Karen struggling; Lorenzo sets a new intensification record

By: Dr. Jeff Masters , 2:42 PM GMT on September 29, 2007

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Tropical Depression Karen has weakened to a tropical depression, thanks to ferociously high wind shear levels exceeding 50 knots. Satellite loops show Karen's exposed low-level center of circulation, visible as a swirl of low clouds. Karen continues to generate new heavy thunderstorm activity, but these cells immediately get pushed several hundred miles east of the center by strong upper level winds from the west. This morning's QuikSCAT pass missed Karen.

Wind shear is expected to remain above 30 knots over Karen through Sunday, then decline to 15 knots by Sunday night. Although the storm has shown an unusual ability to maintain a strong wind pattern in the face of high wind shear, it is uncertain if Karen can survive past today. The GFS and ECMWF models predict the shear will destroy Karen. I put Karen's survival chances at about 25%.

If Karen survives, an upper level environment favorable for strengthening is expected to set up 3-5 days from now, and Karen would probably become a hurricane. Steering currents may become weak during that period, and Karen may move very slowly. By the middle of next week, I expect a ridge of high pressure will build over the eastern U.S. and western Atlantic, forcing Karen westward towards the U.S. The path Karen might take late next week is highly uncertain. Most of the models continue to predict the formation of a new tropical or subtropical cyclone somewhere between the coast of North Carolina and the Western Caribbean on Monday. Some of the models take this new storm northeastward out to sea, which would pull Karen northward in its wake. However, most of the models predict that the new storm will take a more westerly path into Georgia or Florida, or possibly the Gulf of Mexico. A storm-storm interaction between Karen and the new storm might ensue, an event the models are poor at handling.


Figure 1. This morning's visible satellite image with wind shear contours overlaid show a very unhealthy tropical depression. Wind shear of 50 knots is over the low-level circulation center of Karen, thanks to strong upper-level winds from the west (denoted by the big white arrow at the plot's bottom). These high winds have pushed all of Karen's heavy thunderstorm activity several hundred miles downwind of the center. Image credit: University of Wisconsin CIMSS.

Lorenzo sets another rapid intensification record for 2007
Hurricane Lorenzo hit Mexico's Veracruz coast near Tuxpan early Friday morning. The storm's heavy rains have triggered mudslides blamed for at least four deaths. Lorenzo has tied the Atlantic record for fastest intensification from a tropical depression to a Category 1 hurricane--twelve hours. Hurricane Blanche of 1969 was the only other storm on record that intensified from a tropical depression to a Category 1 hurricane in just 12 hours. Hurricane Ethel of 1960 may have done so faster, though. Ethel strengthened from a 45-mph tropical storm to a 85 mph Category 1 hurricane in just 6 hours. We don't know when Ethel started as a tropical depression, since this was before the satellite era.

Reliable record keeping of intensification rates of Atlantic hurricanes began in 1970, when regular satellite coverage became available. Since 1970, Hurricane Humberto of 2007 holds the record for fastest intensification from first advisory issued to hurricane strength--18 hours. (Actually, Humberto did the feat in 14 1/4 hours, but this will get rounded off to 18 hours in the final data base, which stores points every six hours). There have been six storms that accomplished the feat in 24 hours.

Since 1970, Hurricane Felix of 2007 holds the record for fastest intensification from the first advisory to a Category 5 hurricane. It took Felix just 54 hours to accomplish the feat. Hurricane Camille of 1969 also took 54 hours to do so, but the first advisory put Camille as a 60 mph tropical storm. It is likely that Camille would have been classified as a tropical depression earlier had reliable satellite imagery been available.

Is it a statistical fluke that we've had three record-speed intensifying hurricanes this year? It could be. Our reliable data records only go back to 1970, and there may have been periods in the past with similar events. No scientist has published a paper linking rapid hurricane intensification rates with global warming. However, three record-speed intensifying hurricanes in one season certainly raises questions, and is very odd.

Melissa
Tropical Storm Melissa formed this morning, far out in the eastern Atlantic. The storm is under about 10-20 knots of wind shear. Melissa will probably not affect land, since it is starting out too far north and will gain additional latitude in the coming days. The storm's expected track will take it northwest towards a region of high wind shear early next week, which should destroy the storm.

I'll have an update Sunday by noon.

Jeff Masters

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1026. Weather456
8:48 PM AST on September 29, 2007
Posted By: wundergroundfan at 8:42 PM AST on September 29, 2007.
Posted By: Weather456 at 8:38 PM EDT on September 29, 2007.
What and where is that?
Seems Spooky


an occluded cyclone in The NE Atlantic
Member Since: July 24, 2005 Posts: 407 Comments: 19076
1025. Weather456
8:48 PM AST on September 29, 2007
A classic Kona Low is north of Hawaii

A Kona Low is special type of subtropical cyclone. Characterizes as a cut-off upper level low that extends to the mid-levels forming from a previous area of frontal activity.

