Forecasting the volcanic ash plume of Iceland's volcano

By: Dr. Jeff Masters , 2:45 PM GMT on April 19, 2010

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The eruption of Iceland's volcano with the unpronounceable name, Eyjafjallajökull, has virtually ceased over the past few hours, with ash only reaching up to 6,000 feet (1800 meters), according to the latest advisory from the UK Met Office. Lightning images from UK Met Office show no new lightning strikes from the volcano's plume since midnight local time today. The relatively small amount of ash present at low altitudes will probably not be able to make it all the way to mainland Europe before falling to the surface and dissipating, since 6,000 feet is below the altitude that the strong winds of jet stream blow. Wednesday through Sunday, the volcano emitted a towering cloud of volcanic ash 6 - 11 km (20,000 - 36,000') high in the air from its 1666 meter (5500') high peak. The jet stream blows strongly at that altitude range, which allowed for efficient transport of the ash cloud to mainland Europe.


Figure 1. Lightning lights up the night sky in this photo of Eyjafjallajökull's eruption taken on April 16, 2010. Ash particles colliding together separate electric charge, much as ice particles in a thunderstorm do, leading to spectacular lightning displays. Image credit: Marco, Fulle, Stromboli Online.

Forecasts of the movement of the ash cloud are made using trajectory models, which have a number of uncertainties to consider. Firstly, the amount of ash ejected by the volcano is highly uncertain, since our measurements of this quantity are limited. Secondly, the models must compute how high the ash cloud will rise (plume rise), based on the best available measurements of atmospheric stability. Since upper air-observations are taken just twice daily by a very coarse network of balloon soundings, our knowledge of the stability is rather crude. Finally, the trajectory models use forecast winds from a global model such as the GFS model to predict where the plume may go. The forecast winds from this model do not capture much of the complicated structure of the wind field over Europe, leading to a rather fuzzy approximation of where the ash will go. Nevertheless, these models have in general done a respectable job forecasting where the ash from Eyjafjallajökull will go over the past few days.


Figure 2. Cross section of the atmosphere over time over Paliseau, France, on April 16, 2010, as observed using ground-based lidar. Image taken using a 532nm cross polarization NFOV telescope. Note how the ash layer sinks closer to the ground as time progresses, as gravity makes the ash sink to the ground. There may also be some atmospheric subsidence occurring (downward moving air due to large-scale atmospheric processes.) Image credit: Ray Hoff, World Meteorological Organization's Global Atmosphere Watch's Aerosol Lidar Network (GALION).

For the next few days, these models continue to indicate that northwest winds at the jet stream level will continue to affect Iceland. As a result, Spain, Portugal, and Greece will offer the best locations to fly from. The northwesterly winds are expected to continue for the remainder of the week, thanks to an upper-level trough of low pressure over northern Europe. On Saturday April 24, the ECMWF model predicts that the trough will slide eastwards, and a ridge of high pressure will build over Europe. This will bring upper-level winds out of the southwest to Iceland, directing any volcanic ash northwards over the North Pole. Thus for the remainder of this week, expect continued ash clouds over much of Europe if the volcano resumes significant eruptions. But by next Sunday, the ash over Europe should decline considerably. For the latest one-day forecasts of where the ash cloud is expected to go, consult the UKMET Office. The Rhenish Institute for Environmental Research at the University of Cologne also has some excellent simulations from an atmospheric dispersion model of Eyjafjallajökull's eruption plume. The Norwegian Institute for Air Research runs a computer trajectory model called FLEXPART that has 1-day forecasts showing a cross section of the atmosphere. NOAA's Air Resources Laboratory (ARL) lets you perform your own model run using their HYSPLIT model, going out up to 48 hours, using the GFS model as input.


Figure 3. NASA's Aqua satellite captured this image of the eruption at 1:20 UTC on April 17, 2010. Image credit: NASA Earth Observatory.

Links
An excellent source of links of information on the eruption is available at http://islande2010.mbnet.fr/2010/04/eyjafjallajok ul-links-liens-a-propos-de-leyjafjallajokul/. My post on Thursday discusses the likely non-impact of this eruption on Earth's climate. Finally, we need to be keeping an eye on earthquake activity at the dangerous Katla volcano next to Eyjafjallajökull. If that volcano blows, it could mean dwarf the headaches caused by Eyjafjallajökull.

Jeff Masters

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774. xcool
very close 2010 too 2005
Member Since: September 26, 2009 Posts: 2 Comments: 15684
april 19 2010 and 2005 compare map sst's

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Greetings.
Another hot one here today, peaked at 96.8f at the airport (no, the guage is not on the paved runway).
But the showers over the past few days seem to have put out the fires. Nice clear night right now.
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770. xcool
Create a hurricane plan That's all I have to say about that...
Member Since: September 26, 2009 Posts: 2 Comments: 15684
WSI raises 2010 Atlantic hurricane season forecast

NEW YORK, April 20 (Reuters) - Private weather forecaster WSI on Tuesday raised its forecast for the 2010 Atlantic hurricane season, calling for 16 named storms, nine hurricanes and five intense hurricanes of Category 3 or greater.

