WDXS31 PGTW 180300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 05S (BELAL) WARNING NR 
012//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 24.0S 64.9E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 483 NM EAST-SOUTHEAST OF PORT LOUIS,
MAURITIUS
   MOVEMENT PAST 6 HOURS: NORTHEASTWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 21 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TC 05S
(BELAL) WITH A PARTIALLY EXPOSED LOW-LEVEL CIRCULATION CENTER
(LLCC) LOCATED JUST NORTH OF AN OBSERVABLE CONVECTIVE STRUCTURE
BEING HEAVILY INFLUENCED BY A NORTHWESTERLY SHEAR COMPONENT. THE
STORM HAS CREPT NORTHEASTWARD OVER THE LAST SIX HOURS, AS IT IS
INCREASINGLY INFLUENCED BY THE STEERING RIDGES TO THE NORTHEAST AND
SOUTH. THE INITIAL POSITION WAS IDENTIFIED WITH HIGH CONFIDENCE BY
A 172246Z 37GHZ MICROWAVE PASS, INDICATING AN ASYMMETRIC AND
SHALLOW EYE-LIKE FEATURE WITH DEEP, BUT ISOLATED CONVECTION JUST TO
THE SOUTHEAST. THE INITIAL INTENSITY WAS ASSESSED WITH MEDIUM
CONFIDENCE BASED ON PERSISTENCE AND SUSTAINED CONVECTIVE
DEVELOPMENT WITH SUBJECTIVE AND OBJECTIVE FIXES LISTED BELOW.
STRONG NORTHWESTERLY VERTICAL WIND SHEAR (VWS) WITH CONTINUOUS
DRY-AIR ENTRAINMENT FROM THE WEST WILL CONTINUE TO DISSIPATE TC 05S
THROUGH THE FORECAST PERIOD (TAU 48), DESPITE RELATIVELY WARM SEA
SURFACE TEMPERATURES (SST) OF 26-28C.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SOUTHERN PERIPHERY OF A DEEP-LAYER
NEAR-EQUATORIAL RIDGE (NER) TO THE NORTH. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   KNES: T2.5 - 35 KTS
   FMEE: T3.0 - 45 KTS
   FIMP: T3.0 - 45 KTS
   CIMSS ADT: 39 KTS AT 172100Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY
UNFAVORABLE
   VWS: 20-25 KTS
   SST: 26-28 CELSIUS
   OUTFLOW: WEAK POLEWARD

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TC 05S (BELAL) IS FORECASTED TO CONTINUE TO
PROGRESS SLIGHTLY FURTHER TO THE NORTHEAST AND LOOP BACK TO THE
WEST ALONG THE SOUTHERN EDGE OF THE NER TO THE NORTH, SLOWS DOWN TO
A NEAR-STALL, AND EJECTS SHARPLY SOUTHWESTWARD ALONG THE NORTHERN
SIDE OF A LOW TO MID-LEVEL MID-LATITUDE AREA OF ANTICYCLONIC
ROTATION POSITIONED DIRECTLY POLEWARD OF TC 05S BETWEEN TAU 0 AND
TAU 36. THROUGHOUT THE FORECAST PERIOD, THE CYCLONE WILL CONTINUE
TO DECREASE IN INTENSITY AS STRONG WIND SHEAR (25-30 KTS) WILL
FURTHER DISSIPATE THE TROPICAL STRUCTURE OF THE SYSTEM, DEGRADING
ANY OPPORTUNITY FOR FURTHER DEVELOPMENT. TC 05S WILL ALSO CONTINUE
TO BE FURTHER WEAKENED A CONTINUOUS SURGE OF DRY AIR FROM THE
WESTERN PERIPHERY, COMPLETELY ENCIRCLING THE TC BY TAU 48. THE
COMBINATION OF DRY AIR AND STRONG VWS WILL LEAD TO DISSIPATION OVER
WATER BY TAU 48.  

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN AGREEMENT THAT
TC 05S (BELAL) WILL CONTINUE TO STEADILY SLOW IN ITS RE-CURVE TO
THE WEST THROUGH TAU 12. THE MODELS ARE IN RELATIVE AGREEMENT THAT
A DIRECTION SHIFT TO THE WEST IS EXPECTED, BACKING SLIGHTLY TO THE
NORTH BY TAU 12, THEN PROGRESSING WEST AND SOUTHWESTWARD BETWEEN
TAU 24 AND TAU 36. TRACK SPREAD DURING TC 05S RE-CURVE REMAINS IN
CLOSE AGREEMENT WITH A CROSS-TRACK SPREAD OF 45 NM, AND INCREASING
TO A CROSS-TRACK SPREAD DURING ITS SOUTHWESTWARD TREK BETWEEN TAU
24 AND TAU 48. THE CROSS-TRACK SPREAD CONTINUES TO INCREASE TO 150
NM NEAR TAU 48, AS TC 05S DISSIPATES WITH STRONG AND CONSTANT
INFLUENCE FROM DRY-AIR ENTRAINMENT AND STRONG VWS. THE MAJORITY OF
JTWC CONSENSUS MEMBERS AGREE THAT THE CYCLONE WILL STEADILY WEAKEN
THROUGH THE END OF THE FORECAST PERIOD (TAU 48). 

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: MEDIUM
   INTENSITY 0 - 72 HR: MEDIUM//
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