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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Looks like it is erupting again. Still stuck in Toronto but have now got a flight on the 24th instead of the 27th. Link
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New Blog
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Quoting Jeff9641:


C and S FL have been getting rain daily now and more may come this afternoon as our seabreeze fronts get active.


The mean date of the start of the rainy season across southeast florida is May 20, so we probably beginning the transition period. We got very little lightning from the activity yesterday, which means that it's still too early. I'm not sure if whatever is left of El Niño will have an impact on the start of the rainy season. Past starts in El Niño years has varied some, so no clear signal from what I can tell.
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Sorry jeffs..as Ike willtell ya, CoCoRAHS don't lie. No rain.
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day 2 day 3 severe outlook

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818. IKE
Quoting PcolaDan:


I have not had a drop here. Still bone dry.


The system this weekend should break your dry spell.
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g'morning ya'll. Another dry fetch. :(
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Quoting IKE:
I had .60 inches of rain yesterday. 1.59 the last 2 days.

Sunny weather returns today....warmer tomorrow and Friday...chances of rain over the weekend.


I have not had a drop here. Still bone dry.
Member Since: August 22, 2008 Posts: 12 Comments: 6010
813. IKE
I had .60 inches of rain yesterday. 1.59 the last 2 days.

Sunny weather returns today....warmer tomorrow and Friday...chances of rain over the weekend.
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Good Morning.
Gentle showers this morning. Going to be another hot, Humid one.
96.8f yesterday.
Out ....
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Quoting stoormfury:
morning
the start of the tropical wave train in may could tell us how the season will unfold for the MDR. This all depends on how strong these waves exit the african coast and how long they mentain their identity and strengh
That is a good point. The water is so warm there we may even have a early season Cape Verde type storm.
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808. IKE
DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0348 AM CDT WED APR 21 2010

VALID 241200Z - 291200Z

...DISCUSSION...
MEDIUM-RANGE MODELS CONTINUE TO SHIFT A LARGE UPPER SYSTEM EWD
ACROSS THE CENTRAL AND ERN U.S. WITH TIME...WITH A GRADUAL
WEAKENING/DEAMPLIFICATION OF THE SYSTEM PROGGED. AS THE SYSTEM
BEGINS TO OPEN/WEAKEN -- PARTICULARLY FROM DAY 5 /SUN. APR. 25/
ONWARD...MODEL AGREEMENT SLOWLY DECREASES AS WELL. WHILE ENHANCED
SEVERE POTENTIAL WILL LIKELY SPREAD ACROSS THE SERN U.S. UNTIL THE
MAIN SURFACE FRONT MOVES OFFSHORE ON OR AROUND DAY 7 /TUE. APR.
27/...CONFIDENCE WITH RESPECT TO TIMING AND LOCATION DECREASES
STEADILY INTO THE PERIOD.

ATTM...WILL MAINTAIN AN OUTLOOK AREA CENTERED INVOF THE MID AND
LOWER MS AND TN VALLEYS DAY 4 /SAT. APR. 24/...AS A STRONGER
SHORT-WAVE TROUGH EMBEDDED WITHIN THE CYCLONIC FLOW AROUND THE MAIN
UPPER LOW IS PROGGED TO SHIFT ACROSS THIS REGION. WITH STRONG
DEEP-LAYER WIND FIELD AND MOIST/LIKELY UNSTABLE AIRMASS IN PLACE
AHEAD OF THIS FEATURE AND ASSOCIATED SURFACE FRONT...WIDESPREAD
SEVERE WEATHER APPEARS LIKELY.

AGAIN -- WHILE AT LEAST SOME SEVERE THREAT SHOULD SHIFT STEADILY EWD
WITH TIME DAYS 5-6-7...MODEL DIFFERENCES PRECLUDE HIGHLIGHTING
SPECIFIC THREAT AREAS BEYOND DAY 4.

..GOSS.. 04/21/2010
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morning
the start of the tropical wave train in may could tell us how the season will unfold for the MDR. This all depends on how strong these waves exit the african coast and how long they mentain their identity and strengh
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804. xcool
crazy blog 2010 comesoon
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803. HadesGodWyvern (Mod)
Tropical Cyclone Warning Center Perth
TROPICAL CYCLONE OUTLOOK
Forecast for area south of 10S between 90E-125E
2:00 PM WST April 21 2009
=====================================

There is a developing low in the monsoon trough south of Indonesia near 10S 117E. This low is expected to develop into a tropical cyclone late on Thursday or on Friday as it moves to the southwest. It is not expected to affect Christmas or Cocos Islands or the Australian mainland.

There are no other significant systems in the outlook area.

Tropical Cyclone Formation Potential
====================================
Thursday: Moderate
Friday: Moderate
Saturday: High
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we may see are 1st storm in mid May
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this year is going to go nuts on this blog
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spathy!!! I need help on your bog!
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Quoting pottery:
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.

Good to hear about the fires Pottery. No mud slides? Good luck!
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evening pottery or i should say top of the morning to ya

there could be quite a few
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forty days and forty nights
remain till the madness lets loose
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784. xcool
will not Surprise Me if we twenty storm name .imo...
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LOL GAGuy.
How are you faring?
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Quoting Jeff9641:


It supposed to crack 90 in Orlando this weekend for the first time this year.

Well enjoy the "cool weather" while it lasts. Gonna be a hundred in a few...
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The anomalies for 2010 and 2005 are eerily similar. 2005 is now the most similar SST profile analog we have. 1998 is the 2nd closest.

April 10th 2005 SST Anomalies:




April 10th 2010 SST Anomalies:


Member Since: November 24, 2005 Posts: 635 Comments: 26594
way above friend and thats all i have to say about that 2010 is on left or first 09 follows way more red dark red in 2010
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Quoting xcool:
very close 2010 too 2005

Except it is warmer this year...
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Hi Keeper. You think we will get any hurricanes this year anywhere, Bud, Sir?
heheheheh
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774. xcool
very close 2010 too 2005
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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.