The worst is over for the ash clouds from Iceland's volcano

By: Dr. Jeff Masters , 12:56 PM GMT on April 21, 2010

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The worst is now over for European air traffic disruptions from the ongoing eruption of Iceland's Eyjafjallajökull volcano. The eruptions are currently only throwing ash up to 16,000 feet (4900 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 Sunday. The lower amounts of ash are due, in part, to the fact that the volcano has melted most of the ice and snow covering the crater. This ice had caused the hot magma erupting through it to fragment into fine ash capable of reaching much higher heights of 6 - 11 km (20,000 - 36,000') in the early stages of the eruption. Ash is also reduced because the volcano has entered a phase where it is producing more magma. Although it is possible that the volcano could enter a more explosive eruption phase that would throw ash high into the air once again, the winds are expected to shift over Iceland late this week. The northwest winds that have been "stuck" in place over Iceland over the past week due to a persistent trough of low pressure over northern Europe, will gradually shift to westerly by Friday and southwesterly by Saturday. This means that new eruptive material will blow over the northern British Islands and northern Scandanavia late this week, avoiding the main portion of Europe. Ash should be confined to northern Scandanavia and Greenland through most of next week, since the southwesterly winds are expected to continue through most of next week.


Figure 1. Iceland’s Eyjafjallajökull volcano began to ease out of the ash-producing phase of its eruption and started to emit magma on April 19, 2010, said the Icelandic Met Office. The cloud of ash coming from the volcano was lower than it had been in previous days, rising just 4 to 6 kilometers (2 to 3 miles) into the atmosphere. In this photo-like image, taken by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite, the ash extends south in a broad brown plume. Smaller plumes extend from the coast east of the primary plume. These are likely re-suspended ash, fine volcanic ash that had settled on the land, but is now being picked up by the wind. The plume blows south and then curves east over the ocean, blending with the outer bands of a low-pressure system. Image credit: NASA.

I'll have a new post Thursday (Earth Day!)
Jeff Masters

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Thanks Levi :0), I understand.
Member Since: August 25, 2009 Posts: 20 Comments: 6785

Member Since: July 15, 2006 Posts: 170 Comments: 53570
Quoting Bordonaro:

Good afternoon Levi. Can you please explain the increase in the El Nino temps?


Hey Bordo :)

It's all the Kelvin Wave's fault. The last Kelvin Wave that we have seen in a while is currently moving eastward across the east Pacific, and as it goes it has been warming the SSTs in the Nino 1, 2, and 3 regions. Kelvin Waves are associated with bursts of westerly wind anomalies where strong easterly trade winds usually dominate. You can see westerly anomalies over the eastern Pacific on the image below from the CPC, showing the average anomalies for the last 30 days.



Slower trades over the Pacific allow SSTs to warm. This is the same principle as in the Atlantic. Slower winds mean less evaporation and less upwelling of cooler, deeper waters. Kelvin Waves actually promote downwelling of water out in front of them, which forces warm surface water deeper and increases total upper-ocean heat content. The image below is a time-longitude plot of upper-ocean heat content anomalies for the past 12 months (edits are mine). You can see the series of strong Kelvin Waves that have moved across the Pacific this winter, represented by increases in heat content, and this current one is now beginning to move into the eastern-most Pacific.



There is also a noticable absence of warm anomalies in the western and central Pacific since about mid-March. This is because no new Kelvin Waves have developed behind the current one, unlike what has been occurring all winter. This is courtesy of the huge positive SOI burst we are having, which is restoring the easterly trade winds over the west-central Pacific, and thereby cooling the SSTs and lowering ocean heat content. If you notice, Nino 3.4 region (central Pacific) has been cooling while the Nino 1, 2, and 3 regions, all in the eastern Pacific, have been warming. Once this Kelvin Wave sloshes up against South America and dissipates, SSTs should begin to gradually cool in these areas as well, and the overall decline of the El Nino will resume in all areas.
Member Since: November 24, 2005 Posts: 635 Comments: 26607
that cell in north easternmost NM corner just wont budge! flood advisories already present...
Member Since: Posts: Comments:
URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 73
NWS STORM PREDICTION CENTER NORMAN OK
410 PM CDT WED APR 21 2010

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

THE SOUTHERN TEXAS PANHANDLE AND TEXAS SOUTH PLAINS

EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 410 PM UNTIL
1100 PM CDT.

TORNADOES...HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 75 STATUTE
MILES NORTH AND SOUTH OF A LINE FROM 75 MILES WEST NORTHWEST OF
PLAINVIEW TEXAS TO 15 MILES SOUTHEAST OF CHILDRESS TEXAS. FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU3).

