Isaac Just Below Hurricane Strength as it Continues Northwestward, Aug. 28, 2012 UPDATE 10 am CDT

Tropical Storm Isaac Surface Wind Field

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Miami, Florida—(ENEWSPF)—August 28, 2012 – UPDATE 10 am CDT (1600 UTC).  The National Hurricane Center is reporting that Tropical Storm Isaac is still just below hurricane strength as it continues northwestward.  Isaac is located 28.1 north, 88.5 west, about 80 miles (125 km) south-southeast of the mouth of the Mississippi River, about 165 miles (260 km) southeast of New Orleans, Louisiana.  Maximum sustained winds are 70 mph (110 km/h). Present movement is northwest or 310 degrees at 10 mph (17 km/h).

Changes in Watches and Warnings with this Advisory

The Hurricane Warning has been replaced with a Tropical Storm Warning from the Mississippi-Alabama border eastward to Destin, Florida.

The Tropical Storm Warning has been discontinued east of Destin.

Summary of Watches and Warnings in Effect

A Hurricane Warning is in effect for:

  • East of Morgan City, Louisiana to the Mississippi-Alabama border, including metropolitan New Orleans, Lake Pontchartrain, and Lake Maurepas.

A Hurricane Watch is in effect for:

  • Intracoastal City to Morgan City, Louisiana.

A Tropical Storm Warning is in effect for:

  • The Mississippi-Alabama border to Destin, Florida, and
  • Morgan City to Cameron, Louisiana.

A Tropical Storm Watch is in effect for:

  • East of High Island, Texas to just west of Cameron, Louisiana.

A Hurricane Warning means that hurricane conditions are expected somewhere within the warning area. Preparations to protect life and property should be rushed to completion.

A Hurricane Watch means that hurricane conditions are possible within the watch area.

A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area.

A Tropical Storm Watch means that tropical storm conditions are possible within the watch area.

For storm information specific to your area including possible inland watches and warnings, please monitor products issued by your local National Weather Service Forecast Office.

Discussion and 48-hour Outlook

At 1000 am CDT (1500 UTC), the center of Tropical Storm Isaac was located near latitude 28.1 north, longitude 88.5 west. Isaac is moving toward the northwest near 10 mph (17 km/h).  A northwestward motion at a slightly slower speed is expected over the next day or two.  On the forecast track, the center of Isaac should reach the coastline of southeastern Louisiana as early as this evening. Maximum sustained winds are near 70 mph (110 km/h) with higher gusts.  Isaac is expected to become a hurricane before making landfall, and begin to slowly weaken after that. Tropical Storm force winds extend outward up to 185 miles (295 km) from the center. The latest minimum central pressure reported by Hurricane Hunter Aircraft was 976 mb (28.82 inches).

Hazards Affecting Land

Storm Surge. The combination of a storm surge and the tide will cause normally dry areas near the coast to be flooded by rising waters. The water could reach the following depths above ground if the peak surge occurs at the time of high tide:

  • Mississippi and southeastern Louisiana…6 to 12 ft.,  
  • Alabama…4 to 8 ft.,  
  • South-central Louisiana…3 to 6 ft.,  
  • Florida Panhandle…3 to 6 ft.,  
  • Apalachee Bay…2 to 4 ft., and  
  • Remainder of Florida west coast…1 to 3 ft.

The deepest water will occur along the immediate coast in areas of onshore winds.  Surge-related flooding depends on the relative timing of the surge and the tidal cycle, and can vary greatly over short distances.  For information specific to your area, please see products issued by your local Weather Service Office.  Near the coast, the surge will be accompanied by large and dangerous waves.

Wind. Tropical Storm conditions are beginning to occur near the mouth of the Mississippi river, and will reach other portions of the coastline within the tropical storm and hurricane warning areas by late this afternoon.  Hurricane conditions are expected to reach the coast by late afternoon.

Rainfall. Isaac is expected to produce total rainfall amounts of 7 to 14 inches, with possible isolated maximum amounts of 20 inches, in southeastern Louisiana, southern Mississippi, southern Alabama, and the extreme western Florida Panhandle. These rains could result in significant lowland flooding.

Tornadoes. Tornadoes may occur along the northern gulf coast today.

Surf. Dangerous surf and rip current conditions will continue to affect the Florida coastline and portions of the northern gulf coast for the next day or so.

Source: nhc.noaa.gov