Hurricane Ioke thread

[WindRunner]

125kts

WTPA42 PHFO 250250
TCDCP2

HURRICANE IOKE DISCUSSION NUMBER 21
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI CP012006
500 PM HST THU AUG 24 2006

IOKE HAS BEEN ABLE TO MAINTAIN A RATHER NICE EYE AND SYMMETRIC STRUCTURE DURING THE DAY. A 2016 UTC MICROWAVE PASS SHOWED A CLOSED INNER EYEWALL SURROUNDED BY WHAT APPEARED TO BE AN INCOMPLETE OUTER EYEWALL. THIS MAY BE INDICATING THAT IOKE IS GOING THROUGH AN EYEWALL REPLACEMENT CYCLE. IT IS CERTAINLY A STRONG ENOUGH SYSTEM TO MAKE THIS A POSSIBILITY. DVORAK ESTIMATES FROM CPHC...SAB AND JTWC INDICATE 127 KT WHILE AFWA SHOWS 115 KT. WILL MAINTAIN AN INITIAL INTENSITY OF 125 KT...OR CATEGORY 4 ON THE SAFFIR-SIMPSON SCALE FOR THIS PACKAGE. WINDSAT DATA ALSO INDICATE THAT IOKE IS A LARGE SYSTEM SO THE INITIAL WIND RADII HAVE BEEN INCREASED ESPECIALLY IN THE SOUTHWEST QUADRANT.

AN INITIAL MOTION OF 290 AT 6 KT IS BEING USED AGAIN AS IOKE CONTINUES TO MOVE SOUTH OF A WEAK SUBTROPICAL RIDGE. NO MAJOR CHANGES HAVE BEEN MADE FROM THE PREVIOUS FORECAST PACKAGE WHICH EXPECTS A NORTHEAST TO SOUTHWEST ORIENTED RIDGE TO BUILD IN WEST OF THE HURRICANE. THE RIDGE SHOULD IMPART A SOUTHWESTWARD MOTION ON IOKE FROM DAYS 2 THROUGH 4. A WEAKNESS IN THE RIDGE IS FORECAST TO DEVELOP BY DAY 5 WHICH SHOULD PULL IOKE BACK TOWARD THE NORTHWEST. GLOBAL MODELS ARE IN GENERAL AGREEMENT WITH THIS SCENARIO WITH THE MAIN DIFFERENCES BEING THE STRENGTH OF THE RIDGE AT THE END OF THE FORECAST PERIOD. THE ECMWF KEEPS A STRONGER RIDGE AND HAS THE SOUTHERNMOST TRACK WHILE THE GFS WEAKENS THE RIDGE SUBSTANTIALLY TO FORCE A NORTHWESTWARD TURN FARTHER EAST THAN THE OTHER MODELS. THE FORECAST TRACK FOLLOWS THE GUNS...GUNA AND CONU DYNAMIC CONSENSUS AND CALLS FOR IOKE TO CROSS THE DATELINE AND BECOME A TYPHOON SOME TIME BETWEEN DAYS 2 AND 3.

THE INTENSITY FORECAST IS ESSENTIALLY IDENTICAL TO THE PREVIOUS PACKAGE AND MAINTAINS 125 KT THROUGH 36 HOURS FOLLOWED BY A MODEST WEAKENING TO 115 KT AFTERWARD. NOTE THAT A HURRICANE OF THIS INTENSITY IS EXPECTED TO HAVE RAPID AND TOUGH TO FORECAST FLUCTUATIONS. SST VALUES ARE NEARLY 28C AND THE FORECAST TRACK TAKES IOKE OVER 29C WATERS. THIS FAVORS AT LEAST CURRENT INTENSITY MAINTENANCE AND POSSIBLY FURTHER INTENSIFICATION. THE CIMSS SHEAR ANALYSIS FROM 0000 UTC SHOWS ONLY 2.8 M/S VERTICAL SHEAR WHICH IS A VERY LOW VALUE. INTENSITY GUIDANCE FROM THE DYNAMIC MODELS SHOW STEADY VALUES THROUGH 36 HOURS THEN SOME DIVERGENCE IN THE SOLUTIONS THEREAFTER. BOTH THE GFDI AND GFS WANT TO EVENTUALLY INTENSIFY IOKE TO A CATEGORY 5 SYSTEM WHILE THE OTHERS MAINTAIN A CATEGORY 4 SYSTEM. THE SHIPS MODEL IS NOT USED IN THIS PACKAGE DUE TO PROBLEMS WITH THE COMPUTATIONS OVER THE WESTERN EXTREME OF THE MODEL DOMAIN. THE SLIGHT WEAKENING FORECAST AFTER 36 HOURS IS A RESULT OF SOME NORTHERLY TO NORTHEASTERLY SHEAR THAT IS EXPECTED TO AFFECT THE SYSTEM. HOWEVER...THE SHEAR SHOULD NOT PREVENT IOKE FROM BEING A MAJOR HURRICANE THROUGHOUT THE ENTIRE FORECAST PERIOD.