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.

OTHER WATCH INFORMATION...CONTINUE...WW 72...

DISCUSSION...SURFACE HEATING/MIXING HAS REMOVED MUCH OF THE
CONVECTIVE INHIBITION ALONG A STALLED FRONT...AND THUNDERSTORM
DEVELOPMENT WILL BE POSSIBLE IN THE NEXT COUPLE OF HOURS ALONG THE
FRONT AND IMMEDIATELY NE OF A WEAK MESOLOW NW OF LBB. MODERATE
INSTABILITY IS PRESENT ALONG THE BOUNDARY...AND DEEP-LAYER VERTICAL
SHEAR IS SUFFICIENT FOR SUPERCELLS. THE PRIMARY INITIAL THREAT WILL
BE LARGE HAIL...THOUGH A COUPLE OF TORNADOES WILL ALSO BE POSSIBLE
TOWARD EVENING AS LOW-LEVEL MOISTURE AND SHEAR CONTINUE TO INCREASE
GRADUALLY.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 28015.
Member Since: August 25, 2009 Posts: 20 Comments: 6785
CycloneOZ is this Tornado Watch any closer to you? Severe thunderstorms will start to fire off again in parts of the TX Panhandle.
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Tornado watch out for the panhandle.

Member Since: Posts: Comments:
Recent pic of "E" in Iceland, a view of the glacier ravine draining flood waters, the black fissure in the pic on the left:
Member Since: August 25, 2009 Posts: 20 Comments: 6785
176. xcool
Hurricanes101 yes.
Member Since: Posts: Comments:
Quoting xcool:
CycloneOz hey.


Hey! :)
Member Since: August 26, 2006 Posts: 10 Comments: 3625
Quoting xcool:
Hurricanes101 /imo


Still confused, you are aware that the EPAC hurricane season begins May 15th right?

Not too farfetched that a storm can form in the EPAC in early may
Member Since: Posts: Comments:
173. xcool
Hurricanes101 /imo
Member Since: Posts: Comments:
172. xcool
CycloneOz hey.
Member Since: Posts: Comments:
Quoting xcool:
EPAC lmao .i wait on too see .ecmwf.


why is EPAC funny?
Member Since: Posts: Comments:
Quoting CycloneOz:


Yeah...I've been watching that storm...

It's at least 4.5 hours away from me...that's quite a distance!

If I left this minute...I'd be there by 7:30 PM

The joys of living in the High Desert on NM, a zillion tons of snow in the winter, then a few good storms spattered in the summer months!
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Hiya Guys...sunny and warm in NOLA
Member Since: July 3, 2005 Posts: 423 Comments: 127820
Oh well, so much for trying to post that pic of the Science blog on the lil' "E" in Iceland!
Here is the link to the picture:
Link
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Quoting Bordonaro:
Where is Cyclone Oz this afternoon? He has a Severe Thunderstorm Watch #72, just issued by the SPC:

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 72
NWS STORM PREDICTION CENTER NORMAN OK
250 PM MDT WED APR 21 2010

THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

SOUTHEAST COLORADO
NORTHEAST NEW MEXICO
THE EXTREME WESTERN OKLAHOMA PANHANDLE
EXTREME NORTHWEST TEXAS PANHANDLE

EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 250 PM UNTIL
900 PM MDT.

HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 55
STATUTE MILES EAST AND WEST OF A LINE FROM 15 MILES WEST
NORTHWEST OF LA JUNTA COLORADO TO 50 MILES SOUTHWEST OF DALHART
TEXAS. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED
WATCH OUTLINE UPDATE (WOUS64 KWNS WOU2).

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.

DISCUSSION...WIDELY SCATTERED THUNDERSTORMS ARE DEVELOPING IN THE
ZONE OF STRONGER SURFACE HEATING AND LOW-LEVEL UPSLOPE FLOW ACROSS
NE NM/SE CO. THE ENVIRONMENT THROUGH THE EVENING WILL BE
CHARACTERIZED BY SUFFICIENT INSTABILITY AND DEEP-LAYER VERTICAL
SHEAR FOR SUPERCELLS...WITH LARGE HAIL THE PRIMARY SEVERE STORM
THREAT.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450. MEAN STORM
MOTION VECTOR 32015.


...THOMPSON


Yeah...I've been watching that storm...

It's at least 4.5 hours away from me...that's quite a distance!

