WDXS31 PGTW 240300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 08S (CHENESO) WARNING NR 
005//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 20.2S 42.5E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 176 NM NORTHEAST OF EUROPA ISLAND
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 10 KTS
   SIGNIFICANT WAVE HEIGHT: 15 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED SATELLITE IMAGERY AND A 232257Z
GMI SERIES VERIFY THAT TROPICAL STORM CHENESO HAS MOVED INTO THE
MOZAMBIQUE CHANNEL AND RE-INTENSIFIED. THE JTWC DVORAK ASSESSMENT 
IS T2.5 AND THE LOW FREQUENCY MICROWAVE IMAGERY SHOWS WELL ORGANIZED 
BANDING WRAPPING AROUND A CLEAR LOW LEVEL CIRCULATION CENTER WHILE 
THE UPPER FREQUENCIES CONFIRM AN INCREASE IN DEEP CONVECTION. THE
SYSTEM EXISTS IN A NEARLY IDEAL ENVIRONMENT WITH LOW VERTICAL
WIND SHEAR, SATURATION THROUGHOUT THE COLUMN, AND 29-30 DEGREE
SEAWATER. ANIMATED WATER VAPOR IMAGERY SHOWS VIGOROUS EQUATORWARD
OUTFLOW AS WELL AS A DEVELOPING POLEWARD OUTFLOW CHANNEL. THERE IS
SOME SUBSIDENCE DISPLACED FAR TO THE SOUTHWEST BUT IT DOES NOT
APPEAR TO BE AFFECTING THE STORM AT THIS POINT. TC 09S IS WEDGED
BETWEEN THE NEAR EQUATORIAL RIDGE, WHICH IS ANCHORED IN AN
ANTICYCLONE NEAR 10S 58E, AND THE SUBTROPICAL RIDGE, WHICH EXTENDS
ALONG THE 30TH LATITUDE. UNTIL THOSE RIDGES WEAKEN OR SHIFT THE
SYSTEM HAS NOWHERE TO GO AND WILL MEANDER OVER THE CHANNEL. THUS,
UPWELLING WILL HAVE A MAJOR INFLUENCE ON SYSTEM INTENSITY.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: THERE IS NO STEERING. THE SYSTEM IS
TRAPPED BETWEEN THE NEAR EQUATORIAL RIDGE AND THE SUBTROPICAL
RIDGE. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   KNES: T1.5 - 25 KTS
   FMEE: T1.0 - 25 KTS

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG POLEWARD AND EQUATORWARD
   OTHER FACTORS: INCREASED UPWELLING ASSOCIATED WITH SLOW STORM 
   MOTION WILL ACT AS A BRAKING MECHANISM ON INTENSIFICATION.

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: HIGH
   INITIAL WIND RADII: LOW

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THIS IS THE FIRST PROGNOSTIC
REASONING MESSAGE FOLLOWING THE RESUMPTION OF WARNINGS AND
RE-ESTABLISHES THE FORECAST PHILOSOPHY.

FORECAST DISCUSSION: TC 08S WILL CHURN OVER THE CHANNEL FOR THE 
NEXT 48 HOURS THEN BEGIN A POLEWARD TRACK TO THE SOUTHWEST AS THE
SUBTROPICAL RIDGE WEAKENS AND TRACKS DOWNSTREAM. ALTHOUGH THE
SYSTEM WILL REMAIN IN A NEARLY IDEAL ENVIRONMENT FOR THE FIRST 48
HOURS THE SLOW STORM MOTION WILL GENERATE UPWELLING THAT WILL BE AN
IMPEDIMENT TO EXPLOSIVE DEVELOPMENT. PEAK INTENSITY WILL OCCUR NEAR
TAU 96 AS THE SYSTEM APPROACHES THE 24TH LATITUDE AND BEGINS A BEND
TO THE SOUTHEAST.  ENHANCED POLEWARD OUTLOW WILL INITIALLY GIVE THE
SYSTEM A BOOST AS IT INTERACTS WITH THE MID-LATITUDE WESTERLIES. 
ONCE THE SYSTEM MAKES THE TURN, HOWEVER, IT WILL ENCOUNTER
INCREASING SHEAR AS IT BEGINS THE EXTRA-TROPICAL TRANSITION
PROCESS.   

MODEL DISCUSSION: MODEL GUIDANCE HAS BEEN QUALITATIVELY ACCURATE IN
CAPTURING THE SCENARIO BUT IS A STEP BEHIND ON CAPTURING HOW 
QUICKLY THE SYSTEM WOULD REGENERATE. TRACK GUIDANCE IS WIDELY SPREAD 
BUT THE CONSENSUS SHOWS THE BEGINNING OF THE TURN OCCURRING PAST 23S
AND COMPLETING BEFORE 25S.  INTENSITY GUIDANCE HAS BEEN LAGGING BUT 
THE LATEST RUN INDICATES IT IS CATCHING UP. STATISTICAL-DYNAMIC 
GUIDANCE IS IN GOOD ALIGNMENT WITH CONSENSUS. BOTH AGREE ON 
A PEAK IN INTENSITY BETWEEN 70 AND 80 KNOTS NEAR TAU 96. THE JTWC 
FORECAST STAYS CLOSE TO THE MULTI-MODEL CONSENSUS IN BOTH TRACK AND 
INTENSITY. 

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: LOW
   TRACK 72-120 HR: LOW
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: LOW//
NNNN