CPAC: ISELLE - Post-Tropical

[Yellow Evan]

As usual, the CPHC is late for the advisory.

[supercane4867]

105kt flight-level wind with 85kt uncontaminated SFMR report

[Alyono]

87 kt SFMR seems legit

CPHC really needed to be patient with the winds. Pressure a LOT lower than they estimated

No matter what CHPC says, this is a 90-95 kt hurricane now

[Kingarabian]

105kt flight-level wind with 85kt uncontaminated SFMR report

So 85kts for CI maybe a bit too low?

[supercane4867]

105kt flight-level wind with 85kt uncontaminated SFMR report

So 85kts maybe a bit too low?

Likely at least 90kt base on the data

[Kingarabian]

As usual, the CPHC is late for the advisory.

They're probably going to wait until they get a few SFMR samples.

[Yellow Evan]

I'd also go with 90 knts based on the data.

[supercane]

They weren't late; I posted part of the public advisory the previous page. The CPHC site is slow, however. They were late with the discussion.

WTPA43 PHFO 060318
TCDCP3
HURRICANE ISELLE DISCUSSION NUMBER 23
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP092014
500 PM HST TUE AUG 05 2014

ISELLE/S SATELLITE APPEARANCE CONTINUES TO DEGRADE AS THE SYSTEM IS
WEAKENING IN THE FACE OF 10 TO 15 KT SOUTH-SOUTHWESTERLY SHEAR...
BASED ON THE LATEST UW-CIMSS ANALYSIS AND SHIPS GUIDANCE. THE EYE IS
BECOMING INCREASINGLY DIFFICULT TO FIND AS IT BECOMES CLOUD-FILLED...
AND THE INNER CORE HAS BEEN SIGNIFICANTLY DISRUPTED OVER THE PAST 6
TO 12 HOURS. DVORAK CURRENT INTENSITY ESTIMATES ARE 5.0/90 KT...
WHILE FINAL-T NUMBERS INDICATE 4.0/65 KT. BASED ON A BLEND OF THESE
ESTIMATES...THE CURRENT INTENSITY HAS BEEN LOWERED TO 85 KT. AN AIR
FORCE RESERVE HURRICANE HUNTER AIRCRAFT IS PRESENTLY ENROUTE TO
INVESTIGATE ISELLE...AND IS EXPECTED TO PROVIDE GROUND TRUTH FOR THE
NEXT ADVISORY CYCLE. FOR NOW...A RECENT ASCAT PASS LED TO SOME MINOR
ADJUSTMENTS TO THE TROPICAL STORM FORCE WIND RADII.
ISELLE HAS BEEN ACCELERATING TOWARD THE WEST-NORTHWEST TODAY...WITH
THE CURRENT MOTION ESTIMATE 295/11 KT. THIS ACCELERATION SHOULD
ABATE AFTER 36 HOURS...WITH SOME SLOWING IN THE FORWARD MOTION AND
A TURN TOWARD THE WEST LATE IN THE FORECAST PERIOD AS THE SYSTEM
BECOMES INCREASINGLY SHALLOW. FORECAST TRACK GUIDANCE REMAINS
CONSISTENT AND FAIRLY TIGHTLY CLUSTERED...THUS THE LATEST FORECAST
FOLLOWS THE PREVIOUS CLOSELY. ISELLE IS STILL EXPECTED TO PASS NEAR
OR OVER THE HAWAIIAN ISLANDS IN 48-72 HOURS.
RECENT IMAGERY SHOWS WHAT APPEARS TO BE IMPROVING OUTFLOW IN THE
NORTHWEST SEMICIRCLE...AND RESTRICTED OUTFLOW ON THE SOUTH SIDE...
ASSOCIATED WITH A SHARP UPPER-LEVEL TROUGH NEAR 143W/144W. THIS
TROUGH IS OUTLINED NICELY BY DATA RECENTLY RECEIVED BY THE NOAA
G-IV AIRCRAFT...WHICH HAS BEEN SAMPLING THE NEAR-STORM ENVIRONMENT
THROUGHOUT THE DAY. SOME RELAXING OF THE SHEAR OVER THE NEXT 12 TO
36 HOURS IS ANTICIPATED AS THE TROUGH WEAKENS...AND A RIDGE ALOFT
OVER THE MAIN HAWAIIAN ISLANDS SHIFTS WEST. THE INTENSITY FORECAST
RESPONDS BY INDICATING STEADY WEAKENING IN THE SHORT TERM...AND A
SLOWER RATE OF WEAKENING THEREAFTER. THE UPDATED INTENSITY FORECAST
FOLLOWS THE TRENDS DEPICTED BY THE SHIPS/LGEM/IVCN GUIDANCE...BUT
REMAINS SLOWER...WITH SHIPS GUIDANCE WEAKENING ISELLE TO A TROPICAL
STORM IN 18 HOURS.
IT IS IMPORTANT FOR PEOPLE IN THE MAIN HAWAIIAN ISLANDS NOT TO FOCUS
TOO CLOSELY ON THE EXACT FORECAST TRACK OF ISELLE. WITH AN AVERAGE
48 HOUR TRACK ERROR OF APPROXIMATELY 80 MILES...IT IS STILL TOO SOON
TO SAY WITH MUCH CERTAINTY WHICH ISLANDS WOULD BE MOST LIKELY TO
EXPERIENCE THE WORST WEATHER...AND EVERYONE SHOULD BE PREPARED FOR
THE POSSIBILITY OF DIRECT IMPACTS FROM ISELLE. IT IS ALSO IMPORTANT
TO KEEP IN MIND THAT SIGNIFICANT IMPACTS FROM TROPICAL CYCLONES CAN
EXTEND WELL AWAY FROM THE CENTER.


