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I was watching the weather last night and yet another big low pressure system with lots of rain and a cold front is getting ready to slam into the Northwestern U.S. It will then wreak havoc, head across the country to bring snow, ice and misery to the citizens of the country (can you tell how much I love winter?) and then head off into the Atlantic. That's where the story ends for us in the U.S. But does that same low pressure center keep its steam, slam into Europe, bring snow to Moscow, rain to Japan, enter the Pacific and then come right back at us? Are we really getting hit by the same weather systems over and over all winter?
Wow, that's a good question. I really don't know, but I'm thinking that once a storm gets well out into the ocean, it would either die out or change drastically. Hopefully someone can tell us.
The storms you are most likely referring to are called Extratropical or Mid-latitude cyclones. Those are the storms easily identified on satellite or radar imagery and commonly called "storm systems" by broadcast meteorologists.
They thrive upon a strong jet stream and a strong clash of warm and cold air masses. Usually by the time the system reaches the ocean, the airmasses become less pronounced thus the storm weakens.
Here's a current global satellite loop:
Look how much weaker the storm system off the Carolina coast is now compared to just a couple days ago when it wreaked havoc across the Southeast.
Interesting, and thanks for the sat. image. Look at that huge system in southern Russia. I wonder how that thing will effect me next week!
You can see how a storm left North America and then appears to have strengthened over the UK after crossing the Atlantic.
One funny thing - I used to think that weather systems would move from east to west in the southern hemisphere. I figured out I was wrong a long time ago - I have no idea why I thought that.
Last edited by Jammie; 02-21-2008 at 09:35 AM..
Reason: merged
As a forecaster....I do want to say Anthony provided an excellent satellite loop and good info.
But to follow up....the best way I can explain it is that the "energy" from storm systems often do remain as they travel around the globe. Often "energy" from one system will merge with other storms and form new ones. So it isnt quite like the same storm that hit the U.S. east coast goes to Europe then Asia and then back over the Pacific. The same energy from that first storm will survive....but that energy will interact with airmasses and wind patterns over the rest of the world and diminish or intensify over time.
For example...Often storm systems crash into the U.S. west coast. This time of the year they can be very strong systems coming onshore from the Pacific. Now...these storms will tend to weaken often as they move through the Rockies due to topographical affects...then re-form east of the Rockies as this system encounters moisture and perhaps more "energy" or stronger winds from a system coming northeast from the Pacific Ocean across Mexico and into Texas. The new storm system (a combo of two separate systems above) will then become dominate and affect the eastern half of the U.S. and move out to sea and this storm will likely remain in tact as it travels the North Atlantic. This same storm may remain in tact if strong enough and impact Iceland or Great Britian/France....but then it will often merge with additional energy off the North Sea or to the south and re-develop into a storm system across Russia. And this goes on and on.... Oceans provide much less resistance to storms and storms tend to remain in tact across oceans but land provides much friction (especially mountains) and these storms often weaken or breakup or merge with other energy before they re-develop again.
Hope that makes some sense. The above is pretty simplistic however. Note that these storm systems usually travel in the 30 degrees N to 60 degrees N latitude where the westerlies are strongest....lower than 30 degrees and higher than 60 degrees N will often see less dynamical storms (overall - this does not include hurricanes which is a separate type of system than I was talking about above).
As a forecaster....I do want to say Anthony provided an excellent satellite loop and good info.
But to follow up....the best way I can explain it is that the "energy" from storm systems often do remain as they travel around the globe. Often "energy" from one system will merge with other storms and form new ones. So it isnt quite like the same storm that hit the U.S. east coast goes to Europe then Asia and then back over the Pacific. The same energy from that first storm will survive....but that energy will interact with airmasses and wind patterns over the rest of the world and diminish or intensify over time.
For example...Often storm systems crash into the U.S. west coast. This time of the year they can be very strong systems coming onshore from the Pacific. Now...these storms will tend to weaken often as they move through the Rockies due to topographical affects...then re-form east of the Rockies as this system encounters moisture and perhaps more "energy" or stronger winds from a system coming northeast from the Pacific Ocean across Mexico and into Texas. The new storm system (a combo of two separate systems above) will then become dominate and affect the eastern half of the U.S. and move out to sea and this storm will likely remain in tact as it travels the North Atlantic. This same storm may remain in tact if strong enough and impact Iceland or Great Britian/France....but then it will often merge with additional energy off the North Sea or to the south and re-develop into a storm system across Russia. And this goes on and on.... Oceans provide much less resistance to storms and storms tend to remain in tact across oceans but land provides much friction (especially mountains) and these storms often weaken or breakup or merge with other energy before they re-develop again.
Hope that makes some sense. The above is pretty simplistic however. Note that these storm systems usually travel in the 30 degrees N to 60 degrees N latitude where the westerlies are strongest....lower than 30 degrees and higher than 60 degrees N will often see less dynamical storms (overall - this does not include hurricanes which is a separate type of system than I was talking about above).
Dan
Thanks so much for the in-depth explanation! Makes complete sense to me now.
I didn't think that an organized storm system survived for very long after it leaves the east coast of the US. Thanks for the explanation Dan.
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