Categorized | Hurricane, News, Weather

Hurricane Iselle to pass directly over the Big Island, dangerous conditions expected

20140807-1700HST-Hurricane-Iselle-track

Hawaii County Civil Defense Message

Information on closures due to Hurricane Iselle.

Currently Hurricane Iselle has weakened slightly and is barely a Category One Hurricane and will probably be at or near hurricane strength when it reaches the Big Island. At 5 p.m. HST Thursday (Aug 7) the center of Hurricane Iselle was about 90 miles East-Southeast of Hilo moving West at about 19.5 mph. Hurricane strength winds can extend up to 35 miles from this center and Tropical Storm winds up to 140 miles from the center. Do not concentrate on the center of the storm for position of damaging winds, rain and surge.

For a reminder of how to prepare for a possible hurricane read this or go to our ‘Be Prepared’ menu near the top of this page.

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.

HURRICANE ISELLE DISCUSSION NUMBER  32
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP092014
500 PM HST THU AUG 07 2014
 
ISELLE IS BARELY HOLDING ON TO HURRICANE STATUS. ALTHOUGH THE 
MINIMUM CENTRAL PRESSURE CONTINUES TO GRADUALLY RISE...THE 
RECONNAISSANCE AIRCRAFT FOUND MAXIMUM FLIGHT LEVEL WINDS OF 72 
KNOTS TO THE NORTHEAST OF THE CENTER AT 2300 UTC. THE HIGHEST SFMR 
WINDS WERE 68 KNOTS...AND VARIOUS WIND REDUCTION TECHNIQUES RESULTED 
IN MAXIMUM SUSTAINED SURFACE WIND ESTIMATES BETWEEN 65 AND 70 KNOTS. 
THE 00Z SYNOPTIC INTENSITY WAS THUS KEPT AT 70 KNOTS...BUT GIVEN 
THE INCREASINGLY RAGGED APPEARANCE IN THE SATELLITE IMAGERY...THE 
ADVISORY INTENSITY WILL BE 65 KNOTS FOR THIS CYCLE.

EVEN THOUGH THE TRACK FORECAST TAKES ISELLE OVER INCREASINGLY WARM 
SEA SURFACE TEMPERATURES...THE CYCLONE WILL BE ENTERING A HOSTILE 
ENVIRONMENT IN REGARDS TO SHEAR. ISELLE IS CONTINUING TO IMPINGE ON 
STRONGER NORTHERLIES AT THE EASTERN PERIPHERY OF AN UPPER 
ANTICYCLONE LOCATED NEAR JOHNSTON ISLAND. THE SHEAR...ALONG WITH 
INTERACTION OF THE CORE WITH THE BIG ISLAND TERRAIN...WILL RESULT IN 
MORE RAPID WEAKENING DURING THE NEXT 24 HOURS. STRONG SHEAR WILL 
PERSIST THROUGH MUCH OF THE FORECAST PERIOD AS AN UPPER LEVEL LOW 
DIGS SOUTHWARD OVER THE NORTHWEST HAWAIIAN ISLANDS. THE INTENSITY 
FORECAST HAS BEEN ADJUSTED DOWNWARD TO ACCOUNT FOR THESE FACTORS...
AND IS ON THE LOWER END OF THE GUIDANCE ENVELOPE. AS HAS BEEN STATED 
BEFORE...REGARDLESS OF WHETHER ISELLE MAKES IT TO THE BIG ISLAND AS 
A MINIMAL HURRICANE OR TROPICAL STORM...THERE WILL BE SIGNIFICANT 
IMPACTS FROM WIND...RAIN...AND SURF. 

THE TRACK FORECAST HAS BEEN NUDGED JUST SLIGHTLY SOUTHWARD AFTER 12 
HOURS TO ACCOUNT FOR THE EXPECTATION OF A SHALLOWER CYCLONE. ISELLE 
IS MOVING WEST-NORTHWEST TO THE SOUTH OF A RATHER WEAK SUBTROPICAL 
RIDGE ROUGHLY ALONG LATITUDE 39N. THIS RIDGE IS FORECAST TO SINK 
SOUTH...BUT WEAKEN...WHICH SHOULD RESULT IN A SLOWER FORWARD MOTION 
WITH ISELLE IN A COUPLE OF DAYS. SOME ACCELERATION OF ISELLE...OR 
ITS REMNANT LOW...IS FORECAST AT THE LONGER TIME PERIODS AS THE 
SUBTROPICAL RIDGE TO THE NORTH OF THE SYSTEM STRENGTHENS. 
 

FORECAST POSITIONS AND MAX WINDS
 
INIT  08/0300Z 19.1N 153.8W   65 KT  75 MPH
 12H  08/1200Z 19.4N 156.1W   55 KT  65 MPH
 24H  09/0000Z 19.8N 158.8W   50 KT  60 MPH
 36H  09/1200Z 20.3N 161.3W   40 KT  45 MPH
 48H  10/0000Z 20.6N 163.3W   35 KT  40 MPH
 72H  11/0000Z 21.6N 167.8W   30 KT  35 MPH
 96H  12/0000Z 23.5N 173.6W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  13/0000Z 26.4N 179.8E   25 KT  30 MPH...POST-TROP/REMNT LOW
NWS Infrared Satellite Image Loop

Latest NWS Infrared Satellite Image Loop of Iselle

For links to the latest weather forecasts, reports, radar and satellite imagery visit our Weather Page at hawaii247.com/weather

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