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 aspectre:
Odd to have a Name, without an accompanying TropicalStorm. NHC hasn't. ATCF hasn't. So who declared a TropicalStorm?


they did, take a look at past posts
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Odd to have a Name, without an accompanying TropicalStorm.
NHC hadn't and hasn't. ATCF hadn't and hasn't. So who declared a TropicalStorm?
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713. skook
Tampa is getting slammed with this evening thunderstorm, quite a bit of lightning to my west tonight, some of them were close enough to shake my apartment.


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Navy classified 98L as TD
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Quoting HuracanTaino:
Wow,, a 40mph invest !!Stronger winds than a TD !! Nice for 98L....
It's TS Ophelia.
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710. JLPR2
00z SHIPS is more optimistic and says Ophelia could be a 60mph TS in 48hrs, then slowly weaken trough 120hrs.
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Quoting HuracanTaino:
Wow,, a 40mph invest !!Stronger winds than a TD !! Nice for 98L....





98L is a TS now
Member Since: May 21, 2006 Posts: 5091 Comments: 115437
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Quoting nrtiwlnvragn:


Select LGEM from here and you get their last preliminary track.
Looks like a good track. The intensity also seems plausible.
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.
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Wow,, a 40mph invest !!Stronger winds than a TD !! Nice for 98L....
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Roke may cause trouble to already crippled Japan.
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Quoting Tazmanian:




POOF IT IS




sorry i could not help it LOL



when help4you said FISH IT IS



and when i said POOF IT IS i was thinking the word went too geter well
Member Since: May 21, 2006 Posts: 5091 Comments: 115437
Quoting TropicalAnalystwx13:
Good Night All.

I will be back at exactly 7:21:51 tomorrow morning.

7:21 and 51 seconds.
night

I'd wake up to check, but that means I would have to get up before 5. Not gonna happen
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Quoting TropicalAnalystwx13:
Good Night All.

I will be back at exactly 7:21:51 tomorrow morning.

Seven-Twenty-one And Fifty-One Seconds/strong>d .
Why exactly then?
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ophelias track will be very tricky. this isnt a katia where its atomactically out to sea more of after passing the islands does it go into the heart of the carribean, out to sea from a trough OR the trough misses her and further west like irene.. its early. same with maria ALTHOUGH the GFS has been showing maria recurve from day 1..
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Quoting Hurricanes101:


and I bet you thought Maria was a fish storm too


They're all fish storms until they hit land!
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Quoting Drakoen:
Just to be clear, my basis for a closed circulation was not soley on the ASCAT pass, but a combination of both the Windsat and the ASCAT pass. My point was that it is not possible to see say that a closed circulation is not there because you don't see on the partial pass.
Well my basis was just off the latest ASCAT pass and the one before it.

When I said you didn't have any evidence, you should've showed me, the debate would have ended right there lol

But when you said it was undoubtedly closed and didn't bring anything else to the table, I was left with the one pass and had to argue that there's no way you could call it undoubtedly closed.
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Quoting Hurricanes101:


and I bet you thought Maria was a fish storm too




Maria was not a fish lol
Member Since: May 21, 2006 Posts: 5091 Comments: 115437
Quoting will40:



one would think so but i have seen mentioned a piece as big as a bus


Here is the site that has the countdown to reentry.

It's not too precise at the moment. the 23rd, "give or take a day". They will have it narrowed down, two hours before reentry .. . and yes, there is a 300lb chunk that will make it the ground . . . that could ruin one's day.

Link
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I see we have Ophelia, a Caribbean runner looks like, not tracking extremely west, but she will definetley go into the caribbean.
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Quoting MiamiHurricanes09:
Dang bro, 2 days in a row with you getting post 666, LOL.

It's definitely going to be an interesting track. With both the GFS and ECMWF forecasting a track north of the Greater Antilles, I'm more inclined to believe that their cone will mimic what the aforementioned global models foresee.


Select LGEM from here and you get their last preliminary track.
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Quoting wxtropics1998:
Ophelia will be a fish storm.


and I bet you thought Maria was a fish storm too
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691. SLU
At the age of sixteen ..........

16L.SIXTEEN

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Quoting help4u:
FISH IT IS!!!!!!!!!!!!!!!!




POOF IT IS
Member Since: May 21, 2006 Posts: 5091 Comments: 115437
Good Night All.

I will be back at exactly 7:21:51 tomorrow morning.

