Typhoon #24W / Durian

Jim Leonard

Here we go again for the Phillipines another developing typhoon heading they're way. Tropical storm 24W is passing south of Guam and is becoming better organized with time. I see JTWC is really aggressive is intensifying the system to a 135kt supertyphoon just before landfall. There is a solid and a zonal ridge setup across the region for the next week and beyond. It is not at all unusual for November and December storms in the northwest pacific to reach category-5 status. Historically there has been many cat-4's into January. The only time that the northwest pacific climatologically slow is February and March. Although there was a cat-4 in early March 2002 named Mitag which recurved east of the Phillipines.
 
Luzon can't get a break. I just saw warning #2 from JTWC, and the forecast for 135 kt five days out.

Kind of strange coming right after Chebi, although JTWC's forecast of 30 kt of strengthening for Chebi in the 24 hr before landfall wasn't shabby. Except for Chanchu, I don't think I've seen any advance forecasts from JTWC to super typhoon intensity this year, and certainly not that far in advance. Both Xangsane and Cimaron intensified faster than forecast, just before landfall in Luzon.

BTW now I remember where I saw the 40 mb drop for Chebi; it was the JMA advisories, three hours apart.
 
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Yesterday JTWC had forecast 15 kt increase in intensity (from 45 kt to 60 kt) for Durian in the 12-hour period that just completed this evening (to 270000Z) -- instead convection diminished and sat estimates from SAB and JTWC dropped from 3.0 to 2.5. It appears from water vapor and visible sat imagery that mid-level dry air has been affecting Durian on the north and west, dissipating convection. Surface outflow can be seen in this area under the sheer cirrus outflow.

JTWC warning #6 just came out while I was typing this. They didn't appear to change the forecast much...just bumped it up another 6 hours while Durian is in this holding pattern. They are still forecasting 130 kt just prior to landfall on Luzon in the Philippines. Their prognostic reasoning notes the mid-level winds to the northwest that are pulling down the drier air:

DESPITE FAVORABLE OUTFLOW, DEEP CONVECTION ASSOCIATED WITH TS 24W HAS CONTINUED TO REMAIN SOMEWHAT DISORGANIZED. ANIMATED WATER VAPOR IMAGERY AND UPPER LEVEL ANALYSIS INDICATE WEAK TROUGHING NORTHWEST OF THE SYSTEM WHICH IS HAMPERING OUTFLOW. THIS IS EXPECTED TO BE SHORT-LIVED, AND THE SYSTEM IS FORECAST TO CONTINUE CONSOLIDATING IN AN ENVIRONMENT OF LOW TO MODERATE VERTICAL WIND SHEAR AND VERY FAVORABLE DIVERGENCE ALOFT. TS 24W IS FORECAST TO INTENSIFY AT A NEAR-CLIMATOLOGICAL RATE THROUGH TAU 72.​

Remarks from SAB's 0233Z bulletin:

REMARKS...SYSTEM CONTINUES TO BE RATHER RAGGED WITH THE BEST LOW-LEVEL INFLOW ON THE NORTH AND EAST SIDES. WV IMAGERY SHOWS MARGINALLY USEFUL OUTFLOW WORKING UP AGAINST A DRY ENVIRONMENT JUST NORTHWEST OF THE SYSTEM. CENTER IS SURROUNDED BY 5-6 TENTHS BROKEN BANDING FOR A DT OF 2.5 WHICH AGREES WITH MET AND PT.​
 
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Hi Jim, hi all !

Soon it will enter into the "explosion-zone" east of Luzon.

Interestingly, this time models show a break of the ridge more or less south of HK. Even if is late season and dry air would take a tall, I could get a near encounter with Durian. Local BBS starts to get "hot" now, as my chat with friends from HK...

Meteorologically, Durian has a chance and space to become stronger and much wider than Cimaron or Chebi. Jet streak is still in place !! Seems there will be a break right around Luzon, with a usual season trough exiting eastern China.

I'm following it very closely, and SST are high enough along the path to sustain a CAT 4 or 5. They are low near south China coast (25-26C) which would allow a decaing storm, of which intensity would be compensated by excellent poleward outflow.

Cheers,
Simone :cool:
 

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To Jim:

Mitag was an extraordinary storm, I still have a shot of it in my computer, I attach here, during peak intensity. Cheers, Simone.
 

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To Jim:

Mitag was an extraordinary storm, I still have a shot of it in my computer, I attach here, during peak intensity. Cheers, Simone.
I actually was wrong on "Mitag's" intensity, not a cat-4 as I stated but a cat-5, 140kts. The western pacific is an amazing basin for tropical cyclones.
 
