1100 AM HST SUN AUG 09 2015
SATELLITE FIXES FROM HFO...SAB AND JTWC WERE IN GOOD AGREEMENT ON
BOTH LOCATION AND INTENSITY FOR HURRICANE HILDA. I HAVE SET THE
INITIAL INTENSITY AT 95 KT. THE SATELLITE SIGNATURE OF THE
HURRICANE SHOWS IT HAS WEAKENED OVER THE PAST 24 HOURS. THE
EYE IS NO LONGER WELL-DEFINED. HILDA IS EXPECTED TO CONTINUE SLOWLY
WEAKENING DUE TO WEAK SOUTHWEST SHEAR AND DECREASING SEA SURFACE
TEMPERATURES.
HILDA CONTINUES TO MOVE TOWARD THE WEST-NORTHWEST...WITH AN INITIAL
MOTION OF 290/11 KT. THE HURRICANE IS BEING STEERED BY A RIDGE ALOFT
EXTENDING WEST FROM AN ANTICYCLONE ALOFT FAR TO THE NORTHEAST.
HILDA WILL REACH THE WESTERN EDGE OF THE RIDGE BY THIS EVENING AND
WE EXPECT A TURN TOWARD THE NORTHWEST AT THAT TIME. HILDA IS
EXPECTED TO START MOVING MORE SLOWLY AS IT TURNS TOWARD THE
NORTHWEST AS THE STEERING FLOW WILL BE QUITE WEAK.
FOR CLARITY AND CONVENIENCE WE USUALLY WRITE SEPARATE PARAGRAPHS
FOR INTENSITY AND MOVEMENTS...BUT THE TRACK AND INTENSITY FORECASTS
FOR HILDA CANNOT BE CONSIDERED SEPARATELY. IF HILDA WERE TO REMAIN A
STRONG AND DEEP SYSTEM...HER TRACK WOULD LIKELY TO BE INFLUENCED BY
STEERING FLOW THROUGH A DEEPER LAYER OF THE ATMOSPHERE. THAT WOULD
MEAN A MORE NORTHERLY TRACK. THE WEAKER AND SHALLOWER HILDA
BECOMES...THE MORE ITS TRACK WILL BE INFLUENCED BY THE TRADE-WIND
FLOW IN THE LOWER PART OF THE ATMOSPHERE. THAT WOULD GIVE HILDA A
MORE WESTERLY TRACK.
THE MODELS ARE SHOWING GOOD AGREEMENT ON AN ACCELERATING WEAKENING
TREND AS HILDA ENCOUNTERS SOUTHWEST SHEAR NEAR 40 KT DUE TO A
SUBTROPICAL JET STREAM SOUTH OF A TROPICAL UPPER TROPOSPHERIC
TROUGH OR TUTT. THE MODELS ARE INCREASINGLY GOOD AGREEMENT ON HILDA
TAKING A MORE WESTERLY TRACK AS IT WEAKENS. I HAVE SHIFTED THE
TRACK A BIT FURTHER TO THE LEFT...CLOSER TO THE MODEL CONSENSUS...
WHILE CONTINUING A STEADY WEAKENING.
U.S AIR FORCE HURRICANE HUNTERS ARE SCHEDULED TO BEGIN FLYING
MISSIONS INTO HILDA THIS EVENING. THE DATA FROM THESE MISSIONS
SHOULD HELP REFINE OUR FUTURE FORECASTS.
FORECAST POSITIONS AND MAX WINDS
INIT 09/2100Z 15.0N 147.4W 95 KT 110 MPH
12H 10/0600Z 15.6N 148.7W 90 KT 105 MPH
24H 10/1800Z 16.5N 149.8W 85 KT 100 MPH
36H 11/0600Z 17.3N 150.5W 70 KT 80 MPH
48H 11/1800Z 18.0N 151.0W 55 KT 65 MPH
72H 12/1800Z 18.8N 152.0W 40 KT 45 MPH
96H 13/1800Z 19.2N 153.5W 35 KT 40 MPH
120H 14/1800Z 19.5N 155.5W 30 KT 35 MPH
