EWR Blog

Volcano KATLA (Iceland) ready to blow?

Skip — Sun, 04 Dec 2011 14:58:16 +0000

Rumours are flying right now that volcano Katla in Iceland may be ready to blow. Increased seismic activity has observers on high alert to the possibility of a large eruption. Katla is a very large volcano that has erupted before.

Icelandic Met Office, Icelandic Institute of Earth Sciences

More than 500 tremors have been recorded in the last month. Sky News reports:
“A huge Icelandic volcano long overdue an eruption is showing signs of activity – threatening disruption to air traffic, experts have said.
There have been more than 500 tremors at Katla in the south of the country in just the last month. An increase in activity at the site since July has also been causing volcanologists concern, when increasing temperatures and seismic activity caused a flood, washing away a road bridge.

The last major eruption at the volcano was in 1918, and caused such a large glacier meltdown that icebergs were swept by the resulting floods into the ocean.

Significant activity at Katla – which has a huge 6.2 mile (10km) crater – usually occurs every 40 to 80 years. It is feared when it does eventually erupt, it could be the most powerful activity the country has seen in almost a century. Catastrophic flooding could result as the frozen surface of the volcano melts, sending vast amounts of water into the Atlantic Ocean.

Volcano expert Andy Hooper, from Delft University, said although there had been increased activity at the site, it was difficult to predict if and when Katla would erupt. However, he told Sky News Online that the implications for Iceland if an eruption did occur would be “major”. “Because of the glacier on top, massive amounts of ice would melt, washing away the roads. “There could also be a big ash fallout on people living in the area and that will affect the farms. “There could be big implications for people there.

“In terms of the rest of the world, it really depends on the weather at the time of the eruption. “If Katla erupts, it will erupt higher (than recent volcanoes) and that means the ash will stay around longer – that could impact on air traffic.”

A statement on Iceland’s Met Office website warned there was no imminent threat but that “given the heightened levels of seismic activity, the situation might change abruptly”. “Monitoring teams at the Icelandic Met Office are following the ongoing activity closely, and sensor-based networks around the volcano ensure that all seismological, geodetic, and hydrological changes are detected.”

In the meantime, while you’re waiting for Katla-induced global freeze-over, and due enjoy the overwhelming majesty of the Aurora Borealis over Iceland through the lens of Stefan Forster:

Environment Canada: Special Weather Statement: Discussion, S. Ontario rainfall amounts, Tues Nov. 28, 2011

Skip — Wed, 30 Nov 2011 11:45:51 +0000

AWCN11 CWTO 300114
Updated weather summary for all of Southern Ontario and the
National Capital Region issued by Environment Canada
At 8:15 PM EST Tuesday 29 November 2011.

————————————————————-
==weather event discussion==

A moisture laden low pressure area that originated over the
southeastern states will move across Eastern Ontario into Southern
Quebec by Wednesday morning. This system brought a large and well
organized area of rain with it. Southwestern Ontario was soaked the
most with rainfall amounts as high as 81.2 mm at Windsor airport.
Freezing rain has appeared as expected over areas east of
Northern Georgian Bay into Algonquin Park.

Below are some unofficial total rain amounts as of 7.00 PM today
unless otherwise noted.

————————————————————-
Location rainfall amount (mm)

Windsor 81.2
Harrow 67.7
Sarnia 57.3
Thedford (S Grand Bend) 21.0 (as of 8 AM)
Goderich 31.1
Mount Forest 43.8
Ridgetown 72.2
New Glasgow (se Rodney) 47.0
London 58.8
Tillsonburg 25.6 (as of 8 AM)
Dorchester 24.6 (as of 8 AM)
Delhi 49.5
Waterloo intl airport 53.1
Elora 44.9
Hamilton 44.0
Hamilton botanical gardens 42.3
Grimsby mountain 46.1
Beamsville 35.4 (as of 6 PM)
Port Weller 28.4
Welland 22.4
Toronto Pearson 45.6
Buttonville airport 41.4
Toronto Island 44.9
Toronto city 42.5
Toronto East York 39.4 (as of 6 PM)
Oshawa 39.8
Cobourg 27.7
Peterborough 43.6
Trenton 28.7
Collingwood 38.3
Orillia 39.8 (as of 5 PM)
Barrie 38.1
Muskoka 32.9
Beatrice 24.2
Parry Sound 20.8 (possible freezing rain)
Algonquin Park 34.6 (freezing rain since 5 PM)
Bancroft 39.6
Petawawa 23.0
Pembroke 29.3
Ottawa airport 21.2
Ottawa city 19.9

This weather summary contains preliminary information
And may not constitute an official or final report.