The way the this years TC's have behaved recently in this region is I would expect to see rapid to explosive intensification once the storm passes longitude 130E.
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http://www.cyclonejim.com

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The way the this years TC's have behaved recently in this region is I would expect to see rapid to explosive intensification once the storm passes longitude 130E.

You'll likely never see a forecast for rapid intensification, since it's hard to predict, but JTWC does still have Durian peaking at 120 kts, with the big jump in intensification between 129E and 127E. Wind shear is forecast to increase once past 130E, and while it could aid outflow, there's also the possibility it could weaken the storm (Spencer Tracy in Desk Set: "Never assume."). Durian hasn't been able to get jump-started yet, in spite of several days of predictions to the contrary, so what's in store is not at all clear-cut. Plus, Durian is getting a nice dry air "hug" to the north and northwest, which will continue as the TC tracks northwest.

But the big news is with the latest forecast (#9, 271800Z), JTWC also has Durian recurving now and just missing the Philippines. Since another forecast will be out by the time I head home on the evening commute, I'll update if the trend in the track continues (JMA still has the track heading for the center of the Philippines).

Update: With forecast #10, JTWC edged the track a little south and has it skimming Luzon; whether it tracks this way, further poleward, or Xangsane-like, as JMA is still forecasting, depends entirely on how the ridging plays out. They came down again on the intensity -- not surprising -- with a max now of 110 kt. Recent vis sat imagery shows the developing eye clearing out (it could be seen as early as lunchtime today -- around 1800Z -- on microwave imagery), but with the skimpy convection this is still a 55 kt TS. Yawn. Anyway this is all great news for the Philippines.

I'd expect to see it consolidate a little more by the time I wake up tomorrow, but I still don't see any sit-up-and-take-notice spurt of intensification anytime real soon.
 
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Hi All,

Well, Durian is showing signs of "nearly-ready-to-explode" features (see the image attached). Bands have improved dramatically and is entering the critical area, where poleward outflow is superbe. There is a jet streak exiting China and passing over Taiwan. An ideal situation, it looks even more diffluent than with Chebi (front part of a stationary wave over northern China/Korean peninsula).

Track is still a complicate subject. JTWC continuosly bring the recurvature eastward, while HKO, CWB and JMA are equatoward. So JTWC is alone, for the moment.

There is a chaser (James Reynolds) who chased Xangsane before in Vietnam, which is probably going to the Philippines to intercept Durian. I'll keep you informed, if is the case.

Cheers,
Simone
 

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The dvorak rules are that no more than two T-numbers per day as for intensity changes is why you won't hear rapid or explosive intensification in especially JTWC forecasts. JTWC only has satellites for tropical cyclone observations. Over here in the atlantic basin we have benefit recon aircraft to get the most accurate observations along with satellite. Many times during the year especially in the west pacific tropical cyclones intensify well above dvorak criteria. My earlier statement for rapid or explosive intensification is my own opinion of my observation of cyclones in that region where you will find more cat-5's than any other part of the world.
 
Finally-to-be-Typhoon Durian

Good morning.

Two-and-a-half days after this thread was started, Durian will finally complete the slow crawl to typhoon status with the next forecast from JTWC (#12). Overnight, intensity was upgraded from 55 kt to 60 kt as expected, and the most recent satellite intensity estimates are agreed by SAB and JTWC to be T4.0.

In just the last couple of hours, deep convection was finally able to wrap most of the way around the center, under the recently-formed CDO. As recently as 0900Z, microwave imagery showed very spotty convection, but a more recent pass from around 1130Z showed much improvement, and, having gotten past the catch-22, this will provide the protection the core needs to develop. Like trying to start a fire under slightly adverse conditions, Durian's "flames" have finally caught, and we can now expect a modest blaze to begin. And finally the anemic shallow convection of the last couple days has been replaced by colder cloud tops (although still somewhat shallow). The poleward outflow that was mentioned is finally starting to form this morning, concurrent with the development of the core convection, starting around 1000Z; the plume of moisture to the north making inroads into the dry air clearly seen on water vapor imagery.

Last night I understood why typhoons tend to rapid intensification here. The natural positioning of the upper level winds provides tremendous outflow. But to paraphrase Avila from an advisory on Sergio last week, it ain't all about the outflow. The reason development was slow, and was expected to be slow, over the past couple days was due to continued dry air intrusion. Increased outflow means increased inflow, and dry air from the north and west was repeatedly eroding convection.

