Isaias upgraded to major hurricane ahead of possible Florida Panhandle landfall
The National Hurricane Center said Isaias has estimated surface winds of 105 kt and could keep major hurricane intensity until a potential landfall this evening.
AI illustrationIsaias has been upgraded to a major hurricane, with estimated surface winds of 105 kt, the National Hurricane Center said on Friday, October 9, in a forecast discussion issued at 10 AM CDT. The center's forecast shows the storm with 100-kt winds just offshore the western Florida Panhandle this evening, ahead of a potential landfall along the extreme western part of that coast.
The upgrade followed a flight by an Air Force Reserve Hurricane Hunter aircraft, which measured a peak 700-mb flight-level wind of 120 kt in the eastern eyewall a few hours earlier. On a later pass, about a half hour before the discussion, the plane measured 111 kt, which the center said suggests the peak winds may have leveled off. Dropsondes released in the eye indicate the central pressure appears to have leveled off around 959 mb.
Strong deep-layer shear has increased as forecast, with analyses showing 30-40 kt from the southwest. The center said the shear is nearly aligned with the storm's motion, limiting its effects, while upper-level divergence is also increasing. Regional hurricane models and statistical-dynamical models all suggest Isaias could keep major hurricane intensity until landfall.
Aircraft fixes indicate the storm has drifted a bit east of the previous forecast track. Weakening will occur after landfall, but sustained hurricane-force winds will likely occur near the track up to 100 miles inland into southern Alabama, and hurricane-force gusts could reach central Alabama. Isaias is likely to lose its tropical characteristics by 36 hours, over northern Alabama, and is expected to turn northeastward over the Tennessee and Ohio Valleys on Sunday as a post-tropical remnant low.
The center expects a life-threatening storm surge from the Mouth of the Mississippi River to Suwannee, Florida, and said residents under evacuation orders should leave immediately. A Hurricane Warning is in effect for parts of the Florida Panhandle, southern Alabama and southern Mississippi. Damaging gusts are likely across a large part of the southeastern United States, and considerable flash, urban and river flooding is possible. The tornado risk will increase through tonight, mainly across the Florida Panhandle into southern Georgia. Hourly updates were to begin at 11 AM CDT (1600 UTC).