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Archive for November 9th, 2009

The Atbarah and Tekezé Rivers in Sudan

14.9N 35.9E

November 9th, 2009 Category: Rivers

Sudan - October 7th, 2009

Sudan - October 7th, 2009

Green fields can be seen near the banks of the Atbarah River in Sudan. This northeast Africa river rises in northwest Ethiopia, approximately 50 km north of Lake Tana and 30 km west of Gondar. It flows about 805 km (500 mi) to the Nile in north-central Sudan, joining it at the city of Atbarah. The Atbarah is the last tributary of the Nile before it reaches the Mediterranean.

Its tributary, the Tekezé River, can be seen flowing up from the bottom of the image and joining with the Atbarah near the start of the agricultural area and the town of Khashm el Girba. The Tekezé is perhaps the true upper course of the Atbarah, as the Tekezé follows the longer course prior to the confluence of the two rivers.

For much of the year, it is little more than a stream. However during the rainy season (generally June to October), the Atbarah rises some 18 ft (5 m) above its normal level. This image was taken in early October, when the river’s levels are at their highest.

The Ottawa River Flowing Towards the Cities of Ottawa and Gatineau, Canada

45.4N 75.6W

November 9th, 2009 Category: Rivers

Canada - October 25th, 2009

Canada - October 25th, 2009

The Ottawa River runs through the Canadian provinces of Ontario and Quebec, defining the border between these two provinces for most of its length. The total length of the river is 1,271 kilometers (790 mi). It drains an area of 146,300 km2, 65% in Quebec and the rest in Ontario, with a mean discharge of 1,950 m3/s.

The river rises from its source in Lake Capimitchigama in the Laurentian Mountains of central Quebec, flows west to Lake Timiskaming, where it begins defining the interprovincial border with Ontario.

From Lake Timiskaming the river flows southeast to Ottawa and Gatineau where it tumbles over the Chaudière Falls. On the right side of this orthorectified image, the two cities can be seen near its shores. Ottawa, the capital of Canada, lies along the southern banks, with Gatineau parallel to it along the northern banks.

Ida Upgraded to Category 2 Hurricane, Moving Into Southern Gulf of Mexico – November 9th, 2009

21.7N 87.1W

November 9th, 2009 Category: Image of the day, Tropical Storms

Hurricane Ida - November 8th, 2009

Hurricane Ida - November 8th, 2009

Track of Ida - November 8th, 2009 © Univ. of Wisconsin

Track of Ida

Enhanced image

Enhanced image

As of 3:00 PM CST (2100 UTC), the center of Hurricane Ida was located near latitude 22.2 north, longitude 86.3 west, or about 95 miles (155 km) west-northwest of the western tip of Cuba and about 510 miles (815 km) south-southeast of the mouth of the Mississippi River.

Ida is a category two hurricane on the Saffir-Simpson scale, although the system is forecast to gradually weaken on Monday. Here, the hurricane is visible near the coast of the Yucatan Peninsula, with part of the shoreline of Florida visible to the north.

Ida is moving toward the north-northwest near 10 mph (17 km/hr). A gradual turn toward the north and an increase in forward speed are expected during the next 24 to 36 hours. On the forecast track, Ida is expected to cross the Gulf of Mexico Sunday evening and Monday and be near the northern Gulf coast on Tuesday.

Maximum sustained winds are near 100 mph (160 km/hr) with higher gusts. Hurricane force winds extend outward up to 35 miles (55 km) from the center, and tropical storm force winds extend outward up to 140 miles (220 km). The minimum central pressure is 976 mb (28.82 inches).

Ida is expected to produce total rain accumulations of 3 to 5 inches over portions of the Yucatan Peninsula and western Cuba, with possible isolated maximum amounts of 10 inches. Rains will be increasing well in advance of Ida across the central and eastern Gulf coast, but will become steadier and heavier by Monday into Tuesday. Total storm accumulations of 3 to 5 inches with isolated maximum storm totals of 8 inches will be possible through Tuesday from the central and eastern Gulf coast northward into the eastern portions of the Tennessee Valley and the southern Appalachians.

A storm surge could raise water levels by as much as 3 to 4 feet above ground level along the coast of the Yucatan Peninsula. Near the coast, the surge will be accompanied by large and destructive waves.

A hurricane watch remains in effect for the northern Gulf coast from Grand Isle, Louisiana to Mexico Beach, Florida, and the Yucatan Peninsula of Mexico from Tulum to Playa del Carmen. This watch does not include the city of New Orleans. A hurricane watch means that hurricane conditions are possible within the watch area, generally within 36 hours.

A hurricane warning remains in effect for the Yucatan Peninsula of Mexico from Playa del Carmen to Cabo Catoche, meaning that hurricane conditions are expected somewhere within the warning area within 24 hours. Preparations to protect life and property should be rushed to completion in the warning area.

A tropical storm warning remains in effect for the Yucatan Peninsula Punta Allen northward to Playa del Carmen and from Cabo Catoche westward to San Felipe, as well as for the Cuban province of Pinar del Rio. A tropical storm warning means that tropical storm conditions are expected within the warning area within 24 hours. Finally, a tropical storm watch remains in effect for the Isle of Youth.

Tropical Storm 25W Tracking Northeastward

24.5N 158.9E

November 9th, 2009 Category: Tropical Storms

Tropical Storm 25W - November 6th, 2009

Tropical Storm 25W - November 6th, 2009

Track of TS 25W - November 7th, 2009 © Univ. of Wisconsin

Track of TS 25W

Enhanced image

Enhanced image

Tropical Storm 25W is now located near 22.2N 159.5E, or approximately 435 nautical miles west-northwest of Wake Island. The system has tracked northeastward at 13 knots over the past six hours. Maximum significant wave height is 13 feet.

Maximum sustained winds are at 45 knots, with higher gusts of up to 55 knots. The radius of 34 knot winds extending outward from the eye of the storm is 30 nautical miles in the southwest and northwest quadrants, 35 nautical miles in the southeast quadrant, and 40 nautical miles in the northeast quadrant.