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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latest as storm dives se e
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Quoting bappit:


Pardon me if this has already been posted.


that's the first time i have seen it. can you post the link? thanks!
Member Since: August 11, 2008 Posts: 3 Comments: 1745
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Quoting Drakoen:


CFS has verified quite nicely in that department


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.

Member Since: November 24, 2005 Posts: 635 Comments: 26700
#718, awesome loop of the tornado producing supercell. Thankfully that area of the TX Panhandle is very sparsely populated!
Member Since: August 25, 2009 Posts: 20 Comments: 6785
I've been saving loops of that storm Pat.. powerfil cell in there.





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There was a Mesoscale Discussion earlier today concerning the isolated tornado threat. Nothing recently.

Minor damage reports from areas near Canyon, TX.
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Quoting Levi32:


That's an anomaly....means wind shear is 35 knots below normal in that area.


CFS has verified quite nicely in that department
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Member Since: July 3, 2005 Posts: 428 Comments: 129766
Quoting all4hurricanes:
what does -35 shear mean?


That's an anomaly....means wind shear is 35 knots below normal in that area.
Member Since: November 24, 2005 Posts: 635 Comments: 26700
what does -35 shear mean?
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BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE AMARILLO TX
813 PM CDT TUE APR 20 2010

THE NATIONAL WEATHER SERVICE IN AMARILLO HAS ISSUED A

* TORNADO WARNING FOR...
CENTRAL RANDALL COUNTY IN THE PANHANDLE OF TEXAS.

* UNTIL 900 PM CDT

* AT 811 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS HAVE
DETECTED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO.
THE MOST DANGEROUS PART OF THIS STORM WAS LOCATED 3 MILES
SOUTHWEST OF CANYON...MOVING SOUTHEAST AT 15 MPH.

* SOME LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE CANYON.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A TORNADO MAY FORM AT ANY TIME...TAKE COVER NOW! ABANDON MOBILE HOMES
AND VEHICLES FOR MORE SUBSTANTIAL SHELTER. AVOID WINDOWS.

TO REPORT SEVERE WEATHER...PLEASE CALL THE NATIONAL WEATHER SERVICE
AT 8 0 6 3 3 5 1 1 2 1.
Member Since: August 25, 2009 Posts: 20 Comments: 6785
SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE AMARILLO TX
759 PM CDT TUE APR 20 2010

TXC381-210115-
/O.CON.KAMA.TO.W.0003.000000T0000Z-100421T0115Z/
RANDALL TX-
759 PM CDT TUE APR 20 2010

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 815 PM CDT FOR WESTERN
RANDALL COUNTY...

AT 754 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS HAVE
DETECTED A POSSIBLE TORNADO. THIS TORNADO WAS LOCATED NEAR
UMBARGER...OR ABOUT 7 MILES WEST OF CANYON...MOVING SOUTHEAST AT 15
MPH.

* LOCATIONS IMPACTED INCLUDE...
UMBARGER...
CANYON...
BUFFALO LAKE...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

HEAVY RAINFALL MAY OBSCURE THIS TORNADO. TAKE COVER NOW. IF YOU WAIT
TO SEE OR HEAR IT COMING...IT MAY BE TOO LATE TO GET TO A SAFE PLACE.

TO REPORT SEVERE WEATHER...PLEASE CALL THE NATIONAL WEATHER SERVICE
AT 8 0 6 3 3 5 1 1 2 1
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Member Since: November 24, 2005 Posts: 635 Comments: 26700
Member Since: November 24, 2005 Posts: 635 Comments: 26700
Quoting Bordonaro:
Tornado on the ground just west of Canyon, TX:

TORNADO WARNING
TXC381-210115-
/O.NEW.KAMA.TO.W.0003.100421T0048Z-100421T0115Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE AMARILLO TX
748 PM CDT TUE APR 20 2010

THE NATIONAL WEATHER SERVICE IN AMARILLO HAS ISSUED A

* TORNADO WARNING FOR...
WESTERN RANDALL COUNTY IN THE PANHANDLE OF TEXAS.

* UNTIL 815 PM CDT

* AT 745 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS HAVE
DETECTED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THE
MOST DANGEROUS PART OF THIS STORM WAS LOCATED NEAR UMBARGER...OR
ABOUT 9 MILES WEST OF CANYON...MOVING SOUTHEAST AT 15 MPH.

* SOME LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE UMBARGER...
CANYON AND BUFFALO LAKE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A TORNADO MAY FORM AT ANY TIME...TAKE COVER NOW! ABANDON MOBILE HOMES
AND VEHICLES FOR MORE SUBSTANTIAL SHELTER. AVOID WINDOWS.

TO REPORT SEVERE WEATHER...PLEASE CALL THE NATIONAL WEATHER SERVICE
AT 8 0 6 3 3 5 1 1 2 1.

Quoting weathermanwannabe:
That is one wicked looking cell to the South of Amarillo...

It has just produced its second tornado. It is traveling toward a small town named Canyon, TX.

