Tropical Storm ONE Advisory Thu Jul 16

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 01C (HALOLA) WARNING
NR 21//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 01C (HALOLA), LOCATED APPROXIMATELY 222 NM EAST-
SOUTHEAST OF WAKE ISLAND, HAS TRACKED WEST-NORTHWESTWARD AT 13 KNOTS
OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
SHOWS A DISORGANIZED CONVECTIVE SIGNATURE BEING ELONGATED TO THE
NORTHEAST DUE TO MODERATE (15-20 KNOT) SOUTHWESTERLY VERTICAL WIND
SHEAR (VWS). A 150331Z GPM 89GHZ MICROWAVE IMAGE FURTHER ILLUSTRATES
THE WEAK AND DISORGANIZED NATURE OF THE CYCLONE. HOWEVER, TIGHT
SHALLOW CURVED BANDING REMAINS EVIDENT ALONG THE WESTERN QUADRANT
AND SUPPORTS THE CURRENT POSITION WITH GOOD CONFIDENCE. THE INITIAL
INTENSITY HAS BEEN LOWERED SLIGHTLY TO 80 KNOTS BASED ON THE WEAK
STRUCTURE OF THE SYSTEM AND AN ASSESSMENT OF REDUCED DVORAK
INTENSITY ESTIMATES FROM ALL AGENCIES. TY HALOLA IS LOCATED IN AN
AREA OF GOOD POLEWARD OUTFLOW AND FAVORABLE SEA SURFACE
TEMPERATURES; HOWEVER, THE MODERATE VWS IS PREVENTING CONSOLIDATION
AND INTENSIFICATION. TY HALOLA IS TRACKING ALONG THE SOUTHERN
PERIPHERY OF A SUB-TROPICAL RIDGE (STR) TO THE NORTH.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TY 01C WILL REMAIN ON A WEST-NORTHWESTWARD TRAJECTORY AS IT
TRACKS ALONG THE SOUTHERN PERIPHERY OF THE STEERING STR.
ENVIRONMENTAL CONDITIONS WILL REMAIN MARGINAL OVER THE NEXT 36 TO 48
HOURS LEADING TO MINIMAL INTENSIFICATION. THERE IS A POSSIBILITY
THAT THE SYSTEM CONTINUES TO STRUGGLE TO CONSOLIDATE AND WEAKENS
SLIGHTLY OVER THIS TIME PERIOD. BEYOND TAU 48, ENVIRONMENTAL
CONDITIONS WILL IMPROVE AS THE CYCLONE GAINS A POLEWARD OUTFLOW
CHANNEL AND BEGINS A GRADUAL INTENSIFICATION.
   C. BEYOND TAU 72, TY HALOLA WILL BEGIN TO TURN TO THE NORTHWEST
AS IT STARTS TO ROUND THE SOUTHWESTERN PERIPHERY OF THE STEERING
STR. EXPECT CONTINUED INTENSIFICATION AS THE CYCLONE TAPS FURTHER
INTO THE POLEWARD OUTFLOW. SEA SURFACE TEMPERATURES WILL REMAIN
FAVORABLE. AVAILABLE MODEL GUIDANCE REMAINS IN TIGHT AGREEMENT
LENDING TO HIGH CONFIDENCE IN THE JTWC FORECAST TRACK.//
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