Phacops Rana
Thursday, July 28, 2011
Tropical Storm Don in the Gulf
The tropical depression in the Gulf of Mexico has grown, as expected into the fourth tropical storm of the Atlantic season: Don. At 2 p.m. Thursday, Don was in the central Gulf of Mexico on a northwesterly track at 14 miles per hour. Sustained winds were at 45 miles per hour with central pressure at 1005 milibars. The track the storm is following will likely take it to landfall along the central Texas coast. Further strengthening is likely over the warm Gulf waters.
Wednesday, July 27, 2011
Storm in the Gulf
A new storm formed south of Cuba early Tuesday and is moving into the Gulf of Mexico. Still a tropical depression, the storm was located between the western tip of Cuba and the Yucatan Peninsula at mid-day Wednesday moving west-northwest. Winds were 30 miles per hour with central pressure at 1008 milibars. The storm is expected to impact the coast of Texas by the weekend. Sea surface temperatures in the Gulf of Mexico are favorable for storm development.
The high point
Adventures on Earth for the July 27, 2011, edition of The Review
The Allegheny Plateau rises above the Ridge and Valley geological province to its east and south. It is the land that was only gently folded during the collision of what is now North America with Gondwanaland (Africa and South America) during the Allegheny Orogeny approximately 300 million years ago.
In the Ridge and Valley province, rock layers were sharply folded and stacked one against another.
This zone of compression ended at the Allegheny Front, which forms the eastern and southern boundary of the plateau.
Behind the front, in the gently sloping terrain, ridges of resistant rock rise above the floor of the plateau. Here and there, knobs rise above the ridgeline.
One such knob is the highest point in Pennsylvania. Mount Davis rises to 3,213 feet above sea level. It is on the ridge of Negro Mountain, which rises in Maryland and runs well into Pennsylvania.
Negro Mountain was named for a legendary African American who is supposed to have died valiantly fighting Native Americans when he and the party of white settlers was attacked.
Mount Davis is named for John Nelson Davis, a resident of the area, Civil War veteran, surveyor, and naturalist.
Mount Davis is not as spectacular as some high peaks in the United States. It stands not much above the ridgeline.
And the view from the observation tower, a rickety old steel fire observation tower converted to tourist use, is not spectacular.
To the east, Allegheny Mountain stands out and to the west, Laurel Mountain stands out. Between Negro Mountain and these two mountains are a few hills and a lot of the plateau.
To the south the view stretches into Maryland and West Virginia. To the north the view takes in the Allegheny Front and plateau.
Mount Davis is included in Forbes State Forest and is set aside as a nature preserve. Its high elevation means flora and some fauna would be unique to high elevation regions.
The rock that creates Negro Mountain is a hard, resistant sandstone of the Pottsville Group. The Pottsville group includes coal measures as well as layers of sandstone.
On the plateau the sandstone is found as cap rock, or the surface rock of a ridge.
Being harder and more resistant to erosion, it stands higher than the softer rock that is more easily eroded around it.
Faults, or cracks in the rock, allowed for erosion to the east and west.
You won’t find huge crowds on Mount Davis. It is not easy to reach because of the welter of roads in the area, but you can drive nearly to the top. From a parking lot, a gated road leads a short distance up toward the summit, then circles around it. The observation tower stands just off this road.
Just below the summit a display of plaques set into sandstone rocks offers a glimpse into much of the human and natural history of the area.
There is a large picnic area along the highway that crosses Negro Mountain and there are hiking trails through the area.
More information about Forbes State Forest can be found at http://www.dcnr.state.pa.us/forestry/stateforests/forbes/index.htm.
A map of hiking trails at Mount Davis can be found at http://www.dcnr.state.pa.us/ucmprd1/groups/public/documents/document/dcnr_002573.pdf
The Allegheny Plateau rises above the Ridge and Valley geological province to its east and south. It is the land that was only gently folded during the collision of what is now North America with Gondwanaland (Africa and South America) during the Allegheny Orogeny approximately 300 million years ago.
In the Ridge and Valley province, rock layers were sharply folded and stacked one against another.
This zone of compression ended at the Allegheny Front, which forms the eastern and southern boundary of the plateau.
Behind the front, in the gently sloping terrain, ridges of resistant rock rise above the floor of the plateau. Here and there, knobs rise above the ridgeline.
One such knob is the highest point in Pennsylvania. Mount Davis rises to 3,213 feet above sea level. It is on the ridge of Negro Mountain, which rises in Maryland and runs well into Pennsylvania.
Negro Mountain was named for a legendary African American who is supposed to have died valiantly fighting Native Americans when he and the party of white settlers was attacked.
Mount Davis is named for John Nelson Davis, a resident of the area, Civil War veteran, surveyor, and naturalist.
Mount Davis is not as spectacular as some high peaks in the United States. It stands not much above the ridgeline.
And the view from the observation tower, a rickety old steel fire observation tower converted to tourist use, is not spectacular.
To the east, Allegheny Mountain stands out and to the west, Laurel Mountain stands out. Between Negro Mountain and these two mountains are a few hills and a lot of the plateau.
To the south the view stretches into Maryland and West Virginia. To the north the view takes in the Allegheny Front and plateau.
Mount Davis is included in Forbes State Forest and is set aside as a nature preserve. Its high elevation means flora and some fauna would be unique to high elevation regions.
The rock that creates Negro Mountain is a hard, resistant sandstone of the Pottsville Group. The Pottsville group includes coal measures as well as layers of sandstone.
On the plateau the sandstone is found as cap rock, or the surface rock of a ridge.
Being harder and more resistant to erosion, it stands higher than the softer rock that is more easily eroded around it.
Faults, or cracks in the rock, allowed for erosion to the east and west.
