WTPA41 PHFO 210855 TCDCP1 TROPICAL DEPRESSION THREE-C DISCUSSION NUMBER 3 NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI CP032015 1100 PM HST THU AUG 20 2015 FINAL VISIBLE IMAGES OF THE DAY SHOWED THAT THE WELL-DEFINED EXPOSED LOW LEVEL CLOUD SWIRL NOTED IN THE PREVIOUS DISCUSSION CONTINUED TO MOVE GENERALLY NORTHWARD...REMOVED FROM THE DEEP CONVECTION BY ABOUT 150 MILES. THIS FEATURE IS BECOMING INCREASINGLY DIFFICULT TO DISCERN IN INFRARED IMAGERY. WHILE IT IS CERTAINLY PLAUSIBLE THAT THIS IS THE MAIN LOW-LEVEL CIRCULATION CENTER /LLCC/...THIS FORECAST PACKAGE WILL FOLLOW THE ASSUMPTION MADE IN THE PREVIOUS ADVISORY...THAT A DIFFERENT LLCC EXISTS...OR WILL SOON DEVELOP...CLOSER TO THE AREA OF DEEP CONVECTION THAT IS MOVING GENERALLY WESTWARD. NEEDLESS TO SAY...THE CYCLONE IS NOT WELL ORGANIZED. SUBJECTIVE DVORAK CURRENT INTENSITY ESTIMATES...WHICH ARE HIGHLY DEPENDENT ON THE ANALYZED POSITION OF THE LLCC...RANGE FROM 1.0/25 KT TO 2.5/35 KT. WITH LITTLE IMPROVEMENT IN ORGANIZATION NOTED SINCE THE PREVIOUS ADVISORY...THE INITIAL INTENSITY FOR THIS ADVISORY WILL BE MAINTAINED AT 30 KT. THE INITIAL MOTION ESTIMATE FOR THIS PACKAGE IS A SOMEWHAT UNCERTAIN 300/13 KT. DESPITE THE UNCERTAINTY AS TO THE POSITION OF THE LLCC...THE FORECAST TRACK PHILOSOPHY REMAINS AS PRESENTED PREVIOUSLY. THE GUIDANCE ENVELOPE IS TIGHTLY CLUSTERED IN THE SHORT TERM...WITH THREE-C MOVING GENERALLY TOWARD THE WEST-NORTHWEST... STEERED BY WESTWARD-BUILDING MID-LEVEL RIDGE TO THE NORTH. THE UPDATED FORECAST TRACK THROUGH DAY 3 IS VERY SIMILAR TO THE PREVIOUS...AFTER ACCOUNTING FOR A NORTHEASTWARD SHIFT IN THE INITIAL POSITION. A WEAKNESS IN THE RIDGE IS EXPECTED TO DEVELOP ON DAYS 4 AND 5...WHICH IS EXPECTED TO RESULT IN A DECREASE IN FORWARD MOTION...AND A TURN TOWARD THE NORTH-NORTHEAST. THE MAIN DYNAMICAL MODELS DIFFER ON THE TIMING AND LOCATION OF THIS TURN...WITH THE HWRF ON THE EAST SIDE OF THE GUIDANCE ENVELOPE AND THE ECMWF ONCE AGAIN ON THE WEST SIDE. THE LONGER IT TAKES FOR THIS BREAK TO DEVELOP...THE FARTHER WEST THE CYCLONE WILL MOVE BEFORE TURNING...AND THIS ASPECT OF THE FORECAST CONTINUES TO CONTAIN A SIGNIFICANT AMOUNT OF UNCERTAINTY. THE FORECAST POSITIONS ON DAY 4 AND 5 LIE CLOSE TO THE HWRF GUIDANCE...AND A BIT TO THE LEFT OF THE PREVIOUS FORECAST...DUE TO A WESTWARD SHIFT IN THE LATEST ECMWF GUIDANCE...AND ITS INFLUENCE ON THE TVCN CONSENSUS. THREE-C IS MOVING OVER VERY WARM WATER...ABOVE 29C IN THE LATEST ANALYSIS...AND THE OCEAN HEAT CONTENT ANALYSIS FROM RAMMB-CIRA INDICATES INCREASING VALUES ALONG THE FORECAST TRACK. EASTERLY SHEAR ON THE ORDER OF 15 TO 20 KT IS CURRENTLY AFFECTING THE SYSTEM...BUT IT IS EXPECTED TO STEADILY WEAKEN OVER THE NEXT 24 HOURS...AND THEN REMAIN RATHER WEAK THROUGH DAY 3. THESE FACTORS SUGGEST THAT THE DEPRESSION WILL STRENGTHEN...BUT LATEST DYNAMICAL AND STATISTICAL INTENSITY GUIDANCE IS LESS AGGRESSIVE THAN PREVIOUSLY INDICATED. WHILE THE UPDATED INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS... THE RATE OF INTENSIFICATION HAS BEEN SLOWED...AND REPRESENTS A BLEND OF THE PREVIOUS FORECAST AND THE ICON INTENSITY CONSENSUS. U.S. AIR FORCE RESERVE WEATHER RECONNAISSANCE ASSETS ARE IN THE PROCESS OF DEPLOYING TO HAWAII AND A WC-130J IS SCHEDULED TO MAKE AN INITIAL PASS THROUGH THREE-C FRIDAY EVENING. THIS WILL PROVIDE VALUABLE DATA TO HELP BETTER DETERMINE THE LOCATION OF THE SYSTEM CENTER AND THE DISTRIBUTION OF THE WIND FIELD. FORECAST POSITIONS AND MAX WINDS INIT 21/0900Z 12.3N 151.3W 30 KT 35 MPH 12H 21/1800Z 13.0N 153.5W 35 KT 40 MPH 24H 22/0600Z 13.9N 156.3W 40 KT 45 MPH 36H 22/1800Z 15.0N 159.1W 50 KT 60 MPH 48H 23/0600Z 16.0N 161.7W 60 KT 70 MPH 72H 24/0600Z 18.0N 163.0W 70 KT 80 MPH 96H 25/0600Z 19.5N 162.5W 75 KT 85 MPH 120H 26/0600Z 21.0N 161.5W 85 KT 100 MPH $$ FORECASTER BIRCHARD