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WTPA44 PHFO 052054
TCDCP4
TROPICAL STORM GUILLERMO DISCUSSION NUMBER 28
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP092015
1100 AM HST WED AUG 05 2015
THE CENTER OF GUILLERMO HAS BECOME EXPOSED DUE TO STRONG VERTICAL
WIND SHEAR. A U.S. AIR FORCE HURRICANE HUNTER AIRCRAFT FOUND
PERSISTENT FLIGHT LEVEL WINDS OF UP TO 62 KT WITHIN THE NORTHEAST
QUADRANT...WHERE DEEP CONVECTION IS NOW CONFINED...AND CONVERSION OF
THE FLIGHT LEVEL WINDS TO THE SURFACE YIELDS 50 KT. THE SFMR
REPORTED WINDS WERE UP TO 55 KT...BUT GIVEN COLLOCATED RAIN RATES...
THE FLIGHT LEVEL DATA HAVE BEEN USED FOR THE CURRENT INTENSITY OF 50
KT.
STEADY WEAKENING IS EXPECTED TO RESUME TODAY. VERTICAL WIND SHEAR
ACCORDING CIMSS IS NEARLY 45 KT...AND WITH AN UPPER LEVEL TROUGH
OVERHEAD...WIND SHEAR IS FORECAST TO INCREASE FURTHER DURING THE
NEXT 24 HOURS. THIS WILL LEAD TO STEADY WEAKENING AS THE WARM CORE
ALOFT BECOMES FURTHER DISRUPTED AND INCREASINGLY TILTED. THE
INTENSITY FORECAST IS SIMILAR TO THE PRIOR ADVISORY...WEAKENING
GUILLERMO INTO A TROPICAL DEPRESSION BY THURSDAY NIGHT WITH
DEGENERATION INTO A REMNANT LOW BY SATURDAY. THE FORECAST CLOSELY
FOLLOWS ICON. SHIPS IS MORE AGGRESSIVELY WEAKENING THE SYSTEM AND
FORECASTS DEGENERATION INTO A REMNANT LOW BY FRIDAY.
AIRCRAFT RECONNAISSANCE FOUND THE CENTER OF GUILLERMO TO BE
SLIGHTLY NORTH OF ITS EXPECTED POSITION THIS MORNING...AND
SUBSEQUENT VISIBLE SATELLITE IMAGERY SUPPORT THIS LOCATION...GIVING
AN INITIAL MOTION TOWARD THE WEST-NORTHWEST...295 DEGREES...AT 10
KT. THE NORTHWARD JOG IN THE INITIAL POSITION SUGGESTS THAT THE
CIRCULATION...THOUGH TILTED...IS STILL COUPLED AT THE LOWER LEVELS
AND ALOFT. UNDER THE INFLUENCE OF INCREASING VERTICAL WIND
SHEAR...THE LOW LEVEL CENTER COULD BECOME DECOUPLED...CAUSING THE
STEERING FLOW AFFECTING GUILLERMO TO BECOME INCREASINGLY DOMINATED
BY THE LOW LEVEL RIDGE THAT WILL REMAIN FAR TO THE NORTH-NORTHEAST.
WITH THIS IN MIND...THE TRACK FORECAST HAS BEEN CHANGED LITTLE FROM
THE LAST ADVISORY AND IS ALONG THE SOUTHERN EDGE OF THE GUIDANCE
ENVELOPE.
TROPICAL STORM WATCHES FOR MAUI COUNTY AND THE BIG ISLAND OF HAWAII
HAVE BEEN DISCONTINUED WITH THIS ADVISORY. THIS DECISION WAS MADE
GIVEN THE HIGH CONFIDENCE IN THE FORECAST FOR WEAKENING AND THE
DECREASE IN WIND PROBABILITIES OVER THE ISLANDS.
FORECAST POSITIONS AND MAX WINDS
INIT 05/2100Z 21.4N 151.7W 50 KT 60 MPH
12H 06/0600Z 22.0N 153.1W 45 KT 50 MPH
24H 06/1800Z 22.6N 155.3W 35 KT 40 MPH
36H 07/0600Z 23.1N 157.6W 30 KT 35 MPH
48H 07/1800Z 23.8N 159.8W 30 KT 35 MPH
72H 08/1800Z 25.5N 164.1W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 09/1800Z 27.4N 168.7W 20 KT 25 MPH...POST-TROP/REMNT LOW
120H 10/1800Z...DISSIPATED
$$
FORECASTER WROE
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