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 MississippiWx:


:-)

Just kidding.


The shingle didn't do anything to me btw, lol.
Member Since: July 6, 2010 Posts: 113 Comments: 32072
Quoting SLU:
The WINDSAT isn't very accurate with its analysis which is why the NHC never uses it to determine wind speeds and low level circulations.


ASCAT however, different story.. latest past showed what appears to me to have tightened up considerably since the last pass. That could lead to an upgrade, but I've seen much more loosely defined systems this year get upgraded.. one with 12 different vorts *TD Emily off Florida*.
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oops they just did it lol
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Quoting TropicalAnalystwx13:


I knew somebody would respond to that! I knew somebody would!

lol.


:-)

Just kidding.
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well NHC hasnt done the discussion yet. Maybe they waiting on something lol
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Quoting scooster67:
99L is reborn.




no its not its still dead in other words 99L is still EX 99L
Member Since: May 21, 2006 Posts: 5091 Comments: 115131
Quoting MississippiWx:


Geez, what did that shingle do to you?


I knew somebody would respond to that! I knew somebody would!

lol.
Member Since: July 6, 2010 Posts: 113 Comments: 32072
99L is reborn.

Member Since: September 26, 2010 Posts: 0 Comments: 637
405. SLU
The WINDSAT isn't very accurate with its analysis which is why the NHC never uses it to determine wind speeds and low level circulations.
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20/2345 UTC 12.5N 39.6W T2.0/2.0 98L -- Atlantic
20/2345 UTC 13.4N 95.7W T1.0/1.0 96E -- East Pacific
Member Since: May 21, 2006 Posts: 5091 Comments: 115131
Quoting TropicalAnalystwx13:


I did...Knocked our stupid power out, flooded the streets, and took a whole single off the house!

A-WHOLE-SHINGLE!


Geez, what did that shingle do to you?
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Quoting MississippiWx:


The circulation appears to be closed, but is elongated very much to the southwest and northeast. It even gives the hint of two separate circulations, or at least one that is being absorbed into the main circulation.

However, from the way our storms have reached classification this year, I see no reason why 98L shouldn't be a TD. :-)
Lol, if 98L were in the Gulf of Mexico and threatening land, no doubt that it would be a tropical cyclone by now.
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400. SLU
98L might be impressive looking on satellite pictures but the NHC is right in saying that its circulation is poorly defined. There appears to be 2 main areas of cyclonic turning with 98L. One near 13.5n 39.5w and the other near 11.5n 40w. The northern low seems to have been rotating around the southern low all afternoon long. The main reason for the large spread in the guidance today could be because the circulation is poorly defined while it was almost fully closed over the last 2 days. No way this can be called a tropical cyclone based on the criteria for naming/numbering systems. Most of the systems in the deep tropics have had the same circulation issues with 98L which is a good reason why most of them failed to strengthen when climatology suggested that they should have.

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Quoting NCHurricane2009:


I do....errrr is right...if you mean erratic....

Ophelia was the most indecisive woman' cane ever...she couldn't decide whether to be a TS or hurricane and hugged NC coast for a long time...

But...I live inland in Raleigh area so I did not really experience Ophelia 2005...


I did...Knocked our stupid power out, flooded the streets, and took a whole single off the house!

A-WHOLE-SHINGLE!
Member Since: July 6, 2010 Posts: 113 Comments: 32072
Quoting TropicalAnalystwx13:


Errr...Do you not remember 2005's Hurricane Ophelia.

Stupid hurricane :|

lol

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Quoting NCHurricane2009:


Ophelia...I like that storm name....


I detect sarcasm flag on :)
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396. JLPR2
Quoting MississippiWx:


Lol...Well, Jose, Maria, and Lee just to name a few.


It is a good bet Maria actually didn't have a LLC for some hours and it was kept a TS so what the heck, 98L deserves its name.
Member Since: September 4, 2007 Posts: 7 Comments: 8698
98L is a very large system
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394. Skyepony (Mod)
Quoting will40:
the center has been closed its the deep convection that NHC is waiting on


Yeah..I'd be positive of an upgrade if it was firing from the center.

Still taken by it's size.
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Quoting TropicalAnalystwx13:


Errr...Do you not remember 2005's Hurricane Ophelia.

Stupid hurricane :|


I do....errrr is right...if you mean erratic....

Ophelia was the most indecisive woman' cane ever...she couldn't decide whether to be a TS or hurricane and hugged NC coast for a long time...

But...I live inland in Raleigh area so I did not really experience Ophelia 2005...
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Wow. Didn't expect for it to look that good.... haven't been looking at the graphics [ta, skye and petrol]. So an upgrade at 11 p.m. doesn't seem out of the question....
Member Since: October 25, 2005 Posts: 19 Comments: 22140
Quoting MississippiWx:


Lol...Well, Jose, Maria, and Lee just to name a few.
Jose came near to us and was a potent storm!!
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389. JLPR2
Ascat pass should catch part of 98L.


Still loading.
Member Since: September 4, 2007 Posts: 7 Comments: 8698
Quoting NCHurricane2009:


Are you referring to Jose? LOL...