END/OSPC

Big Blue Marble from the ISS

Skip — Sat, 19 Nov 2011 15:11:54 +0000

Time-lapse video from the International Space Station as it circles the globe. Note especially the auroras and the lightning in the thunderstorms. Just for fun, see if you can pick up where its overflying as it moves around its orbits.

Earth | Time Lapse View from Space, Fly Over | NASA, ISS from Michael König on Vimeo.

NWS station KBUF is down again.

Skip — Wed, 19 Oct 2011 20:45:40 +0000

KBUF is down again for a day at least, apparently. This station is developing a fairly poor reliability record….

NOUS61 KBUF 191727
FTMBUF
Message Date: Oct 19 2011 17:27:28

THE KBUF WSR-88D IS DOWN. ELECTRONICS TECHNICIANS HAVE INVESTIGATED THE PROBLEM AND PARTS ARE ON ORDER FOR THE TRANSMITTER. THE ESTIMATED RETURN TO SERVICE TIME IS LATE THURSDAY AFTERNOON. SURROUNDING RADARS INCLUDE KCLE…KPIT…KCCX…KBGM…KTYX.

A spectacular cyclonic radar display.

Skip — Mon, 26 Sep 2011 22:09:39 +0000

It not very often that the weather radar displays show so neatly the action of a low pressure system, a cyclone, rotating over North America. The lower atmosphere is a constant swirl of high and lows as they move around the hemisphere under a huge array of influences. The basic counterclockwise rotation of a low pressure system in the northern hemisphere is a result of the rotation of the earth and the drag of the atmosphere. This display of a such a well defined cell occurs in the lower 50,000 feet of the atmosphere, and is artificially animated by the time-lapse traces of the NEXRAD radar pattern, compiled from a host of NWS radar sites. You can clearly see the comma shape, and if you click on the image to bring up the animation, you can see the distinct rotation [Ed. note: this system is now mostly dissipated and animations will show current patterns]

Cyclonic rotation of a low pressure system as evidenced by the NEWS NEXRAD radar network. Click on image to load the current real-time animation. Eventually the low will break down. Image courtesy Anthony Watts and www.intelliweather.com

The radar is visualizing water density consistent with rainstorms. The long comma tail is the confluence of the cold frontal air being dragged down from the north by the low, against the warm moist air being dragged up from the south. This instability is swirled into the centre of the low by its rotation, forming rain bands, as the low pressure cell itself slowly moves eastward.

The same system as seen as a visible cloud satellite view.

The same low pressure system seen a visible cloud cover. Clcick on image to animate. Image coutesy Anthony Watts and www.intelliweather.com

Southern Ontario will take a swipe and a miss, mostly, from Hurricane Irene.

Skip — Sat, 27 Aug 2011 11:12:32 +0000

[Updated 10:00 AM EDT 2011-08-28] Southern Ontario will awake to the outer cloud bands of Irene Sunday morning, and may see rain bands out of the northeast by Sunday evening. The GH-GTA will see only cloud and perhaps the odd light shower, due to the presence of a large dome of high pressure developing over northwestern Ontario. Southwestern Ontario is only expected to receive increased cloudiness. Since Irene’s expected track remains able to feed on Atlantic moisture, periods of moderate rain with gusty winds remain possible in the eastern corner of the province.

Ephemerata Weather Radar will be set up to monitor the approaching rain bands as they move toward southern Ontario.

Now downgraded to a tropical storm, the eye of Hurricane Irene moved inland yesterday. Impact with land and the cooler extra-tropical waters has reduced Irene’s intensity to tropical storm status, but Irene remains a very large and locally dangerous storm. Model track guidance remains mostly consistent with the path following up the US seaboard, across New England and over the Eastern Townships and New Brunswick. Irene will continue to be capable of large amounts of rain and strong winds throughout its journey as a tropical storm.

Go to our Atlantic and Pacific Hurricane page for more information and links to official monitoring sites.

Hurricane Irene 2011-08-28: 07:35 AM EDT: Official track in white. Purple -GFDL model. Blue-HWRF model. Green-GFS model. Red-TVCN model. Numbers in dots are estimated category strength. Storm image is GOES visible view wih NWS NEXRAD radar overlaid. Click on image to enlarge to full size.

