WDPN31 PGTW 111500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 05W (FIVE) WARNING 
NR 03//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 05W (FIVE), LOCATED APPROXIMATELY 220 NM 
SOUTH OF GUAM, HAS TRACKED WESTWARD AT 12 KNOTS OVER THE PAST SIX 
HOURS. ANIMATED INFRARED (IR) SATELLITE IMAGERY CONTINUES TO DEPICT 
A STRUGGLING SYSTEM WITH FLARING DEEP CONVECTION OVER AN ILL-DEFINED 
LOW-LEVEL CIRCULATION CENTER (LLCC). OVER THE PAST SIX HOURS, THE 
WELL-DEFINED MID-LEVEL CIRCULATION CENTER HAS WEAKENED AND IT HAS 
BECOME INCREASINGLY EVIDENT THAT THE PRIMARY LLCC WAS LOCATED TO THE 
EAST. ANIMATED IR IMAGERY AS WELL AS A 110426Z AMSU IMAGE AND A 
111156Z METOPA IMAGE DEPICT FORMATIVE CONVECTIVE BANDS WRAPPING INTO 
A DEFINED LLCC. ADDITIONALLY, THE 111156Z ASCAT IMAGE SUPPORTS THE 
CURRENT POSITION WITH GOOD CONFIDENCE AND SHOWS 20 TO 25 KNOT WINDS 
SUPPORTING (ALONG WITH DVORAK ESTIMATES OF 25 KNOTS) THE CURRENT 
INTENSITY ASSESSMENT OF 25 KNOTS. UPPER-LEVEL ANALYSIS INDICATES 
MARGINAL OUTFLOW AND WEAK INTERACTION WITH THE TUTT CELL TO THE 
NORTH. TD 05W IS TRACKING WESTWARD ALONG THE SOUTHERN PERIPHERY OF A 
DEEP, EAST-WEST ORIENTED SUBTROPICAL RIDGE (STR) POSITIONED TO THE 
NORTH. UPPER-AIR SOUNDINGS FROM GUAM, KOROR AND YAP INDICATE DEEP 
EASTERLY FLOW AND SUPPORT THE MODEL DEPICTION OF THE STR.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS 
PROGNOSTIC REASONING MESSAGE.
   B. TD 05W IS FORECAST TO TRACK WESTWARD TO WEST-NORTHWESTWARD 
THROUGH THE PERIOD UNDER THE DEEP SUBTROPICAL STEERING RIDGE. 
AVAILABLE MODEL GUIDANCE IS IN TIGHT AGREEMENT WITH THE EXCEPTION OF 
THE UKMET TRACKER, WHICH TURNS THE SYSTEM SHARPLY NORTHWESTWARD INTO 
THE SUBTROPICAL RIDGE (STR). BASED ON THE STRENGTH AND ORIENTATION 
OF THE STR, AS VERIFIED BY RECENT SOUNDINGS, THIS SCENARIO IS 
UNLIKELY, THEREFORE, THIS FORECAST IS POSITIONED LEFT OF THE MODEL 
CONSENSUS FAVORING A MORE WESTWARD TRACK AS DEPICTED BY GFDN AND THE 
ECMWF MODEL. THERE IS A HIGH AMOUNT OF UNCERTAINTY IN THE INTENSITY 
FORECAST DUE TO THE POORLY-DEFINED NATURE OF THE LLCC AND THE 
MARGINAL ENVIRONMENT. IN GENERAL, THIS FORECAST FAVORS A SLOW BUT 
GRADUAL DEVELOPMENT THROUGH TAU 24-36 THEN A SHARPER INTENSIFICATION 
TREND AS THE SYSTEM ORGANIZES.
   C. IN THE EXTENDED PERIOD, TD 05W IS FORECAST TO TRACK MORE 
NORTHWESTWARD AS IT ROUNDS THE SOUTHWEST PERIPHERY OF THE STR AND 
BEGINS TO TURN MORE POLEWARD AHEAD OF AN APPROACHING MIDLATITUDE 
TROUGH EXPECTED TO DEEPEN OVER EASTERN CHINA NEAR TAU 72. AVAILABLE 
MODEL GUIDANCE DIVERGES AND THERE IS LOW CONFIDENCE IN THE RE-CURVE 
POINT ALTHOUGH, BASED ON THE POSITION OF THE MIDLATITUDE SHORT-WAVE 
TROUGH, TD 05W WILL RE-CURVE CLOSE TO OKINAWA. THERE IS HIGH 
CONFIDENCE, HOWEVER, IN THE RE-CURVE SCENARIO SINCE THE WESTERN STR 
IS WEAK AND HAS RETROGRADED WEST DUE TO PERSISTENT, STRONG EASTERLY 
FLOW OVER EASTERN CHINA. THE JTWC FORECAST TRACK IS POSITIONED LEFT 
OF CONSENSUS TO OFF-SET THE UNLIKELY UKMET SOLUTION, FAVORING THE 
MORE WESTWARD TRACK. AT THIS TIME, THE PEAK INTENSITY REMAINS SET AT 
90 KNOTS BUT THERE IS HIGH UNCERTAINTY, AS MENTIONED PREVIOUSLY.//
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