FORECAST POSITIONS AND MAX WINDS

INITIAL 25/0300Z 19.1N 173.7W 125 KT
12HR VT 25/1200Z 19.5N 174.5W 125 KT
24HR VT 26/0000Z 19.9N 176.0W 125 KT
36HR VT 26/1200Z 19.9N 177.4W 125 KT
48HR VT 27/0000Z 19.5N 178.9W 120 KT
72HR VT 28/0000Z 18.6N 178.6E 115 KT
96HR VT 29/0000Z 19.0N 176.1E 115 KT
120HR VT 30/0000Z 20.4N 174.0E 115 KT


$$
FORECASTER KODAMA/BURKE

[Ptarmigan]

Hurricane Ioke is now even stronger. I am totally amazed by it.

[btangy]

What a beaut! Ioke continues to impress. IMO, I think the CPHC is underestimating the intensity. I can't imagine background pressures would be so low as to make this only 125knots. It's hard to say when all you have are satellite estimates. But, if you were to randomly show me this, I would say it's a 5.

http://wind.mit.edu/~btangy/ioke.jpg

http://wind.mit.edu/~btangy/ioke2.jpg

[Ptarmigan]

What a beaut! Ioke continues to impress. IMO, I think the CPHC is underestimating the intensity. I can't imagine background pressures would be so low as to make this only 125knots. It's hard to say when all you have are satellite estimates. But, if you were to randomly show me this, I would say it's a 5.

http://wind.mit.edu/~btangy/ioke.jpg

http://wind.mit.edu/~btangy/ioke2.jpg

Hurricane Ioke keeps going and going and going.....................

[btangy]

Check out these MODIS images (warning: large images):

LINK

LINK

Just amazing!

[bostonseminole]

I was looking at the GFS 00Z.. never really makes it past 160 just hangs out there and then gets picked up and head north.. other models are not hinting at such.. but we are still 10+ days.. anyone know what is the longest a hurricane has maintained cat 4/5 status in the pacific? or anywhere?

[Cyclenall]

Wow! I'm loving this image!

[Normandy]

meh...thats a near cat 5

[wxmann_91]

The pressures are higher than normal... I'm going with 150 which is near the CPHC estimate.

edit: lower than normal, not higher... sorry about that.

[clfenwi]

TXPN40 PHFO 250650
TCSCP

CENTRAL PACIFIC TROPICAL CYCLONE SUMMARY - FIXES
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI
0630 UTC FRI AUG 25 2006

HURRICANE IOKE LOCATED AT 19.1N 174.2W AT 25/0530 UTC BASED ON 4 KM
IR RESOLUTION SECTOR IMAGES AND ANIMATION. POSITION ACCURATE WITHIN
15 NM. ESTIMATED MAXIMUM 1 MINUTE MEAN WIND SPEED 140 KT. MOVEMENT
ESTIMATED TOWARDS 285 DEGREES AT 7 KT OVER THE PAST 6 HOURS.

T7.0/7.0/D1.5/24 HOURS

REMARKS...IOKE EYE REMAINS VERY APPARENT WITH CONVECTION MORE
SYMETRICAL. USED A WMG EYE WITH THE WHITE SURROUNDING BAND WIDTH OF
41 NM AND A EYE ADJUSTMENT OF +1. THIS YIELD A DT OF 7.0 = 6.0 + 1.0.
THE MET WAS 6.5 AND FINAL T IS 7.0. AODT 6.9

$$
LAU/DONALDSON

------------------------------------------------------------------------------------

TPPZ1 KGWC 250644
A. HURRICANE IOKE (01C)
B. 25/0531Z (67)
C. 19.1N/1
D. 174.0W/2
E. TWO/MTSAT
F. T7.0/7.0/D1.5/24HRS STT:D1.0/06HRS -25/0531Z-
G. IR/EIR/VIS/MSI

07A/ PBO SML EYE/ANMTN. SMALL 22NM WMG EYE SURROUNDED
BY A 41NM WHT BAND GIVING AN EYE NUMBER OF 6.0. ADDED 1.0
FOR EYE ADJ GIVING A DT OF 7.0. FT BASED ON DT. MET
SUPPORTS. PT YIELDS 6.0.