I wouldn't be overly surprised to see Durian reach 90 kt by this evening (290000Z), although, since there is some evidence that a smaller eye is forming, and the storm has organized rapidly in the last couple of hours, already shedding the spiral bands for a compact core (however, still pulling moisture from the ITCZ -- in fact has pulled a considerable amount of moisture from there overnight, increasing the "boundary" between the core and the drier air, which is probably what enabled it to get going), I wouldn't think it completely out of the question to see Durian reach 100 kt to 105 kt today either.

Update: With forecast #12, JTWC stayed with 65 kt, citing the less-than-impressive Quikscat from 0941Z, which however was timed just at the beginning of the recent organization of the convection. They also mention the developing poleward outflow. They are forecasting 80 kt by 29000Z, and, reviewing recent water vapor imagery, I may have gotten carried away just a smidgen with an estimate of 90 kt. But, in spite of some drier air which has managed to wrap almost completely around the core of the the typhoon, starting from the northwest at around 0900Z, a more recent microwave pass from around 1300Z shows continued improvement in the small core.

The track forecast is very touch-and-go, and the JTWC discussion was thorough; it appears likely that northern Luzon will be grazed, and that a more direct hit cannot be ruled out. JMA has not diverged from their forecast of a more westward track landfalling in the central portion of the Philippines.
 
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Looks like Durian's intensity is around 75 to 80 kt this afternoon. JMA increased the current intensity to 70 kt (10-minute average), and the most recent JTWC sat intensity estimate was T4.5 (77 kt), and notes the eye diameter is 10 nm. The eye has been apparent on IR for a couple hours and there is a small (about 30 nm wide) band of convection around the eye, surrounded by a moat which appears to have been caused by dry air wrapping into the storm.

Update: With forecast #13, JTWC finally changed their track to correspond roughly to JMA's. I was wondering, because it wasn't gaining any latitude today. So it's another Xangsane-type track (even though it's a shade to the north, I anticipate the trend will continue and that it will drop south a little over the next couple forecasts), and, they anticipate more strengthening now, and are back up to 120 kt forecast for two days from now, just prior to landfall. This is considerably higher than JMA's, however the JMA forecast is only every 24 hours. JTWC set the current intensity to 75 kt.

Earlier today PAGASA said in an interview that there was the potential for Durian to become a super-typhoon, based only on the fact that it was already a TS when it crossed into their area of responsibility. They are calling Durian "Reming." Anyway this seems unlikely, and I don't think we'll be seeing a "Chebi" happening here.

Evng update: Durian must have heard that last remark, and, in the hour and a half that it took me to commute home, decided to embark on a period of rapid intensification, and with a pinhole eye, to boot. Satellite intensity estimates for the next go-round may break the rules again, if the organization of the eyewall and eye matures as Chebi's did -- especially since AFWA and SAB stayed with T4.5 when JTWC went with T5.0 -- but the same question will remain of whether the windspeeds are catching up to the perceived pressure drops. And if this is going to happen again, in real time, and I don't have any new ways of looking at this and trying to figure it out, I'm going to be in a funk.

JMA's 290000Z update increased the (10-minute average) winds to 80 kt -- so there's the 90 kt I thought I'd see by that time. And now, with further intensification occuring, it looks like 105 kt won't be long in coming. JMA also forecast 90 kt (10-minute average) winds for 24 hours from now, and JMA is very conservative with their intensity forecasts.

JTWC forecast #14 just came out, current intensity set to 90 kt, they only forecast an additional 10 kt over the next 12 hours, but they do increase the max intensity forecast now to 125 kt before landfall. Maybe they'll end up back where they started three days ago. :) They also dropped the track south like I expected.
 
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Here we go...

First, JMA set the 10-minute intensity to 100 kt for 0600Z, equating to a current intensity of 113 kt.

Here's the JTWC sat fix:

001
TPPN10 PGTW 290608

A. TYPHOON 24W (DURIAN)

B. 29/0530Z

C. 13.1N/5

D. 127.3E/3

E. ONE/MTSAT

F. T6.5/6.5/D2.5/24HRS STT: D1.5/06HRS (29/0530Z)

G. IR/EIR/VIS/MSI LLCC

07A/PBO SMALL EYE/ANMTN. 14NM OW EYE SURROUNDED BY CMG
RING YIELDS A DT OF 7.0. PT EQUALS 6.5. DBO PT.
UNREPRESENTATIVE MET EQUALS 5.5. BROKE CONSTRAINTS FOR
INTENSITY DUE TO RAPID INTENSIFICATION OVER PAST 06
HOURS.


