CPAC: ISELLE - Post-Tropical

[Alyono]

may have to weaken today, because conditions look more favorable tomorrow. Also, the dynamical models aren't showing weakening tomorrow and Thursday

[Alyono]

Structural changes are now occurring

http://www.nrlmry.navy.mil/htdocs_dyn_p ... .75pc.html

This is no longer annular. A well defined rainband is now present

[Yellow Evan]

Structural changes are now occurring

http://www.nrlmry.navy.mil/htdocs_dyn_p ... .75pc.html

This is no longer annular. A well defined rainband is now present

Could that promote weakening?

[Alyono]

hopefully, that allows this to weaken

[Yellow Evan]

000
WTPZ34 KNHC 051451
TCPEP4

BULLETIN
HURRICANE ISELLE ADVISORY NUMBER 21
NWS NATIONAL HURRICANE CENTER MIAMI FL EP092014
800 AM PDT TUE AUG 05 2014

...ISELLE CHANGES LITTLE IN STRENGTH...
...EXPECTED TO MOVE TOWARD THE HAWAIIAN ISLANDS THROUGH THURSDAY...


SUMMARY OF 800 AM PDT...1500 UTC...INFORMATION
----------------------------------------------
LOCATION...16.0N 139.5W
ABOUT 1055 MI...1700 KM ESE OF HILO HAWAII
MAXIMUM SUSTAINED WINDS...125 MPH...205 KM/H
PRESENT MOVEMENT...W OR 270 DEGREES AT 9 MPH...15 KM/H
MINIMUM CENTRAL PRESSURE...955 MB...28.20 INCHES


WATCHES AND WARNINGS
--------------------
THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

INTERESTS IN THE HAWAIIAN ISLANDS SHOULD MONITOR THE PROGRESS OF
ISELLE. WATCHES MAY BE REQUIRED FOR PORTIONS OF THE ISLANDS BY
LATER TODAY OR EARLY WEDNESDAY.


DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
AT 800 AM PDT...1500 UTC...THE CENTER OF HURRICANE ISELLE WAS
LOCATED NEAR LATITUDE 16.0 NORTH...LONGITUDE 139.5 WEST. ISELLE IS
MOVING TOWARD THE WEST NEAR 9 MPH...15 KM/H...AND THIS GENERAL
MOTION IS EXPECTED TO CONTINUE THIS MORNING. ISELLE SHOULD TURN
TOWARD THE WEST-NORTHWEST AT A FASTER FORWARD SPEED LATER TODAY AND
WEDNESDAY.

MAXIMUM SUSTAINED WINDS ARE NEAR 125 MPH...205 KM/H...WITH HIGHER
GUSTS. ISELLE IS A CATEGORY THREE HURRICANE ON THE SAFFIR-SIMPSON
HURRICANE WIND SCALE. WEAKENING IS FORECAST DURING THE NEXT 48
HOURS.

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 35 MILES...55 KM...FROM
THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO
115 MILES...185 KM.

THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 955 MB...28.20 INCHES.


HAZARDS AFFECTING LAND
----------------------
NONE.


NEXT ADVISORY
-------------
THIS IS THE LAST PUBLIC ADVISORY ISSUED BY THE NATIONAL HURRICANE
CENTER ON ISELLE. FUTURE ADVISORIES WILL BE ISSUED BY THE CENTRAL
PACIFIC HURRICANE CENTER UNDER AWIPS HEADER HFOTCPCP3 AND WMO
HEADER WTPA33 PHFO...BEGINNING AT 1100 AM HST.

$$
FORECASTER BEVEN

[windnrain]

Intensity forecast nudged up with the NHC saying it could be potentially higher than forecast now.

[Yellow Evan]

000
WTPZ44 KNHC 051453
TCDEP4

HURRICANE ISELLE DISCUSSION NUMBER 21
NWS NATIONAL HURRICANE CENTER MIAMI FL EP092014
800 AM PDT TUE AUG 05 2014

Iselle has changed little in organization during the past six
hours. The eye remains well defined, with cloud tops to -70C
occurring in the eyewall. Analyses from the SHIPS model and from
CIMSS at the University of Wisconsin indicate 15-20 kt of
southwesterly vertical wind shear over the system. However, this
has not yet disrupted the inner core. The initial intensity remains
110 kt based on a combination of subjective and objective satellite
intensity estimates. An Air Force Reserve Hurricane Hunter aircraft
is scheduled to investigate Iselle near 06/0600Z, which will provide
ground truth for the intensity.

