Typhoon Roke bears down on Japan; 98L continues to grow more organized

By: Dr. Jeff Masters , 6:48 PM GMT on September 20, 2011

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Powerful Category 3 Typhoon Roke is bearing down on Japan, and is expected to hit the main island of Honshu on Wednesday morning, local time. Roke is on a dangerous track for Japan, one that would take the storm over some of the most heavily populated areas of the country. Heavy rains from Roke have already reached the coast of Japan, as seen on Japanese radar. However, Roke is starting to weaken, as seen in latest satellite imagery. The eye is no longer apparent, the cloud tops have warmed, and a slot of dry air has gotten wrapped into the storm's northwest side. Wind shear should continue to weaken Roke as it approaches landfall; shear is currently a high 20 knots, and will increase to 30 knots by Wednesday morning. Given the current weakening trend, I expect Roke is most likely to be a Category 2 typhoon at landfall.

Typhoon's Roke's storm surge, winds, and heavy rains will all be a concern. A damaging storm surge is likely to the right of where the center makes landfall, since Roke is a large storm whose winds are spread out over a wide area. If Roke tracks farther to the east than expected, a large storm surge may affect Tokyo Bay. Perhaps the biggest concern from the storm is heavy rain. The soils over much of Japan are saturated from the passage of Tropical Storm Talas during the first week of September. Talas was a very slow moving storm, and brought extreme rainfall amounts of over six feet to some portions of Japan. Roke is expected to bring up to 20 more inches of rain along its path. Roke could bring winds of 30 - 40 mph and heavy rains of 3 - 5 inches to the damaged Fukishima-Dai-Iche nuclear plant northeast of Tokyo.


Figure 1. MODIS image of Typhoon Roke taken at 1:45 pm local time (4:45 UTC) on Tuesday, September 20, 2011. At the time, Roke was a Category 2 storm with 110 mph winds. Image credit: NASA Earth Observatory.

Invest 98L continues to grow more organized
A tropical wave midway between Africa and the Lesser Antilles (Invest 98L) has increased in organization this afternoon, but still lacks a well-defined surface circulation. Satellite imagery shows a number of curved spiral bands have formed this afternoon, and the area covered by heavy thunderstorms has steadily increased. An ASCAT pass from 8:21 am EDT this morning did not capture the full circulation of the storm, but did show winds of 30 mph on the east side of the center. Wind shear as diagnosed by the SHIPS model has increased to a moderate 10 - 15 knots, and is predicted to stay moderate through Friday. Ocean temperatures are 28 - 28.5°C, well above the threshold typically needed for a tropical storm to spin up. Water vapor satellite images show 98L is embedded in a moist environment, but there is dry air to the system's northwest. Given that the shear has now increased to the moderate level, this dry air may begin to hinder development on Wednesday. An analysis of upper level winds from the University of Wisconsin CIMMS group shows a pattern favorable for development, with an outflow channel open to both the north and south available to ventilate the storm and allow 98L to efficiently lift plenty of moisture to high levels.


Figure 2. Afternoon satellite image of 98L.

The latest 8 am EDT (12Z) runs of the computer models show either no development of 98L, or development of 98L into a tropical depression or weak tropical storm by Saturday. 98L's westward motion of 5 - 10 mph should bring the storm into the Lesser Antilles Islands by Saturday, though the models are not in strong agreement about the forward speed of the storm. The GFDL model brings 98L into the islands on Friday, while the HWRF model keeps the storm east of the islands through Sunday. If 98L takes a more west-northwesterly path through northern Lesser Antilles, which has been the preferred track for tropical systems this year, the disturbance should encounter high wind shear in excess of 20 knots due to strong upper-level winds out of the west. This shear should make it difficult for 98L to intensify as it moves though the islands. However, if 98L takes a more southerly path across Barbados, as predicted by the GFDL model, the storm will miss seeing the high shear area that lies over the northern islands, and the storm would have more opportunity to strengthen. The most likely scenario I see at this point is for 98L to be a weak tropical storm on Saturday as it moves through the Lesser Antilles--but there is more than the usual amount of uncertainty in both the track and intensity forecast. NHC gave the disturbance a 70% chance of developing into a tropical depression by Thursday in their 2 pm Tropical Weather Outlook.

