WTPA41 PHFO 220903
TCDCP1

TROPICAL DEPRESSION COSME DISCUSSION NUMBER  32
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP062007
1100 PM HST SAT JUL 21 2007

COSME CONTINUES TO CHURN STEADILY WESTWARD OVER THE OPEN WATERS OF
THE CENTRAL NORTH PACIFIC OCEAN. EXCEPT FOR LAST EVENING...THIS
SYSTEM HAS DEVELOPED DEEP CONVECTION BRIEFLY AROUND DUSK SINCE IT
MOVED INTO THE CENTRAL NORTH PACIFIC. THE DURATION OF THESE
CONVECTIVE FLARE UPS HAS USUALLY BEEN BRIEF...ON THE ORDER OF 4 TO
6 HOURS. THESE ACTIVE PERIODS HAVE BEEN TYPICALLY FOLLOWED BY LESS
PERSISTENT DEEP CONVECTION DURING THE NEXT SEVERAL HOURS. COSME HAS
HAD A HISTORY OF MUCH LESS DEEP CONVECTION DURING THE DAYTIME
HOURS. 

ONCE AGAIN...COSME HAD SIGNIFICANT THUNDERSTORM DEVELOPMENT NEAR THE
LOW LEVEL CIRCULATION CENTER...OR LLCC. THE ANVIL PRODUCED BY THESE
THUNDERSTORMS HAS ALSO OBSCURED THE LLCC MAKING IT VERY DIFFICULT
FOR THE SATELLITE FIX AGENCIES TO DETERMINE THE 0600 UTC POSITION.
VISIBLE IMAGERY FROM LATE SATURDAY AFTERNOON...WHICH INCLUDED A
VERY BENEFICIAL RAPID SCAN OPERATION...SHOWED THE NEARLY COMPLETELY
EXPOSED LLCC OF COSME. THE SHORT TERM TRACK FROM THESE SATELLITE
IMAGES...PLUS 0337 UTC AMSU-B MICROWAVE IMAGERY PROVIDED BY NRL AND
FNMOC...WERE USEFUL FOR EXTRAPOLATING A COUPLE OF HOURS TO ESTIMATE
THE 0600Z CENTER LOCATION. THE CURRENT MOTION IS 270/15.

BASED ON THE ESTIMATED POSITION AT 0600 UTC...IT APPEARED THE DEEP
CONVECTION MUST BE VERY CLOSE TO THE LLCC. THIS IS DESPITE THE
UW-CIMMS ESTIMATE OF ENVIRONMENTAL VERTICAL WIND SHEAR SHOWING
VALUES OF AROUND 20 KT FROM THE NORTHWEST. THE GFS MODEL INDICATES
THERE IS A LARGE UPPER TROPOSPHERIC ANTICYCLONE CENTERED NEAR 19N
172W. THE FLOW BETWEEN THIS FEATURE AND AN UPPER LEVEL LOW JUST
NORTHEAST OF THE MAIN HAWAIIAN ISLANDS IS CAUSING THIS STRONG
SHEAR.

THE SUBJECTIVE DVORAK INTENSITY ESTIMATES WERE 2.0 FROM SAB AND
PHFO...AND 1.0 FROM JTWC. UNFORTUNATELY...THE INNER CIRCULATION OF
COSME WAS MISSED BY THE QUICKSCAT PASS A FEW HOURS AGO. THE
SATELLITE INTENSITY ESTIMATES SUPPORT MAINTAINING THE SYSTEM AT 30
KT. 

THE CURRENT FORECAST TRACK AND INTENSITY FOLLOWED THE PREVIOUS
PACKAGE VERY CLOSELY THROUGH 48 HOURS. SLIGHT ADJUSTMENTS WERE MADE
BEYOND DAY 2...INCLUDING CARRYING THE SYSTEM FARTHER WEST OF THE
DATELINE AS A DISSIPATING TROPICAL DEPRESSION. NOTE THAT IF COSME
SURVIVES THE HOSTILE SHEARING THAT IS FORECAST TO BE MAINTAINED
DURING THE NEXT FEW DAYS...THE OCEAN HEAT CONTENT GETS MORE
INTERESTING ACCORDING TO THE CIRA WEB SITE. COSME HAS PERSISTED
DESPITE MANY THREATS TO ITS EXISTENCE AS A TROPICAL CYCLONE DURING
THE PAST FEW DAYS...SO THERE IS A CHANCE THAT IT COULD
RE-INTENSIFY.

NOTE THAT THE FORECAST TRACK TAKES THE CENTER OF COSME VERY CLOSE TO
JOHNSTON ISLAND EARLY SUNDAY EVENING. THIS WILL LEAD TO A GRADUAL
DETERIORATION OF WEATHER AND OCEANIC CONDITIONS THERE DURING THE
NEXT 12 TO 18 HOURS.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      22/0900Z 16.5N 163.3W    30 KT
 12HR VT     22/1800Z 16.6N 165.9W    30 KT
 24HR VT     23/0600Z 16.8N 169.5W    30 KT
 36HR VT     23/1800Z 17.1N 173.1W    30 KT
 48HR VT     24/0600Z 17.6N 176.7W    30 KT
 72HR VT     25/0600Z 19.1N 177.3E    25 KT...DISSIPATING
 96HR VT     26/0600Z 20.6N 173.5E    20 KT...REMNANT LOW
 
$$
FORECASTER HOUSTON