The supercell thunderstorm keeps pulsing, strengthening, dropping a tornado. Then it weakens, then strengthens again, dropping its second confirmed tornado.
Member Since: August 25, 2009 Posts: 20 Comments: 6785
That is one wicked looking cell to the South of Amarillo...
Member Since: Posts: Comments:
Tornado on the ground just west of Canyon, TX:


Basically no damage, no injuries, traveling over open grasslands per NWS Amarillo rep on the line with TWC.

TORNADO WARNING
TXC381-210115-
/O.NEW.KAMA.TO.W.0003.100421T0048Z-100421T0115Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE AMARILLO TX
748 PM CDT TUE APR 20 2010

THE NATIONAL WEATHER SERVICE IN AMARILLO HAS ISSUED A

* TORNADO WARNING FOR...
WESTERN RANDALL COUNTY IN THE PANHANDLE OF TEXAS.

* UNTIL 815 PM CDT

* AT 745 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS HAVE
DETECTED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THE
MOST DANGEROUS PART OF THIS STORM WAS LOCATED NEAR UMBARGER...OR
ABOUT 9 MILES WEST OF CANYON...MOVING SOUTHEAST AT 15 MPH.

* SOME LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE UMBARGER...
CANYON AND BUFFALO LAKE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A TORNADO MAY FORM AT ANY TIME...TAKE COVER NOW! ABANDON MOBILE HOMES
AND VEHICLES FOR MORE SUBSTANTIAL SHELTER. AVOID WINDOWS.

TO REPORT SEVERE WEATHER...PLEASE CALL THE NATIONAL WEATHER SERVICE
AT 8 0 6 3 3 5 1 1 2 1.

Member Since: August 25, 2009 Posts: 20 Comments: 6785
Good Evening......Steady drizzle in Tallahassee area now for about the last two hours...Have heard a few rumbles of thunder in the distance but no wind at all in my parts North of town whatsoever.....Basically a quiet tropical like drizzle with slightly cooler temps overnight.....We really needed the rain to wash away the heavy pollen blanketing everything; guess it will be time to break out the lawnmower this weekend.
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Good evening, all. Now that I know there's the possibility (at least according to the models, though obviously, the probability of such actually occurring is another matter entirely) of a tropical cyclone in the SW Caribbean, along with an increase in moisture, associated with the MJO, I'll begin lurking more often.

More importantly, I've also been taking a look at the computer models ever since this time yesterday, and the GFS is hinting at a significant relaxation of the vertical shear during the final days of this month.
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Pardon me if this has already been posted.
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Trade winds have been weakening over the past 10 days over the Atlantic and are once again well-below normal in the eastern MDR.

Member Since: November 24, 2005 Posts: 635 Comments: 26700
Here's some cool pics of volcano lightning.
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Quoting VAbeachhurricanes:


wow, thats a beaut of a supercell

The cell has weakened, Jim Cantore at TWC has been watching it, a large tornado was spotted about 5 miles west of the town of Bushland, TX. To make matters worse, it was "rain wrapped".
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Quoting Bordonaro:
CycloneOz was going to check out his new camera, tracking storms is NM. Too bad he couldn't "storm chase", he missed his chance to catch a Tornado currently on the ground in the western TX Panhandle.


wow, thats a beaut of a supercell
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Quoting Drakoen:
One thing to note is that the GFS and GEFS largely disagree on the upcoming upward motion of the MJO. The GFS shows a very strong MJO upward motion while the GEFS hardly shows the signal at all.



ECMWF is closest to the GEFS


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TORNADO WARNING
TXC375-381-210045-
/O.NEW.KAMA.TO.W.0002.100421T0022Z-100421T0045Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE AMARILLO TX
722 PM CDT TUE APR 20 2010

THE NATIONAL WEATHER SERVICE IN AMARILLO HAS ISSUED A

* TORNADO WARNING FOR...
SOUTHWESTERN POTTER COUNTY IN THE PANHANDLE OF TEXAS.
NORTHWESTERN RANDALL COUNTY IN THE PANHANDLE OF TEXAS.

* UNTIL 745 PM CDT

* AT 720 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS HAVE
DETECTED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THE
MOST DANGEROUS PART OF THIS STORM WAS LOCATED NEAR BUSHLAND...OR
ABOUT 15 MILES WEST OF AMARILLO...MOVING SOUTHEAST AT 10 MPH.

* SOME LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE BUSHLAND.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A TORNADO HAS BEEN CONFIRMED!
TAKE COVER IN A STURDY BUILDING NOW.
MOBILE HOMES AND VEHICLES ARE NOT SAFE.

TO REPORT SEVERE WEATHER...PLEASE CALL THE NATIONAL WEATHER SERVICE
AT 8 0 6 3 3 5 1 1 2 1.

