WDPN32 PGTW 041500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 11W (HAISHEN) WARNING NR
017//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUPER TYPHOON (STY) 11W (HAISHEN), LOCATED APPROXIMATELY 385 NM
SOUTHEAST OF KADENA AB, OKINAWA, HAS TRACKED NORTHWESTWARD AT 09 KNOTS
(KTS) OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY REVEALS A 29 NM DIAMETER ROUND EYE, PLACING GOOD CONFIDENCE IN
THE INITIAL POSITION. A 041238Z MHS 89 GHZ MICROWAVE IMAGE DEPICTS A
MICROWAVE EYE FEATURE WITH A COMPACT EYEWALL (75 NM IN DIAMETER) AND
BANDING OVER THE SOUTHERN AND EASTERN SEMICIRCLES. THE PROBABILITY OF
AN IMMINENT EYEWALL REPLACEMENT CYCLE HAS DECREASED IN THE CIMSS M-
PERC PRODUCT. THE INITIAL INTENSITY REMAINS AT 135 KTS BASED ON MULTI-
AGENCY DVORAK CURRENT INTENSITY ESTIMATES RANGING FROM T6.5 (127 KTS)
TO T7.0 (140 KTS) AND A 041236Z SATCON ESTIMATE OF 132 KTS WITH GOOD CONFIDENCE. STY 11W IS TRANSITING THROUGH AN OVERALL FAVORABLE
ENVIRONMENT CHARACTERIZED BY LOW VERTICAL WIND SHEAR (VWS), RADIAL
OUTFLOW, AND WARM (30-31 CELSIUS) SEA SURFACE TEMPERATURES (SST). THE
04/0000Z 500MB ANALYSIS SHOWS A DEEP MIDLATITUDE SHORTWAVE TROUGH OVER
THE EAST CHINA SEA AND WESTERN JAPAN WITH A BROAD SUBTROPICAL RIDGE
(STR) ENTRENCHED NORTH OF THE SYSTEM WITH A WEAK STR EXTENSION
EXTENDING SOUTHWESTWARD. STY 11W IS TRACKING WEST-NORTHWESTWARD UNDER
THE STEERING INFLUENCE OF THE DEEP-LAYERED STR AND IS TRACKING TOWARD
A COL REGION POSITIONED SOUTH OF OKINAWA.
3. FORECAST REASONING.
A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM
THE LAST PROGNOSTIC REASONING MESSAGE.
B. IN THE NEAR-TERM, THE STR IS EXPECTED TO BUILD, REMAINING
STATIONARY OVER JAPAN AS THE SHORTWAVE TROUGH SLOWLY FILLS OVER THE
KOREAN PENINSULA. NUMERICAL MODEL GUIDANCE REMAINS IN GOOD AGREEMENT
NEAR OKINAWA WITH A SPREAD OF 42 NM AT TAU 36. THE CURRENT FORECAST
TRACK IS VERY CONSISTENT WITH THE PREVIOUS FORECAST AND DEPICTS A NORTH-NORTHWESTWARD TRACK THROUGH TAU 48, PASSING JUST EAST OF AMAMI
OSHIMA. AFTER TAU 48, THE SYSTEM WILL TURN POLEWARD AND IS FORECAST TO
TRACK JUST WEST OF KYUSHU. HOWEVER, DUE TO INCREASING SPREAD IN THE
MODELS (80 NM NEAR SASEBO), THE SYSTEM COULD SHIFT CLOSER TO SASEBO /
KYUSHU. SIMILARLY, AS THE SYSTEM MAKES LANDFALL IN SOUTH KOREA, THE
LARGE MODEL SPREAD LEADS TO SOME UNCERTAINTY IN THE EXACT TRACK OVER
SOUTH KOREA. THROUGH TAU 24, STY 11W IS EXPECTED TO MAINTAIN SUPER
TYPHOON INTENSITY. AFTERWARDS, AS THE SYSTEM TRACKS POLEWARD, IT WILL
WEAKEN FIRST GRADUALLY AND THEN MORE RAPIDLY AS IT INTERACTS WITH THE MOUNTAINOUS TERRAIN OF THE KOREAN PENINSULA.
C. IN THE EXTENDED PERIOD, NUMERICAL MODEL GUIDANCE MAINTAINS A
SPREAD OF 125-130 NM THROUGH TAU 96, LEADING TO UNCERTAINTY IN THE
TRACK. BY TAU 72, STY 11W IS EXPECTED TO COMMENCE EXTRATROPICAL
TRANSITION (ETT) AS IT INTERACTS WITH THE SHORTWAVE TROUGH. THE SYSTEM
WILL ACCELERATE POLEWARD AND SIGNIFICANTLY WEAKEN AS IT TRANSITS OVER
THE KOREAN PENINSULA DUE TO INCREASING VWS AND TERRAIN INTERACTION.
