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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Quoting Bordonaro:

Really hard to say, we have had the quietest Severe Weather Season on record so far.

The next several days, Th-Su will be very, very busy, we're looking at our first real "widespread severe weather" outbreak. Most of the Spring storms so far has been high winds/hail producers. The emphasis of this next outbreak will be leaning towards higher tornado production.

My understanding is that El Nino spring produce fewer tornadoes, La Nina spring produces more tornadoes.



Thats true for the rest of the country.

But usually the opposite for Florida, weather in Florida is in a different league then the rest of the United States. What drives the weather here is different, and much harder to forecast in most cases, then the rest of the U.S. Normally EL Nino means lots of tornados and other severe weather in the spring for Florida. But we haven't had much of either this year yet, we have had plenty of heavy downpours as far as the dry season standards go, but not severe weather that usually comes with El Nino as well.
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BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE AMARILLO TX
620 PM CDT WED APR 21 2010

THE NATIONAL WEATHER SERVICE IN AMARILLO HAS ISSUED A

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

* UNTIL 645 PM CDT

* AT 615 PM CDT...TRAINED WEATHER SPOTTERS REPORTED A FUNNEL CLOUD
NEAR ADRIAN...OR ABOUT 16 MILES NORTHWEST OF VEGA...MOVING
NORTHEAST AT 10 MPH.

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

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
Quoting Tazmanian:
and it dos not have any thing too do with the weather or mode runs has some in too do with gas

The Southern Jet will load the atmosphere with plenty of moist, warm air. The Upper Level L will add shear/dry. cool air, makings for a widespread severe weather event.
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Quoting Levi32:


That's true.
La Nina allows the Jet Stream to inject drier, colder air into the mid-upper levels, adding more shear/lift dynamics to the atmosphere.
Member Since: August 25, 2009 Posts: 20 Comments: 6785
and it dos not have any thing too do with the weather or mode runs has some in too do with gas
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by the way has any one been following whats been going on in the gulf
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Quoting StSimonsIslandGAGuy:


We've been dry here, under 10" so far this year even now. Although at the house last night we almost tripled the official rainfall total at KSSI 2 miles south---they got 0.21" and we had 0.60" Greened everything up around here, but still below normal rainfall.




Thats pretty bad... go figure that southern Georgia would be that much dryer then here... January and February were pretty normal rainfall wise, we had frequent systems due to El Nino, but too cold and dry to pick up anything really heavy. But when the warmer air and humidity arrived in March, we had an amazing 9 inches of rain for the month. April was completely dry here up until this past sunday, which we had over 4 inches of rain! Which all came in torrential rain bursts, as it often does in Florida. Now up to about 5.21 for the month since additional rain on monday and tuesday after that. April is usually the one month we count on not getting any huge rain events, but we've pulled well out of the long term drought in central Florida, so I guess even April can't be counted out for torrential downpours!
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Quoting alexhurricane1991:
Hello everyone! how are you guys doing i have some free time right now so i felt like posting again its hard to stop but its going to be a busy couple of days severe weather wise! see you guys soon!

Hello Alex, did you receive my e-mail? We're going to see "Mother Nature" put on one "heckuva" show over the next 3-4 days.
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Quoting Bordonaro:

Really hard to say, we have had the quietest Severe Weather Season on record so far.

The next several days, Th-Su will be very, very busy, we're looking at our first real "widespread severe weather" outbreak. Most of the Spring storms so far has been high winds/hail producers. The emphasis of this next outbreak will be leaning towards a higher tornado producer.

My understanding is that El Nino spring produce fewer tornadoes, La Nina spring produces more tornadoes.


That's true.
Member Since: November 24, 2005 Posts: 635 Comments: 26647
Quoting ecflawthr:
what is the forecast look like for sever weather for Florida the rest of spring

Really hard to say, we have had the quietest Severe Weather Season on record so far.

The next several days, Th-Su will be very, very busy, we're looking at our first real "widespread severe weather" outbreak. Most of the Spring storms so far has been high winds/hail producers. The emphasis of this next outbreak will be leaning towards higher tornado production.