VIAULT​

And AFWA:


731
TPPN10 KGWC 290640
A. TYPHOON 24W (DURIAN)
B. 29/0531Z (110)
C. 13.0N/4
D. 127.3E/3
E. ONE/MTSAT
F. T6.5/6.5/D3.5/24HRS STT:D2.0/06HRS -29/0531Z-
G. IR/EIR/VIS/MSI

03A/ PBO 5NM ROUND EYE/ANMTN. OW EYE SURROUNDED BY
48NM WHITE RING. OW EYE AND CMG RING ADDED A 0.5 EYE
ADJUSTMENT. BANDING FEATURE ADDED A 0.5 FOR A UNREP
DT OF 7.0. FT BASED ON PT WHILE MET YIELDED AN UNREP
5.0. CONSTRAINTS BROKEN DUE TO THE RAPID DEVELOPMENT
IN THE PAST 24HRS.


AODT: T5.9 (CLEAR EYE)

CRUZ/LAING​


This equates to 125 kt. And I don't think we're quite done for the evening.

I don't know how to determine if and when winds catch up to these estimates, or, since it appears landfall won't occur for another 24-36 hours, what this may mean for landfall intensity, and whether this will be a brief bright flame like Chebi, or persistent strengthening or maintaining a significant intensity up until landfall. It appears to be the latter to me.

Too bad I can't stay up to watch this as I've got to get up in five hours, and work an extended twelve-hour day tomorrow (the life of a DBA).
 
Again, another explosion undergoing. As I suspected, diffluent jet streak and a tropical point of source linked directly over the storm. It is on its way to CAT 5.... According to present tracks, it will hit Manila at full strength or something less than that......... I've been there the year after Angela (November 1995, I've been there in 1996), the mega-city was still shaken. It will be a mess, unfortunately.

There are tops at < -90C in the northern eyewall !!!
 

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JTWC has 1200Z intensity as T7.0 and 135 kt -- super typhoon status, and the track set to hit Manilla directly. Even if the track continues to shift south, Manilla will still be on the worst side of the storm.

JMA peaked the intensity at 105 kt at 1200Z, which equates to 120 kt. AFWA determined T6.5, which is 125 kt. So there is some question as to whether the typhoon has reached "super typhoon" status. This is academic. I'm sure I've heard Max Mayfield say this (which means he's probably said it at least several hundred times) in so many words, "The difference between a Cat 4 and a Cat 5 is like the difference between being run over by a mac truck and a train." Unlike Chebi, Durian has maintained fairly good structure, so it is surely at least a Cat 4. However a very recent microwave pass from about 1130Z showed a spiral band structure, with the strongest convection slightly further away from the very small eye -- and the proximity to land has resulted in a slight lack of symmetry on IR, so maybe quite a bit of weakening could occur prior to landfall. Also Manilla won't see the worst of the storm because it will weaken as it crosses land.

Update -- looking at the last couple IR images, it does appear that some weakening is occuring and fairly quickly. I'm not sure how to interpret the microwave image, but possibly the pinhole eye is about to collapse. There would be some time before landfall for changes in the organization and structure of the storm, but with the proximity to land it isn't clear to me whether this would allow for restrengthening. However even given the recent appearance, I'd assume JTWC will still go with their 1200Z sat fix and upgrade to a super typhoon (they upgraded Chebi just prior to landfall when it was also obvious that the structure of the storm was not as coherent).
 
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Yeah, it's beginning to weaken now - possibly an eyewall replacement cycle, similar to what happened to Chebi. I don't expect reintensification before landfall in Luzon.
 
Haven't been able to post as I've been swamped at work today, and am about to jump into another couple hours of database migrations that have to be done after work hours.

Simone -- the tropo is colder in the West Pacific, so cloud tops that cold are not so impressive. They may not even be reaching the top, even at that temp.

I kind of jumped the gun in mid-morning and assumed a major weakening trend was underway. Doesn't look to be the case now. Intensity estimates are holding steady at Cat 4, and what is worse, the ERC seems to be completing, and fairly quickly. That close to land, I was a little surprised, especially after earlier microwave passes today.