ETT COMPLETION IS EXPECTED BY TAU 96 AS THE SYSTEM GAINS FRONTAL CHARACTERISTICS AND NEARS THE JET. OVERALL, THERE IS MODERATE
CONFIDENCE IN THE JTWC FORECAST TRACK WHICH IS PLACED NEAR THE MULTI-
MODEL CONSENSUS.//=


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WDPN31 PGTW 161500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 13W (NOUL)
WARNING NR 005//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM 13W (NOUL), LOCATED APPROXIMATELY 445 NM
EAST-SOUTHEAST OF DA NANG, VIETNAM, HAS TRACKED WEST-NORTHWESTWARD
AT 11 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED
(EIR) SATELLITE IMAGERY DEPICTS BUILDING CONVECTION OBSCURING A
PARTIALLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC). THE INITIAL
POSITION IS PLACED WITH FAIR CONFIDENCE BASED ON THE LOCATION OF THE
LOW LEVEL BANDING IN THE EIR LOOP AS WELL AS THE LOW LEVEL FEATURES
PRESENT IN A 161022Z WINDSAT 37GHZ IMAGE. THE INITIAL INTENSITY OF
45 KTS IS PLACED WITH FAIR CONFIDENCE AND IS HEDGED ABOVE MULTI-
AGENCY DVORAK CURRENT INTENSITY ESTIMATES OF T2.5 (35 KTS, PGTW AND
RJTD) BASED ON CONSISTENT CIMSS ADVANCED DVORAK TECHNIQUE CURRENT
INTENSITY ESTIMATES OF T3.1 (47 KTS). TS NOUL CONTINUES TO TRACK
ALONG THE SOUTHERN PERIPHERY OF THE SUBTROPICAL RIDGE (STR)
POSITIONED TO THE NORTHEAST AND THROUGH AN ENVIRONMENT THAT IS
MARGINALLY FAVORABLE FOR FURTHER DEVELOPMENT WITH VERY WARM (30-32
CELSIUS) SEA SURFACE TEMPERATURES (SST) AND SUFFICIENT EQUATORWARD
AND WESTWARD OUTFLOW ALOFT OFFSET BY MODERATE TO HIGH (15-25
KTS) VERTICAL WIND SHEAR (VWS) ALONG THE SOUTHWESTERN PERIPHERY OF
THE SYSTEM. UPPER LEVEL CONVERGENCE DUE TO THE DEEP EASTERLY FLOW
ALOFT ALSO CONTINUES TO STIFLE POLEWARD OUTFLOW AND LIMIT
INTENSIFICATION, DESPITE THE CONDUCIVE SSTS.
3. FORECAST REASONING.
A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM
THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
B. TS NOUL WILL CONTINUE TO TRACK GENERALLY WEST-NORTHWESTWARD
UNDER THE STEERING INFLUENCE OF THE STR THROUGHOUT THE FORECAST
PERIOD. AS IT TRAVERSES OVER THE VERY WARM WATERS OF THE SOUTH CHINA
SEA, IT WILL CONTINUE TO STEADILY INTENSIFY DESPITE CONTINUED MODERATE
TO HIGH (15-25 KTS) VWS AS A RESULT OF THE WARM SSTS AND REACH A
MAXIMUM INTENSITY OF 65 KTS BY TAU 36. SHORTLY AFTER TAU 36 THE SYSTEM
WILL MAKE LANDFALL NEAR HUE, VIETNAM. AFTER MAKING LANDFALL THE SYSTEM
WILL BEGIN TO WEAKEN DUE TO INTERACTION WITH THE UNDERLYING TERRAIN. AS
TS NOUL DRAGS DEEPER INTO THE INDOCHINA PENINSULA AND INTO LAOS, IT WILL
BEGIN TO DISSIPATE OVER LAND AND WEAKEN TO 45 KTS BY TAU 48. THEREAFTER
IT WILL DISSIPATE OVER LAND BY TAU 72. NUMERICAL MODEL SOLUTIONS ARE IN
FAIR AGREEMENT WITH A MAXIMUM 150 NM ACROSS TRACK SPREAD IN TRACK
GUIDANCE AT TAU 72, LENDING OVERALL HIGH CONFIDENCE IN THE OVERALL JTWC FORECAST TRACK.//
NNNN
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