My understanding is that El Nino spring produce fewer tornadoes, La Nina spring produces more tornadoes.
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Hello everyone! how are you guys doing i have some free time right now so i felt like posting again its hard to stop but its going to be a busy couple of days severe weather wise! see you guys soon!
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<
Member Since: July 15, 2006 Posts: 171 Comments: 53835
The ECMWF may now be seeing the potential tropical storm in the eastern Pacific as well in the long-range. It has not shown it the last several days because it only goes out to 240 hours, but the GFS is now showing development beginning around 240 hours as we get closer in time, and the Euro 12z forecast today looks to be showing a low near 100W south of Mexico around the same time at the end of the forecast run.





The last few runs of the models have been shifting the most favorable conditions for tropical development westward into the EPAC more than the SW Caribbean, but they are still expecting a significant reversal from the current troughing over the Caribbean to more of a strong equatorial ridge during the 10-15 day period. This will, at the very least, start to warm up the NW Caribbean and Gulf of Mexico SSTs painfully fast during the beginning of May, and may also set the stage for potential tropical mischief at some point during the month.
Member Since: November 24, 2005 Posts: 635 Comments: 26647
Member Since: August 25, 2009 Posts: 20 Comments: 6785
what is the forecast look like for sever weather for Florida the rest of spring
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Possible Tornado - TORNADO WARNING - Las Animas County, CO
Member Since: August 26, 2006 Posts: 10 Comments: 3684
BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE PUEBLO CO
441 PM MDT WED APR 21 2010

THE NATIONAL WEATHER SERVICE IN PUEBLO HAS ISSUED A

* TORNADO WARNING FOR...
NORTH CENTRAL LAS ANIMAS COUNTY IN SOUTHEAST COLORADO...

* UNTIL 545 PM MDT

* AT 439 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS DANGEROUS
STORM WAS LOCATED 11 MILES WEST OF TYRONE...OR 25 MILES NORTH OF
TRINIDAD...AND MOVING NORTHEAST AT 15 MPH.

* LOCATIONS IMPACTED INCLUDE...
MAINLY RURAL AREAS OF NORTHERN LAS ANIMAS COUNTY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS TORNADO WARNING REPLACES THE SEVERE THUNDERSTORM WARNING THAT
WAS IN EFFECT FOR THE SAME AREA. GO TO A BASEMENT OR SMALL INTERIOR
ROOM ON THE LOWEST FLOOR!

TAKE COVER NOW. MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
STURDY BUILDING. AVOID WINDOWS. IF IN A MOBILE HOME...A VEHICLE OR
OUTDOORS...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT
YOURSELF FROM FLYING DEBRIS.
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Quoting StSimonsIslandGAGuy:
Does that 30% line mean that each county inside it each have a 30% chance of having a severe thunderstorm? Or that each and every point inside that line have a 30% or more chance?


Its just like an NWS forecast or what we use here in the StormCenter - 30% of the forecast area or in this case the "hatched" or "drawn" area WILL see a certain weather event - in this case severe thunderstorms.
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<
Member Since: July 15, 2006 Posts: 171 Comments: 53835
<
Member Since: July 15, 2006 Posts: 171 Comments: 53835
Quoting Stormchaser2007:
Anyone see the hurricane the 12z GFS develops in the EPAC?

Yes I saw that. Levi noticed a couple of days back that that low has been alternating from the Caribbean to the EPAC. We might have something develop in the Caribbean early in May or in the EPAC. I guess we will have to wait and see.
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<
Member Since: July 15, 2006 Posts: 171 Comments: 53835
<
Member Since: July 15, 2006 Posts: 171 Comments: 53835
<
Member Since: July 15, 2006 Posts: 171 Comments: 53835
Quoting 1900hurricane:

That day 3 outlook was issued for Friday, not Saturday. That GFS forecast would coincide with the day 4 outlook, which matches much better (but still not perfectly).



Oh thanks my bad....didn't check update time.
Member Since: November 24, 2005 Posts: 635 Comments: 26647
BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE LUBBOCK TX
515 PM CDT WED APR 21 2010

THE NATIONAL WEATHER SERVICE IN LUBBOCK HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
SOUTHEASTERN HALE COUNTY IN NORTHWEST TEXAS.

* UNTIL 600 PM CDT

* AT 513 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL...AND
DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM WAS LOCATED 6 MILES
NORTHEAST OF ABERNATHY...AND MOVING NORTHEAST AT 20 MPH.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

LARGE HAIL...DAMAGING WINDS...AND VERY HEAVY RAINS ARE EXPECTED WITH
THIS STORM. TAKE COVER IN A SUBSTANTIAL SHELTER.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 1100 PM CDT WEDNESDAY EVENING
FOR THE PANHANDLE AND NORTHWEST TEXAS.
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Good work 1900..and your correct.

