t02436 發表於 2014-4-2 20:47
其實有鋒面系統連接就算是溫帶氣旋
熱帶副熱帶氣旋都是與鋒面不相關的
所以應該編號開始就是溫帶性質

題外:
所以說兩年前侵襲紐約的Sandy是個例外!?
NHC認為Sandy接近美國東北的時候
仍保有颶風的性質 不過此時已經有類似溫帶氣旋的結構
天氣圖上也標了個四不像的系統
颶風的圖標 卻擁有冷/暖鋒、囚固鋒、滯留鋒等系統
話說那時我也是第一次見過 @@


http://www.weather.gov/okx/HurricaneSandy
正題
這系統大概已經是溫帶氣旋了
緯度已經來到30度以上了
環境真的完全不適合發展
當初JTWC會評Medium 根據前面的報文似乎是認為
因為它的本體有與鋒面分離成為獨立個體
且暖心有從不對稱有要轉對稱的趨勢

接下來要命名 恐怕是沒什麼機會了
似乎有逐漸變性為溫帶氣旋的跡象...
底層跟之前相比也差很多了

對流很強，發展應該頗佳，不過風切很強，應該…不會太大影響吧。

此外紐西蘭氣象局MetService
也對這個系統發出SW 預測在未來的6到24小時
有機會再增強到50kt
不過最近一張風場 似乎就已經掃出50kt了
不知道稍後有沒有機會升格 話說他的緯度還挺高的

STORM WARNING 020
This affects ocean areas: SUBTROPIC and PACIFIC
AT 020000UTC
Low 990hPa near 29S 165W moving south 10kt.
1. Within 300 nautical miles of low in southern semicircle: Clockwise 40kt rising to 50kt next 6-12 hours.
2. Outside area 1 and within 180 nautical miles of low in northern semicircle: Clockwise 35kt at times.
Storm and gale areas moving with low.
This warning cancels and replaces warning 017.

Issued at 1:05pm Wednesday 2 Apr 2014

升評Medium
還沒升格

THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 24.6S
167.4W, IS NOW LOCATED NEAR 28.6S 164.3W, APPROXIMATELY 937 NM SOUTH-
SOUTHEAST OF PAGO PAGO, AMERICAN SAMOA. ANIMATED MULTISPECTRAL
SATELLITE IMAGERY DEPICTS A WELL-DEFINED SYSTEM WITH A BROKEN
FRONTAL BAND WRAPPING INTO THE SYSTEM CENTER FROM THE EASTERN
QUADRANTS. THE ANIMATED TOTAL PRECIPITABLE WATER PRODUCT SHOWS AN
ISOLATED SYSTEM SLOWLY GAINING ORGANIZATION AND SYMMETRY FUELED BY
INTERMITTENT CHANNELS OF TROPICAL MOISTURE. A 010928Z PARTIAL ASCAT
PASS REVEALS 45 TO 50 KNOT WINDS IN THE WESTERN PERIPHERIES. UPPER-
LEVEL ANALYSIS INDICATES THE SYSTEM IS POLEWARD OF THE SUBTROPICAL
RIDGE IN AN ENVIRONMENT CHARACTERIZED BY STRONG (20-40 KNOTS)
VERTICAL WIND SHEAR. SEA SURFACE TEMPERATURES ARE ESTIMATED TO BE
NEAR 24 DEGREES CELSIUS. AMSU TEMPERATURE ANOMALY CROSS SECTIONS
INDICATE A WARM SURFACE ANOMALY PROBABLY DUE TO FRONTAL PROCESSES AS
WELL AS A WARM UPPER LEVEL ANOMALY. BASED ON ANALYSIS THIS SYSTEM IS
CURRENTLY CLASSIFIED AS SUBTROPICAL. HOWEVER, THE FRONTAL BAND
APPEARS TO BE BREAKING AND THE SYSTEM IS GAINING SYMMETRY. FSU
CYCLONE PHASE DIAGRAMS INDICATE AN ASYMMETRIC WARM-CORE SYSTEM
TRENDING TOWARD A SYMMETRIC WARM-CORE. MAXIMUM SUSTAINED SURFACE
WINDS ARE ESTIMATED AT 45 TO 50 KNOTS. MINIMUM SEA LEVEL PRESSURE IS
ESTIMATED TO BE NEAR 988 MB. DUE TO BREAKING FRONTAL BAND AND
IMPROVING SYMMETRY THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS UPGRADED TO
MEDIUM.

JTWC跳級升40kts 風速達標
究竟是升格了 還是還沒升
還不清楚 不過熱帶氣旋的性質還挺明顯的