查看完整版本 : [June 30] 美國東部的颮線事件 Derecho Event in Eastern US

"Derecho" 是颮線的一種..在西班牙語中的意思是"一直向前"
[url=http://www.crh.noaa.gov/iwx/?n=june_29_derecho]http://www.crh.noaa.gov/iwx/?n=june_29_derecho[/url]
[b]中文版:
[url=http://bbs.typhoon.gov.cn/read.php?tid=51265]http://bbs.typhoon.gov.cn/read.php?tid=51265[/url][/b]
Radar loop:
[url=http://www.youtube.com/watch?v=0MG7aOjZciY]http://www.youtube.com/watch?v=0MG7aOjZciY[/url]



CNN:  Americans' 'amazing' feats against storm and heat
"As of Wednesday night, 699,000 customers scattered across 11 states had no electricity, down from about 1.8 million late Monday -- and from a peak of 4 million over the weekend."
[url=http://www.cnn.com/2012/07/04/us/extreme-heat/index.html?hpt=us_c1]http://www.cnn.com/2012/07/04/us/extreme-heat/index.html?hpt=us_c1[/url]

[attach]1858688[/attach]

Here's an image from the NWS Storm Prediction Center (SPC) highlighting the movement of the severe thunderstorm system that slammed through the region last night. This organized storm complex is called a "derecho" (pronounced "deh-REY-cho"). It is a long-lived damaging wind storm associated with a band of rapidly moving thunderstorms. Derechos can travel immense distances over 250 miles. Primary damage from derechos, as was the case last night, is the widespread nature of damaging wind. As the image from SPC shows, this derecho originated in northern IL/IN around noontime Friday (6/29)...traveling a distance of 600 miles from Northern Indiana to the Chesapeake Bay. Our region averages 1 derecho every 2 or 3 years. This is one of the strongest in recent memory...the last significant one occurred on June 4, 2008.

More information on derechos can be found on SPC's website at: [url=http://www.spc.noaa.gov/misc/AbtDerechos/derechofacts.htm]http://www.spc.noaa.gov/misc/AbtDerechos/derechofacts.htm[/url]

IR Image(after it went to Atlantic Ocean):
[attach]1858849[/attach]

[attach]1858850[/attach]

[attach]1858851[/attach]



Other example of a [font=Arial, Helvetica, sans-serif][font=Arial, Helvetica, sans-serif] Bow echoes (弓狀特徵的颮線):
[attach]1858774[/attach]
[/font][/font]

[[i] 本帖最後由 joseph0101hk 於 2012-7-5 06:36 PM 編輯 [/i]]

我看不懂英文，請問是次事所測得最高的風速是多少?

[quote]原帖由 [i]lichakfu[/i] 於 2012-7-5 06:21 PM 發表 [url=http://www.discuss.com.hk/redirect.php?goto=findpost&pid=334674877&ptid=19822802][img]http://www.discuss.com.hk/images/common/back.gif[/img][/url]
我看不懂英文，請問是次事所測得最高的風速是多少? [/quote]

我會一陣找中文版
最高的風速約146km/hr (91 mph - Fort Wayne Airport)

中文版:
[url=http://bbs.typhoon.gov.cn/read.php?tid=51265]http://bbs.typhoon.gov.cn/read.php?tid=51265[/url]

就甘睇都覺誇張!!

雷達雲圖顯示, 係成個州甘長範圍
(即影響長度係十幾個香港)
仲要連掃幾個州

係極不尋常!!
:smile_43::smile_43::smile_43:

[quote]原帖由 [i]jyeung123[/i] 於 2012-7-5 07:59 PM 發表 [url=http://www.discuss.com.hk/redirect.php?goto=findpost&pid=334684576&ptid=19822802][img]http://www.discuss.com.hk/images/common/back.gif[/img][/url]
就甘睇都覺誇張!!

雷達雲圖顯示, 係成個州甘長範圍
(即影響長度係十幾個香港)
仲要連掃幾個州

係極不尋常!!
:smile_43::smile_43::smile_43: [/quote]
TBB仲報話受颱風影響:smile_30:

他們形容這次如同三十個弱龍倦風同時覆蓋地面...

(比喻)這次颮線事件就好像一下雷電,把其中一片很乾和熱的大平草原點燃(高度不穩定 strong instability),一發不可收拾,乘着風勢燒過去,並在大海洋前停止和熄滅...而事前,一些抑制點燃的因素,結果令大平草原變得越來越乾又避免火災...

在氣象,那燃料是 "Convective Available Potential Energy" CAPE ...可對流的位能 (對流有效位能); 1K-2K CAPE -> 暴風雨
那抑制對流是 "Convective Inhibition" CIN

[quote]原帖由 [i]joseph0101hk[/i] 於 2012-7-6 08:59 AM 發表 [url=http://www.discuss.com.hk/redirect.php?goto=findpost&pid=334748424&ptid=19822802][img]http://www.discuss.com.hk/images/common/back.gif[/img][/url]
他們形容這次如同三十個弱龍倦風同時覆蓋地面...

(比喻)這次颮線事件就好像一下雷電,把其中一片很乾和熱的大平草原點燃(高度不穩定 strong instability),一發不可收拾,乘着風勢燒過去,並在大海洋前停止和熄 ... [/quote]

那邊的 CAPE 經常都很高:

[img]http://www.wohk.org/synoptic/gfs/2012070500/cape_NH.gif[/img]

[url]http://www.spc.noaa.gov/misc/AbtDerechos/derechofacts.htm[/url]

關於颮線的專題介紹

老實說
香港有一兩年無明顯的颮線

[quote]原帖由 [i]§皮§[/i] 於 2012-7-6 10:54 PM 發表 [url=http://www.discuss.com.hk/redirect.php?goto=findpost&pid=334829198&ptid=19822802][img]http://www.discuss.com.hk/images/common/back.gif[/img][/url]
老實說
香港有一兩年無明顯的颮線 [/quote]


上面果條咪今年個囉...

[quote]原帖由 [i]田三少[/i] 於 2012-7-7 12:36 PM 發表 [url=http://www.discuss.com.hk/redirect.php?goto=findpost&pid=334883296&ptid=19822802][img]http://www.discuss.com.hk/images/common/back.gif[/img][/url]



上面果條咪今年個囉... [/quote][attach]1862552[/attach]

[attach]1862553[/attach]

近幾年都無一條較強烈既颮線途經香港~:smile_35:

[quote]原帖由 [i]volgrenfan[/i] 於 2012-7-19 12:49 AM 發表 [url=http://www.discuss.com.hk/redirect.php?goto=findpost&pid=336080067&ptid=19822802][img]http://www.discuss.com.hk/images/common/back.gif[/img][/url]
近幾年都無一條較強烈既颮線途經香港~:smile_35: [/quote]

風幾多先夠強?