FORECAST POSITIONS AND MAX WINDS

INIT 06/0300Z 16.8N 141.6W 85 KT 100 MPH
12H 06/1200Z 17.3N 143.6W 75 KT 85 MPH
24H 07/0000Z 18.0N 146.8W 65 KT 75 MPH
36H 07/1200Z 18.7N 150.1W 60 KT 70 MPH
48H 08/0000Z 19.3N 153.2W 55 KT 65 MPH
72H 09/0000Z 20.7N 158.7W 45 KT 50 MPH
96H 10/0000Z 21.5N 164.0W 40 KT 45 MPH
120H 11/0000Z 22.0N 168.0W 35 KT 40 MPH

$$
FORECASTER BIRCHARD

[Chris_in_Tampa]

The CPHC site is just slow as others have said. As of 11:21pm EDT, the full public advisory is not yet on their site.

[Yellow Evan]

The CPHC site is just slow as others have said. As of 11:21pm EDT, the full public advisory is not yet on their site.

It's on there now.

[Kingarabian]

The CPHC site is just slow as others have said. As of 11:21pm EDT, the full public advisory is not yet on their site.

On behalf of the people of Hawaii, I'm going to embarrassingly apologize.

[supercane4867]

Lowest Extrap. Sfc. Press: 970.1 mb (~ 28.65 inHg)

[cycloneye]

Finnally!

HURRICANE ISELLE DISCUSSION NUMBER 23
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP092014
500 PM HST TUE AUG 05 2014

ISELLE/S SATELLITE APPEARANCE CONTINUES TO DEGRADE AS THE SYSTEM IS
WEAKENING IN THE FACE OF 10 TO 15 KT SOUTH-SOUTHWESTERLY SHEAR...
BASED ON THE LATEST UW-CIMSS ANALYSIS AND SHIPS GUIDANCE. THE EYE IS
BECOMING INCREASINGLY DIFFICULT TO FIND AS IT BECOMES CLOUD-FILLED...
AND THE INNER CORE HAS BEEN SIGNIFICANTLY DISRUPTED OVER THE PAST 6
TO 12 HOURS. DVORAK CURRENT INTENSITY ESTIMATES ARE 5.0/90 KT...
WHILE FINAL-T NUMBERS INDICATE 4.0/65 KT. BASED ON A BLEND OF THESE
ESTIMATES...THE CURRENT INTENSITY HAS BEEN LOWERED TO 85 KT. AN AIR
FORCE RESERVE HURRICANE HUNTER AIRCRAFT IS PRESENTLY ENROUTE TO
INVESTIGATE ISELLE...AND IS EXPECTED TO PROVIDE GROUND TRUTH FOR THE
NEXT ADVISORY CYCLE. FOR NOW...A RECENT ASCAT PASS LED TO SOME MINOR
ADJUSTMENTS TO THE TROPICAL STORM FORCE WIND RADII.

ISELLE HAS BEEN ACCELERATING TOWARD THE WEST-NORTHWEST TODAY...WITH
THE CURRENT MOTION ESTIMATE 295/11 KT. THIS ACCELERATION SHOULD
ABATE AFTER 36 HOURS...WITH SOME SLOWING IN THE FORWARD MOTION AND
A TURN TOWARD THE WEST LATE IN THE FORECAST PERIOD AS THE SYSTEM
BECOMES INCREASINGLY SHALLOW. FORECAST TRACK GUIDANCE REMAINS
CONSISTENT AND FAIRLY TIGHTLY CLUSTERED...THUS THE LATEST FORECAST
FOLLOWS THE PREVIOUS CLOSELY. ISELLE IS STILL EXPECTED TO PASS NEAR
OR OVER THE HAWAIIAN ISLANDS IN 48-72 HOURS.