"The primary drivers for tropical activity have reversed course this year and the stage appears to be set for a very busy season in 2010," WSI seasonal forecaster Todd Crawford said.

The coastal region from the Outer Banks of North Carolina northward to Maine is twice as likely as normal to experience a hurricane this year, according to WSI.

"Our model suggests that the threat to the Northeast coast this season is on par with that in Florida and the Gulf coastal states," Crawford said.

Last year was the quietest tropical season since 1997 due to an El Nino event and relatively cool tropical Atlantic waters, but El Nino events tend to be followed by more activity, WSI said.

This year, another factor that increases the likelihood of storms, warmer Atlantic sea surface temperatures, are also in place.

"Eastern and central tropical Atlantic sea surface temperatures are currently at record warm levels for April, even warmer than the freakishly active season of 2005," Crawford said.

The current forecast numbers are more likely to be adjusted upwards rather than downwards as the season, which runs from June 1 through November 30, approaches, Crawford said.

The 2010 forecast numbers are well above the long-term average for 1950-2009 of 10 named storms, six hurricanes, and three intense hurricanes, but below the average from the more recent 15-year period of 14 names storms, eight hurricanes and four intense hurricanes.

(Reporting by Rebekah Kebede; Editing by David Gregorio)
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767. xcool
16-7-4 just like my nunmber wow




Our model suggests that the threat to the Northeast coast this season is on par with that in Florida and the Gulf coastal states," Crawford said .by WSI wowwww
Member Since: September 26, 2009 Posts: 2 Comments: 15684

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765. JRRP



well see you tomorrow
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"WSI raises 2010 Atlantic hurricane season forecast"
Link
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Quoting Ossqss:


Do ya think so? I often wonder how we oode oode in the models for anomalies. Earthquakes, Volcano's, Comets being absorbed by the sun, the connections etc., must be hard to understand. They all do play in our arena, if you will.

The P wave item we viewed from the earthquake in Chile was interesting to watch with respect to the influence on the lakes near NOLA and the readings from the Tsunami warning buoy's in the Pacific.

We learn everyday! That's a good thing :)


Indeed I do. It could actually end up considerably warmer than normal for much of the southern US.

And yeah, it is definitely intriguing to wonder about how all these things fit together.
Member Since: November 24, 2005 Posts: 635 Comments: 26684
Quoting Jeff9641:


Nickle size hail was just reported in windermere just SW of me. Lightning is becoming more and more frequent.

Nothing Severe here!!
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Quoting Jeff9641:


There is a tremendous amount of lightning right now and now the storm is about 15 to 20 minutes from me. Other storms are beginning to erupt around Tampa. It has already pour once a couple hours ago.

Sounds like the thunderstorms I remember from growing up in Long Island, NY. Energy releases in the atmosphere in the NE US involve heavy rain, lightning and thunder galore.

The t-storms in the S Plains and Midwest are wind producers, hail, and the infamous tornadoes.
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Quoting Levi32:


Well....next winter will be nothing like this winter was for the eastern half of the US. Nowhere near as cold.


Do ya think so? I often wonder how we code in the models for anomalies. Earthquakes, Volcano's, Comets being absorbed by the sun, the connections etc., must be hard to understand. They all do play in our arena, if you will.

The P wave item we viewed from the earthquake in Chile was interesting to watch with respect to the influence on the lakes near NOLA and the readings from the Tsunami warning buoy's in the Pacific.

We learn everyday! That's a good thing :)
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Quoting Jeff9641:
There is a very strong storm moving my way right now in Apopka. There very frequent cloud to groung lightning going on and there maybe some hail in this storm. The storm is due SW of me right now.

Hopefully everything will be ok, just a good thunderstorm and nothing else.
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Quoting Levi32:


Some may still be reported from some of the cells they were tracking. It can take a couple hours for some tornado reports to get to the SPC map.

The NWS Amarillo, TX office will send out a 2 meteorologists to the field to confirm whether there was 1 or 2+ tornadoes, per Sarah Johnson from NWS Amarillo :o)!
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Quoting Snowlover123:

Weather Channel... oh boy they said there were so many twisters that touched town. I guess they were wrong. THX Levi.


Some may still be reported from some of the cells they were tracking. It can take a couple hours for some tornado reports to get to the SPC map.
Member Since: November 24, 2005 Posts: 635 Comments: 26684
I have to go now. Goodnight everybody.
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Quoting Levi32:


None so far.


Weather Channel... oh boy they said there were so many twisters that touched town. I guess they were wrong. THX Levi.
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Quoting Snowlover123:


If the CFS is right about the upcoming change in Global Temps, I may have another 80 inches of snow next winter! Yea!


Well....next winter will be nothing like this winter was for the eastern half of the US. Nowhere near as cold.
Member Since: November 24, 2005 Posts: 635 Comments: 26684
Quoting Snowlover123:
In today's severe weather outbreak, how many tornados touched down?