If I left this minute...I'd be there by 7:30 PM
Member Since: August 26, 2006 Posts: 10 Comments: 3625
Question. During the 2004 hurricane season, did we have ENSO neutral conditions or was it a weak El Nino? I welcome your response.......
Member Since: Posts: Comments:
Quoting Levi32:


Well you never know in the east Pacific, even with early-season storms. SSTs are already boiling hot over there by this time of year. Besides wind shear, the only thing that keeps the EPAC absent of storms in April is the lack of tropical disturbances or tropical waves.


Good afternoon Levi. Can you please explain the increase in the El Nino temps?
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Quoting xcool:
Bordonaro hi and pat too

Hey XCool and Patrap! Hope everyone is enjoying their Wednesday afternoon.
Member Since: August 25, 2009 Posts: 20 Comments: 6785
163. xcool
Bordonaro hi and pat too
Member Since: Posts: Comments:
Quoting Patrap:
Maybe out buying a NOAA Weather Alert Radio?

That was funny :o). I figured he had at least one of them!
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Maybe out buying a NOAA Weather Alert Radio?
Member Since: July 3, 2005 Posts: 423 Comments: 127820
Where is Cyclone Oz this afternoon? He has a Severe Thunderstorm Watch #72, just issued by the SPC:

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 72
NWS STORM PREDICTION CENTER NORMAN OK
250 PM MDT WED APR 21 2010

THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

SOUTHEAST COLORADO
NORTHEAST NEW MEXICO
THE EXTREME WESTERN OKLAHOMA PANHANDLE
EXTREME NORTHWEST TEXAS PANHANDLE

EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 250 PM UNTIL
900 PM MDT.

HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 55
STATUTE MILES EAST AND WEST OF A LINE FROM 15 MILES WEST
NORTHWEST OF LA JUNTA COLORADO TO 50 MILES SOUTHWEST OF DALHART
TEXAS. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED
WATCH OUTLINE UPDATE (WOUS64 KWNS WOU2).

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.

DISCUSSION...WIDELY SCATTERED THUNDERSTORMS ARE DEVELOPING IN THE
ZONE OF STRONGER SURFACE HEATING AND LOW-LEVEL UPSLOPE FLOW ACROSS
NE NM/SE CO. THE ENVIRONMENT THROUGH THE EVENING WILL BE
CHARACTERIZED BY SUFFICIENT INSTABILITY AND DEEP-LAYER VERTICAL
SHEAR FOR SUPERCELLS...WITH LARGE HAIL THE PRIMARY SEVERE STORM
THREAT.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450. MEAN STORM
MOTION VECTOR 32015.


...THOMPSON
Member Since: August 25, 2009 Posts: 20 Comments: 6785
159. xcool
EPAC lmao .i wait on too see .ecmwf.
Member Since: Posts: Comments:
Quoting Snowlover123:


Wouldn't that be a TD, if its pressure is so high, at around 1000 mb?


Global models dont have a handle on the exact pressure for tropical systems. For example, the GFS initialized Cat 5 hurricane dean at 1006 mb when it was about to make landfall on the Yucatan.
Member Since: Posts: Comments:
Quoting Stormchaser2007:
Anyone see the hurricane the 12z GFS develops in the EPAC?



Wouldn't that be a TD, if its pressure is so high, at around 1000 mb?
Member Since: April 1, 2010 Posts: 9 Comments: 2699
Quoting Tropicsweatherpr:
What is the latest on El Nino 3.4 and the subsurface waters in the Pacific?


Still some sub-surface warm waters to take care of.

Member Since: Posts: Comments:
All Nino regions experiencing an increase in temps.

Member Since: Posts: Comments:
What is the latest on El Nino 3.4 and the subsurface waters in the Pacific?
Member Since: April 29, 2009 Posts: 75 Comments: 14224
Quoting Stormchaser2007:


Yeah I noticed that as well. It would make sense for something to possibly develop there due to the fact that their season is less than a month away. Doubt it would be that strong though.


Well you never know in the east Pacific, even with early-season storms. SSTs are already boiling hot over there by this time of year. Besides wind shear, the only thing that keeps the EPAC absent of storms in April is the lack of tropical disturbances or tropical waves.

Member Since: November 24, 2005 Posts: 635 Comments: 26607
Quoting Levi32:


Yeah, the last few runs of the GFS have been shifting the most favorable environment for tropical development more into the eastern Pacific than the SW Caribbean.


Yeah I noticed that as well. It would make sense for something to possibly develop there due to the fact that their season is less than a month away. Doubt it would be that strong though.
Member Since: Posts: Comments:
Quoting Stormchaser2007:
Anyone see the hurricane the 12z GFS develops in the EPAC?



