01L.Alex 北大西洋61年來最強1月颶風由溫帶氣旋轉暖

krichard2011 · 2016-1-14 20:16

~~這個型態這個風眼說他是副熱帶風暴什麼的我才不信 = =~~
紅外線衛星雲圖對流弱弱的
從可見光來看完全是另外一回事
但該處超低的海溫甚只有20度C左右的確符合副熱帶氣旋的環境
難以想像太神啦
20160114.1115.goes13.x.vis1km_high.01LALEX.55kts-986mb-293N-296W.100pc.jpg

20160114.1115.goes13.x.vis1km_high.01LALEX.55kts-986mb-293N-296W.100pc.jpg

補充:
稍早 NHC 速報升格颶風

AL, 01, 2016011412, , BEST, 0, 308N,  287W,  75,  981, HU,  34, NEQ,  120,  130,  100, 30, 1012,  300,  15, 0, 0, L, 0, , 0, 0,    ALEX, D,
AL, 01, 2016011412, , BEST, 0, 308N,  287W,  75,  981, HU,  50, NEQ, 30, 30, 0, 0, 1012,  300,  15, 0, 0, L, 0, , 0, 0,    ALEX, D,
AL, 01, 2016011412, , BEST, 0, 308N,  287W,  75,  981, HU,  64, NEQ, 20, 20, 0, 0, 1012,  300,  15, 0, 0, L, 0, , 0, 0,    ALEX, D,

krichard2011 · 2016-1-14 22:38

正式破紀錄大西洋史上最強的一月當月生成颶風
文中提到此颶風所在的海溫只有 20 度左右
而雲頂溫度甚至達到 -60度左右雲層發展高度甚至比熱帶對流層頂高度為高
算是個相當特別的案例
後期上看 80 KT 有機會與 1955 年 Alice 颶風並列一月史上最強
目前是一月自1955 以來最強颶風

000
WTNT41 KNHC 141434
TCDAT1

HURRICANE ALEX DISCUSSION NUMBER 4
NWS NATIONAL HURRICANE CENTER MIAMI FL    AL012016
1100 AM AST THU JAN 14 2016

Remarkably, Alex has undergone the transformation into a hurricane.
A distinct eye is present, embedded within a fairly symmetric mass
of deep convection.  Water vapor imagery shows that the upper-level
trough is now west of the cyclone, with divergent flow over the
center - indicative of a tropical transition. It is very unusual to
have a hurricane over waters that are near 20 deg C, but the
upper-tropospheric temperatures are estimated to be around -60 deg
C, which is significantly colder than the tropical mean. The
resulting instability is likely the main factor contributing to the
tropical transition and intensification of Alex.  With these
changes, the government of the Azores has issued warnings for most
of the Azores islands.

The initial intensity is set to 75 kt in accordance with the
analyzed Dvorak T-number of 4.5.  Only slight additional
intensification seems possible since the system will be passing
over even colder waters during the next day or two.  In 36 hours,
the global models suggest that the cyclone will become
extratropical as it begins to merge with a large low pressure area
at high latitude.  The post-tropical cyclone is then likely to lose
its identity after 48 hours.

The initial motion is north-northeastward or 020/17 kt.  Alex is
being steered by a shortwave mid-level trough that is rotating
around a larger trough to the northwest.  This should cause the
cyclone to turn northward and north-northwestward and accelerate
over the next couple of days.  The official track forecast is very
similar to the previous one and also quite close to the consensus
of the tightly-packed dynamical model forecast tracks.

Alex is the first hurricane to form in the month of January since
1938, and the first hurricane to occur in this month since Alice of
1955.

FORECAST POSITIONS AND MAX WINDS

INIT  14/1500Z 31.5N  28.4W 75 KT  85 MPH
12H  15/0000Z 34.3N  27.7W 80 KT  90 MPH
24H  15/1200Z 38.9N  27.7W 75 KT  85 MPH
36H  16/0000Z 45.3N  28.6W 60 KT  70 MPH...POST-TROP/EXTRATROP
48H  16/1200Z 53.0N  31.5W 60 KT  70 MPH...POST-TROP/EXTRATROP
72H  17/1200Z...DISSIPATED

$$
Forecaster Pasch