None so far.

Member Since: November 24, 2005 Posts: 635 Comments: 26684
Quoting Levi32:


The reason the CFS is showing that is the same reason why it has a cold summer over most of the central-eastern US. I don't believe that will verify, and the shear should be weaker close to the coast than the CFS currently thinks. However, having low shear in the MDR and higher-than-normal shear overall near the coast is still very dangerous. With many storms forming in the tropics, it only takes a few breaks in the shear barrier to allow one or more major hurricanes to come up to the north and hit the US.


Thanks, Levi.
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Quoting KEEPEROFTHEGATE:
after this winter some people may not like that


If the CFS is right about the upcoming change in Global Temps, I may have another 80 inches of snow next winter! Yea!
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In today's severe weather outbreak, how many tornados touched down?
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Quoting Levi32:


Oh you can bet on that.
after this winter some people may not like that
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Quoting Drakoen:


Nope lol! It's only the GFS showing this so more model support is necessary.


It will take a while to get that as the GFS is the only model we have that goes out past 240 hours. For now it's just another blip on the long-range GFS that is indicating that the conditions may be there for mischief during the first week of May.
Member Since: November 24, 2005 Posts: 635 Comments: 26684
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Quoting Snowlover123:


It may also verify the crash in Global Temps, that it's forecasting for the fall-winter 2010-2011.


Oh you can bet on that.
Member Since: November 24, 2005 Posts: 635 Comments: 26684
Quoting Drakoen:


CFS has verified quite nicely in that department


It may also verify the crash in Global Temps, that it's forecasting for the fall-winter 2010-2011.
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Quoting Chicklit:

R U kidding me?!
Is this unprecedented this early in the season?


Nope lol! It's only the GFS showing this so more model support is necessary.
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Quoting SevereHurricane:


You don't find the band of strong upper level winds in the Gulf Of Mexico and off the East Coast strange since we should be in a La Nina by that time?


The reason the CFS is showing that is the same reason why it has a cold summer over most of the central-eastern US. I don't believe that will verify, and the shear should be weaker close to the coast than the CFS currently thinks. However, having low shear in the MDR and higher-than-normal shear overall near the coast is still very dangerous. With many storms forming in the tropics, it only takes a few breaks in the shear barrier to allow one or more major hurricanes to come up to the north and hit the US.
Member Since: November 24, 2005 Posts: 635 Comments: 26684
Quoting KEEPEROFTHEGATE:
yep and rebuilding to the sw in the rain

The threat is changing, from rotating supercell/tornado development to a squall line, straight-line winds > 50MH, heavy rain, golf-ball sized hail.
Member Since: August 25, 2009 Posts: 20 Comments: 6785
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Quoting Snowlover123:

It also looks like the storm is starting to weaken substantially as well.
yep and rebuilding to the sw in the rain
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Quoting KEEPEROFTHEGATE:


latest as storm dives se e

It also looks like the storm is starting to weaken substantially as well.
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Quoting Levi32:


Yes it has. The CFS forecasts the low wind shear anomalies to gradually expand westward to encompass the entire Caribbean as we head into the hurricane season.



You don't find the band of anomalously strong upper level winds in the Gulf Of Mexico that extends out into the Sub-Tropical Atlantic strange since we should be in a La Nina by that time?
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Quoting Chicklit:

R U kidding me?!
Is this unprecedented this early in the season?
both the pacific and atlantic is primed and ready in all likly hood the epac should fire up first as this devs it is possible cross over system is typical this early in the season as things are still feeling themselves out
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Quoting Chicklit:

R U kidding me?!
Is this unprecedented this early in the season?


Keep in mind that we've had a named storm form in May for the last 3 years in a row. It is not uncommon for the first blob to watch to occur in May. If the trends on the models hold true, then the pattern could become conducive to allow something to try to form in the Caribbean during next month. If something forms in the eastern Pacific, it won't be that surprising, as their season starts earlier on May 15th.
Member Since: November 24, 2005 Posts: 635 Comments: 26684
Quoting Chicklit:

R U kidding me?!
Is this unprecedented this early in the season?

There have actually been storms in the Eastern Pacific that have formed during the winter months, so it's not totally unprecedented, but certainly rare.
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yeah indianrivguy,I spect were gonna see some Storm reports soon on than Cell and Cluster.
Member Since: July 3, 2005 Posts: 426 Comments: 129093
Oopsie... :0
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Quoting Drakoen:
For what it's worth, the GFS continues to indicate the formation of a broad area of low pressure that may coalesce into a tropical cyclone in the Eastern Pacific or Southern Caribbean.

R U kidding me?!
Is this unprecedented this early in the season?
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Quoting Snowlover123:

Where do you get those SST charts? Could you also provide a link for it? THX. :)


Link is on the image....lol. Link
Member Since: November 24, 2005 Posts: 635 Comments: 26684
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Quoting Levi32:
Quoting Levi32:
Quoting Levi32:

Where do you get those SST charts? Could you also provide a link for it? THX. :)
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latest as storm dives se e
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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