AODT: 7.0 (CLR EYE)

CAMPBELL/LAING

[clfenwi]

WTPA42 PHFO 250852
TCDCP2

HURRICANE IOKE DISCUSSION NUMBER 22
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI CP012006
1100 PM HST THU AUG 24 2006

WITH LOW SHEAR AND WARM WATER...IOKE HAS CONTINUED TO INTENSIFY OVER THE PAST 6 HOURS AND HAS BECOME EXTREMELY POWERFUL. THE SUBJECTIVE DVORAK ESTIMATE FROM CPHC FOR 25/0530 IS T7.0...OR 140KT WITH SUBJECTIVE INTENSITIES OF 6.5 FROM JTWC AND 7.0 FROM AFWA. AODT INTENSITIES WERE 6.9 FROM CPHC AND 7.0 FROM GWC. WE HAVE BOOSTED THE INITIAL INTENSITY TO 140 KT...IN LINE WITH THE MAJORITY OF THE SATELLITE ANALYSES. WE HAVE ALSO INCREASED THE WIND RADII AGAIN BASED ON A 0456Z WINDSAT PASS.

THE MODEL FORECASTS REMAIN IN VERY CLOSE AGREEMENT AND WE HAVE ADJUSTED THE TRACK SLIGHTLY TO KEEP IT IN LINE WITH THE MODEL CONSENSUS. IOKE HAD BEEN TRACKING TOWARDS THE WEST NORTHWEST...BUT THE TRACK IS NOW BENDING TO THE WEST DUE TO AN ANTICYCLONE ALOFT BUILDING NORTH OF THE HURRICANE. THE FORECAST TRACK CONTINUES BENDING TO WEST SOUTHWEST...A BIT MORE THAN THE PREVIOUS FORECAST...AS THE ANTICYCLONE CONTINUES TO BUILD. AFTER 72 HOURS... THE TRACK SHIFTS BACK TO WEST NORTHWEST AS THE ANTICYCLONE SHIFTS WEST AND WEAKENS AND A TROUGH ALOFT STARTS TO DIG NORTH NORTHWEST OF THE HURRICANE. THE CURRENT FORECAST HAS IOKE CROSSING THE DATELINE AND BECOMING A TYPHOON SHORTLY AFTER 27/06Z.

WE HAVE BOOSTED THE INTENSITY FORECAST AGAIN DUE TO THE RECENT RAPID DEEPENING OF THE SYSTEM. THE CIMSS SHEAR ANALYSIS SHOWS ONLY 1.1 M/S SHEAR OVR IOKE. WITH VERY LITTLE SHEAR OVER THE SYSTEM... WE HAVE KEPT THE INTENSITY AT 140 KT THROUGH 48 HOURS AND THEN SLOWLY WEAKENED IT DUE TO INCREASING SHEAR.

FORECAST POSITIONS AND MAX WINDS

INITIAL 25/0900Z 19.2N 174.5W 140 KT
12HR VT 25/1800Z 19.5N 175.5W 140 KT
24HR VT 26/0600Z 19.7N 176.9W 140 KT
36HR VT 26/1800Z 19.5N 178.1W 140 KT
48HR VT 27/0600Z 18.8N 179.5W 140 KT
72HR VT 28/0600Z 17.8N 177.8E 135 KT
96HR VT 29/0600Z 18.4N 175.2E 135 KT
120HR VT 30/0600Z 21.1N 173.4E 130 KT

$$
FORECASTER DONALDSON

[RQSTR]

I love this storm!!

[JonathanBelles]

i knew she could do it!!!!!

[Normandy]

SO much for Dereks prediction....amazing storm

[WmE]

Wohoo! What a powerful storm!!

[HURAKAN]

By the way, when was the last time the CPAC had a homegrown category 5 hurricane?

[WmE]

It is the first Category 5 hurricane in the CPac that actually formed in the CPac.

[HURAKAN]

It is the first Category 5 hurricane in the CPac that actually formed in the CPac.

That's what I thought. WE ARE WATCHING HISTORY IN THE MAKING!!!

[KWT]

an amazing system indeed and a very powerful one, quite stunning, mind you as others have said Derek was about as wrong as you can be!

it has to encounter very strong shear before its gets there. Could be down to a TD by then

This will not become a cat 5, sorry

[WindRunner]

The real stunner hear is the forecast. A Cat 5 for 48 straight hours? That would be crazy to see!