The SI Weather
29Aug/14Fri

2:45 PM | The Iceland volcano erupts, but a far bigger explosion occurs on the other side of the world

NG_volcano
[Ash plume from Rabaul volcano in Papua New Guinea]

Discussion

Summary
The Bardarbunga volcano in Iceland that we have been tracking in recent days has finally erupted, but it was not a big explosive event. Meanwhile, there has actually been a far bigger eruption in Papua New Guinea at the Rabaul volcano on Mount Tavurvur and this has the potential to do more damage to nearby population centers. In addition to the direct threat to people in nearby locations, volcano eruptions can produce ash that is extremely hazardous to jet aircraft that inadvertantly fly through it. The ash is composed primarily of silicate particles that melt when ingested into the combustion chamber of a jet engine, causing severe loss of engine performance and perhaps, a complete shutdown of the engine.

Iceland
The Iceland volcano which sits beneath a glacier has been receiving most of the attention lately and last night it finally started erupting as lava emerged from a fissure. A fissure eruption is one in which lava essentially flows up through vents in the ground spread out over a larger area. The eruption lasted about four hours and came after weeks of earthquakes in the region. The eruption did not spew ash into the atmosphere and has had minimal effects on flights and it is in a relatively remote area of Iceland. Even though the eruption has stopped for the time being, earthquakes continue to rumble indicating magma is still on the move, and this volcano will continue to be closely monitored. By the way, in an odd twist of fate by Mother Nature, the remains of Hurricane Cristobal raced from off the US east coast into the North Atlantic during the past couple of days and actually dumped some serious snow on Iceland as well as on eastern sections of Greenland.

Papua New Guinea
Meanwhile, on the other side of the world, the large Rabaul volcano began erupting earlier today and it has spewed out plenty of ash into the atmosphere. The ash plume has apparently reached about 11 miles into the air and has indeed disrupted air travel in that part of the world. This was the first major eruption of this volcano – one of the most active in Papua New Guinea - in about twenty years. In 1994, an eruption there nearly destroyed Rabaul altogether, forcing residents to flee.

Impact
Volcanic eruptions along with oceanic and solar cycles play crucial roles in our global climate. The most substantive climatic effect from volcanoes results from the production of atmospheric haze. Large eruption columns inject ash particles and sulfur-rich gases into the troposphere and stratosphere and these clouds can circle the globe within weeks of the volcanic activity. The small ash particles decrease the amount of sunlight reaching the surface of the earth and lower average global temperatures. The sulfurous gases combine with water in the atmosphere to form acidic aerosols that also absorb incoming solar radiation and scatter it back out into space. In fact, the formation of atmospheric sulfur aerosols has a more substantial effect on global temperatures than simply the volume of ash produced during an eruption.

Not only does the type and amount of ash from volcanic eruptions play a critical role in its potential effect on global temperatures, but the location of the eruption is also very important. Volcanic eruptions in the tropics, for example, can be much more important than those in the mid-latitudes for a couple of reasons. First, the sun heats equatorial regions more than in mid-latitude or polar regions; therefore, any disruption to solar radiation in the tropics can have more serious effects on global temperatures. Second, upper level winds - which act to spread and disperse ash plumes – are typically weak over tropical regions as compared with the mid-latitudes, for example, and this could impact the longevity of any ash cloud in a particular region.

The atmospheric effects of volcanic eruptions were confirmed by the 1991 eruption of Mount Pinatubo, in the Philippines. Pinatubo’s eruption cloud reached over 40 kilometers into the atmosphere and ejected about 17 million tons of SO2, just over two times that of the El Chichon, Mexico volcano in 1982. The sulfur-rich aerosols circled the globe within three weeks and produced a global cooling effect approximately twice that of El Chichon. The Northern Hemisphere cooled by up to 0.6 degrees C during 1992 and 1993.

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29Aug/14Fri

7:00 AM | Increasing warmth and humidity this weekend leads to a greater risk for showers and thunderstorms

6-Day Forecast

Today

Mostly sunny skies, still pleasant, light winds, near 80

Tonight

Partly cloudy and cool, lows by morning not far from 60 degrees

Saturday

Partly sunny skies, a bit warmer and more humid, low 80’s

Saturday Night

Partly cloudy, mild, mid-to-upper 60’s

Sunday

More clouds than sun, quite warm and humid, chance for showers and thunderstorms, mid-to-upper 80’s

Monday

More clouds than sun, quite warm and humid, chance for showers and thunderstorms, mid-to-upper 80’s

