Low Pressure System off Iceland

[HURAKAN]

This may be off-topic but it's interesting the low pressure system off the Iceland coast. You can see it in the webpage below, the image is excellent.

http://earthobservatory.nasa.gov/Natura ... g_id=12172

Sandy Delgado

[Stormsfury]

That's a wrapped up beauty ...

[Hurricanehink]

Wow... nice.

[USAwx1]

That would be a polar low -- a cousin to tropical cyclones and hurricanes. here's some background for those that are interested.

Polar lows normally form in response to the following things:

1) Cold outbreak w/ cold air flowing from land over a warmer ocean
2) Shallow baroclinic zone.
3) An Upper trough and/or closed low.
4) Cold 500H temps, within the -30 to -35C range (Rasmussen (1994)
5) Upper speed maximum and area of positive Vorticity Advection.
6) enhanced convection or meso-vorticies

The primary difference between Polar lows and tropical systems is that as we know, tropical systems normally have a 500H temperature which is a degree or so warmer than the rest of the environment at the same pressure level, thus the term "warm core". the developmental processes of Polar lows have more characteristics of mid-latitude systems. However CAN develop the warm core and Eye structure.

take a look at the 500H analysis from 12z this afternoon over the North Atlantic.



When forecasting the development of a polar low look for area in which the low level disturbance and upper level forcing are most likely to meet up.

the transference of a vortex to a polar low can occur VERY quickly in response to the approach of the upper trough, and associated convective development due to decreased stability, where land-sea interactions or the combination of that an CSIK (Conditional Instability of the second kind), contribute to intensification.

Polar lows (like tropical systems) may develop VERY strong winds, up to hurricane force, In cases of EXTREMELY RAPID DEEPENING. Normally this requires strong upper level divergence placed above low level convergence.

Polar lows may also move at speeds above 20KT, produce heavy snow showers and snow squalls, and blowing snow as a result of the strong winds associated w/ polar lows when over land.

Not unlike tropical systems, once polar lows move over land, or Ice-capped regions, they will rapidly weaken as the contrast between the cold air above them and warmer SSTs is lost.

[zoeyann]

So is this one of those amazing day after tommorrow hurricane blizzards. Just kidding could not help it. It is a really amazing picture though.

[USAwx1]

So is this one of those amazing day after tommorrow hurricane blizzards. Just kidding could not help it. It is a really amazing picture though.

You think that image of a polar low was impressive, zoey, check this one out:



this one is particularly strong, note the well defined eye.

and another that i was able to find:

[HURAKAN]

Impressive is not enough, I will say astonishing.

Sandy Delgado

[senorpepr]

Quite honestly this is nothing out of the ordinary. During my days of forecasting in Europe, this Icelandic lows were very common. In this situation, this low is fairly weak in comparision to the average low -- of course being summer. Sorry, no blizzards with this system. Just some rainshowers associated with the trough along with some rain associated with the frontolysizing (dieing) occluded boundary.

Here's a satellite analysis of Europe, with the featured low SSE of Iceland. Of course, this image is an IR shot with cloud temperates of greater than -8°C removed. You can see this low isn't all that impressive at all. Wait until around mid-winter. Then you'll see some fairly impressive lows.

[HurricaneBill]

I think I read somewhere on the internet that Europe actually names these storms. I think they call them "oktenfiels" (I know I definitely misspelled that). I think that is German for "hurricane low". I think there was a powerful one in 1990 named Daria and a recent one named Gerda.

[senorpepr]

I think I read somewhere on the internet that Europe actually names these storms. I think they call them "oktenfiels" (I know I definitely misspelled that). I think that is German for "hurricane low". I think there was a powerful one in 1990 named Daria and a recent one named Gerda.

Actually... you remembered correctly. The University of Berlin assigns names to the significant lows and highs throughout Europe. They have an interesting naming convention. I believe somewhere on their site they talk about it. In early 2003, they allowed the public to bid on naming rights on eBay. Someone could bid for a slot starting with a certain letter. The highest bidder was allowed to name that storm using that specific letter. The money was directed to the meteorology department. Here's the link along with their 36-hr forecast.

http://www.met.fu-berlin.de/de/wetter/bodenvorhersage/

[HurricaneBill]

Boy, I was way off with that word.

It's actually "orkantief".

[zoeyann]

Thanks for posting the pics USAwx1. I can not explain why, but I think storms like that are just beautiful, nature at her most powerful.

[HURAKAN]

I think I read somewhere on the internet that Europe actually names these storms. I think they call them "oktenfiels" (I know I definitely misspelled that). I think that is German for "hurricane low". I think there was a powerful one in 1990 named Daria and a recent one named Gerda.

Actually... you remembered correctly. The University of Berlin assigns names to the significant lows and highs throughout Europe. They have an interesting naming convention. I believe somewhere on their site they talk about it. In early 2003, they allowed the public to bid on naming rights on eBay. Someone could bid for a slot starting with a certain letter. The highest bidder was allowed to name that storm using that specific letter. The money was directed to the meteorology department. Here's the link along with their 36-hr forecast.

Interesting.... I didn't know they named lows and highs. Everyday we learn something new. I think we should begin naming tornadoes as well.

Sandy Delgado

[USAwx1]

Quite honestly this is nothing out of the ordinary. During my days of forecasting in Europe, this Icelandic lows were very common. In this situation, this low is fairly weak in comparision to the average low -- of course being summer. Sorry, no blizzards with this system. Just some rainshowers associated with the trough along with some rain associated with the frontolysizing (dieing) occluded boundary.

Here's a satellite analysis of Europe, with the featured low SSE of Iceland. Of course, this image is an IR shot with cloud temperates of greater than -8°C removed. You can see this low isn't all that impressive at all. Wait until around mid-winter. Then you'll see some fairly impressive lows.

http://131.54.120.150/GifImages/metsatanal.gif

great posts....the 1987 PL in the example i provided occurred during the heart of the 1986-87 winter and was VERY strong.

[HURAKAN]

EXTRATROPICAL LOW PRESSURE SYSTEM OFF AUSTRALIA, FEBRUARY, 2002....

http://earthobservatory.nasa.gov/NaturalHazards/Archive/Feb2002/AussieLow_S2002051_lrg.jpg


LOW-PRESSURE SYSTEM OVER NORTHWESTERN PACIFIC, SOUTH OF ALASKA, DECEMBER, 2002....

http://earthobservatory.nasa.gov/NaturalHazards/Archive/Dec2002/pacificlow.TMO2002346_lrg.jpeg

Sandy Delgado

[bahamaswx]

Could you possibly post pictures any more massive please? I have to squint to make it out... it's simply too small.

[HurricaneBill]

Could you possibly post pictures any more massive please? I have to squint to make it out... it's simply too small.

What do you mean? That last one broke through my screen and knocked me out of my chair!

[wx247]

Well actually, not to go off-topic, but we do name tornadoes. The first town that they hit or area of impact becomes the name of the tornado.

For example, in May of this year, the tornado that hit Hallam, NE hit a couple of other places afterwards, but because it hit Hallam first... it was named the Hallam tornado.

[Josephine96]

LOL I was going to say.. Those pics are definitely massive

[Matthew5]

I call those Artic hurricanes which I heard some one say that the only system that can form a eye is a tropical cyclone? I believe that was the discussion on the movie The day after tomarrow. But yes the there is a cold core system just like a tropical cyclone