WTPA41 PHFO 290259
TCDCP1

TROPICAL DEPRESSION TWO-C DISCUSSION NUMBER   1
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   CP022009
500 PM HST FRI AUG 28 2009

THE AREA OF LOW PRESSURE WEST-SOUTHWEST OF JOHNSTON ATOLL...AND
APPROACHING THE INTERNATIONAL DATELINE...HAS GAINED SUFFICIENT
ORGANIZATION TO BE DESIGNATED A TROPICAL DEPRESSION...THE SECOND TO
FORM WITHIN THE CENTRAL PACIFIC BASIN THIS YEAR.  LOW-LEVEL CLOUD
LINES IN VISIBLE IMAGERY...ALONG WITH MANUAL ANALYSIS OF
DIRECTIONAL AMBIGUITIES FROM AN 18Z QUIKSCAT PASS...PROVIDE STRONG
EVIDENCE OF A FAIRLY WELL-DEFINED CLOSED SURFACE CIRCULATION. 
MEANWHILE...THE SURROUNDING CIRRUS CLOUD PATTERN INDICATES AN
UPPER-LEVEL ANTICYCLONE OVERHEAD.  A SMALL AREA OF DEEP CONVECTION
HAS PERSISTED OVER THE LOW-LEVEL CENTER FOR SEVERAL HOURS...ENOUGH
TO RESULT IN SUBJECTIVE DVORAK CLASSIFICATIONS OF 1.5 TO 2.0.  VERY
RECENTLY...HOWEVER...THE CONVECTION HAS BECOME A LITTLE LESS
CONCENTRATED.  THE ADVISORY INTENSITY IS SET TO 30 KT BASED ON THE
DVORAK CLASSIFICATIONS AND THE QUIKSCAT DATA.

THE DEPRESSION IS HEADED SLOWLY WESTWARD OR ABOUT 280/6...TO THE
SOUTH OF A LOW- TO MID-LEVEL RIDGE CENTERED TO ITS NORTH AND
NORTHEAST.  A BREAK IN THE RIDGE ALREADY IN PLACE ALONG THE
DATELINE MEANS THAT THE CYCLONE IS NOT LIKELY TO GAIN MUCH FORWARD
SPEED DURING THE NEXT COUPLE OF DAYS.  IN FACT...MOST DYNAMICAL
MODELS FORECAST THE CYCLONE TO TURN NORTHWARD WITHIN THE FIVE-DAY
FORECAST PERIOD AS A DEEP-LAYER MID-LATITUDE LOW DROPS DOWN FROM
THE NORTH ALONG THE DATELINE.  WHILE THE MODELS GENERALLY AGREE ON
THE NORTHWARD TURN...THE SPREAD IS QUITE SIGNIFICANT SINCE SOME
MODELS ACCELERATE A STRONGER AND DEEPER SYSTEM AHEAD OF THE
MIDLATITUDE LOW...WHILE OTHERS FORECAST A SLOW MOTION WITHIN THE
BREAK IN THE RIDGE.  THE OFFICIAL FORECAST PRESUMES THE SYSTEM WILL
NOT BE QUITE STRONG ENOUGH TO QUICKLY RECURVE...AND SHOWS A SLOW
MOTION TO THE NORTH BY DAY 5...IN CLOSEST AGREEMENT WITH THE HWRF.

THE CYCLONE IS CURRENTLY OVER SEA-SURFACE TEMPERATURES OF ABOUT 28
CELSIUS...AND THE UNDERLYING WATERS WILL NOT CHANGE SIGNIFICANTLY
ALONG THE FORECAST TRACK.  THE ATMOSPHERIC ENVIRONMENT AHEAD OF THE
SYSTEM IS SOMEWHAT FAVORABLE FOR INTENSIFICATION FOR ABOUT 48
HOURS...THEN IT SHOULD ENCOUNTER INCREASING SHEAR TO THE SOUTH OF
THE DEEP-LAYER LOW APPROACHING FROM THE NORTH.  IN ACCORDANCE WITH
THE DYNAMICAL MODEL INTENSITY GUIDANCE...ONLY MODEST STRENGTHENING
IS FORECAST...WITH WEAKENING AT THE END UNDER STRONG SHEAR.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      29/0300Z 14.9N 177.7W    30 KT
 12HR VT     29/1200Z 15.1N 178.9W    30 KT
 24HR VT     30/0000Z 15.3N 179.6E    35 KT
 36HR VT     30/1200Z 15.7N 178.2E    40 KT
 48HR VT     31/0000Z 16.2N 176.8E    40 KT
 72HR VT     01/0000Z 17.5N 175.0E    35 KT
 96HR VT     02/0000Z 19.5N 174.5E    35 KT
120HR VT     03/0000Z 21.5N 175.5E    30 KT
 
$$
FORECASTER KNABB