恭喜莫蘭蒂勇奪2016西太風王 - 颱風討論

這份巔峰強度的老J報文 可以留著紀念

0912 1500Z / 155KT

1. FOR METEOROLOGISTS.

2. 6 HOUR SUMMARY AND ANALYSIS.
SUPER TYPHOON 16W (MERANTI), LOCATED APPROXIMATELY 457 NM SOUTH
OF KADENA AB, HAS TRACKED WEST-NORTHWESTWARD AT 12 KNOTS OVER THE
PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY HAS
INDICATED CONTINUED RAPID INTENSIFICATION SINCE 120600Z, WITH CLOUD
TOPS CONTINUING TO COOL AND THE DEEP CONVECTION SURROUNDING THE WELL-
DEFINED EYE BECOMING EVEN MORE SYMMETRIC. EYE TEMPERATURES HAVE ALSO
WARMED SIGNIFICANTLY, WITH THERMOMETRIC ESTIMATES OF OVER 18C IN THE
CENTER OF THE EYE.

從120600Z開始快速增強
雲頂溫度持續下降，眼牆週圍深對流更為對稱
眼溫顯著上升，估計為18度

A 121247Z AMSU-B 89GHZ MICROWAVE IMAGE DEPICTS
THE PRESENCE OF MULTIPLE SPIRAL BANDS OF DEEP CONVECTION WRAPPING
INTO A WELL-DEFINED EYE. CONVECTIVE SYMMETRY AND BANDING CONTINUES
TO IMPROVE AS OF THIS WRITING. DVORAK INTENSITY ESTIMATES FROM BOTH
PGTW AND RJTD HAVE RISEN TO T7.5. GIVEN THE ABOVE ANALYSIS, THE
CURRENT INTENSITY IS ASSESSED AT 155 KNOTS.

微波頻道看到多重深對流螺旋帶圍繞清晰的颱風眼
寫這篇的同時，對流雲帶對稱正在更為完整
Dvorak分析都達到T7.5，因此給定155kt

STY 16W IS CURRENTLY IN
AN EXTREMELY FAVORABLE ENVIRONMENT FOR THE MAINTENANCE OF AN INTENSE
SUPER TYPHOON, WITH EXCELLENT RADIAL OUTFLOW IN ALL QUADRANTS, VERY
LOW VERTICAL WIND SHEAR (LESS THAN 5 TO 10 KNOTS), AND WARM SSTS (30
TO 31C). CURRENT WIND RADII WERE ADJUSTED OUTWARD BASED ON A 120928
WINDSAT PASS. STY 16W CONTINUES TO TRACK TOWARD THE WEST-NORTHWEST
UNDER THE STEERING INFLUENCE OF A SUBTROPICAL RIDGE (STR) TO THE
NORTH.

非常良好的環境(在每個象限都極佳的外流、非常低的垂直風切、30~31度的高海溫)，
支持颱風維持超級颱風的強度。
現在的風圈已經過衛星掃描校正過。


3. FORECAST REASONING.
A. NO CHANGE IN THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
B. THROUGH TAU 72, STY 16W WILL TRACK GENERALLY WEST-
NORTHWESTWARD UNDER THE STEERING INFLUENCE OF THE STR. THE MAJORITY
OF MODEL GUIDANCE HAS NOW SETTLED ON A TRACK THAT TAKES THE SYSTEM
TOWARD SOUTHERN TAIWAN OR ACROSS THE NORTHERN PORTION OF THE LUZON
STRAIT. THE ONLY EXCEPTIONS ARE THE EGRR, JGSM, AND JENS TRACKERS,
WHICH INDICATE A MORE SOUTHERN TRACK. THE CURRENT JTWC FORECAST
PREFERS THE SLIGHTLY MORE NORTHERN SOLUTION, GIVEN THE RECENT MOTION
TOWARD THE NORTHWEST. BEYOND TAU 36, TRACK SHIFTS DUE TO VORTEX
INTERACTION WITH THE CENTRAL MOUNTAIN RANGE OF TAIWAN ARE POSSIBLE,
AND THE INTENSITY FORECAST WILL DEPEND ON THESE TRACK SHIFTS. STY
16W IS LIKELY APPROACHING IS THERMODYNAMIC MAXIMUM POTENTIAL
INTENSITY, SO SHORT-TERM FLUCTUATIONS IN INTENSITY ARE LIKELY OVER
THE NEXT 24 HOURS, DRIVEN PREDOMINANTLY BY EYEWALL REPLACEMENT
CYCLES. A SLOW WEAKENING IS FORECAST AFTER TAU 24 AS SSTS BEGIN TO
GRADUALLY COOL AND LAND INTERACTION WITH TAIWAN COMMENCES.

大致上颱風將往西北西(北巴士海峽至台灣南端)，但JTWC傾向較為偏北，
原因為最近颱風較偏向西北方行進。
36小時候颱風將與台灣地形互動，路徑飄移也是可能的。
颱風大概已經接近熱、動力上的巔峰強度，
未來24小時可能有強度上的調整，例如眼牆置換。

C. AFTER TAU 72, DYNAMIC MODEL GUIDANCE SUGGEST THAT STY 16W WILL
CROSS THE TAIWAN STRAIT AS A WEAKER SYSTEM AND MAKE A SECOND
LANDFALL OVER MAINLAND CHINA BY AROUND TAU 60. WEAKENING AND
DISSIPATION OVER LAND IS EXPECTED THEREAFTER, WITH A POLEWARD TURN
DUE TO A WEAKNESS IN THE STR. DUE TO THE LARGE MODEL SPREAD BEYOND
48 HOURS, THERE IS LOW CONFIDENCE IN THE JTWC TRACK FORECAST BEYOND
THAT TIME.//
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