comments: 11709
7. EmmyRose
2:02 AM GMT on September 17, 2010
Igor is taking up the whole Atlantic.

Member Since: July 15, 2005 Posts: 347 Comments: 76405
6. 1900hurricane
1:59 AM GMT on September 17, 2010
Igor sure has made alot of improvements to his eyewall since I put this blog up!

Member Since: August 2, 2006 Posts: 47 Comments: 11709
5. 1900hurricane
1:59 AM GMT on September 17, 2010
Quoting EmmyRose:
When is Karl making landfall?

Probably tomorrow around midday.
Member Since: August 2, 2006 Posts: 47 Comments: 11709
4. EmmyRose
1:51 AM GMT on September 17, 2010
When is Karl making landfall?
Member Since: July 15, 2005 Posts: 347 Comments: 76405
3. 1900hurricane
1:47 AM GMT on September 17, 2010
Member Since: August 2, 2006 Posts: 47 Comments: 11709
2. 1900hurricane
12:38 AM GMT on September 17, 2010
GOES-15 has switched over from Igor to Karl:



Click the image for a loop
Member Since: August 2, 2006 Posts: 47 Comments: 11709
1. 1900hurricane
12:34 AM GMT on September 17, 2010
Julia is holding tough too! Her structure still looks very good, and she might even strengthen a little too!



This should be relatively short lived though, as she is getting dangerously close to the behemoth Igor. Here is a size comparison, Julia is right and Igor is left:

Member Since: August 2, 2006 Posts: 47 Comments: 11709

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Texas A&M meteorology major; hardcore weather enthusiast. Class of 2013 (+ a victory lap or two). My raw passion for extreme weather is hard to match.m@

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