Environment Canada: Weather summary for Sunday Aug 21, 2011 – Goderich, GTA and eastern Ontario.

Skip — Mon, 22 Aug 2011 21:35:57 +0000

AWCN11 CWTO 222108
Weather summary for all of Southern Ontario and the
National Capital Region issued by Environment Canada
At 2:15 PM EDT Monday 22 August 2011.

————————————————————-
==weather event discussion==

A series of severe thunderstorms affected Southern Ontario on Sunday
afternoon, associated with a sharp cold front.

Environment Canada has confirmed that, at approximately 4:00 PM
Sunday, a tornado tracked from the Lake Huron shoreline through
Goderich and southeastward to just east of summerhill. A survey team
has done an assessment of the damage and has rated the tornado as
Fujita scale three, with peak wind speeds estimated at 280 km/h. The
length of the tornado track was approximately 20 km, with a width
that varied from as wide as 500 m in Goderich to less than 200 m
further to the southeast. The survey team has reported that the most
extensive damage was in downtown Goderich, including structural
damage to buildings, roofs removed, numerous vehicles overturned and
trees down. There is one reported fatality, and a number of people
with unknown injuries. The last confirmed Fujita scale three tornado
to occur in Ontario was on April 20th, 1996 when two Fujita scale
three tornadoes occured (one from williamsford to blantyre, the
Other from Arthur to violet hill).

Elsewhere over Southern Ontario on Sunday, there were also reports
Of torrential downpours, large hail and damaging winds over several
areas extending from Goderich through the greater Toronto area and
east towards the St Lawrence river. Reports of damage in Gananoque
At around 12:45 PM, along with associated eye witness reports of
funnel clouds, suggest a brief tornado may have occured there as
well, although this has yet to be confirmed by Environment Canada
And continues to be investigated.

Following are some of the reports of weather and damage received by
Environment Canada as of 5:00 PM Monday.

————————————————————-
Location time weather/damage report

Gananoque 12:45 PM several trees down damage to above
Ground pool and roof few power lines
Down

Brampton 2:30 PM heavy rain and intense small hail
3:00 PM 19 mm rain in 10 minutes

Toronto 2:40 PM EST. Gust 80 to 100 km/h
Flooding over Hwy 401 near yorkdale
Flooding on donway west

Toronto East York 2:55 PM wind gust 72.4 km/h,
43.6 mm in 10 min

Goderich airport 4:00 PM gust to 87 km/h

Goderich 4:00 PM several roofs removed from buildings
And walls crumbled. Structural
Damage to arena, factories and
Houses. Report of 1 fatality, number
Of people injured. Grain elevator
Damaged several trees down
Numerous cars damaged.

Stratford 4:45 PM very large hail reported

This weather summary contains preliminary information
And may not constitute an official or final report.

END/OSPC

Hurricane Irene may become season’s first significant hurricane.

Skip — Sun, 21 Aug 2011 11:50:42 +0000

Update 2011-08-27: The eye of Hurricane Irene is expected to move inland later today. Impact with land and the cooler extra-tropical waters has reduced Irene’s intensity to category 1, but Irene remains a very large and locally dangerous storm. Model track guidance remains mostly consistent with the path following up the US seaboard, across New England and over the Eastern Townships and New Brunswick. By this point, Irene is expected to be a weak category 1 or tropical storm. In either case, Irene will be capable of large amounts of rain and strong winds.

Update 2011-08-26: Preliminary over-flight observations this morning indicate Irene has dropped just below category 3 status. Further analysis suggests that intensification is not likely, but will still make landfall at the Outer Banks at or near category 3 strength in 36 hours. Current tracking places it into New England in 60 hours.

Update 2011-08-25: Hurricane Irene is now a category 3 storm on the Saffir-Simpson scale. Further strengthening is expected. Irene is considered a large tropical cyclone, with hurricane winds out to 80 miles and tropical storm force winds out to 290 miles.

Update 2011-08-24: Hurricane Irene is expected to reach category 3 later today.

Update 2011-08-23: Hurricane Irene is now category 2. Upper level shear is holding back development some, but it is expected to intensify to category 3 (major hurricane) over the next 36 hours. All models are coming into track agreement (see image below).

Update 2011-08-22: TS Irene has now attained hurricane status. Expectations are that Irene could become a major hurricane (Category 3 or greater).

