Hanna Hanging On

By Gannon Medwick
Morning & Noon Edition Meteorologist
Published: September 3, 2008

As of 11am, the National Hurricane Center notes that Tropical Storm Hanna, still near the southern Bahamas, is moving north at 6mph.  The motion is slow, but this now makes 6 straight hours that Hanna is moving – actually moving – in one solid direction.  This is a sign that the consistent northward track we had been expected Hanna to take is starting.

Track

As I discussed this morning, recent computer models have shifted Hanna to a more easterly track.  The official National Hurricane Center landfall point has, accordingly, shifted from near Charleston, SC early this morning to near the NC/SC border as of this latest advisory.  These trends certainly suggest an increased likelihood that Eastern North Carolina will have more direct Hanna impacts.  Still, given Hanna’s current level of organization and history of erratic motion, the storm’s future track is hardly concrete at this time.  Some models have even trended so far east with Hanna’s track that the storm stays off the coast.  We will keep you updated with these trends!

Intensity

Hanna is still likely to regain hurricane strength as it approaches the U.S., but I am guardedly optimistic that dry air and still some leftover wind shear should hamper Hanna from intensifying into a monster storm.  One wild card: Hanna will be passing over the warm waters of the Gulf Stream as it approaches the Southeast.

Time

The brunt of Hanna (be it tropical storm or hurricane conditions depending on the storm track) will occur in a ~6-hour window beginning late Friday or Friday night and continuing into early Saturday.  Outer bands of Hanna could begin to reach parts of Eastern North Carolina as early as the daytime on Friday, however.

Forward Speed

Regardless of where Hanna exactly tracks, the storm will not stay in one place for long!  Hanna’s forward speed as it gets to our latitude will likely be greater than 20mph.  This is good news as the quick “get in, get out” speed of Hanna will limit its potential to produce rainfall flooding.

Threats

I borrow this section straight from Phillip’s assessment of Hanna last night: 

Hanna will pose several threats.  The initial threat to our market will be a tornado threat in the initial rain bands likely on Friday with the threat lasting into the night. (if the storm stays out to sea as some of those new models are suggesting, Eastern North Carolina would be on the west side of Hanna and the tornado threat would be minimal in this case.) Wind will be a threat if the storm moves as quickly as expected and if the center is along a path that is near or east of the triangle area.  Rain flooding will not be as big of a threat as most storms because of the rapid movement of the Hanna.  Saltwater flooding would be a problem IF the center of Hanna came directly over Eastern NC.  Places like southern mainland Hyde County, Jacksonville, Belhaven, and possibly New Bern could have some flooding then.