Tropical Storm MATMO Advisory Per, 17.07.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 10W (TEN) WARNING
NR 01//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 10W (TEN), LOCATED APPROXIMATELY 175 NM
WEST-NORTHWEST OF YAP, HAS TRACKED WESTWARD AT 02 KNOTS OVER THE
PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY
DEPICTS PERSISTENT CENTRAL CONVECTION WITH FORMATIVE BANDING ALONG
THE SOUTHERN PERIPHERY WRAPPING INTO A CONSOLIDATING LOW-LEVEL
CIRCULATION CENTER (LLCC). A SERIES OF RECENT MICROWAVE SATELLITE
PASSES, INCLUDING A 170844Z SSMIS IMAGE, SUPPORT THE CURRENT
POSITION WITH GOOD CONFIDENCE. THE CURRENT INTENSITY OF 30 KNOTS IS
BASED ON CONSISTENT DVORAK INTENSITY ESTIMATES FROM ALL REPORTING
AGENCIES. UPPER-LEVEL ANALYSIS INDICATES THE SYSTEM IS LOCATED IN A
FAVORABLE ENVIRONMENT WITH LOW (05 TO 10 KNOT) VERTICAL WIND SHEAR
(VWS) AND EXCELLENT OUTFLOW AS EVIDENT IN THE WATER VAPOR IMAGERY.
TD 10W IS CURRENTLY POSITIONED IN A WEAK STEERING ENVIRONMENT
BETWEEN A DEEP-LAYER SUBTROPICAL RIDGE (STR) ENTRENCHED TO THE NORTH
AND A NEAR EQUATORIAL RIDGE (NER) TO THE SOUTHEAST.
3. FORECAST REASONING.
   A. THIS IS THE INITIAL PROGNOSTIC REASONING AND SETS THE FORECAST
PHILOSOPHY.
   B. TD 10W IS EXPECTED TO TRACK SLOWLY WITH A POSSIBILITY OF QUASI-
STATIONARY IN THE NEAR TERM DUE TO THE WEAK STEERING INFLUENCE
BETWEEN TWO RIDGES. BY TAU 36, THE STR IS FORECAST TO BECOME THE
DOMINANT STEERING PATTERN, TURNING THE SYSTEM TO THE NORTH. AROUND
TAU 48, A MID-LATITUDE TROUGH DIGGING OVER SOUTHERN JAPAN IS
EXPECTED TO WEAKEN THE STR, CAUSING TD 10W TO TURN MORE POLEWARD AND
EVENTUALLY TRACK NORTHEASTWARD AS THE STR REORIENTS TO THE EAST OF
THE SYSTEM. WARM SEA SURFACE TEMPERATURES (SST), FAVORABLE VWS AND
WESTWARD DIFFLUENCE ALOFT ARE EXPECTED TO PERSIST, ALLOWING THE
SYSTEM TO GRADUALLY INTENSIFY THROUGH TAU 72.
   C. IN THE EXTENDED TAUS, ANOTHER STR IS EXPECTED TO BUILD OVER
EASTERN CHINA, DOMINATING THE STEERING PATTERN FOR THE REMAINDER
OF THE FORECAST PERIOD. THE COMBINED EFFECTS OF FAVORABLE SST AND
IMPROVED UPPER-LEVEL CONDITIONS WILL ALLOW THE SYSTEM TO FURTHER
INTENSIFY, LEADING TO TYPHOON STRENGTH BY TAU 120. AVAILABLE DYNAMIC
MODEL SOLUTIONS DIVERGE AT TAU 24 WITH A SPREAD OF 175 NM BETWEEN
THE WESTERN AND EASTERN TRACKERS. HOWEVER, THE MAJORITY OF THE
GUIDANCE DEPICTS A SLOW TRACK OVER THE NEXT 36. DUE TO THE SLOW
AND/OR ERRATIC MOVEMENT IN THE NEAR TERM AND THE UNCERTAINTY IN THE
EXACT TIMING OF THE NORTHWARD TURN, THERE IS LOW CONFIDENCE IN THE
JTWC FORECAST.//
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