Tropical Storm NANMADOL Advisory Tue Jul 04

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 05W (NANMADOL)
WARNING NR 06//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 05W (NANMADOL), LOCATED APPROXIMATELY 399 NM
SOUTHWEST OF SASEBO, JAPAN, HAS TRACKED NORTH-NORTHEASTWARD AT 19
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL AND ENHANCED
INFRARED SATELLITE IMAGERY INDICATE A COMPACT, CONSOLIDATING LOW-
LEVEL CIRCULATION CENTER WITH DEEP CONVECTIVE BANDING WRAPPING
TIGHTLY INTO A WELL-DEFINED CENTER. THE MOST RECENT IMAGERY AT
03/0730Z SHOWS A DEVELOPING SMALL EYE. OVERALL, THERE IS EXCELLENT
CONFIDENCE IN THE CURRENT POSITION AND RECENT TRACK MOTION. THE
CURRENT INTENSITY IS ASSESSED AT 60 KNOTS, HEDGED HIGHER THAN DVORAK
ESTIMATES OF T3.5 (55 KNOTS), BASED ON THE IMPROVING ORGANIZATION
AND DEVELOPING EYE. THE 34-KNOT WIND RADII HAVE BEEN ADJUSTED
SLIGHTLY BASED ON THE 03/0153Z ASCAT BULLS-EYE IMAGE. UPPER-LEVEL
ANALYSIS INDICATES ROBUST POLEWARD OUTFLOW ENHANCED BY THE
MIDLATITUDE WESTERLIES TO THE NORTH. TS 05W IS TRACKING QUICKLY
POLEWARD ALONG THE NORTHWESTERN EDGE OF THE DEEP SUBTROPICAL RIDGE
(STR).
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY
SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TS 05W IS FORECAST TO TRACK NORTHEASTWARD THROUGH TAU 24 AS IT
ROUNDS THE NORTHWEST PERIPHERY OF THE STR AND BEGINS TO INTERACT
WITH MIDLATITUDE WESTERLY FLOW. TS NANMADOL IS EXPECTED TO INTENSIFY
TO TYPHOON STRENGTH (65 KNOTS) WITHIN THE NEXT SIX TO TWELVE HOURS.
DUE TO THE LIKELY EYE FORMATION, THERE IS INCREASED UNCERTAINTY IN
THE EXACT PEAK INTENSITY, WHICH WILL LIKELY OCCUR BETWEEN THE TAU 0
AND TAU 12 FORECAST POSITIONS. AN ADDITIONAL CONSIDERATION IS THAT
THE SYSTEM IS FORECAST TO TRACK OVER COOLER SST (26 TO 25C) BY TAU
12 TO TAU 18, WHICH SHOULD BEGIN TO WEAKEN THE SYSTEM AS IT
APPROACHES THE WESTERN COAST OF KYUSHU. AFTER TAU 12, TS 05W SHOULD
WEAKEN FURTHER AS IT BEGINS TO INTERACT WITH THE ROUGH TERRAIN OF
KYUSHU. AFTER TAU 18, RAPID WEAKENING IS FORECAST AS THE SYSTEM
TRACKS ACROSS KYUSHU, SHIKOKU AND HONSHU WHILE UNDERGOING EXTRA-
TROPICAL TRANSITION (ETT). STRONG VERTICAL WIND SHEAR AND LAND
INTERACTION WILL SERVE TO SIGNIFICANTLY WEAKEN THE SYSTEM BEFORE IT
COMPLETES ETT BY TAU 48. THE DYNAMIC AIDS ARE IN UNUSUALLY TIGHT
AGREEMENT FOR A RE-CURVE SCENARIO LENDING HIGH CONFIDENCE TO THE
FORECAST TRACK.//
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