Hurricane Hilda Update

Hurricane Hilda Update 5am HST

500 AM HST SAT AUG 08 2015
 
THE CLOUD-FILLED EYE OF HILDA HAD BEEN FAIRLY PERSISTENT IN
INFRARED SATELLITE IMAGERY IN THE HOURS LEADING UP TO SYNOPTIC 
TIME...WITH A RING OF VERY COLD CLOUD TOPS NEARLY ENCIRCLING THE
CENTER AT TIMES. THIS LED TO DVORAK SUBJECTIVE INTENSITY ESTIMATES
FROM PHFO/SAB/PGTW THAT RANGED BETWEEN 5.0/90 KT AND 5.5/102 KT.
THE ADDITIONAL WARMING OF THE EYE IN THE LAST COUPLE OF SATELLITE
IMAGES...AND COOLING EYE WALL TEMPERATURES...SUPPORTS INCREASING THE 
INITIAL INTENSITY FOR THIS ADVISORY TO 100 KT...WHICH MAKES HILDA A 
CATEGORY 3 HURRICANE. 
 
LITTLE SIGNIFICANT CHANGE TO THE TRACK AND INTENSITY FORECAST
PHILOSOPHY ACCOMPANIES THIS FORECAST PACKAGE. HILDA IS CURRENTLY
BEING STEERED STEADILY WEST-NORTHWESTWARD BY A DEEP LAYER RIDGE
CENTERED TO ITS NORTHEAST...WITH AN INITIAL MOTION ESTIMATE OF
280/13 KT. HILDA IS FORECAST TO TRACK TOWARD THE WEST-NORTHWEST
WITH A GRADUAL DECREASE IN FORWARD SPEED OVER THE NEXT 48 HOURS...
AND THEN TURN TOWARD THE NORTHWEST ON DAYS 3 AND 4 WITH A FURTHER
DECREASE IN FORWARD SPEED. THIS WILL OCCUR AS HILDA REACHES AND THEN
ROUNDS THE WESTERN EXTENT OF THE RIDGE...AND BEGINS TO INTERACT WITH
A DEVELOPING DEEP LAYER LOW ALOFT NORTH OF THE MAIN HAWAIIAN
ISLANDS. AT THE END OF THE FORECAST PERIOD...A RELATIVELY WEAK HILDA
IS FORECAST TO MAKE A TURN BACK TOWARD THE WEST-NORTHWEST...AS IT IS
EXPECTED TO BE A SHALLOW SYSTEM THAT IS STEERED BY THE LOW-LEVEL
TRADE WINDS. THE OFFICIAL TRACK FORECAST IS SIMILAR TO THE
PREVIOUS...CLOSELY FOLLOWS A TIGHTLY CLUSTERED GUIDANCE ENSEMBLE IN
THE EARLIER PERIODS...AND IS CLOSE TO THE TVCN CONSENSUS IN THE
LATER PERIODS WHEN THE GUIDANCE ENVELOPE BEGINS TO INCREASE
DUE TO DIFFERENCES IN MODEL INTENSITIES.
 
A SMALL WINDOW FOR SOME INTENSIFICATION APPEARS TO EXIST FOR THE
NEXT 24 HOURS OR SO...AS SHEAR IS FORECAST TO REMAIN LIGHT AND THE
HURRICANE TRAVERSES SUFFICIENTLY WARM WATER. AFTER ABOUT 48 HOURS
HILDA WILL ENCOUNTER STEADILY INCREASING SHEAR AND GRADUALLY
DIMINISHING WATER TEMPERATURES AS IT ROUNDS THE RIDGE. ONCE HILDA
MOVES NORTH OF THE RIDGE AXIS...IT/S CIRCULATION IS EXPECTED TO BE
COMPROMISED AS IT BEGINS TO FEEL THE STRONG DEEP-LAYER WESTERLY FLOW
ALOFT ASSOCIATED WITH THE AFOREMENTIONED CLOSED LOW DEVELOPING NORTH
OF HAWAII. SHIPS GUIDANCE INDICATES SHEAR VALUES NEAR 20 KT MONDAY
MORNING WILL STEADILY INCREASE TO OVER 50 KT BY EARLY THURSDAY...AND
FORECASTS DISSIPATION AT THAT TIME. THUS SLIGHT INTENSIFICATION IS
FORECAST THROUGH TONIGHT...WITH GRADUAL WEAKENING FORECAST TO 
COMMENCE THEREAFTER...AND RAPID WEAKENING ANTICIPATED IN THE LATTER
PART OF THE FORECAST PERIOD. THE OFFICIAL INTENSITY FORECAST CLOSELY
FOLLOWS THE PREVIOUS AND THE IVCN CONSENSUS...BUT IS LESS AGGRESSIVE
IN FORECAST WEAKENING THAN SHIPS GUIDANCE ON DAY 5.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  08/1500Z 13.6N 142.2W  100 KT 115 MPH
 12H  09/0000Z 14.2N 143.8W  105 KT 120 MPH
 24H  09/1200Z 15.0N 145.8W  105 KT 120 MPH
 36H  10/0000Z 16.0N 147.3W   95 KT 110 MPH
 48H  10/1200Z 16.9N 148.6W   85 KT 100 MPH
 72H  11/1200Z 18.7N 150.3W   65 KT  75 MPH
 96H  12/1200Z 20.0N 152.0W   40 KT  45 MPH
120H  13/1200Z 21.0N 153.5W   30 KT  35 MPH