CPAC: ISELLE - Post-Tropical

[Yellow Evan]

701
WTPA33 PHFO 071754
TCPCP3

BULLETIN
HURRICANE ISELLE INTERMEDIATE ADVISORY NUMBER 30A
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP092014
800 AM HST THU AUG 07 2014

...DANGEROUS ISELLE MAKING A BEELINE FOR THE BIG ISLAND...


SUMMARY OF 800 AM HST...1800 UTC...INFORMATION
----------------------------------------------
LOCATION...18.6N 151.4W
ABOUT 255 MI...410 KM ESE OF HILO HAWAII
ABOUT 460 MI...740 KM ESE OF HONOLULU HAWAII
MAXIMUM SUSTAINED WINDS...80 MPH...130 KM/H
PRESENT MOVEMENT...WNW OR 285 DEGREES AT 17 MPH...28 KM/H
MINIMUM CENTRAL PRESSURE...986 MB...29.12 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES IN WATCHES AND WARNINGS WITH THIS ADVISORY...

NONE.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

A HURRICANE WARNING IS IN EFFECT FOR...
* HAWAII COUNTY

A TROPICAL STORM WARNING IS IN EFFECT FOR...
* MAUI COUNTY...INCLUDING THE ISLANDS OF MAUI...MOLOKAI...LANAI...
AND KAHOOLAWE.
* OAHU
* KAUAI COUNTY INCLUDING THE ISLANDS OF KAUAI AND NIIHAU.

A HURRICANE WARNING MEANS THAT HURRICANE CONDITIONS ARE EXPECTED
SOMEWHERE WITHIN THE WARNING AREA. PREPARATIONS TO PROTECT LIFE AND
PROPERTY SHOULD BE RUSHED TO COMPLETION.

A TROPICAL STORM WARNING MEANS THAT TROPICAL STORM CONDITIONS ARE
EXPECTED SOMEWHERE WITHIN THE WARNING AREA WITHIN 36 HOURS.

INTERESTS IN THE NORTHWEST HAWAIIAN ISLANDS SHOULD MONITOR THE
PROGRESS OF ISELLE.

FOR STORM INFORMATION SPECIFIC TO YOUR AREA...PLEASE MONITOR
PRODUCTS ISSUED BY THE NATIONAL WEATHER SERVICE OFFICE IN
HONOLULU HAWAII.


DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
AT 800 AM HST...1800 UTC...THE CENTER OF HURRICANE ISELLE WAS
LOCATED NEAR LATITUDE 18.6 NORTH...LONGITUDE 151.4 WEST. THE MOTION
OF ISELLE HAS NOT CHANGED...AND THE HURRICANE IS STILL MOVING TOWARD
THE WEST-NORTHWEST NEAR 17 MPH...28 KM/H. THIS MOTION IS EXPECTED TO
CONTINUE THROUGH FRIDAY...WITH SOME SLOWING IN FORWARD SPEED ON
FRIDAY NIGHT. ON THE FORECAST TRACK...THE CENTER OF ISELLE IS
EXPECTED TO PASS OVER THE BIG ISLAND TONIGHT...AND PASS JUST SOUTH
OF THE SMALLER ISLANDS FRIDAY.

MAXIMUM SUSTAINED WINDS ARE NEAR 80 MPH...130 KM/H...WITH HIGHER
GUSTS. SOME WEAKENING IS FORECAST DURING THE NEXT 48 HOURS...BUT
ISELLE IS EXPECTED TO STILL BE NEAR HURRICANE STRENGTH AS IT MAKES
LANDFALL ON THE BIG ISLAND TONIGHT.

REMEMBER THAT THE EFFECTS OF HURRICANES ARE FAR REACHING. DO NOT
FOCUS ON THE CENTER POSITION ALONE. HURRICANE FORCE WINDS EXTEND
OUTWARD UP TO 35 MILES...55 KM...FROM THE CENTER...AND TROPICAL
STORM FORCE WINDS EXTEND OUTWARD UP TO 140 MILES...220 KM.

THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 986 MB...29.12 INCHES.


HAZARDS AFFECTING LAND
----------------------
WIND...CONDITIONS WILL STEADILY DETERIORATE OVER THE BIG ISLAND
THIS AFTERNOON...WITH TROPICAL STORM CONDITIONS EXPECTED TO ARRIVE
WELL BEFORE DARK. HURRICANE CONDITIONS ARE EXPECTED FOR PORTIONS OF
THE BIG ISLAND TONIGHT. TROPICAL STORM CONDITIONS ARE EXPECTED OVER
MAUI COUNTY TONIGHT...AND FOR OAHU LATE TONIGHT AND FRIDAY. TROPICAL
STORM CONDITIONS ARE EXPECTED FOR KAUAI COUNTY LATER FRIDAY.