Classic Kona Low north of Hawaii



Member Since: July 24, 2005 Posts: 407 Comments: 19076
1024. HIEXPRESS
12:45 AM GMT on September 30, 2007
Wherefor art thou?
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1023. KarenRei
12:46 AM GMT on September 30, 2007
2007SEP29 231500 2.7 1005.1/ +2.1 / 39.0 2.7 2.7 2.9 3.2 0.5T/hour OFF OFF 17.44 -13.25 SHEAR N/A 17.26 54.75 EXTRP
2007SEP29 234500 2.7 1005.1/ +2.1 / 39.0 2.6 2.7 2.5 2.5 NO LIMIT ON OFF 0.04 -9.90 CRVBND N/A 17.28 54.78 EXTRP


Weakening flag is back on for Karen's remains. Still, with that intensity, she still bears watching in case she wants to spin back up.

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1022. CosmicEvents
12:40 AM GMT on September 30, 2007
Baja...I went to that link. It appeared that the cruise ships were in the exact waters I thought. I didn't see anything that indicated a return tonite. Wouldn't be a bad idea if they could get in quickly, but I think it's too late. It's barf night on The Love Boat.
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1021. moonlightcowboy
12:43 AM GMT on September 30, 2007
Posted By: katadman at 12:18 AM GMT on September 30, 2007.
If anybody has been looking for a way to help the victims of Felix in Nicaragua, email me. My wife is going down there the end of next week and will be involved in disiaster relief. We lived there for eight years and relief was a major component of our work there.


...awesome, Katadman!
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1020. Patrap
7:46 PM CDT on September 29, 2007
BULLETIN
TROPICAL STORM MELISSA ADVISORY NUMBER 6
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL142007
500 PM AST SAT SEP 29 2007

...MELISSA MOVING WEST-NORTHWESTWARD OVER THE FAR EASTERN
ATLANTIC...NO THREAT TO LAND...

AT 500 PM AST...2100Z...THE CENTER OF TROPICAL STORM MELISSA WAS
LOCATED NEAR LATITUDE 15.6 NORTH...LONGITUDE 29.5 WEST OR ABOUT 365
MILES...590 KM...WEST OF THE CAPE VERDE ISLANDS.

MELISSA IS MOVING TOWARD THE WEST-NORTHWEST NEAR 13 MPH...20 KM/HR
...AND THIS MOTION IS EXPECTED TO CONTINUE DURING THE NEXT 24 HOURS.

MAXIMUM SUSTAINED WINDS ARE NEAR 40 MPH...65 KM/HR...WITH HIGHER
GUSTS. LITTLE CHANGE IN STRENGTH IS FORECAST DURING THE NEXT 24
HOURS.

TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 70 MILES...110 KM
FROM THE CENTER.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 MB...29.68 INCHES.

REPEATING THE 500 PM AST POSITION...15.6 N...29.5 W. MOVEMENT
TOWARD...WEST-NORTHWEST NEAR 13 MPH. MAXIMUM SUSTAINED WINDS...40
MPH. MINIMUM CENTRAL PRESSURE...1005 MB.

THE NEXT ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE CENTER AT
1100 PM AST.

$$
FORECASTER AVILA
Member Since: July 3, 2005 Posts: 432 Comments: 132023
1019. InTheCone
12:44 AM GMT on September 30, 2007
456 -

Wow - that is an awesome storm!!
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1017. Patrap
7:44 PM CDT on September 29, 2007
6
Member Since: July 3, 2005 Posts: 432 Comments: 132023
1016. wundergroundfan
8:40 PM EDT on September 29, 2007
Posted By: Weather456 at 8:38 PM EDT on September 29, 2007.
What and where is that?
Seems Spooky
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1015. Patrap
7:41 PM CDT on September 29, 2007
Infrared Loop,Melissa
Link

WV Loop,Melissa
Link
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1013. Weather456
8:38 PM AST on September 29, 2007
Very cool animation
Member Since: July 24, 2005 Posts: 407 Comments: 19076
1012. BajaALemt
12:39 AM GMT on September 30, 2007
Cosmic...looks like they're coming in tonite


Link
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1011. Patrap
7:37 PM CDT on September 29, 2007
GOES-12 Channel 3 (WV) Atlantic,(Central)


2
Member Since: July 3, 2005 Posts: 432 Comments: 132023
1010. Weather456
8:38 PM AST on September 29, 2007
Member Since: July 24, 2005 Posts: 407 Comments: 19076
1009. Weather456
8:32 PM AST on September 29, 2007
456 Do you have a link to the animation loop?

those images i posted i could only get them in still...but this is great animation.

LINK

Closer

Smaller
Member Since: July 24, 2005 Posts: 407 Comments: 19076
1007. InTheCone
12:26 AM GMT on September 30, 2007
After all those sat. pics. and links showing the tiny flecks of any blob - I should have known!!!
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1006. zoomiami
12:27 AM GMT on September 30, 2007
Earlier there was a post about the difficulties of tracking the blobs - my 16 year old daughter watches the blobs - 'cause if its going to rain buckets - she can't wear her best sneakers LOL
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1005. decimus785
12:25 AM GMT on September 30, 2007
Weather456 at 12:22 AM GMT on September 30, 2007.