Tuesday

More clouds than sun, quite warm and humid, chance for showers and thunderstorms, mid-to-upper 80’s

Wednesday

Mostly sunny, warm, mid-to-upper 80’s

Discussion

Very nice weather conditions will continue in the region for another day as we close out the work week, but then as high pressure pushes off the east coast this weekend, changes will come to our air mass with increasing heat and humidity. By Sunday afternoon, high temperatures around here should reach the mid-to-upper 80's and could even flirt with the 90 degree mark in spots. There will also be an increased shot at showers and thunderstorms by Sunday afternoon although most of the day will be rain-free. The shower and thunderstorm threat will continue on Monday and Tuesday in the Mid-Atlantic region, but most of those days should be rain-free as well.

At the Jersey Shore, the high waves and rip currents of recent days should subside this weekend as the remains of Hurricane Cristobal continue to race away into the North Atlantic. In fact, it may one of those rare occasions in which there are no tropical storms to talk about in the Atlantic Basin during the normally active period around Labor Day - and perhaps no tropical cyclones anywhere across the globe.

Video

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29Aug/14Fri

7:00 AM | Increasing warmth and humidity this weekend will lead to a greater risk of showers and thunderstorms

6-Day Forecast

Today

Mostly sunny skies, still pleasant, light winds, near 80

Tonight

Partly cloudy and cool, lows by morning in the low-to-mid 60’s

Saturday

Partly-to-mostly sunny skies, perhaps a bit more humid, but still comfortable temperatures, low 80’s

Saturday Night

Partly cloudy, mild, near 70

Sunday

More clouds than sun, quite warm and humid, chance for showers and thunderstorms, mid-to-upper 80’s

Monday

More clouds than sun, quite warm and humid, chance for showers and thunderstorms, mid-to-upper 80’s

Tuesday

More clouds than sun, quite warm and humid, chance for showers and thunderstorms, mid-to-upper 80’s

Wednesday

Mostly sunny, warm, mid 80’s

Discussion

Very nice weather conditions will continue in the region for another day as we close out the work week, but then as high pressure pushes off the east coast this weekend, changes will come to our air mass with increasing heat and humidity. By Sunday afternoon, high temperatures around here should reach the mid-to-upper 80's and could even flirt with the 90 degree mark in spots. There will also be an increased shot at showers and thunderstorms by Sunday afternoon although most of the day will be rain-free. The shower and thunderstorm threat will continue on Monday and Tuesday in the Mid-Atlantic region, but most of those days should be rain-free as well.

At the nearby beaches, the high waves and rip currents of recent days should subside this weekend as the remains of Hurricane Cristobal continue to race away into the North Atlantic. In fact, it may one of those rare occasions in which there are no tropical storms to talk about in the Atlantic Basin during the normally active period around Labor Day - and perhaps no tropical cyclones anywhere across the globe.

Video

Filed under: NYC Comments Off
29Aug/14Fri

7:00 AM | Heat and humidity build up this weekend leading to an increased risk of showers and thunderstorms

6-Day Forecast

Today

Mostly sunny skies, still pleasant, light winds, low 80’s

Tonight

Partly cloudy and cool, lows by morning in the low-to-mid 60’s

Saturday

Partly sunny skies, a bit warmer and more humid, mid 80’s

Saturday Night

Partly cloudy, mild, near 70

Sunday

More clouds than sun, quite warm and humid, chance for showers and thunderstorms, near 90

Monday

More clouds than sun, quite warm and humid, chance for showers and thunderstorms, near 90

Tuesday

More clouds than sun, quite warm and humid, chance for showers and thunderstorms, near 90

Wednesday

Mostly sunny, quite warm, upper 80’s

Discussion

Very nice weather conditions will continue in the region for another day as we close out the work week, but then as high pressure pushes off the east coast this weekend, changes will come to our air mass with increasing heat and humidity. By Sunday afternoon, high temperatures around here should flirt with the 90 degree mark and there will be an increased shot at showers and thunderstorms although most of the day will be rain-free. The shower and thunderstorm threat will continue on Monday and Tuesday in the Mid-Atlantic region, but most of those days should be rain-free as well.

At the nearby Atlantic beaches, the high waves and rip currents of recent days should subside this weekend as the remains of Hurricane Cristobal continue to race away into the North Atlantic. In fact, it may one of those rare occasions in which there are no tropical storms to talk about in the Atlantic Basin during the normally active period around Labor Day - and perhaps no tropical cyclones anywhere across the globe.

Video

Filed under: WMA Comments Off