RAINFALL...RAINFALL TOTALS OF 5 TO 8 INCHES...WITH ISOLATED MAXIMUM
AMOUNTS TO 12 INCHES...ARE EXPECTED ALONG THE TRACK OF ISELLE.
THESE RAINS COULD CAUSE LIFE-THREATENING FLASH FLOODS AS WELL AS
ROCK AND MUD SLIDES.

SURF...SWELLS GENERATED BY ISELLE WILL CONTINUE TO RISE ALONG EAST
FACING SHORES. VERY LARGE...DAMAGING SURF IS EXPECTED ALONG SOME
EAST AND SOUTH SHORES STARTING TODAY.

STORM SURGE...THE COMBINATION OF A DANGEROUS STORM SURGE AND THE
TIDE WILL CAUSE NORMALLY DRY AREAS NEAR THE COAST TO BE FLOODED BY
RISING WATERS. THE WATER COULD REACH THE FOLLOWING HEIGHTS ABOVE
GROUND IF THE PEAK SURGE OCCURS AT THE TIME OF HIGH TIDE...

BIG ISLAND WINDWARD AND KAU...1 TO 3 FT

THE HIGHEST WATER WILL OCCUR ALONG THE IMMEDIATE COAST IN AREAS OF
ONSHORE FLOW. THE SURGE WILL BE ACCOMPANIED BY LARGE AND DAMAGING
WAVES. SURGE RELATED FLOODING DEPENDS ON THE RELATIVE TIMING OF THE
SURGE AND THE TIDAL CYCLE...AND CAN VARY GREATLY OVER SHORT
DISTANCES.


NEXT ADVISORY
-------------
NEXT COMPLETE ADVISORY...1100 AM HST.

[Andrew92]

pressure continues to rise... likely around 990mb now

still... sfmr has 60 kt winds in the NWQ, and the peak winds have been in the NEQ. so this likely does remain a hurricane

I'm an amateur at reading recon data, but I did notice this:

175500 1847N 15135W 6957 03051 9868 +139 +070 091014 015 /// /// 03

Am I correct in the area that I bolded, that this implies pressure of 986.8 millibars? This does verify it went up, but not quite to 990, at least if I'm right.

Also, another observation seemed to indicate 99 knot flight level winds. That would indicate we definitely have a hurricane right, or was that one flagged?

-Andrew92

[supercane4867]

Dropsonde measures 990mb near the center with 8kt surface wind

[hurricaneCW]

So what are some good webcams to watch Iselle for Hawaii.

[supercane4867]

Dvorak estimates holding steady at T4.5/77kt

TXPN23 KNES 071746
TCSCNP

A. 09E (ISELLE)

B. 07/1730Z

C. 18.6N

D. 151.4W

E. ONE/GOES-W

F. T4.5/4.5/D0.5/24HRS

G. IR/EIR/VIS

H. REMARKS...OW EYE EMBEDDED IN DG AND SURROUNDED BY MG FOR DT=4.5.
MET AND PT AGREE. FT IS BASED ON DT.

I. ADDL POSITIONS

NIL


...SALEMI

[yzerfan]

maybe Bonnie and Charley in 2004? I believe there at one point was a continuous hurricane warning to cover both storms (Bonnie's warning ended where Charley's began)

I had a look at the advisory archives, and on August 11, 2004, here's Bonnie:


AT 4 PM CDT...2100Z...A HURRICANE WARNING HAS BEEN ISSUED FOR
PORTIONS OF THE FLORIDA PANHANDLE AND NORTHWEST FLORIDA FROM
DESTIN EASTWARD TO THE MOUTH OF THE SUWANNEE RIVER.

A HURRICANE WATCH AND A TROPICAL STORM WARNING REMAIN IN EFFECT FOR
THE WESTERN FLORIDA PANHANDLE FROM WEST OF DESTIN WESTWARD TO THE
ALABAMA/FLORIDA BORDER.

And here's Charley:

AT 5 PM EDT...2100Z...THE HURRICANE WATCH HAS BEEN EXTENDED TO
INCLUDE THE FLORIDA KEYS EAST OF CRAIG KEY TO OCEAN REEF INCLUDING
FLORIDA BAY...AND A HURRICANE WATCH HAS BEEN ISSUED FOR THE
SOUTHWEST COAST OF FLORIDA FROM FLAMINGO NORTHWARD TO BONITA BEACH.
A HURRICANE WATCH IS NOW IN EFFECT FROM DRY TORTUGAS TO OCEAN REEF
INCLUDING FLORIDA BAY...AND FROM FLAMINGO NORTHWARD TO BONITA
BEACH. A HURRICANE WATCH MEANS THAT HURRICANE CONDITIONS ARE
POSSIBLE WITHIN THE WATCH AREA...GENERALLY WITHIN 36 HOURS.
THE HURRICANE WATCH WILL LIKELY BE EXTENDED NORTHWARD ALONG THE
FLORIDA WEST COAST TONIGHT OR EARLY THURSDAY.

