Tropical Storm KAMMURI Advisory 11月27日

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 29W (TWENTYNINE)
WARNING NR 01//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION 29W (TWENTYNINE), LOCATED APPROXIMATELY 449
NM SOUTHEAST OF ANDERSEN AFB, GUAM, HAS TRACKED WEST-NORTHWESTWARD
AT 15 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED
(EIR) SATELLITE IMAGERY DEPICTS AN EXTREMELY BROAD LOW-LEVEL
CIRCULATION (LLC) WITH ENHANCED CONVECTION THAT DISPLAYS MID-LEVEL
TURNING THAT PULLS THE EYE NORTHWARD. THE INITIAL POSITION IS PLACED
WITH LOW CONFIDENCE BASED ON EXTRAPOLATION FROM A 251134Z METOP-C
ASCAT PASS THAT INDICATES THE LLC IS SOUTH OF THE AFOREMENTIONED
CONVECTION. THE INITIAL INTENSITY IS BASED ON 20 KNOTS DEPICTED
NORTH OF THE LLC ON THE 251134Z METOP-C ASCAT PASS. HOWEVER, FURTHER
TO THE NORTH OF THE CIRCULATION ARE 35 KNOT WINDS ASSOCIATED WITH
GRADIENT FLOW BETWEEN TD 29W AND THE SUBTROPICAL RIDGE (STR) TO THE
NORTHEAST. ENVIRONMENTAL ANALYSIS REVEALS A FAVORABLE ENVIRONMENT
FOR DEVELOPMENT WITH LOW VERTICAL WIND SHEAR (VWS), ROBUST UPPER-
LEVEL OUTFLOW, AND HIGH SEA SURFACE TEMPERATURES.
3. FORECAST REASONING.
   A. THIS IS THE FIRST PROGNOSTIC REASONING MESSAGE ON THIS SYSTEM
AND SETS THE FORECAST PHILOSOPHY.
   B. TD 29W IS FORECAST TO TRACK WEST-NORTHWESTWARD ALONG THE
SOUTHERN PERIPHERY OF A STR POSITIONED TO THE NORTH-NORTHEAST
THROUGH TAU 48. BETWEEN TAUS 48 AND 72 AN UPPER-LEVEL TROUGH TO THE
NORTH WILL TRACK EASTWARD PROVIDING A BREAK BETWEEN THE PREVIOUSLY
MENTIONED STR AND A SECOND TO THE WEST OVER THE SOUTH CHINA SEA.
THIS BREAK IN THE RIDGES WILL ALLOW THE SYSTEM TO TURN MORE POLEWARD
INTO THE CULL AFTER TAU 48. TD 29W IS EXPECTED TO GRADUALLY
INTENSIFY THROUGH TAU 36 REACHING 45 KNOTS AT TAU 36. AS THE SYSTEM
BEGINS TO ROUND THE STR ENHANCED POLEWARD OUTFLOW WILL LEAD TO MORE
RAPID INTENSIFICATION, REACHING 80 KNOTS BY TAU 72. THERE IS GOOD
AGREEMENT AMONG THE MODELS THROUGH TAU 36, COMBINED WITH THE LOW
CONFIDENCE IN THE INITIAL POSITION OF THE LLCC THERE IS FAIR
CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST TRACK. AFTER TAU 48,
THE MODELS DIVERGE IN THE TIMING FOR THE SYSTEM RECURVING, THEREFORE
CONFIDENCE IN THE JTWC TRACK AFTER TAU 48 DECREASES.
   C. AFTER TAU 72, THERE IS PERSISTENT LOW CONFIDENCE IN THE EXACT
FORECAST TRACK AS THE TIMING OF THE TROUGH WILL SIGNIFICANTLY AFFECT
THE TRACK. TD 29W IS EXPECTED TO SLOW DOWN AS IT SITS IN THE CULL
BETWEEN THE TWO STRS AND HAS MINIMAL STRONG STEERING INFLUENCES IN
THE LATTER PORTION OF THE FORECAST.//
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