Tropical Storm NALGAE Advisory 10月29日

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 26W (NALGAE) WARNING NR
008//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
   INITIAL POSITION: 14.1N 123.6E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 154 NM EAST OF MANILA, PHILIPPINES
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 19 KTS
   SIGNIFICANT WAVE HEIGHT: 22 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED SATELLITE IMAGERY (EIR) DEPICTS DEEP
CONVECTIVE BANDING WITH A CENTRAL DENSE OVERCAST OBSCURING A
LOW-LEVEL CIRCULATION CENTER (LLCC). A 281804Z ATMS 88.2GHZ
MICROWAVE IMAGE REVEALS DEEP CONVECTIVE BANDING MOSTLY RESIDING
OVER THE EASTERN AND SOUTHERN SEMICIRCLE, BEGINNING TO WRAP AROUND
THE NORTHERN QUADRANT WITH FRAGMENTED BANDING OVER THE NORTHERN
SEMICIRCLE. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE
BASED ON THE EIR LOOP AND THE ATMS IMAGE. THE INITIAL INTENSITY OF
55KTS IS ASSESSED WITH MEDIUM CONFIDENCE WITH THE AGREEMENT OF THE
AGENCY DVORAK INTENSITY ESTIMATES AND THE OBJECTIVE INTENSITY
ESTIMATES LISTED BELOW. ENVIRONMENTAL CONDITIONS HAVE REMAINED
FAVORABLE OVER THE LAST SIX HOURS, WITH IMPROVED NEAR RADIAL
OUTFLOW, LOW VERTICAL WIND SHEAR, AND WARM (28-29C) SST VALUES.
INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK
CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR)
POSITIONED TO THE NORTH.
AGENCY DVORAK AND AUTOMATED FIXES:
   PGTW: T3.5 - 55 KTS
   RJTD: T3.0 - 45 KTS
   KNES: T3.5 - 55 KTS
   CIMSS SATCON: 65 KTS AT 281714ZZ
   CIMSS ADT: 55 KTS AT 281740Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG POLEWARD
ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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:  TS 26W WILL CONTINUE TO MOVE WEST-NORTHWEST
ALONG THE SOUTHERN PERIPHERY OF THE STR TO THE NORTH. THE SYSTEM WILL
TRACK OVER THE CENTRAL PHILIPPINE ISLAND OF LUZON THROUGH TAU 24. THE
SYSTEM WILL MAINTAIN INTENSITY AS THROUGH TAU 24 WITH THE POSSIBILITY
OF ONLY SLIGHTLY WEAKENING DUE TO FRICTIONAL EFFECTS. HOWEVER, AS THE
SYSTEM REEMERGES INTO THE THE SOUTH CHINA SEA AND GAIN A GREATER
POLEWARD OUTFLOW CHANNEL. IT IS EXPECTED TO INTENSIFY TO TYPHOON
STRENGTH BY TAU 48. ONCE ON THE WESTERN PERIPHERY OF THE STR, THE
SYSTEMS TRACK BECOMES A LITTLE MORE DIVERGENT AS THERE REMAINS A
POSSIBLE CHANCE FOR THE DEVELOPMENT OF A NORTHEAST SURGE OVER THE
EAST CHINA SEA BETWEEN TAUS 72 AND 96. THE STRONGER NORTH-
NORTHEASTERLY WINDS FUNNELING THROUGH THE TAIWAN STRAIT AND LUZON
STRAIT WILL FURTHER COMPLICATE THE STEERING AND OVERALL MOTION OF THE
SYSTEM. THE SYSTEM APPEARS TO SLOW IN TRACK SPEED AS IT BEGINS
TRACKING TO THE NORTH FROM TAU 48 TO TAU 120 DUE TO THE MORE STABLE
AIR FROM THE SURGE EVENT.
MODEL DISCUSSION: DETERMINISTIC AND PROBABILISTIC MODEL GUIDANCE
SHOW BIFURCATION REMAINS A FACTOR DUE TO THE NORTHEAST SURGE EVENT.
A LARGE MAJORITY OF ENSEMBLE SOLUTIONS SHOW A QUASI-STATIONARY OR
SLOW WESTWARD TURN TOWARD SOUTHERN CHINA, WHILE THE DETERMINISTIC
MOVE THE SYSTEM TOWARDS THE NORTH-NORTHEAST AS THE JTWC TRACK
INDICATES. DUE TO THE ERRATIC NATURE OF THE MODEL TRACK GUIDANCE,
THE OVERALL JTWC FORECAST TRACK CONFIDENCE REMAINS LOW AT THIS TIME
BEYOND TAU 72. INTENSITY GUIDANCE REMAINS IN FAIR AGREEMENT RANGING
FROM 50 TO 55 KNOTS, WITH GFS AS A FAR OUTLIER OF 80+KTS BY TAU 72.
HOWEVER, ALL MODELS INDICATE A SLIGHT RE-INTENSIFICATION PHASE OVER
THE SOUTH CHINA SEA TO A PEAK OF 55-65 KNOTS. THE JTWC INITIAL
INTENSITY CONFIDENCE IS MEDIUM UP TO TAU 48 BUT DECREASES TO LOW
THEREAFTER WITH THE SURGE EVENT WREAKING HAVOC ON THE LATEST MODEL
SOLUTIONS.
FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: MEDIUM
   TRACK 72-120 HR: LOW
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: LOW//
NNNN
NNNN