September temperatures return to normal over the U.S.
The summer of 2011 was the second hottest in U.S. history, but September of 2011 is so far shaping up to be an average one for temperature. A series of cold fronts and cold-cored low pressure systems have moved southwards out of Canada this month, bringing typical amounts of cool air to the country. If you want to select dates for the start and end of the U.S. heat wave of 2011, the dates to pick would be May 20 - September 4. During the period May 20 - September 4, 2011, the number of daily record high temperatures at the 515 major airports in the U.S. exceeded the number of daily low temperature records every day but one. That's an astonishing 107 out of 108 days! Only July 15 had more record daily lows than highs during that 108-day period. I doubt one could find a similar stretch of days anytime in U.S. weather history where such a lopsided ratio of high temperature to low temperature records existed. For the 3-month summer period of June, July, and August, 2703 daily high temperature records were set, compared to 300 daily low temperature records--a ratio of 9-to-1. Not surprisingly, the summer of 2011 wound up as the hottest summer in 75 years in the U.S., and was only 0.1°F cooler than the all-time record hottest summer, during the Dust Bowl year of 1936. But so far this September, the ratio of high temperature records to low temperature records has been close to 1-to-1. There were 283 daily high temperature records set during the first sixteen days of September, and 246 low temperature records. Eight of the first sixteen days of September have seen the lows outnumber the highs, and eight have seen the highs outnumber the lows. The latest 2-week forecast from the GFS model shows a continuation of pretty normal weather over the U.S. for the rest of the month, and September temperatures will end up close to average.

Jeff Masters

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Quoting WxLogic:


Well, quite conclusive of a TS in my eyes. I was expecting it to be a TD by 8PM but we'll see if it makes it by 2AM, but I would lean towards a TS than a TD.


In my eyes in needs to develop convection where WindSat indicated a possible circulation.





Since designation is a subjective decision, it will always be "discussed"
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what are you talking about threat to bermuda, it is going west into the carribean...
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I think the COC of 98L is around 12.5N/39.5W
Member Since: April 29, 2007 Posts: 0 Comments: 8043
Quoting Speeky:
I know this is not weather related. However I am going to ring the siren that there may be a huge earthquake somewhere in the ring of fire on September 25 - 27. This due to the alignment of a comet named Elenin. It seems to be very large. The alignment of March 11th, 2011 (the 9.0 earthquake in Japan) was just slightly less of that on December 26th, 2004 (The planets Mercury, Mars, Jupiter and Saturn alignment) Just thought that you should know that.


Earthquakes give me significant anxiety even if not near me. Thanks .____.
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Quoting TomTaylor:
I lol'd.

Undoubtedly?

Let's draw a line through the last ASCAT pass to pretend that the pass was an incomplete pass like the current one and see what we get.






Look closely and we have SW to ENE winds. Not quite as complete of a circulation as the current pass, but if you look at the rest of the circulation it is clearly open.

There is definitely doubt that this is closed, Drakoen.


No, there really isn't.

I'd explain my reasoning but I'm too lazy :P
Member Since: July 6, 2010 Posts: 113 Comments: 32532
Quoting Chicklit:
98L's only hope is to lay low along the monsoonal trough until it makes it into the Caribbean.
Currently its fate is unclear of unusual proportion.


How low? 16n?
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559. JLPR2
Quoting TropicalAnalystwx13:


Yes, it appears so.

I don't usually go against the NHC, but...they are wrong.


Well to justify this:
BUT RECENT SATELLITE
IMAGERY INDICATES THAT THIS SYSTEM DOES NOT YET HAVE A WELL-DEFINED
CIRCULATION CENTER.

They didn't have any Windsat or ASCAT images to work with at the moment.
Member Since: September 4, 2007 Posts: 7 Comments: 8747
I suspect when the NHC does pull the trigger on 98L it will go straight to TS status, jmo.
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Quoting Drakoen:


Right because you are looking at a partial pass and a not a complete pass. The system undoubtedly has a closed circulation.

Should be Ophelia if any upgrade is made:

I lol'd.

Undoubtedly?

Let's draw a line through the last ASCAT pass to pretend that the pass was an incomplete pass like the current one and see what we get.






Look closely and we have SW to ENE winds. Not quite as complete of a circulation as the current pass, but if you look at the rest of the circulation it is clearly open. The current pass has SSW/SW to northerly winds and unknown vectors further to the west.

There is definitely doubt that this is closed, Drakoen. Have to disagree with your arrogance.

Will it close up soon? Absolutely, but there is definitely doubt about it being closed at the time of the ASCAT pass and right now. That is the very reason the NHC has kept the system at 70%.
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Member Since: April 29, 2007 Posts: 0 Comments: 8043
Quoting beell:


I have for the most part. From a purely personal/selfish/over-inflated-sense-of-my-own-val ue standpoint, posting here is no longer a good use of my time. But I could not resist a post for the left-coasters!