Yeah, the last few runs of the GFS have been shifting the most favorable environment for tropical development more into the eastern Pacific than the SW Caribbean.
Member Since: November 24, 2005 Posts: 635 Comments: 26607
Anyone see the hurricane the 12z GFS develops in the EPAC?

Member Since: Posts: Comments:
Quoting tornadofan:
6.2-Magnitude Earthquake Strikes Samoa

Slow news day...

Police in the Samoan capital, Apia, say they have no reports on the temblor. "We didn't feel any earthquake," an officer, who declined to be named, said.


Didn't one or two days ago, I predicted that there would be another Earthquake? This is not surprising. Those experts that say "oh... it's only happening in more populated areas" are rubbish. Pure rubbish.
Member Since: April 1, 2010 Posts: 9 Comments: 2699
Very cool stuff coming from he new SDO as of this afternoon. They now have recent imagery (today) on their You-tube channel also :)

http://www.youtube.com//SDOmission2009

http://sdo.gsfc.nasa.gov/
Member Since: Posts: Comments:
Quoting StSimonsIslandGAGuy:
Also an earthquake in the Florida panhandle Link

The description seems odd and the event is questionable as it happened at night "during a violent storm"


The storm is described as "Possibly a hurricane" That seems a tad unlikely on February 6th in the Florida panhandle too.


There is a first person account of the 1979 one in Camping and Cruising by Dr. James Henshell, who was on a camping trip in Florida when we experienced it. The Cape Canaveral Lighthouse shook bad enough for the oil to be shaken out of it's reservoir for the wick. At Jupiter Light, the Keeper who was in the tower came down in "record" time.


My source for the 1780 one is from an article in Pensacola History Illustrated by Thomas Muir Jr. found in Jay Barnes Florida's Hurricane History book. He says the earthquake was Feb 6 1780 and that there was a "tidal wave" the source is a diary from a Spanish Priest and I have been trying to acquire it for years.

A tsunami from this event would indicate a Gulf Of Mexico origin...
Member Since: Posts: Comments:
Quoting belizeit:
Link You should check out or temps for Friday and be thankful your not here


At least the humidity will be low. Until Sunday/Monday. Thursday through Saturday I feel dewpoints will crash(to the 40's) each afternoon as dry air mixes to the surface(due to high pressure overhead). Choking out any chance of duirmal activity until at least Sunday.

Sunday and Monday will be a different story altogether. A combination of a strong front with daytime heat, rising humidity, and seabreeze circulations will easily destabilize the atmosphere-Producing popcorn thunderstorms especially Monday(as the front get ever closer).

Also it appears a brief cool down(70's) will commence behind that cold front for next week.
Member Since: Posts: Comments:
6.2-Magnitude Earthquake Strikes Samoa

Slow news day...

Police in the Samoan capital, Apia, say they have no reports on the temblor. "We didn't feel any earthquake," an officer, who declined to be named, said.
Member Since: Posts: Comments:
Quoting StormChaser81:


Ya 965 degrees for Friday Inland is nothing to mess around with. You will have problems keeping the metal objects and glass from melting.

Over 600 degrees and I really start to feel like im burning alive.

LMAO
Member Since: September 2, 2009 Posts: 130 Comments: 21129
Quoting StSimonsIslandGAGuy:
Also an earthquake in the Florida panhandle Link

The description seems odd and the event is questionable as it happened at night "during a violent storm"


The storm is described as "Possibly a hurricane" That seems a tad unlikely on February 6th in the Florida panhandle too.


Consider it was 1780, I'll give them a pass on calling it a hurricane.

In addition, the description states violent thunder and lightning. That also is not typical of hurricanes. This storm may have more closely resembled the 1993 Storm of the Century.
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Quoting StormW:


LMAO Oz!

The TUTT.


Well, not to be picky or anything lol, but the TUTT is primarily a summer-time feature and does not yet climatologically exist in April. Hence, I'm not sure why you say it's "missing" lol.



You can see it quite well in August:

Member Since: November 24, 2005 Posts: 635 Comments: 26607
Quoting CycloneOz:


When I say "easterlies," what I'm alluding to are winds moving towards the east.

I'm guessing I'm wrong...and those winds moving towards the east are westerlies, huh? :P


Well, think of the "mid-latitude westerlies" when we are talking about the jetstream. I get it wrong a lot too lol...."easterly" means winds coming from the east. "EastWARD" means winds moving towards the east.

So what you are talking about in the eastern Pacific are anomalous surface westerlies, associated with the Kelvin Wave.

Member Since: November 24, 2005 Posts: 635 Comments: 26607
135. HadesGodWyvern (Mod)
Tonga had a 6.0 earthquake about a few hours ago.
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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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