7:21 and 51 seconds.
Member Since: July 6, 2010 Posts: 113 Comments: 32706
Ophelia will be a fish storm.
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686. JLPR2
Quoting CybrTeddy:


ATCF had a renumber gam, we've got Ophelia out of 98L.
AL, 16, 2011092100, , BEST, 0, 120N, 396W, 35, 1007, LO, 34, NEQ, 150, 0, 0, 120, 1012, 175, 100, 0, 0, L, 0, , 0, 0, OPHELIA, M,


I'm gone for a few minutes and this happens? Dang! XD
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Typhoon Roke
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Quoting MiamiHurricanes09:
Dang bro, 2 days in a row with you getting post 666, LOL.

It's definitely going to be an interesting track. With both the GFS and ECMWF forecasting a track north of the Greater Antilles, I'm more inclined to believe that their cone will mimic what the aforementioned global models foresee.


lol.
Member Since: July 6, 2010 Posts: 113 Comments: 32706
Yay, Ophelia is here. Now I can fall asleep.
15-3-2
Member Since: July 7, 2010 Posts: 0 Comments: 5725

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Just to be clear, my basis for a closed circulation was not soley on the ASCAT pass, but a combination of both the Windsat and the ASCAT pass. My point was that it is not possible to see say that a closed circulation is not there because you don't see (insert wind direction here) on the partial pass.
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16-15-3-2
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I don't want to pheel Ophelia!
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IMO NHC track will have it passing just north of the island of Guadeloupe as a 50 mph Tropical Storm.
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Quoting TropicalAnalystwx13:


Probably not.
Dang bro, 2 days in a row with you getting post 666, LOL.

Quoting nrtiwlnvragn:
Now the discussion can turn to NHC track.
It's definitely going to be an interesting track. With both the GFS and ECMWF forecasting a track north of the Greater Antilles, I'm more inclined to believe that their cone will mimic what the aforementioned global models foresee.
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Quoting BDADUDE:
Yes, looks like it will follow a Katia type of track.




no it wont
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Well then, I guess 98L has been or has very nearly been closed all along. I admit I was wrong earlier about it not being closed, although I really wish I would have seen or been shown some earlier ASCAT passes. I haven't been checking them so I wasn't aware the thing was already closed.

Guess I lost that little debate, but it's all good.
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Thank you all, at least we have a few days to watch....

I did not expect so much change so quickly!!!

I do appreciate you answering my questions.

I will be back tomorrow.

Thank you.

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673. SLU
Quoting TomTaylor:
That is true. I wish I would have seen this ASCAT pass earlier




Definitely closed, just poorly defined and very broad.


That pass was from last night. 98L's center became even more broad this morning and started developing multiple centers. Now that a well defined center has formed it is now a tropical cyclone.
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Quoting CybrTeddy:
For those keeping up at home.

That's 15-3-2.
Quoting MiamiHurricanes09:
Damn it. I take back what I said, LOL.
curios to see the intensity forecasty im thinking moderate to strong ts. 60mph peak im thinkin.
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Quoting BDADUDE:
Yes, looks like it will follow a Katia type of track.


No-It-Does-Not

Member Since: July 6, 2010 Posts: 113 Comments: 32706
Quoting seflagamma:
Thank you all it was confusing at first because I had not kept up...


OK, we have TS Ophelia...

is it suppose to curve out to sea like all the ones before her this year???


Yes, looks like it will follow a Katia type of track.
Member Since: September 3, 2008 Posts: 0 Comments: 605
Quoting TomTaylor:
A partial ASCAT pass revealed NE to SW winds associated with 98L. Since this was only a partial pass, the circulation may have been closed at the time, however, there was no conclusive evidence to say that it was in fact closed at the time of the pass. There were no westerly winds on the pass.

The reason for the strong winds is because of the intense thunderstorm activity around the storm.


You are correct Tom
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Quoting SLU:
HI OPHELIA.

Just to add my piece on the closed circulation discussion a while ago ...

The circulation was always closed. The only issue today was that it did not have a well defined center which is different from not having a closed circulation. That was the only reason why it wasn't renumbered since morning.
That is true. I wish I would have seen this ASCAT pass earlier




Definitely closed, just poorly defined and very broad.
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*sigh* I was hoping she would wither up & die…
Quoting seflagamma:


HUH???? What.. where did TS Ophelia form??

is it 98?


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Quoting seflagamma:
Thank you all it was confusing at first because I had not kept up...


OK, we have TS Ophelia...

is it suppose to curve out to sea like all the ones before her this year???




Probably not.
Member Since: July 6, 2010 Posts: 113 Comments: 32706
Thank you all it was confusing at first because I had not kept up...


OK, we have TS Ophelia...

is it suppose to curve out to sea like all the ones before her this year???


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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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