The initial motion estimate is 270/8 kt. The subtropical ridge to
the north of Iselle should strengthen during the next several days,
which should steer the cyclone generally west-northwestward with an
increase in forward speed. The track model guidance remains
tightly clustered and forecasts Iselle to pass near or over the
Hawaiian Islands in 72-84 hours. Based on this, the new forecast
track is again just an update of the previous track, and it lies in
the center of the track guidance envelope.

The analyzed and 24-hour forecast shear have both increased since
the previous advisory, and it is likely that Iselle will lose its
annular structure later today or tonight. This should result in
weakening along the lines of the previous forecast since a
significant part of the circulation is over sea surface temperatures
of less than 26C. The intensity forecast becomes more uncertain
after 36 hours. The cyclone will be moving over increasing sea
surface temperatures west of 152W. The dynamical models are in poor
agreement on how much shear the Iselle will experience, with the
UKMET forecasting strong shear while the GFS/ECMWF forecast less
shear. One last factor is that the cyclone is likely to encounter a
very dry air mass as it approaches Hawaii. The intensity guidance
responds to these factors by diverging. The SHIPS and Florida State
Superensemble forecast an intensity near 40 kt when Iselle gets near
Hawaii, while the GFDL and HWRF forecast it to be a hurricane. The
intensity forecast from 48-120 hours has been nudged upward in
agreement with the LGEM model and the intensity consensus, and it
calls for Iselle to be just below hurricane strength near Hawaii.

Interests in the Hawaiian Islands should closely monitor the
progress of Iselle. However, it is important not to focus too
closely on the exact track and intensity forecasts because the
average track error 72 hours out is about 100 miles, the average
intensity error is about 15 kt. In addition, the hazards of a
tropical cyclone can extend over a broad area well away from the
center.

This is the last advisory issued by the National Hurricane Center on
Iselle. Future Public Advisories will be issued by the Central
Pacific Hurricane Center under AWIPS header HFOTCPCP3 and WMO header
WTPA33 PHFO, while Forecast/Advisories will be issued under
AWIPS header HFOTCMCP3 and WMO header WTPA23 PHFO.

FORECAST POSITIONS AND MAX WINDS

INIT 05/1500Z 16.0N 139.5W 110 KT 125 MPH
12H 06/0000Z 16.3N 141.1W 100 KT 115 MPH
24H 06/1200Z 16.9N 143.9W 85 KT 100 MPH
36H 07/0000Z 17.6N 147.2W 70 KT 80 MPH
48H 07/1200Z 18.3N 150.4W 65 KT 75 MPH
72H 08/1200Z 20.0N 156.5W 55 KT 65 MPH...NEAR HAWAII
96H 09/1200Z 21.0N 162.0W 45 KT 50 MPH
120H 10/1200Z 21.5N 166.5W 35 KT 40 MPH

$$
Forecaster Beven

[galaxy401]

If it continues to maintain its structure throughout the day, I think they might need to issue hurricane watches to Hawaii.

[Yellow Evan]

If it continues to maintain its structure throughout the day, I think they might need to issue hurricane watches to Hawaii.

They might regardless.

[hawaiigirl]

oh great...

[WeatherGuesser]

Not looking for damage or destruction, but making history could be interesting.

[Hurricane_Luis]

Southern eye wall weakening. Could this be a saving grace for Hawaii?

[HurricaneRyan]

It's always the I storms that hit Hawaii. Iwa, Iniki, Ioke and now Iselle

[Yellow Evan]

It's always the I storms that hit Hawaii. Iwa, Iniki, Ioke and now Iselle

Ioke did not hit Hawaii.

[CrazyC83]

Eyewall replacement cycle perhaps? Definitely no longer annular.

[Yellow Evan]

Eyewall replacement cycle perhaps? Definitely no longer annular.

Eye still looks pretty good. But if an ERC occurs and it is only being sheared, that is a formula for rapid weakening.

[Kingarabian]

It's still a major Hurricane in my opinion. Gonna be interesting what recon finds tomorrow. Especially since intensity models HWRF and GFDL show a hurricane landfall.

[Kingarabian]

If it continues to maintain its structure throughout the day, I think they might need to issue hurricane watches to Hawaii.

Yeah that's true. Every day, the NHC bumps up the intensity of the storm as it makes landfall. HWRF and GFDL maybe verifying. Heck, that Euro hurricane prediction last week seems to be dead on. Time will tell.

[Yellow Evan]

It's still a major Hurricane in my opinion. Gonna be interesting what recon finds tomorrow. Especially since intensity models HWRF and GFDL show a hurricane landfall.

I thought Recon goes in this evening.

[Yellow Evan]

Weakening.