熱帶風暴漢娜 - 第三十三報 - 颱風討論

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WTNT43 KNHC 050246
TCDAT3
TROPICAL STORM HANNA DISCUSSION NUMBER 33
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082008
1100 PM EDT THU SEP 04 2008

A RECONNAISSANCE AIRCRAFT MEASURED A MINIMUM PRESSURE OF 987 MB AND
60 KNOTS AT FLIGHT LEVEL ON ITS WAY HOME A FEW HOURS AGO. SINCE
THEN SATELLITE IMAGES HAVE SHOWN AN INCREASE IN THUNDERSTORM
ACTIVITY AND THERE ARE SOME INDICATIONS THAT THE CENTER COULD BE
UNDER THE CONVECTION OR VERY NEAR THE SOUTHERN EDGE. THE CLOUD
PATTERN ON IR IMAGES INDICATE THAT HANNA LOOKS A LITTLE MORE
TROPICAL THAN EARLIER TODAY BUT THE CYCLONE STILL HAS A LARGE WIND
FIELD AND LACKS AN INNER CORE. INITIAL INTENSITY IS KEPT AT 55
KNOTS AND ANOTHER PLANE WILL BE IN THE AREA IN A FEW HOURS TO CHECK
IF THE WINDS HAVE INCREASED. NONE OF THE GUIDANCE INDICATE
SIGNIFICANT STRENGTHENING AND THE OFFICIAL FORECAST BRINGS HANNA TO
60 KNOTS BEFORE IT REACHES THE UNITED STATES COAST. PEOPLE ARE
REMINDED THAT THERE IS VERY LITTLE DIFFERENCE BETWEEN A STRONG
TROPICAL STORM AND A MINIMAL HURRICANE...ONLY A FIVE KNOT
DIFFERENCE.

一架偵察機在數小時前返航時測量得出最低氣壓九八七毫巴和六十節飛行高度風.
從那時起衛星影像已顯示出雷雨活動的增加,以及這裡有些跡象顯示中心應該在
對流之下或非常接近南緣. 在紅外影像中的雲層分布指示漢娜看起來比今日
稍早有點更加熱帶但是氣旋依然有龐大的風場以及缺乏內核.
初始強度保持在五十五節,另外一架飛機將會在數小時內到達並確認風速是否增加.
沒有一個指引指示明顯的增量,官方預報在她接觸美國海岸前帶漢娜到六十節.
人們已提醒在強烈熱帶風暴和輕度颶風之間有非常小的差別...只有五節的差異


SURFACE DATA AND EXTRAPOLATION FROM EARLIER RECONNAISSANCE FIXES
INDICATE THAT HANNA IS MOVING TOWARD THE NORTHWEST OR 320 DEGREES
AT 12 KNOTS...STEERED BY STRONG SUBTROPICAL RIDGE OVER THE WESTERN
ATLANTIC. THE WESTERN EDGE OF THE RIDGE IS FORECAST TO BE ERODED BY
AN APPROACHING SHORT WAVE. THIS PATTERN SHOULD FORCE HANNA TO MOVE
ON A MORE NORTHERLY TRACK DURING THE NEXT 24 TO 48 HOURS WITH AN
INCREASE IN FORWARD SPEED. THEREAFTER...HANNA IS EXPECTED TO BE
FULLY EMBEDDED WITHIN THE MID-LATITUDE WESTERLIES AND RACE TO THE
NORTHEAST WHILE BECOMING EXTRATROPICAL. THIS IS BASICALLY THE
SOLUTION PROVIDED BY MOST OF THE GUIDANCE.

從稍早的偵察機定位的表面資料和推斷指示漢娜正移動往西北,或三二零度/十二節...
由在西大西洋上空的強烈副熱帶脊領帶. 預報脊的西緣被接近中的短波侵蝕.
此分布應該迫使漢娜在接下來二十四到四十八小時加速更加向北移動.
此後... 預期漢娜會全力鑲入中緯度西風帶並當成為溫帶(氣旋)之際疾向東北部.
基本上此解釋已由大部分的指引證明

IF HANNA BECOMES MORE TROPICAL AS SUGGESTED BY THE INCREASE IN
CONVECTION...THE WIND FIELD MOST LIKELY WILL CONTRACT A LITTLE BIT.

假如漢娜更加成為熱帶當推測對流增加時... 風場極可能將會稍為收縮

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Geheimer Wetter- und Seeschlüssel der Kriegsmarine
Teil 2
Watterkurzschlüssel (3 Auflage)

Oberkommando de Kriegsmarine Berlin 1942


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