WTPN31 PGTW 301500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE WARNING//
RMKS/
1. TYPHOON 26W (BOPHA) WARNING NR 020
01 ACTIVE TROPICAL CYCLONE IN NORTHWESTPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
301200Z --- NEAR 4.2N 144.3E
MOVEMENT PAST SIX HOURS - 295 DEGREES AT 10 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 035 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT
075 NM SOUTHEAST QUADRANT
070 NM SOUTHWEST QUADRANT
070 NM NORTHWEST QUADRANT
REPEAT POSIT: 4.2N 144.3E
REMARKS:
301500Z POSITION NEAR 4.4N 143.8E.
TYPHOON (TY) 26W (BOPHA) LOCATED APPROXIMATELY 605 NM EAST-SOUTHEAST
OF PALAU, HAS TRACKED WEST-NORTHWESTWARD AT 10 KNOTS OVER THE PAST
SIX HOURS. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 301200Z IS 26 FEET.
NEXT WARNINGS AT 302100Z, 010300Z, 010900Z AND 011500Z.
//
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PROGNOSTIC REASONINGWDPN31 PGTW 301500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 26W (BOPHA) WARNING NR 20//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TYPHOON (TY) 26W (BOPHA) LOCATED APPROXIMATELY 605 NM EAST-
SOUTHEAST OF PALAU, HAS TRACKED WEST-NORTHWESTWARD AT 10 KNOTS OVER
THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED IMAGERY (EIR)
DEPICTS TIGHTLY CURVED SPIRAL BANDING WRAPPING AROUND A GROWING LOW
LEVEL CIRCULATION CENTER. THE CURRENT POSITION IS BASED ON
POSITION FIXES FROM PGTW AND RJTD, WHICH ARE IN CLOSE AGREEMENT. THE
INTENSITY IS ASSESSED AT 65 KNOTS BASED ON DVORAK ESTIMATES OF THE
SAME FROM ALL AGENCIES. UPPER-LEVEL ANALYSIS INDICATES TY 26W IS
SOUTH OF A RIDGE AXIS, WITH GOOD DIFFLUENCE, LOW (10 KNOTS)
VERTICAL WIND SHEAR (VWS), AND A POINT SOURCE OVERHEAD PROVIDING
FAVORABLE RADIAL OUTFLOW. THIS OUTFLOW IS READILY APPARENT IN THE
ANIMATED WATER VAPOR LOOP. ADDITIONALLY, THE UPPER-LEVEL WARM CORE
ANOMALY HAS INCREASED TO PLUS FOUR DEGREES, INDICATIVE OF A STRONG
VERTICAL CIRCULATION. THE SYSTEM IS CONTINUING TO TRACK WEST-
NORTHWESTWARD UNDER THE STEERING INFLUENCE OF THE DEEP-LAYERED
SUBTROPICAL RIDGE POSITIONED TO THE NORTH.
3. FORECAST REASONING.
A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
B. TY 26W IS FORECAST TO TRACK WEST-NORTHWESTWARD THROUGHOUT THE
PERIOD AS IT MOVES ALONG THE SOUTHWESTERN PERIPHERY OF THE CURRENT
STEERING RIDGE. CONTINUED FAVORABLE ENVIRONMENTAL CONDITIONS,
INCLUDING FAVORABLE OUTFLOW, LOW VWS, AND PASSAGE OVER VERY WARM
WATER, SHOULD ALLOW FOR STEADY INTENSIFICATION TO A PEAK NEAR 110
KNOTS BY TAU 72. DYNAMIC MODEL GUIDANCE HAS REMAINED IN FAIR
AGREEMENT THROUGH TAU 72, WITH ALL MODELS INDICATING A NEAR CONSTANT
WEST-NORTHWESTWARD MOVEMENT. THERE IS HIGH CONFIDENCE IN THIS
PORTION OF THE TRACK FORECAST.
C. IN THE EXTENDED TAUS, TY 26W IS EXPECTED TO TRACK
NORTHWESTWARD TOWARD A WEAKNESS IN THE STR, WHICH WILL DEVELOP IN
RESPONSE TO A BROAD UPPER-LEVEL TROUGH OVER THE EAST CHINA SEA. BY
TAU 96 THE INTENSITY SHOULD BEGIN TO DECREASE AS THE SYSTEM
APPROACHES THE CENTRAL PHILIPPINES. BY TAU 120, INTERACTION WITH THE
PHILIPPINE ISLANDS AND INCREASING VWS WILL RESULT IN ADDITIONAL
WEAKENING. THE OFFICIAL FORECAST IS CLOSE TO CONSENSUS, BUT ADJUSTED
SLIGHTLY SLOWER AND POLEWARD IN FAVOR OF THE GFS, ECMWF, AND UKMET
MODEL SOLUTIONS, WHICH DEPICT SLIGHTLY MORE WEAKENING IN THE STR
VERSUS NOGAPS AND GFDN WHICH ARE TOO FAST DUE TO A STRONGER STR.
TRACK FORECAST CONFIDENCE IS LOW DURING THIS PERIOD DUE TO THE
UNCERTAINTY OF THE DEPTH AND POSITION OF THE UPPER-LEVEL TROUGHING
AND ORIENTATION OF THE SUBTROPICAL RIDGE AT THIS TIME.//
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it is developing a cold dense overcast on its center.