Lol...Well, Jose, Maria, and Lee just to name a few.
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387. Skyepony (Mod)
Should be soon with a windsat like that... Definitely best it's looked. Was a T2.0 six hours ago . Next one coming any minute. Improved a bit.. I could see it getting 2.5 & going right to TS.
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Quoting MississippiWx:


The circulation appears to be closed, but is elongated very much to the southwest and northeast. It even gives the hint of two separate circulations, or at least one that is being absorbed into the main circulation.

However, from the way our storms have reached classification this year, I see no reason why 98L shouldn't be a TD. :-)


Are you referring to Jose? LOL...
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Quoting NCHurricane2009:


Ophelia...I like that storm name....


Errr...Do you not remember 2005's Hurricane Ophelia.

Stupid hurricane :|
Member Since: July 6, 2010 Posts: 113 Comments: 32072
Quoting rkay1:
The same like it was this season, all storms will hit CONUS.  Meanwhile, there has only been 1 true Hurricane threat this year (Irene). 



I want to know the number of storms forecasted not where they will go.
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the center has been closed its the deep convection that NHC is waiting on
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Quoting stormpetrol:


Windsat , closed?


The circulation appears to be closed, but is elongated very much to the southwest and northeast. It even gives the hint of two separate circulations, or at least one that is being absorbed into the main circulation.

However, from the way our storms have reached classification this year, I see no reason why 98L shouldn't be a TD. :-)
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Quoting CybrTeddy:


Probably closed, could very well be a TS instead of a TD according to that.


Ophelia...I like that storm name....
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Quoting stormpetrol:


Windsat , closed?


Probably closed, could very well be a TS instead of a TD according to that.
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Quoting MississippiWx:
98L has continued to become better organized throughout the day. Personally, I would have raised the percentage to at least 80%, if not 90. However, it's obviously not my call. The issue remains with the broad structure of the invest and the lack of one dominant area of circulation. I mentioned earlier in the day how we seemed to have at least a couple vort maxes spinning around a common center of circulation. This is a common issue with monsoonal systems and the main reason why they take longer to be classified.


I would've given it ~100% and initiated advisories at 11PM.

They're waiting until 5AM at the very earliest.
Member Since: July 6, 2010 Posts: 113 Comments: 32072
Quoting stormpetrol:


Windsat , closed?


Oh yes...if Jose was a tropical cyclone...then 98L is defenitely worthy of tropical cyclone status (sorry for Jose reference again...I will let it go someday LOL)...
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Typhoon kills 2, with 2 missing

Typhoon Roke has brought heavy rain to western and central Japan, killing 2 people and leaving 2 others missing.

Police say a man in Nagoya City, central Japan, was fixing a drain on the rooftop of a building when he fell to his death on Tuesday afternoon. Another man in Seiyo City, Ehime Prefecture, was found dead in a nearby river after he went to take a look at it.

In Gifu Prefecture, a 4th-grade boy went missing after being swept away in a waterway in the city of Tajimi. An 84-year-old man remains missing in the town of Shirakawa.

As of 7 AM on Wednesday, about 640 homes across the nation had been inundated by heavy rain.

More than 1.1 million people have been urged to evacuate their homes and take shelter in 13 prefectures in central and western Japan.

http://www3.nhk.or.jp/daily/english/21_06.html

Wednesday, September 21, 2011 05:39 0900 (JST)
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Quoting Skyepony:
Fresh WINDSAT of 98L. Little elongated but expecting an upgrade~ probably TS soon.

Well, it's circulation is ~100% closed.
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Quoting PensacolaDoug:



DOOM!


How is it going to be doom?
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Quoting NCHurricane2009:

I don't see a problem with Greg Fishel (WRAL) myself, better than the meteorologists that blow up threats out of proportion in mainstream media (i.e. The Weather Channel...CNN Chad Myers to name a few)....


WRAL in general does not over-hype storms at all. That's why I love their whole met team. Gave a whole 15 seconds to 98L just to point out it was there, latest potential tracks and a comment that it might do the recurve thing. They always close their commentary on storms that far out with "too early to predict".

Their coverage of the tornado outbreak here in April was outstanding, even more so considering the head met (Greg) was in PA helping his elderly Dad out.

Must admit, miss Tom Skilling of WGN in Chicago. Greg Fishel is the only other met that comes close to him in educating people about weather (at least in this area).
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369. JLPR2
Quoting Skyepony:
Fresh WINDSAT of 98L. Little elongated but expecting an upgrade~ probably TS soon.


jaw drops...
Wasn't expecting it to look so good.
Member Since: September 4, 2007 Posts: 7 Comments: 8698
368. Skyepony (Mod)
98L is huge..
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Quoting Skyepony:
Fresh WINDSAT of 98L. Little elongated but expecting an upgrade~ probably TS soon.
Probably the most well-defined the circulation has ever been.
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98L has continued to become better organized throughout the day. Personally, I would have raised the percentage to at least 80%, if not 90. However, it's obviously not my call. The issue remains with the broad structure of the invest and the lack of one dominant area of circulation. I mentioned earlier in the day how we seemed to have at least a couple vort maxes spinning around a common center of circulation. This is a common issue with monsoonal systems and the main reason why they take longer to be classified.
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Quoting Skyepony:
Fresh WINDSAT of 98L. Little elongated but expecting an upgrade~ probably TS soon.



if recon was there it would already be one imo
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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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