Tropical Storm RAI Advisory 12月15日

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 28W (RAI) WARNING NR
008//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
   INITIAL POSITION: 8.8N 133.3E
   INITIAL INTENSITY: 60 KTS
   GEOGRAPHIC REFERENCE: 111 NM NORTHWEST OF KOROR, PALAU
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 13 KTS
   SIGNIFICANT WAVE HEIGHT: 18 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS THE
SYSTEM CONTINUES TO MAINTAIN AN IMPRESSIVE CONVECTIVE SIGNATURE.
THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON
EXTRAPOLATION FROM A 141247Z ASCAT-C PASS, AS WELL AS A MICROWAVE
EYE FEATURE IN THE 141610Z GMI 37GHZ IMAGE. THE INITIAL INTENSITY OF
60 KTS IS PLACED WITH MEDIUM CONFIDENCE BASED ON ANALYSIS OF ULTRA
HIGH RESOLUTION ASCAT DATA, AGENCY AND AUTOMATED DVORAK ESTIMATES
AND CONSISTENT WITH THE ONSET OF A MICROWAVE EYE FEATURE. ANALYSIS
INDICATES A FAVORABLE ENVIRONMENT WITH STRONG WESTWARD OUTFLOW, LOW
(10-15 KTS) VERTICAL WIND SHEAR AND WARM (29-30 C) SEA SURFACE
TEMPERATURES. TS 28W IS TRACKING ALONG THE SOUTHERN PERIPHERY OF THE
SUBTROPICAL RIDGE (STR) TO THE NORTH.
INITIAL WIND RADII BASIS: PERSISTENCE
CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE NORTH.
AGENCY DVORAK AND AUTOMATED FIXES:
   PGTW: T4.0 - 65 KTS
   RJTD: T4.0 - 65 KTS
   RCTP: T3.5 - 55 KTS
   KNES: T4.5 - 77 KTS
   CIMSS ADT: 61 KTS AT 141740Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG WESTWARD
ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: MEDIUM
3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.
FORECAST DISCUSSION: TS RAI WILL CONTINUE ON ITS CURRENT TRACK,
MAKING LANDFALL OVER SURIGAO, PHILIPPINES, JUST AFTER TAU 36, TRACK
ACROSS THE ARCHIPELAGO, AND EXIT INTO THE SOUTH CHINA SEA (SCS)
SHORTLY AFTER TAU 72. THE POSSIBILITY OF RAPID INTENSIFICATION
REMAINS BEFORE LANDFALL WITH A PEAK INTENSITY SET AT 90 KTS BY TAU
36. AFTERWARD, INTERACTION WITH THE PHILIPPINE ISLANDS WILL
SLIGHTLY ERODE THE SYSTEM TO 85 KTS AS IT EXITS INTO THE SCS. THE
WARM SST IN THE SCS AND CONTINUED LOW VWS, AND GOOD POLEWARD
OUTFLOW WILL PROMOTE A PEAK OF 105 KTS BY TAU 96. AFTERWARD, THE
INFLUX OF COLD DRY AIR ASSOCIATED WITH A NORTHEASTERLY WIND SURGE
IN THE SCS WILL BEGIN TO WEAKEN THE SYSTEM DOWN TO 90 KTS BY TAU
120.
MODEL DISCUSSION: NUMERICAL MODELS CONTINUE TO BE IN VERY TIGHT
AGREEMENT ON TRACK PROGRESSION THROUGHOUT THE ENTIRE FORECAST
PERIOD, LENDING HIGH CONFIDENCE IN THE JTWC TRACK FORECAST UP TO
TAU 120. THE JTWC INTENSITY FORECAST IS SET WITH MEDIUM CONFIDENCE
AND HIGHER THAN MODEL CONSENSUS (ICNW). THE POSSIBILITY OF RAPID
INTENSIFICATION BEFORE LANDFALL MAY STILL OCCUR CONSIDERING THE
FAVORABLE ENVIRONMENT.
FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   TRACK 72-120 HR: HIGH
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//
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