The Local Mets and NWS Slidell are already jabber jawing on that system.

&&


Long term...
current water vapor imagery shows the next system that will affect
the area early this weekend. This upper low is still prognosticated to dig
a little farther south down the state of California before swinging
northeast towards southern Great Lakes by the end of the weekend. A
surface low will develop near the the NE/KS/co borders and move
towards the middle miss valley. Moisture will substantially increase by
Friday with dew point/S in the upper 60s that afternoon. Model soundings
are looking slightly less conducive than previous runs. Question is
whether warm layer depicted on 18z Friday soundings will erode enough
for cape to be realized. May not be very widespread but is plausible
to think so...at least north of I-12. Looking at
instability...favorable conditions increase from east to west. With
that said...looks like northwestern half of County Warning Area will have the best shot for
severe weather.


As the boundary nears the area on Saturday...pressure falls and
cooling in the middle levels bring even more unstable environment into
play. 18-00z looks to be the best time for all modes of severe weather to
develop. Li/S around -7...cape upwards of 2000j/kg and srh/S around
400m2/s2 will be quite sufficient for supercells but would like to
see more directional shear for strong rotating storms. Although
northern half of the area will be in the best setup...dont want to
completely throw out areas south of I-10. More like just less
potential.


With European model (ecmwf) coming in closer line to GFS/S faster solution...have
decided to adjust weather grids to depict a sooner ending to precipitation.
Thinking is that the western edge of the line of storms should be
east of btr/mcb/hum before midnight Sat. Sunday should be quiet weather
wise with clearing skies and slightly above norm temperatures. Similar
setup from this week for early next week. Weak northwest flow will
transition to weak ridging before next trough moves towards the
area.


Meffer
&&

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Member Since: August 25, 2009 Posts: 20 Comments: 6785
moderate risk for thurs. and fri.
Member Since: July 15, 2006 Posts: 171 Comments: 53835
Quoting Levi32:
Man....Saturday does not look pretty near and east of the Mississippi Valley. The 18z GFS has one heck of a low-level jet coming out of the Gulf of Mexico at 72 hours.



SPC has a large slight risk area for day 3, further west than it would be if the current GFS verifies, and that will probably go up to moderate when we get closer.


That day 3 outlook was issued for Friday, not Saturday. That GFS forecast would coincide with the day 4 outlook, which matches much better (but still not perfectly).

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Quoting Levi32:
Man....Saturday does not look pretty near and east of the Mississippi Valley. The 18z GFS has one heck of a low-level jet coming out of the Gulf of Mexico at 72 hours.



SPC has a large slight risk area for day 3, further west than it would be if the current GFS verifies, and that will probably go up to moderate when we get closer.




here is latest grapic from my blog of day 2 day 3 severe prop.
Member Since: July 15, 2006 Posts: 171 Comments: 53835
Quoting Levi32:
Man....Saturday does not look pretty near and east of the Mississippi Valley. The 18z GFS has one heck of a low-level jet coming out of the Gulf of Mexico at 72 hours.



SPC has a large slight risk area for day 3, further west than it would be if the current GFS verifies, and that will probably go up to moderate when we get closer.



Yea, just looking at that. This may be the first real widespread outbreak of the year. A large portion of the deep south and southeast will be well into the warm sector of this storms and any sunshine will just help to further destabilize the atmosphere. Saturday and Sunday will be rather interesting for sure.
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201. ozprof
10:16 PM GMT on April 21, 2010
I am in Lubbock and we are under that tornado warning. Seems pretty mild outside at the moment, not much cloud. (yet!)

I think it has been caused by some of my studetns doing a rain dance....... A group of them were supposed to be doing an observing lab out at the observatory tonight!

Cheers

Ozprof
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200. Stormchaser2007
10:09 PM GMT on April 21, 2010
.
Member Since: June 9, 2007 Posts: 4 Comments: 15891
199. Levi32
10:04 PM GMT on April 21, 2010
Man....Saturday does not look pretty near and east of the Mississippi Valley. The 18z GFS has one heck of a low-level jet coming out of the Gulf of Mexico at 72 hours.



