WDPN31 PGTW 160900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 02W (SURIGAE) WARNING NR 012//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
    TYPHOON 02W (SURIGAE), LOCATED APPROXIMATELY 89 NM NORTHWEST OF 
KAYANGEL, PALAU, HAS TRACKED WEST-NORTHWESTWARD AT 09 KNOTS OVER THE 
PAST SIX HOURS. ANIMATED MULTI-SPECTRAL SATELLITE IMAGERY (MSI) 
SHOWS CONVECTION BUILDING AROUND THE LOW-LEVEL CIRCULATION CENTER 
(LLCC) AND REVEALS AN EYE TRYING TO FORM IN THE UPPER LEVELS, BUT 
HAS NOT FULLY FORMED YET. THE INITIAL POSITION IS BASED ON THE 
ANIMATED MSI, SUPPORTED BY A 160439Z ATMS 88.2GHZ MICROWAVE IMAGE 
THAT SHOWS A COARSE MICROWAVE EYE, DUE TO THE LOW RESOLUTION OF THE 
SENSOR. THE WIND RADII HAVE BEEN UPDATED BASED ON THE 152342Z METOP-
A AND 160056Z METOP-B ASCAT PASSES. THE SYSTEMS INTENSITY HAS 
INCREASED TO 80 KNOTS OVER THE PAST SIX HOURS BASED ON AN AVERAGE OF 
PGTW AND RJTD DVORAK CURRENT INTENSITY ESTIMATES OF T4.5 (77 KNOTS), 
ADT OF 79.6 KNOTS, AND SATCON ESTIMATE OF 83 KNOTS. ENVIRONMENTAL 
ANALYSIS INDICATES FAVORABLE CONDITIONS FOR INTENSIFICATION WITH LOW 
(<15KT) VERTICAL WIND SHEAR (VWS), ROBUST EQUATORWARD AND IMPROVING 
POLEWARD OUTFLOW ALOFT WITH DECREASING PRESSURE ON THE EASTERN SIDE, 
AND WARM (29-30C) SEA SURFACE TEMPERATURES (SST) IN THE PHILIPPINE 
SEA. TY 02W IS CURRENTLY TRACKING ALONG THE SOUTHEASTERN PERIPHERY 
OF AN EXTENSION OF THE DEEP LAYER SUBTROPICAL RIDGE (STR) TO THE 
NORTHWEST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE 
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TY 02W IS FORECAST TO TRACK TO THE NORTHWEST DUE TO AN 
APPROACHING MID-LATITUDE TROUGH WEAKENING THE STR AND FORCING IT TO 
BREAK INTO TWO DISTINCT ANTICYCLONIC CIRCULATIONS BY TAU 12. THE 
TROUGH DEEPENS AND FULLY BREAKS BETWEEN THESE AT TAU 48, CAUSING TY 
02W TO TURN NORTHWARD. THE SYSTEM WILL STEADILY INTENSIFY DUE TO 
ROBUST UPPER-LEVEL OUTFLOW AMPLIFIED BY THE MID-LATITUDE TROUGH WITH 
TY 02W REACHING PEAK INTENSITY OF 120KTS BY TAU 48. NUMERICAL MODEL 
GUIDANCE REMAINS IN GOOD AGREEMENT THROUGH TAU 48 LENDING HIGH 
CONFIDENCE TO THE JTWC FORECAST TRACK THROUGH THIS TIME. HOWEVER, 
AFTER TAU 48 THE GUIDANCE DIVERGES WITH THE MOST RECENT ECMWF RUN 
TRACKING SIGNIFICANTLY FURTHER WEST THAN PREVIOUS RUNS BEFORE 
RECURVING THE SYSTEM, INCREASING THE CROSS-TRACK SPREAD TO 230NM AT 
TAU 72.
   C. AFTER TAU 72, THE STR EAST OF TY SURIGAE BUILDS AND TAKES OVER 
AS THE PRIMARY STEERING MECHANISM, CAUSING TY SURIGAE TO TRACK 
NORTHWARD ALONG THE WESTERN PERIPHERY OF THE STR. THE ENVIRONMENTAL 
CONDITIONS WILL BECOME SLIGHTLY LESS FAVORABLE AS THE AMOUNT OF 
UPPER-LEVEL DIVERGENCE DECREASES AND SEA SURFACE TEMPERATURES LOWER 
THROUGH THE END OF THE FORECAST PERIOD. THE SYSTEM WILL DECREASE TO 
90KTS BY TAU 120. NUMERICAL MODEL CROSS-TRACK SPREAD HAS INCREASED 
TO 670NM AT TAU 120 AS TRACK SOLUTIONS DIVERGE FURTHER, LENDING LOW 
CONFIDENCE TO THE EXTENDED PORTION OF THE JTWC TRACK FORECAST.//
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