RECENT IMAGERY SHOWS WHAT APPEARS TO BE IMPROVING OUTFLOW IN THE
NORTHWEST SEMICIRCLE...AND RESTRICTED OUTFLOW ON THE SOUTH SIDE...
ASSOCIATED WITH A SHARP UPPER-LEVEL TROUGH NEAR 143W/144W. THIS
TROUGH IS OUTLINED NICELY BY DATA RECENTLY RECEIVED BY THE NOAA
G-IV AIRCRAFT...WHICH HAS BEEN SAMPLING THE NEAR-STORM ENVIRONMENT
THROUGHOUT THE DAY. SOME RELAXING OF THE SHEAR OVER THE NEXT 12 TO
36 HOURS IS ANTICIPATED AS THE TROUGH WEAKENS...AND A RIDGE ALOFT
OVER THE MAIN HAWAIIAN ISLANDS SHIFTS WEST. THE INTENSITY FORECAST
RESPONDS BY INDICATING STEADY WEAKENING IN THE SHORT TERM...AND A
SLOWER RATE OF WEAKENING THEREAFTER. THE UPDATED INTENSITY FORECAST
FOLLOWS THE TRENDS DEPICTED BY THE SHIPS/LGEM/IVCN GUIDANCE...BUT
REMAINS SLOWER...WITH SHIPS GUIDANCE WEAKENING ISELLE TO A TROPICAL
STORM IN 18 HOURS.

IT IS IMPORTANT FOR PEOPLE IN THE MAIN HAWAIIAN ISLANDS NOT TO FOCUS
TOO CLOSELY ON THE EXACT FORECAST TRACK OF ISELLE. WITH AN AVERAGE
48 HOUR TRACK ERROR OF APPROXIMATELY 80 MILES...IT IS STILL TOO SOON
TO SAY WITH MUCH CERTAINTY WHICH ISLANDS WOULD BE MOST LIKELY TO
EXPERIENCE THE WORST WEATHER...AND EVERYONE SHOULD BE PREPARED FOR
THE POSSIBILITY OF DIRECT IMPACTS FROM ISELLE. IT IS ALSO IMPORTANT
TO KEEP IN MIND THAT SIGNIFICANT IMPACTS FROM TROPICAL CYCLONES CAN
EXTEND WELL AWAY FROM THE CENTER.


FORECAST POSITIONS AND MAX WINDS

INIT 06/0300Z 16.8N 141.6W 85 KT 100 MPH
12H 06/1200Z 17.3N 143.6W 75 KT 85 MPH
24H 07/0000Z 18.0N 146.8W 65 KT 75 MPH
36H 07/1200Z 18.7N 150.1W 60 KT 70 MPH
48H 08/0000Z 19.3N 153.2W 55 KT 65 MPH
72H 09/0000Z 20.7N 158.7W 45 KT 50 MPH
96H 10/0000Z 21.5N 164.0W 40 KT 45 MPH
120H 11/0000Z 22.0N 168.0W 35 KT 40 MPH

$$

FORECASTER BIRCHARD

[Chris_in_Tampa]

The CPHC site is just slow as others have said. As of 11:21pm EDT, the full public advisory is not yet on their site.

It's on there now.

They must be having issues. The 11am HST data just popped back up here:
http://www.prh.noaa.gov/cphc/tcpages/ISELLE.php

[Alyono]

that is why you want for DATA before making major wind speed adjustments as I just did for the advisory I just issued on this

[Kingarabian]

that is why you want for DATA before making major wind speed adjustments as I just did for the advisory I just issued on this

I was thinking they were being slow on purpose, waiting for recon. I guess not.

85kts is way too low like you folks have mentioned. Pressure is 970?

[Alyono]

with the shear dropping off... I wouldn't expect much weakening during the next 24 hours. Maybe 10 kts at most. The structure should preclude intensification, however

[Alyono]

0Z GFS passes about 50 miles SOUTH of the island

[Kingarabian]

0Z GFS passes about 50 miles SOUTH of the island

Weaker or as a TS?

[Yellow Evan]

0Z GFS passes about 50 miles SOUTH of the island

Do they show a stronger ridge?