; - )


Your coverage of the EPAC storm was really good to see!
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Quoting nrtiwlnvragn:
Storm centered WindSat, if you believe the rain contaminated barbs a broad NE to SW circulation 60-100 nm wide





Well, quite conclusive of a TS in my eyes. I was expecting it to be a TD by 8PM but we'll see if it makes it by 2AM, but I would lean towards a TS than a TD.
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Quoting hurricanejunky:
Vorticity looks great. Does it have a well defined closed LLC yet?


Yes, it appears so.

I don't usually go against the NHC, but...they are wrong.
Member Since: July 6, 2010 Posts: 113 Comments: 32532
Quoting islandeye:


Do you have anything to support this idea? Because this was the first thing I found in regards to elenin..

Link


I'm a hell of a lot more worried about the satellite hitting me on the head
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Quoting Speeky:
I know this is not weather related. However I am going to ring the siren that there may be a huge earthquake somewhere in the ring of fire on September 25 - 27. This due to the alignment of a comet named Elenin. It seems to be very large. The alignment of March 11th, 2011 (the 9.0 earthquake in Japan) was just slightly less of that on December 26th, 2004 (The planets Mercury, Mars, Jupiter and Saturn alignment) Just thought that you should know that.

Good looken out Speeky. :)
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550. beell
Quoting FrankZapper:
Nice to see you back Beell! I thought you had closed shop!


I have for the most part. From a purely personal/selfish/over-inflated-sense-of-my-own-val ue standpoint, posting here is no longer a good use of my time. But I could not resist a post for the left-coasters!

; - )
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548. JLPR2
Quoting nrtiwlnvragn:
Storm centered WindSat, if you believe the rain contaminated barbs a broad NE to SW circulation 60-100 nm wide





WPac style.
Member Since: September 4, 2007 Posts: 7 Comments: 8747
Vorticity looks great. Does it have a well defined closed LLC yet?
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People of WUnderground, I think That We have ourselves Ophelia, just not oh-fficial.
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545. JLPR2
Quoting Drakoen:


I don't know. I don't work for the NHC.


Ha!

Quoting TomTaylor:
It's a partial pass, but if it were a non-elongated circulation, the pass would have been enough to see westerly winds.

Since it is an elongated circulation, the ASCAT pass may have missed those westerly winds, but I still wouldn't go about assuming it's closed. I'd wait for another ASCAT pass, or a conclusive buoy or ships report. I know that's what the NHC is doing, anyway. There is no question in my mind for why they left it as a 70% invest, rather than upgrading it to TD 16.


Yes, well, we do have Oceansat that should be passing through that area in a few hours, hope it doesn't miss.
Member Since: September 4, 2007 Posts: 7 Comments: 8747
Storm centered WindSat, if you believe the rain contaminated barbs a broad NE to SW circulation 60-100 nm wide



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Quoting Drakoen:


I don't know. I don't work for the NHC.


lol
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Quoting Drakoen:


I don't know. I don't work for the NHC.


lol, good response.

XD
Member Since: July 6, 2010 Posts: 113 Comments: 32532
98L looks like it could be a HUGE storm.
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Quoting Tropicsweatherpr:
Drakoen,why NHC says it still does not have a well defined closed circulation?.


I don't know. I don't work for the NHC.
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Quoting Tazmanian:



i would wait in tell a new passs
agreed taz

Quoting JLPR2:


You are not supposed to see those on a partial pass, especially when the circulation is so large, ASCAT probably missed those. To my belief it is elongated NE to SW but probably closed.
It's a partial pass, but if it were a non-elongated circulation, the pass would have been enough to see westerly winds.

Since it is an elongated circulation, the ASCAT pass may have missed those westerly winds, but I still wouldn't go about assuming it's closed. I'd wait for another ASCAT pass, or a conclusive buoy or ships report. I know that's what the NHC is doing, anyway. There is no question in my mind for why they left it as a 70% invest, rather than upgrading it to TD 16.
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538. JLPR2
Quoting interstatelover7165:
=??? Mph?


A little over 40mph

Around 41-42mph
Member Since: September 4, 2007 Posts: 7 Comments: 8747
Once she straightens up maybe she'll make an impression.Linkfunktoploopcatl
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518. hurricanejunky 9:08 PM EDT on September 20, 2011 Models looking even crazier than before...

GFS is showing a strong trough that would pick it up. That is the various turns N that is being shown.