I'll be back later, although my posts are probably boring everyone here out of their minds! -- but I notice hardly anyone reads this thread anyway. :)

Update: This more recent microwave image just became available on the web, and it is very bad as you can see (if anyone wouldn't mind, please send me a PM on how to embed an image in this post rather than providing a link -- thanks in advance):

tc_home2.cgi


I have never seen an ERC complete this quickly.

A second microwave image from only an hour later -- look how much the eye warmed and cleared out in just that short time:

tc_home2.cgi
 
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I've noticed that typhoons this year have been really dependent on the diurnal maximum for strong intensification, then just as day comes out, the storm stablizes. This is threading the needle, going through Lagonoy Gulf, it seems, just south of Catanduanes Island. I've seen significant intensification occur even in bays in gulfs this year (Xangsane being an example).

I am afraid that with such slow motion and the eyewall grinding through the big cities Virac and Legazpi, and with the track taking it through Manila, that when all is set and done, the devastation will be immense indeed. This is not a quick-hitter in mountainous, rural terrain as Cimaron and Chebi was. This is definitely more similar to Xangsane, and it decimated the Philippines.

Here's a map: http://upload.wikimedia.org/wikipedia/commons/6/6f/Ph_physical_map.png

Virac is on the southern end of Catanduanes island.
 
Durian is smashing the Philippines right now. Geoff Mackley is in Naga, and in two hours it will be filming a direct hit of a monster ! Eye recently reorganized and cleared out, while deep convection expanded. Central Philippines are notorious to support brief re-intensification of cyclones that come from the East or E-SE, while Luzon island dramatically weaken them.

This is the last observation available from Virac:
10:00 AM78 °F / 26 °C 77 °F / 25 °C 96%27.80 in / 941 hPa 5 miles / 8 kilometers NE73.8 mph / 118.8 km/h

I guess we will loose the strongest one (center still not passed at 10:00 AM), but is surely a good one ! TY sustained winds, I cannot imagine the gusts ! And the average is hourly in these observation.... Maybe they are in the range of 100 mph + 1-minute, gusting to over 130 mph.

http://www.weatherunderground.com/h...tml?req_city=NA&req_state=NA&req_statename=NA

Cheers,
Simone

PS: let's pray for the Philippines...
 
Just out on the news is that 146 people were killed from landslides caused by Durian on Mount Mayon, south of Manilla. Also in the article:

On the island of Marinduque, trees were uprooted, lamp posts wrenched out and roofs swept from homes.

"It's the worst in our history. Almost all houses were damaged by the typhoon in the province," Congressman Edmund Reyes said on local radio.​

As news trickles in over the next couple days, it looks like the country will have taken a very hard hit from this typhoon. Another news article lists over 100 dead, but only 20 of those were from the mudslide. The islands that were in the initial path of the typhoon, that took the highest winds, appear to have been practically leveled:

Fernando Gonzales, governor of badly hit Albay province, said 108 bodies had been found but that recovery operations were continuing. The figure did not include at least one person killed in adjacent Camarines Sur province, which reported that its capital was flattened.

Undersecretary Dr. Graciano Yumul of the Department of Science and Technology said the storm was particularly damaging because wind gusts hit 165 mph when Durian came ashore Thursday in Catanduanes, an island province with no mountains to break the storm’s momentum.

“So it really destroyed the island that it hit,â€￾ Yumul said.​

The Philippine web site, Typhoon2000, reported that as the eye passed over Virac there were gusts of 265 kph (roughly 145 kt, or 165 mph).

After emerging into the South China sea, microwave passes showed that Durien still had some notable organization -- an eye and partial eyewall remained -- but water vapor imagery showed dry air repeatedly slicing into the storm, and so basically it is done and will spin down over the next couple days.

Fri aft -- news continues to be quite horrible. No one has been able to get to what is likely the hardest-hit island, Catanduanes. They undoubtably took the highest winds, from the northern eyewall, when Durian had just about finished an ERC, the eye was clearing out, and it was still intensifying.

I also found out that the Bicol area of Albay, which includes Mount Mayon, where the lahars occured, is one of the poorer areas, so I'm sure many of the buildings were not of the type that were built to a building code to withstand typhoons, although there were some concrete structures for this purpose. Unfortunately people in the path of the lahar were trapped in those concrete buildings. I read that Mount Mayon is around 2500m, and since the highest winds are usually around 500m (the avg dropsounde profile), it's no wonder that the mudslides occured, between the extensive rain (they received on the order of 20 inches of rain) and the winds -- and that day's high-res vis sat image showed the area where the volcano is located was under a convective burst in the southwestern eyewall as the storm moved inland.
 
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