WTPA42 PHFO 190243
TCDCP2

TROPICAL DEPRESSION THREE-C DISCUSSION NUMBER   2
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   CP032009
500 PM HST SUN OCT 18 2009

TROPICAL DEPRESSION THREE-C HAS CONTINUED TRACKING WEST.

SATELLITE IMAGERY SHOWS THAT THREE-C REMAINS WELL-ORGANIZED...WITH A
GOOD CURVED BAND STRUCTURE...BUT CLOUD TOPS HAVE WARMED SINCE THIS
MORNING. THE 00Z SATELLITE FIXES FROM SAB...CPHC AND JTWC WERE
CLOSE TOGETHER AND FARTHER WEST THAN EXPECTED BASED ON THE 18Z
FIXES. WE SUSPECT THE 18Z POSTION MAY HAVE BEEN TOO FAR EAST AND WE
HAVE RE-BESTED THE POSITION FARTHER WEST. SHIPS GUIDANCE AT 00Z
SHOWED A HIGH PROBABILITY OF RAPID INTENSIFICATION BUT THE WARMING
OF THE CLOUD TOPS MAKES RI UNLIKELY IN THE NEAR TERM.
 
THREE-C HAS CONTINUED MOVING WEST SINCE THIS MORNING...STEERED BY
DEEP EASTERLY FLOW SOUTH OF THE SUBTROPICAL RIDGE. HOWEVER...A
STRONG TROUGH ALOFT AND AN ASSOCIATED SURFACE FRONT NEAR MIDWAY ARE
DIGGING SOUTHEAST. THE MEAN FLOW AHEAD OF THE DIGGING TROUGH WILL
VEER TO SOUTHEAST AND STEER THREE-C ON A TRACK TOWARD THE WEST
NORTHWEST GRADUALLY CURVING TOWARD THE NORTHWEST. THE TRACK
GUIDANCE IS IN GOOD AGREEMENT ON SUCH A TRACK THROUGH 96 HOURS. WE
HAVE MADE ONLY MINOR ADJUSTMENTS TO OUR FORECAST TRACK...KEEPING
THREE-C MOVING DOWN THE MIDDLE OF THE ENVELOPE OF THE FAVORED TRACK
MODEL GUIDANCE. AFTER 96 HOURS...AS THE TROUGH ALOFT MOVES OFF TO
THE EAST AND RIDGING ALOFT BUILDS IN NORTH OF THE CYCLONE...THREE-C
WILL TURN BACK TOWARD THE WEST NORTHWEST. THREE-C SHOULD REMAIN
WELL SOUTHWEST OF THE MAIN HAWAIIAN ISLANDS...BUT THE TRACK DOES
TAKE IT FAIRLY CLOSE TO JOHNSTON ISLAND IN ABOUT 84 HOURS. THE
TRACK AND INTENSITY FORECASTS ARE TOO UNCERTAIN AT THIS POINT TO
HAVE MUCH CONFIDENCE ABOUT WHAT EFFECT THREE-C MIGHT HAVE ON
JOHNSTON BUT IF OUR FORECAST REMAINS ON TRACK WE MIGHT NEED TO
CONSIDER A WATCH FOR JOHNSTON ISLAND MONDAY NIGHT.
 
THREE-C IS OVER 84 DEGREE F WATER...WHICH SHOULD BE AMPLE TO SUPPORT
DEVELOPMENT...AND WATER TEMPERATURES WILL COOL ONLY ONE OR TWO
DEGREES OVER THE NEXT FOUR DAYS ALONG OUR FORECAST TRACK. THE SHIPS
MODEL SHOWS STRONGER SHEAR...20 KT...INITIALLY WITH THE SHEAR
GRADUALLY DECREASING THROUGH 96 HOURS. MODEL GUIDANCE STILL SHOWS
THREE-C INTENSIFYING STEADILY FOR THE NEXT 72 HOURS. WE HAVE KEPT
THIS TREND IN OUR FORECAST BUT THE WARMING CLOUD TOPS MAKE US LESS
CONFIDENT ABOUT THE INTENSITY TREND.
  
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      19/0300Z  8.8N 157.3W    30 KT
 12HR VT     19/1200Z  9.7N 159.3W    35 KT
 24HR VT     20/0000Z 11.0N 162.0W    40 KT
 36HR VT     20/1200Z 12.6N 164.3W    50 KT
 48HR VT     21/0000Z 14.0N 166.0W    60 KT
 72HR VT     22/0000Z 16.5N 168.5W    65 KT
 96HR VT     23/0000Z 18.0N 170.5W    75 KT
120HR VT     24/0000Z 19.0N 173.0W    75 KT
 
$$
FORECASTER DONALDSON