SPC has a large slight risk area for day 3, further west than it would be if the current GFS verifies, and that will probably go up to moderate when we get closer.

Member Since: November 24, 2005 Posts: 635 Comments: 26647
197. Bordonaro
10:02 PM GMT on April 21, 2010
Quoting indianrivguy:


that was the picture at the end of your link....

Yes, I posted it on the blog, then it disappeared, so I added it at a link instead.

Watching thunderstorms blossoming over the TX Panhandle and South Plains region, near Lubbock, TX.

Dew point in Lubbock is 58F, pretty high for the "High Desert" area of W TX.

Then we have the dryline near Midland-Odessa, TX, with dew points in the lower 40's.

SE and E winds on the east side of the dryline, SW winds behind the dryline, wind shear is pretty high, all the ingredients for super-cells!!

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196. Levi32
10:00 PM GMT on April 21, 2010
Quoting Tropicsweatherpr:


Thank you for explaining in detail all the proccess about the Kevin Waves and how things stand right now.


No problem :)
Member Since: November 24, 2005 Posts: 635 Comments: 26647
195. WaterWitch11
10:00 PM GMT on April 21, 2010
Santa Rosa, Santa Rosa Sonoma County Airport
Last Update on 21 Apr 13:53 PDT

Mostly Cloudy

57°F
(14°C)
Humidity: 49 %
Wind Speed: NW 12 G 24 MPH
Barometer: 29.77 in (1007.60 mb)
Dewpoint: 38°F (3°C)
Wind Chill: 54°F (12°C)
Visibility: 10.00 Miles
Member Since: August 11, 2008 Posts: 3 Comments: 1610
194. indianrivguy
9:54 PM GMT on April 21, 2010
Quoting Bordonaro:

I saw that earlier today, I thought that was cool also. The lovely low clouds are ruining our Volcano viewing this afternoon :0(..


that was the picture at the end of your link....
Member Since: September 23, 2006 Posts: 1 Comments: 2541
193. Tropicsweatherpr
9:54 PM GMT on April 21, 2010
Quoting Levi32:


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.


Thank you for explaining in detail all the proccess about the Kevin Waves and how things stand right now.
Member Since: April 29, 2009 Posts: 75 Comments: 14258
192. CycloneOz
9:54 PM GMT on April 21, 2010
Quoting Bordonaro:
Here we go again the TX Panhandle:


This is unfortunate.

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191. Bordonaro
9:51 PM GMT on April 21, 2010
Here we go again the TX Panhandle:
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190. Bordonaro
9:47 PM GMT on April 21, 2010
Quoting CycloneOz:


I'm not really feeling too bad about missing this storm. Here's why:


I can understand, no fun being stuck in the middle of nowhere, as the storm floods everything around you.
Member Since: August 25, 2009 Posts: 20 Comments: 6785
189. CycloneOz
9:47 PM GMT on April 21, 2010
Points west of Amarillo are going to get another tornado this PM...

And I am 4.5 hours away....

Too bad, so sad... :(
Member Since: August 26, 2006 Posts: 10 Comments: 3684
188. Bordonaro
9:46 PM GMT on April 21, 2010
Quoting indianrivguy:
Bord..


I saw that earlier today, I thought that was cool also. The lovely low clouds are ruining our Volcano viewing this afternoon :0(..
Member Since: August 25, 2009 Posts: 20 Comments: 6785
187. indianrivguy
9:44 PM GMT on April 21, 2010
Bord..

Member Since: September 23, 2006 Posts: 1 Comments: 2541
186. CycloneOz
9:42 PM GMT on April 21, 2010
Quoting Bordonaro:
URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 73
NORTH AND SOUTH OF A LINE FROM 75 MILES WEST NORTHWEST OF
PLAINVIEW TEXAS TO 15 MILES SOUTHEAST OF CHILDRESS TEXAS.


I mentioned Childress, TX today! :(

See Post 45...
Member Since: August 26, 2006 Posts: 10 Comments: 3684
185. CycloneOz
9:39 PM GMT on April 21, 2010
Quoting Bordonaro:

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!


I'm not really feeling too bad about missing this storm. Here's why:

Member Since: August 26, 2006 Posts: 10 Comments: 3684
184. Bordonaro
9:37 PM GMT on April 21, 2010
Thanks Levi :0), I understand.
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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