By Alex Sosnowski, Expert Senior Meteorologist
STATE COLLEGE – AccuWeather.com reports that while from a core meteorological standpoint Isaac will not be another Katrina in terms of intensity, it’s still categorized as a dangerous storm.
Isaac is forecast by AccuWeather.com to make landfall as a hurricane in Louisiana and will bring the risk of storm surge flooding, inland flooding, damaging wind, tornadoes and beach erosion to part of the central Gulf Coast area.
“The angle at which Isaac could come ashore could still drive a substantial amount of water inland quickly over southeastern Louisiana and southern Mississippi,” said AccuWeather.com Hurricane Expert Dan Kottlowski.
As a result a relatively weaker storm, a Category 1 or 2, when compared to Katrina, a Category 3 at landfall in Louisiana and Mississippi, could still pack a considerable punch.
Isaac will test the New Orleans levees.
Katrina moved up from the south over the Mississippi Delta on a curved path. Isaac is likely to be rolling in straight from the southeast, so the counterclockwise flow around the storm could drive a significant surge toward Chanderleur Sound, Lake Borgne and Lake Pontchartrain early on.
Isaac is a large storm in terms of surface area with its circulation extending out hundreds of miles from the center, especially on its eastern and northern side.
Isaac is a fast-moving storm at present. Nasty conditions and water rises are likely to occur quickly, as the center approaches the coast Tuesday afternoon and moves inland Tuesday evening.
People are urged to speed necessary preventative measures on their property and evacuate if told to do so by officials. Some low-lying roads and communities soon could be cut off by rising surf and storm surge.
Isaac will bring flooding, downed trees and power outages at the very least in portions of Louisiana, Mississippi and Alabama. Outer bands from the storm, essentially severe thunderstorms can still cause damage and disruptions over portions of Florida.
“There is always a potential for a swarm of tornadoes being spawned by a hurricane making landfall,” said Severe Weather Expert Henry Margusity.
With a storm moving in from this direction, winds in the wake of the storm over the Lake Pontchartrain area would be from the west, southwest and south, tending to pushing water away from the shores of New Orleans.
Recall that during Katrina, southeast winds drove water into Lake Pontchartrain initially. And, that is likely to happen again with Isaac to some extent. However, due to the south to north path of the Katrina, north to northwest winds drove the elevated lake water toward the city, contributing to levee failure.
“Isaac is large, but not an exceptionally healthy tropical storm,” said Kottlowski. “Isaac continued to struggle with dry air entrainment and wind shear Monday midday.”
Despite Isaac’s current struggles, the combination of warm Gulf waters and lowering wind shear into Tuesday could lead to strengthening prior to landfall.
“People along the Louisiana, Mississippi and Alabama coasts need to take the threat from Isaac seriously,” Kottlowski said. “It is better to be safe than sorry.”
As a precaution petroleum rigs in the central and northeastern Gulf of Mexico were being shut down and evacuated.