TS Issac starts its march onshore
Issac is poised right on the brink of becoming a hurricane. Surface winds have been measured only at 70 MPH but hurricane hunter aircraft have recorded windspeeds as high as 105 higher up. The central pressure from the storm has been dropping steadily since last night. All indications are that this storm should strengthen to a hurricane. Now that the storm is interacting with land, however, I am guessing that any further intensification will be minimal (and that is my uneducated guess).
Isaac makes its final approach towards Louisiana (Weather Underground - Dr. Jeff Master's Blog)
The winds and water are rising all along the coast from Louisiana to the Florida Panhandle as Tropical Storm Isaac makes its final approach. Two hurricane hunter aircraft in the storm are measuring a steadily lowering pressure and increasing winds aloft, but hurricane-force winds have not yet been observed at the surface. The 8:30 am center fix found a pressure of 976 mb, which is very low for a tropical storm. Top surface winds measured with the SFMR instrument were 70 mph, but the plane measured 102 mph at an altitude of 5,000 feet. It's more typical to see surface winds of 85 mph with a storm with these characteristics. Infrared and visible satellite loops and hurricane hunter reports from this morning have shown that Isaac has developed a 25-mile diameter eye, though the eyewall has not yet formed a full circle around the eye. Heavy thunderstorm activity is lacking on the north side, where light wind shear of 5 -10 knots is still pumping some dry air into the circulation.Rain and the storm surge are the biggest threats with Issac and the heaviest effect will be in southeastern Louisiana and along the Mississippi and Alabama Gulf Coasts. AccuWeather is predicting that how the storm comes ashore could have a major effect on the level of flooding possible.
Isaac Not Another Katrina, But Still Dangerous UPDATED (AccuWeather)
Isaac is forecast by AccuWeather.com to make landfall as a hurricane in Louisiana Tuesday night 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.
According to AccuWeather.com Hurricane Expert Dan Kottlowski, "The angle at which Isaac could come ashore could still drive a substantial amount of water inland over southeastern Louisiana and southern Mississippi."
As a result a relatively weaker storm (up to a Category 1), when compared to Katrina (Category 3 at landfall in La./Miss.), could still pack a considerable punch.