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Quoting Speeky:
I know this is not weather related. However I am going to ring the siren that there may be a huge earthquake somewhere in the ring of fire on September 25 - 27. This due to the alignment of a comet named Elenin. It seems to be very large. The alignment of March 11th, 2011 (the 9.0 earthquake in Japan) was just slightly less of that on December 26th, 2004 (The planets Mercury, Mars, Jupiter and Saturn alignment) Just thought that you should know that.


Do you have anything to support this idea? Because this was the first thing I found in regards to elenin..

Link
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534. JLPR2
Quoting Chicklit:
Is 98L acquiring an anticyclone?


98L is busy getting ready, yes, it seems to have acquired a weak one.
Member Since: September 4, 2007 Posts: 7 Comments: 8747
ATCF just raised 98L to 35 knots, but no renum:

AL, 98, 2011092100, , BEST, 0, 120N, 396W, 35, 1007, LO, 34, NEQ, 150, 0, 0, 120, 1012, 175, 60, 0, 0, L, 0, , 0, 0, INVEST, M,
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Quoting TropicalAnalystwx13:


Would you agree that the NHC is being conservative with this system?

I mean...come on! 70% for an invest that looks better than Jose?


Probably
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Drakoen,why NHC says it still does not have a well defined closed circulation?.
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Quoting JLPR2:


Some approx 36-37knots winds in there. Impressive.
=??? Mph?
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529. JLPR2
Quoting Drakoen:


Right because you are looking at a partial pass and a not a complete pass. The system undoubtedly has a closed circulation.

Should be Ophelia if any upgrade is made:



Some approx 36-37knots winds in there. Impressive.
Member Since: September 4, 2007 Posts: 7 Comments: 8747
Quoting Drakoen:


Right because you are looking at a partial pass and a not a complete pass. The system undoubtedly has a closed circulation.

Should be Ophelia if any upgrade is made:



Would you agree that the NHC is being conservative with this system?

I mean...come on! 70% for an invest that looks better than Jose?
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wISH CASTING 98l
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Quoting Tazmanian:



Bermuda needs too watch 98L
I dont think it will come near us.
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Quoting TomTaylor:


Here's the hi-res of the latest ASCAT pass. I see SW to N winds. Still no sign of anything from NW to WSW.


Right because you are looking at a partial pass and a not a complete pass. The system undoubtedly has a closed circulation.

Should be Ophelia if any upgrade is made:

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Is 98L acquiring an anticyclone?
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Quoting BDADUDE:
Cant see it making the Caribbean. Its destined to take a track similiar to Katia.



Bermuda needs too watch 98L
Member Since: May 21, 2006 Posts: 5091 Comments: 115362
I know this is not weather related. However I am going to ring the siren that there may be a huge earthquake somewhere in the ring of fire on September 25 - 27. This due to the alignment of a comet named Elenin. It seems to be very large. The alignment of March 11th, 2011 (the 9.0 earthquake in Japan) was just slightly less of that on December 26th, 2004 (The planets Mercury, Mars, Jupiter and Saturn alignment) Just thought that you should know that.
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Quoting Chicklit:
98L's only hope is to lay low along the monsoonal trough until it makes it into the Caribbean.
Cant see it making the Caribbean. Its destined to take a track similiar to Katia.
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Quoting TomTaylor:




I wouldn't call that closed.

It's elongated, and open to the SW. Note the lack of any westerly, northwesterly, or southwesterly wind vectors. All I see is SSW-N winds.

Not enough to call it closed, imo.


regardless, it still looks open.



i would wait in tell a new passs
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Here's the hi-res of the latest ASCAT pass. I see SW to N winds. Still no sign of anything from NW to WSW.
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Models looking even crazier than before...



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517. JLPR2
Quoting TomTaylor:




I wouldn't call that closed.

It's elongated, and open to the SW. Note the lack of any westerly, northwesterly, or southwesterly wind vectors. All I see is SSW-N winds.

Not enough to call it closed, imo.


regardless, it still looks open.


You are not supposed to see those on a partial pass, especially when the circulation is so large, ASCAT probably missed those. To my belief it is elongated NE to SW but probably closed.
Member Since: September 4, 2007 Posts: 7 Comments: 8747
98L's only hope is to lay low along the monsoonal trough until it makes it into the Caribbean.
Currently its fate is unclear of unusual proportion.
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Quoting JLPR2:


Sure.





I wouldn't call that closed.

It's elongated, and open to the SW. Note the lack of any westerly, northwesterly, or southwesterly wind vectors. All I see is SSW-N winds.

Not enough to call it closed, imo.

Quoting Tazmanian:




thats old

regardless, it still looks open.
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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.