You won’t find huge crowds on Mount Davis. It is not easy to reach because of the welter of roads in the area, but you can drive nearly to the top. From a parking lot, a gated road leads a short distance up toward the summit, then circles around it. The observation tower stands just off this road.
Just below the summit a display of plaques set into sandstone rocks offers a glimpse into much of the human and natural history of the area.
There is a large picnic area along the highway that crosses Negro Mountain and there are hiking trails through the area.
More information about Forbes State Forest can be found at http://www.dcnr.state.pa.us/forestry/stateforests/forbes/index.htm.
A map of hiking trails at Mount Davis can be found at http://www.dcnr.state.pa.us/ucmprd1/groups/public/documents/document/dcnr_002573.pdf
Wednesday, July 20, 2011
A convergence of conditions
Adventures on Earth for the July 20, 2011, edition of The Review\
By George E. Beetham Jr.
Tropical storm season 2011 got off to a slow start as it normally does. Bret, just the second Atlantic tropical storm of the year, was making its way across the Bahamas on Monday, heading on a track that would take it out to sea.
While Bret appeared to be no threat to the mainland, the season is proceeding apace and will pick up as we move into August.
By mid-August we will move into the heaviest part of tropical season.
Going forward, Atlantic storms will form in the Eastern Atlantic near the Cape Verde Islands off the west coast of Africa – the area known as the inter-tropical convergence zone.
As storms and disturbances move off the African coast they move out over warmer water, drawing heat and moisture from the ocean. The heat and moisture rise as convection currents, building huge clouds.
Unless something happens to disturb these storms, the convection builds into the counter-clockwise spin of tropical storms.
Pressure drops and the storm builds in wind speed as the pressure drops.
Cape Verde storms generally move westward across the Atlantic and over the Windward and Leeward Islands.
They can turn to the northwest or west into the Caribbean Ocean.
They can enter the Gulf of Mexico or spin up along the East Coast of the United States. In either case, they threaten the United States.
Not all Cape Verde storms intensify into serious hurricanes, but some do. When they do, it is wise if we monitor the progress of storms as they approach.
A storm entering the Gulf of Mexico can still turn northeastward and cross the Appalachian Mountains as a heavy rain storm, causing widespread flooding and landslides.
East Coast storms present dual threats. In addition to torrential rains, high winds, possible tornadoes, and storm surge are threats, particularly along the coast.
As tropical storms move over land they are cut off from the essentials they need: warm ocean water.
Without the warm moisture, the convection shuts down. Winds die down, but can still be a threat. At that point the main threat is heavy rains.
It is a good idea at this time of year to go to the National Oceanographic and Atmospheric Administration’s National Hurricane Center website. Bookmark the page for future reference.
There you will find tons of information about hurricanes and what you should do to prepare for them.
You can also find a list of tropical storm names through 2016, hurricane tracking charts, and more. The site includes advisories for active storms and an archive of storms that have passed.
Tropical storm activity increased in the late 1990s. Some meteorologists say the increase is a normal surge in a long lasting cycle. Others suspect global warming may be making storms more powerful.
It is a reality that surface temperatures in our oceans are rising. The increased temperatures make storm formation more likely, and as storms progress over warmer water they increase in intensity.
We are both at a high point in the natural cycle and at a point where sea surface temperatures or elevated.
It’s a convergence of conditions.
By George E. Beetham Jr.
Tropical storm season 2011 got off to a slow start as it normally does. Bret, just the second Atlantic tropical storm of the year, was making its way across the Bahamas on Monday, heading on a track that would take it out to sea.
While Bret appeared to be no threat to the mainland, the season is proceeding apace and will pick up as we move into August.
By mid-August we will move into the heaviest part of tropical season.
Going forward, Atlantic storms will form in the Eastern Atlantic near the Cape Verde Islands off the west coast of Africa – the area known as the inter-tropical convergence zone.
As storms and disturbances move off the African coast they move out over warmer water, drawing heat and moisture from the ocean. The heat and moisture rise as convection currents, building huge clouds.
Unless something happens to disturb these storms, the convection builds into the counter-clockwise spin of tropical storms.
Pressure drops and the storm builds in wind speed as the pressure drops.
Cape Verde storms generally move westward across the Atlantic and over the Windward and Leeward Islands.
They can turn to the northwest or west into the Caribbean Ocean.
They can enter the Gulf of Mexico or spin up along the East Coast of the United States. In either case, they threaten the United States.
Not all Cape Verde storms intensify into serious hurricanes, but some do. When they do, it is wise if we monitor the progress of storms as they approach.
A storm entering the Gulf of Mexico can still turn northeastward and cross the Appalachian Mountains as a heavy rain storm, causing widespread flooding and landslides.
East Coast storms present dual threats. In addition to torrential rains, high winds, possible tornadoes, and storm surge are threats, particularly along the coast.
As tropical storms move over land they are cut off from the essentials they need: warm ocean water.
Without the warm moisture, the convection shuts down. Winds die down, but can still be a threat. At that point the main threat is heavy rains.
It is a good idea at this time of year to go to the National Oceanographic and Atmospheric Administration’s National Hurricane Center website. Bookmark the page for future reference.
There you will find tons of information about hurricanes and what you should do to prepare for them.
You can also find a list of tropical storm names through 2016, hurricane tracking charts, and more. The site includes advisories for active storms and an archive of storms that have passed.
Tropical storm activity increased in the late 1990s. Some meteorologists say the increase is a normal surge in a long lasting cycle. Others suspect global warming may be making storms more powerful.
It is a reality that surface temperatures in our oceans are rising. The increased temperatures make storm formation more likely, and as storms progress over warmer water they increase in intensity.
We are both at a high point in the natural cycle and at a point where sea surface temperatures or elevated.
It’s a convergence of conditions.
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