[Yellow Evan]

So what are some good webcams to watch Iselle for Hawaii.

I posted some on the previous two pages.

[wxman57]

No evidence of any hurricane-force winds in the NE or SE quadrants. None likely in the SW quadrant, either. Most likely the only remaining hurricane force winds are north and northeast of the center. With surface pressure up to 990mb the peak winds may just barely be at hurricane strength. I still think it will make landfall as a TS, not a hurricane.

[Frank2]

Per the latest recon, not sure why the CPHC is calling Iselle "dangerous" in their intermediate advisory - it is dangerous of course when it comes to wave height, but per the latest recon and without saying too much here, they are going to have to make a decision for the next advisory...

P.S. Oops - sorry wxman, didn't mean to step on your post (guess I was typing while you were posting)...

Frank

[Yellow Evan]

EP, 09, 2014080718, , BEST, 0, 187N, 1515W, 70, 990, HU, 34, NEQ, 120, 50, 20, 120, 1011, 180, 20, 0, 20, E, 0, , 0, 0, ISELLE, D,
EP, 09, 2014080718, , BEST, 0, 187N, 1515W, 70, 990, HU, 50, NEQ, 50, 20, 0, 50, 1011, 180, 20, 0, 20, E, 0, , 0, 0, ISELLE, D,
EP, 09, 2014080718, , BEST, 0, 187N, 1515W, 70, 990, HU, 64, NEQ, 30, 10, 0, 30, 1011, 180, 20, 0, 20, E, 0, , 0, 0, ISELLE, D,

[hurricaneCW]

Per the latest recon, not sure why the CPHC is calling Iselle "dangerous" in their intermediate advisory - it is dangerous of course when it comes to wave height, but per the latest recon and without saying too much here, they are going to have to make a decision for the next advisory...

P.S. Oops - sorry wxman, didn't mean to step on your post (guess I was typing while you were posting)...

Frank

Any strong tropical storm or minimal hurricane is dangerous so I'm not sure what you're getting at. There will be very high waves, surge, high flooding and road closures and some of those winds could be very strong in the higher elevations. They are also quite foreign to storms that threaten them directly like this.

[Frank2]

Per the NHC "tradition" the word "dangerous" is only used in the byline for hurricanes measured to be Cat 3 or higher...

[WeatherGuesser]

I still think it will make landfall as a TS, not a hurricane.

Kinda lookin' that way.

Still makes history though as a named storm coming ashore from the east? Or no?

[Yellow Evan]

I still think it will make landfall as a TS, not a hurricane.

Kinda lookin' that way.

Still makes history though as a named storm coming ashore from the east? Or no?

Yes.

[tallywx]

Most of Hawaii away from the immediate shore (including most parts of Hilo) are at elevation. Winds will be higher than "standard sea-level height". There could also be funneling effects from terrain. Remember how Hurricane Marilyn in 1995 was a borderline cat 2/3 but had damage akin to a 4/5 in the Virgin Islands because of poor construction code and terrain effects.

[Kingarabian]

Per the NHC "tradition" the word "dangerous" is only used for hurricanes measured to be Cat 3 or higher...

Dangerous because:
1. Hurricanes are rare in Hawaii, residents aren't used to them.
2. Building codes aren't that great.
3. Lot's of ocean around the islands, and a lot of activities take place on these beaches.
4. The islands are all very mountainous to an extent. Winds on these heights can be deadly.
5. On the big island, those who do not live in dense Hilo, live far from each other and emergency help may take a while to get places in need.

I don't remember the NHC preaching hurricane Ike as dangerous as I would like. But look at its aftermath. Better to be safe than sorry.

[Alyono]

Per the latest recon, not sure why the CPHC is calling Iselle "dangerous" in their intermediate advisory - it is dangerous of course when it comes to wave height, but per the latest recon and without saying too much here, they are going to have to make a decision for the next advisory...

P.S. Oops - sorry wxman, didn't mean to step on your post (guess I was typing while you were posting)...

Frank

its still dangerous as it likely has 95 kt winds aloft. Those winds will be crashing into the elevated areas. Most of Hawaii is elevated

[CrazyC83]

Based on Recon, most likely dropping to 65 kt unless stronger winds found elsewhere. While that would likely place the landfall intensity at 55-60 kt, best to keep a Hurricane Warning to be on the safe side.

[CrazyC83]

Also, have you been in sustained hurricane winds? Those are definitely dangerous, even at Cat 1 level. Heck, tropical storm winds can still be dangerous.

[Kingarabian]

Just look at this picture that Equilibrium posted:



And that's from a normal weather system.