296
WTPA43 PHFO 190243
TCDCP3
TROPICAL DEPRESSION TWO-C DISCUSSION NUMBER 1
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI CP022006
500 PM HST MON SEP 18 2006
THAT AREA OF DISTURBED WEATHER WELL TO THE SOUTH OF THE ISLANDS WE
HAVE BEEN WATCHING FOR DAYS HAS FINALLY GOTTEN ORGANIZED ENOUGH TO
BE CLASSIFIED AS A TROPICAL DEPRESSION...THE SECOND ONE OF THE
SEASON HERE IN THE CENTRAL PACIFIC. THE CONVECTION THAT FLARED LATE
LAST NIGHT HAS DIMINISHED SOME TODAY...BUT FROM A MORNING QUICKSCAT
PASS IT APPEARS AS THOUGH A DECENT SURFACE CIRCULATION IS IN PLACE.
IN FACT QUICKSCAT DATA INDICATED A QUITE A FEW 35KT...ALBEIT RAIN
FLAGGED...WIND BARBS AROUND THE CIRCULATION. WITH THE DEMISE OF
CONVECTION SOME TODAY AND THE POORER LOOK ON SATELLITE...WILL START
TD-2C AT A POTENTIALLY QUITE CONSERVATIVE 25KT.
TD-2C IS IN A SIMILAR AREA TO WHERE IOKE GOT ITS BIRTH...AND THE
OVERALL SYNOPTIC CONDITIONS LOOK SIMILAR. VERY WARM WATER AND UPPER
LEVEL SHEAR VALUES LESS THAN 10KT. CIRRUS FROM THE SYSTEM SHOW
DECENT UPPER LEVEL OUTFLOW CHANNELS TO THE NORTH OF THE SYSTEM.
ONLY NEGATIVE IS THAT THERE IS STILL A CONSIDERABLE AMOUNT OF ITCZ
CONVECTION WITHIN 10 DEGREES SOUTHWEST OF THE SYSTEM. SUBSIDENCE
AROUND THAT CONVECTION MAY BE HAMPERING TD-2C DEVELOPMENT.
SOME MIXED SIGNALS WITH THE NEAR TERM FUTURE OF TD-2C ESPECIALLY
WITH INTENSITY. LATEST GUIDANCE SUITE IS NOT AS GUNG-HO ON
DEVELOPING IT MUCH FOR THE NEXT 48HRS...PERHAPS THIS IS DUE TO ITS
PULSE DOWNWARD THIS MORNING. SURPRISINGLY EVEN THE GFDL...WHICH
ACCURATELY PORTRAYED THE RAPID SPIN UP OF IOKE...IS LESS THAN
ENTHUSIASTIC WITH TD-2C THRU 60HRS. IT KEEPS IT AS A TD/WEAK TS
BEFORE FINALLY STRENGTHENING IT TO A STRONG TS THEN HURRICANE AFTER
96HRS. SHIPS GUIDANCE STEADILY STRENGTHENS IT TO TS IN 18HRS THEN
TO MINIMAL HURRICANE IN 60HRS. SHOULD BE NOTED THAT EARLIER SHIPS
GUIDANCE WAS SHOWING A 60 TO 80% LIKELIHOOD OF RAPID INTENSIFICATION
(25KT INCREASE WITHIN 24HRS) BUT THE 00Z SHIPS WAS DOWN TO 36%
CHANCE DUE TO THE LACK OF DEEP CONVECTION.
DUE TO CONVECTION STILL WITH ITCZ...HAVE GIVEN CREDENCE TO A
SLIGHTLY SLOWER START TO TD-2C. EXPECT IT TO CUT THE UMBILICAL CORD
TO THE ITCZ TOMORROW AND AT THAT TIME WILL BE ABLE TO DEVELOP QUITE
QUICKLY. WILL PROJECT HURRICANE STRENGTH IN 48 HRS. IF IT CAN NOT
GET AWAY FROM THE ITCZ...IT MAY NOT HAVE MUCH OF A LIFE. AFTER THAT
MAKE OR BREAK TIME...GLOBAL MODELS SHOW UPPER LEVEL RIDGING
BUILDING IN ACROSS 15N BETWEEN 160W AND 175W AND MAKING FOR A LOW
SHEAR ENVIRONMENT. SORTA LIKE WHAT WE HAD WITH IOKE...SO DONT SEE
ANY REASON FOR THE STORM TO NOT TO CONTINUE INTENSIFYING HOWEVER I
DONT HAVE ENOUGH CONFIDENCE TO BE FORECASTING A MAJOR HURRICANE
THIS EARLY OUT. AS A RESULT THE INTENSITY FORECAST IS CLOSE TO THE
GFDL AND A LITTLE WEAKER THAN SHIPS THRU 24HRS...THEN CLOSE TO
SHIPS IN THE MID TERM AND THEN SOMEWHAT ABOVE ALL GUIDANCE AFTER
72HRS.
TRACK-WISE...MUCH MORE CONSISTENCY WITH VARIOUS MODELS...GENERALLY A
WNW TRACK THRU THE PERIOD. DID SLOW THE FORWARD SPEED DOWN AT DAYS
4 AND 5 AS THE EXPECTED HURRICANE IS EXPECTED TO BE IN A LIGHTER
STEERING FLOW DUE TO THE RIDGE OF HIGH PRESSURE. ON THE PROJECTED
COURSE...THE SYSTEM WOULD PASS SAFELY OVER 200 MILES SOUTH OF
JOHNSTON ATOLL LATE THURSDAY. HOWEVER INTERESTS AROUND JOHNSTON
SHOULD PAY ATTENTION TO LATER FORECASTS FROM CPHC.
FOR WHAT IT MATTERS...IF TD-2C CAN ACHIEVE 35KTS IT WILL BE NAMED
KIKA (KEE-KAH)...EMPHASIS ON FIRST SYLLABLE. THERE ARE A COUPLE OF
MEANINGS FOR THIS WORD...AS A NOUN IT MEANS A SMALL OPELU FISH AND
AS A VERB ONE MEANING IS STRONG AND ENERGETIC. THE VERB FORM IS THE
ONE THAT WOULD BE MOST FITTING...ESPECIALLY IF IT DECIDES TO BECOME
A HURRICANE.
FORECAST POSITIONS AND MAX WINDS
INITIAL 19/0300Z 10.0N 157.2W 25 KT
12HR VT 19/1200Z 10.4N 159.2W 30 KT
24HR VT 20/0000Z 10.7N 161.2W 40 KT
36HR VT 20/1200Z 11.2N 163.2W 55 KT
48HR VT 21/0000Z 11.9N 165.1W 65 KT
72HR VT 22/0000Z 13.7N 168.6W 75 KT
96HR VT 23/0000Z 15.3N 172.3W 80 KT
120HR VT 24/0000Z 16.4N 175.3W 80 KT
$$
FORECASTER NASH
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