Tropical Storm Irene continues to develop and represents the first major storm of the season with true hurricane potential. Irene is the 9th named storm so far. Current model track estimates suggest hurricane strength along much of the Leewards and warnings have been raised. The NHC offical track still puts it at a tropical storm reaching Category 1 by the time it gets to Florida.

Hurricane Irene 2011-08-27. Official track in white. Purple -GFDL model. Blue-HWRF model. Green-GFS model. Red-TVCN model. Numbers in dots are estimated category strength. Radii about centre are the hurricane and tropical storm wind radii. Light blue traces over the storm are air recon flights (when idicated). Storm image is GOES infared view.

Go to our Atlantic and Pacific Hurricane page for more information and links to official monitoring sites.

The Ottawa Bluesfest Stage Collapse Storm Line

Skip — Mon, 25 Jul 2011 01:14:51 +0000

The dramatic stage collapse that occurred at the Ottawa Bluesfest July 17, 2011 was the result of a well defined squall line that moved through the area. Forming a storm line classically described as a “bow echo” on radar displays, and known meteorologically as a “mesoscale convective system (MCS)”, the squall line is a tight line of convective thunderstorm cells that push out in a bow shape due to the strong outflowing winds that develop, particularly in the center of the line.

The storm line characteristically has a strong elevated rear inflow jet along its rear that create a low pressure differential which further enhances the jet flow. Once this flow gets to the leading edge of the convective updraft, it descends and flows outward from the squall in strong straight line winds. Bow echos are not rare – they are a very common product of summer heating across the north American continent, and can produce some very dramatic dark and fearsome skies. While tornadic activity can develop between the cells, its not a common feature on these storm lines. When the storm lines become large, long and very powerful (winds greater than 58 mph) they are referred to as Derechos.

EWR logged most of the composite reflectivity scan of the bow echo/squall line that passed over Ottawa and cause the stage collapse at the festival. The following radar reflectivity animation shows its dramatic passage across Ottawa. A few frames are missing in the animation; we were monitoring other areas when we noticed the bow echo and had to retrace for scans.

Bow Echo of the July 18, 2011 "Bluesfest Storm"

(Click on the image if it doesn’t self-animate)

F0-F1 Tornado for Lambton County July 23, 2011?

Skip — Sun, 24 Jul 2011 23:32:46 +0000

Probably. Environment Canada will make the official determination, but the radar evidence from last night suggests a small strong F0 and perhaps a weak F1 one was quite likely. A compact but intense cell crossed into Southwestern Ontario east of Sarnia about 7PM in the evening July 23, 2011.

We watched the cell develop strong verticality over the next couple of hours with high hail densities evident high in the updraft. We noted an MDA event (“mesocyclone detection algorithm” – an automated detection of updraft rotation in a thunderstorm, converting it from an ordinary thunderstorm to a supercell) over this cell about an hour after it crossed the lake shore. The reflectivity radar trace indicated a large upper hail core.

The overall presentation of the cell didn’t suggest a classic tornadic mesocyclonic cell. However, when we looked at the storm relative velocity profile on the lowest tilt we found the couplet (yellow arrow) shown in fig. 1. The couplet didn’t show on further upward tilts, indicating some degree of rotation was occurring near or at the base of the cell. Since the distance between KDTX and the location of the couplet is about 80 miles, the SRV couplet indicated a velocity disturbance around 5000 feet. Since the beam is narrow, and above the ground, it cannot determine how low the disturbance went.

Figure 1. Storm Relative Velocity couplet, July 23, 2011, Lambton Co.

A velocity couplet in a storm relative velocity profile indicates a rapid change in the direction component of the velocity vector (velocity, by definition, is the combination of speed and its direction context). Storm relative velocity profiles measure changes within a wind profile, and therefore will show when there is a significant change in direction of wind, like occurs in a tight rotating air column).

Though the scale is not shown in fig. 1, the wind shift in the couplet can be measured. The light green portion of the couplet measures to -44 knots, to +15 knots for the immediately adjacent red bin. This translates to a wind shift (rotation) occuring at approximately 120 km/h. This measured amount puts the event at the high end of the F0 scale (64-116 km/h and the low end of the F1(117-180 km/h) range. The couplet doesn’t indicate whether or not any rotation actually reached the ground. Damage evaluation will confirm further if the duration was enough to consider a full fledged low power tornado. The SRV couplet survived on the radar scan for more than one cycle, indicating the event would possibly have been in play for several minutes.