Posted By: decimus785 at 8:18 PM AST on September 29, 2007.
Weather456 where is that extra tropical going?
to France?


forecast to move eastward towards Spain/Portugal


456 Do you have a link to the animation loop?
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1004. CosmicEvents
12:20 AM GMT on September 30, 2007
It's going to be a very rough night on the cruise ships tonite. Most cruises out of SFla return early Sunday morning, so that means they'll be spending the night cruising through those high seas in the Bahamas and off the Florida East Coast.
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1003. Patrap
7:26 PM CDT on September 29, 2007
I have sources..LOL
Member Since: July 3, 2005 Posts: 432 Comments: 132023
1002. InTheCone
12:25 AM GMT on September 30, 2007
Double dang it - how'd you get in and get a pic. of me - lol!!! Sneaky bugger..
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1001. Patrap
7:22 PM CDT on September 29, 2007
One sometimes need to break away from the Frays..


Member Since: July 3, 2005 Posts: 432 Comments: 132023
1000. zoomiami
12:22 AM GMT on September 30, 2007
Baha - I second that, miss the voices of reason when I'm lurking..
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999. Weather456
8:18 PM AST on September 29, 2007
Posted By: decimus785 at 8:18 PM AST on September 29, 2007.
Weather456 where is that extra tropical going?
to France?


forecast to move eastward towards Spain/Portugal
Member Since: July 24, 2005 Posts: 407 Comments: 19076
998. Patrap
7:21 PM CDT on September 29, 2007
LOL...The season has to have some lighter moments here.Thanx
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997. BahaHurican
8:14 PM EDT on September 29, 2007
Pat,

I forgot to say this earlier, but it is really, REALLY good to have u back.....
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996. zoomiami
12:18 AM GMT on September 30, 2007
http://www.ndbc.noaa.gov/maps/Florida.shtml

Nice link to all the buoys along the coast, shows a major increase in the winds and the wave heights. Most wave heights have gone from around 2 ft last night to up 9 ft today. Our blob is making its presence known!!
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995. CatastrophicDL
12:15 AM GMT on September 30, 2007
456, GREAT picture!
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994. decimus785
12:15 AM GMT on September 30, 2007
Weather456 where is that extra tropical going?
to France?
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993. InTheCone
12:16 AM GMT on September 30, 2007
Dang it Patrap - how'd you get a pic. of my house- lol!!!
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992. Drakoen
12:16 AM GMT on September 30, 2007
Looks like tonights QuickSat will catch the area in the Bahamas. I doubt it has a closed surface circulation. Appears very broad at this point.
Member Since: October 28, 2006 Posts: 57 Comments: 31625
991. katadman
12:15 AM GMT on September 30, 2007
If anybody has been looking for a way to help the victims of Felix in Nicaragua, email me. My wife is going down there the end of next week and will be involved in disiaster relief. We lived there for eight years and relief was a major component of our work there.
Member Since: Posts: Comments:
990. InTheCone
12:13 AM GMT on September 30, 2007
You go caymanite -

I was down visiting your lovely island in Aug. - just as Dean approached. The waters there are just - well incredible!!

Go get the fish!!
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989. Patrap
7:15 PM CDT on September 29, 2007
4-panel Water Vapor Loop

Link
Member Since: July 3, 2005 Posts: 432 Comments: 132023
988. moonlightcowboy
12:14 AM GMT on September 30, 2007
..."two" funny, Pat! lol
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987. BahaHurican
8:13 PM EDT on September 29, 2007
BBL

Around 10:30 EDT.
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986. Patrap
7:13 PM CDT on September 29, 2007
Here we see the Main Blog Patiently awaiting the Next TWO.

Member Since: July 3, 2005 Posts: 432 Comments: 132023
985. Caymanite
12:09 AM GMT on September 30, 2007
What will I be doing Dec_May ? Hopefully catching lots of wahoo and tuna. LOL
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984. CosmicEvents
12:09 AM GMT on September 30, 2007
Quick check before the Florida game.
Is Karen still dead?
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982. Weather456
7:59 PM AST on September 29, 2007
Member Since: July 24, 2005 Posts: 407 Comments: 19076
980. Drakoen
12:09 AM GMT on September 30, 2007
No west winds yet.
Member Since: October 28, 2006 Posts: 57 Comments: 31625
979. Patrap
7:09 PM CDT on September 29, 2007
GOES WV Loop of Tropical Basin


Link
Member Since: July 3, 2005 Posts: 432 Comments: 132023
978. BahaHurican
8:07 PM EDT on September 29, 2007
LOL zoomiami.

What happens if it passes north of here? I won't get any rain in Nassau . . .

Oh wait; that prolly means u won't get any either . . . :o)
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977. Chicklit
12:07 AM GMT on September 30, 2007
Regarding the Bahama disturbance, are we expected to believe the predictions of a person named "Stoopid?"
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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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