Member Since: August 25, 2009 Posts: 20 Comments: 6785
91S is looking quite healthy.
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695. Skyepony (Mod)
91S
Member Since: August 10, 2005 Posts: 222 Comments: 39354
CycloneOz was going to check out his new camera, tracking storms is NM. Too bad he couldn't "storm chase", he missed his chance to catch a Tornado currently on the ground in the western TX Panhandle.
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Well, let's talk about law suits then. Just kidding. No, really.

Edit: Ummm, here's another link unrelated to the first.
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692. JRRP

mmmmm less dust
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I'm glad we're finally talking about the tropics again on the blog. It's interesting to talk about the volcano that erupted as well as when a big quake hits, but sheesh, thats all this blog has been talking about lately. 3.5 earthquakes in rural areas frankly shouldn't be talked about more than the tropics.

Just my two cents fellas :)
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Quoting Skyepony:


From what each forecast a week ago GEFS was more right but neither really had a handle on it.


That is true:

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Quoting Levi32:


That's true, since the east Pacific is climatologically favored early-on, but upper-level conditions are forecasted to be favorable over both areas, so there is as much of a chance for Caribbean mischief as EPAC mischief.


Or maybe 2 systems form, one in each basin?
Member Since: April 29, 2009 Posts: 75 Comments: 14883
688. Skyepony (Mod)
Quoting Drakoen:
One thing to note is that the GFS and GEFS largely disagree on the upcoming upward motion of the MJO. The GFS shows a very strong MJO upward motion while the GEFS hardly shows the signal at all.



From what each forecast a week ago GEFS was more right but neither really had a handle on it.
Member Since: August 10, 2005 Posts: 222 Comments: 39354
Quoting FLWeatherFreak91:
Models in the early season like to spin things up in the SW Caribbean, but it usually turns out that the indicated storm forms in the EPAC. I've noticed this over the past few years.


That's true, since the east Pacific is climatologically favored early-on, but upper-level conditions are forecasted to be favorable over both areas, so there is as much of a chance for Caribbean mischief as EPAC mischief.
Member Since: November 24, 2005 Posts: 635 Comments: 26700
Quoting NRAamy:
hey bord...wouldn't a good rain storm just wash all that ash outa the sky?



Hiya Amy
A good rain would indeed wash the ash away provided the rain level starts above the ash. Believe it or not though, with enough ash it can basically rain mud. A good rain is the best way to clear the air of the smallest ash that may still remain after the main ash events passes.
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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.
Models in the early season like to spin things up in the SW Caribbean, but it usually turns out that the indicated storm forms in the EPAC. I've noticed this over the past few years.
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684. xcool



not much....
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Quoting Drakoen:
One thing to note is that the GFS and GEFS largely disagree on the upcoming upward motion of the MJO. The GFS shows a very strong MJO upward motion while the GEFS hardly shows the signal at all.



They have been strongly disagreeing all winter long due to the El Nino, at least during the times when I actually checked. To me the GFS makes a bit more sense because the Kelvin Wave currently moving across the eastern Pacific argues for upward motion near central America around that time.
Member Since: November 24, 2005 Posts: 635 Comments: 26700
One thing to note is that the GFS and GEFS largely disagree on the upcoming upward motion of the MJO. The GFS shows a very strong MJO upward motion while the GEFS hardly shows the signal at all.

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681. xcool
hmmmm ts by GFS 50 mph lmao.
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african sat image

nice spot on the sun
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Quoting Levi32:


No, it's not that kind of volcano. Katla could, but this one not so much. The ash wasn't blasted high enough.


Thanks Levi!

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Quoting NRAamy:
hey bord...wouldn't a good rain storm just wash all that ash outa the sky?

Most of the ash is being dispersed around Europe and parts of Russia, A big Low pressure area would help wash a good part of the ash out of the sky.
Member Since: August 25, 2009 Posts: 20 Comments: 6785
677. xcool
The latest Nino and SOI data are showing that the CFS is playing catch up again, as it normally does, with major changes in Pacific signaling. I have long opined, and been trying to prove by forecasting first and then showing you, that this climate model is poor in its dynamics, only catching on to a change when its obvious. Like last years el nino, this is again late to the party with the change as the La Nina is coming on.

by joe.




\\\\
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hey bord...wouldn't a good rain storm just wash all that ash outa the sky?
Member Since: January 24, 2007 Posts: 317 Comments: 31946
Quoting Levi32:
An area of strong upward motion associated with the MJO is expected to be over the eastern Pacific and Caribbean during the first week of May.



Yes, it appears the GFS shows a broad monsoon gyre to develop, with the system following the advancement of the MJO eastward. Potentially our first true AOI if the GFS continues to be consistent.
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Quoting SomeRandomTexan:
so is it likely that the volcano will effect this hurricane season?

At this current state of the Iceland eruption, probably not, as it is a relatively small eruption at the 65N parallel, prevailing winds will keep whatever aerosols that are present way up north, far away from the Tropics.

However, if there is a larger eruption, things may change, but at this moment, there is no sign that will occur.
Member Since: August 25, 2009 Posts: 20 Comments: 6785

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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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