Tag Archives: wind fields

5am: Hurricane watches now up for the area

5am Hanna Watches

As of 5am, hurricane watches are now up from Surf City, NC, to just north of Hilton Head, SC. Tropical storm watches extend from roughly Hilton Head down to almost the Georgia/Florida border.

Hanna’s still a 65 MPH storm, headed to the northwest at 11 MPH. Its satellite presentation has been less than impressive this morning; however, strengthening is still fairly likely and Category 1 strength at landfall is to be expected.

Tropical Storm Hanna 5am 09/04:  Wind Field

The 5am track speeds up the timeline a bit and shifts landfall slightly left. As of now we’re looking at a landfall a bit closer to the NC/SC border (almost right on top of Wilmington) around 2am Saturday. Tropical storm force winds should begin to arrive in Charleston around noon tomorrow, or so. Today is another clear day, so today is the day to finish your preparations. Conditions will turn drastically downhill as Friday comes along. On the current track — still very subject to change — the center of the storm will probably pass to the east of here from around 7 to 9 PM Friday night. Once this occurs, conditions will begin to improve as Hanna’s not expected to have much on its southwest side.

More after 8 or so with the new model runs and the intermediate advisory.

11 PM: Hanna begins northwest turn; watches likely tomorrow

Tropical Storm Hanna 11PM Advisory 09/03:  Satellite Photo

The 11PM advisory is now out on a steadily reorganizing Hanna. Winds remain around 65 MPH, and pressure is sticking around 989 millibars. The Turn has really started to happen, as NHC states forward motion is north-northwest at 13 MPH.

The Track

Tropical Storm Hanna 11PM Advisory 09/03:  Track + Uncertainty Cone

The track seems to have shifted a bit more leftward before landfall; there’s still a fair bit of uncertainty. In the discussion, NHC acknowledges low confidence in the track, citing some spread in the forecast models.

Tropical Storm Hanna 11PM Advisory 09/03:  Forecast Models

There’s good consensus for a turn to the north and then the northeast; the big question is where it will happen. There’s decent consensus heading toward Wilmington, but there’s spread on the western periphery of the consensus — including a HWRF model that generally gets a fair bit of weight from NHC forecasters — hence the uncertainty and the slight leftward jog in the track.

NHC is saying that hurricane watches are likely for a “large portion of the southeast US coast” by tomorrow morning. It’s probably safe to assume that we in Charleston will be included in this watch.

It’s worth noting that the storm will be relatively short-lived; it’ll be increasing in forward speed throughout its approach. In Charleston, it’s likely that Hanna will have largely cleared the area by Saturday night. This is good for reducing the threat of severe flooding. There will still be heavy rains, but at least they will be short-lived.


Charleston should start feeling effects from Hanna as Friday wears on. As it gets closer, winds will increase. I’ve been able to use an experimental forecast wind field product as a decent guideline for what we might see here.

Tropical Storm Hanna 11PM Advisory 09/03:  Forecast Wind Field

The forecast says that we’ll see some of the worst of the weather Friday night into early Saturday morning, as the center passes within 75 miles or so of Charleston. Sustained winds of 58 miles per hour or greater — as indicated by the purple shading in the map above — are possible for a brief period. As mentioned above, rain totals will probably hit 6″ in some places, but this won’t be a storm that sits and spins and dumps 30″ of rain like a Fay over Florida.

Again, a lot of this is contingent on something resembling the current track holding. There’s more time for stuff to wobble back and forth, and Charleston is still in the cone of uncertainty, so there’s still stuff to watch. However, the direct strike scenario is looking less and less likely.

Closures, etc.

Keep an eye to media outlets and other sources for closure information in the Charleston area tomorrow, as I expect most of those closures (or lack thereof) would be announced during the day. A good resource for this is the @news2 Twitterstream.

Check out Lowcountry Bloggers’ Storm Buzz

The Lowcountry Bloggers roundup site has launched Storm Buzz, an automated feed of hurricane-related posts from the Lowcountry blogosphere. This is a good one-stop resource to see what Charleston bloggers have to say about Hanna and Ike.

Speaking of Ike…

Ike exploded into a dangerous but equally gorgeous Category 4 storm during the day Wednesday. It’s in a perfect environment for strengthening and could be a 5 before it’s all said and done. It’s expected to weaken to a 3; tentatively, it’s headed to the Bahamas, but there’s a lot of spread and uncertainty. It could recurve out into the sea — which would be ideal, of course — or it could threaten the U.S. within the next five or so days. Ike is one to watch because it’s expected to retain major hurricane status as it traverses the Atlantic, with fluctuations in intensity characteristic of huge storms.

For now, though, all eyes will continue to be on Hanna as she makes her move toward the coast. I’ll have more in the morning, probably shortly after the 8am advisory unless there’s a major shift in track that needs immediate attention.

Coverage Continues

Another video briefing will be broadcast at about 9:15 PM, with a roundup of the day’s information and hopefully a better fix on what Hanna’s going to do. She’s still got a history of behaving badly and needs to be watched closely.

Coverage will be more frequent as conditions deteriorate; I’m planning on bringing in additional folks to assist with coverage. Additional streams are planned for as long as power is viable. Now’s the time to follow @chswx and my own personal Twitter account for information and accounts of the storm, too.

Wait and see continues…

The wait and see game continues with Hanna at the 11PM advisory. The storm’s back to being virtually stationary, drifting eastward every now and again, but movement is not very pronounced. NHC continues to list Hanna’s intensity at 65 MPH; however, this could be generous. Check out Hanna’s satellite appearance.

Tropical Storm Hanna at 11PM 09/02:  Satellite

Here’s what the Hurricane Center discussion has to say:


This apparent weakening is undoubtedly good news and appears to have gone on a little longer than previously expected. (We’ll take what we can get here.)

Back on Track?

Tropical Storm Hanna at 11PM 09/02: Forecast Path w/ Cone

The forecast path has not changed much during the day. The angle of approach has been adjusted somewhat, but NHC has been very careful not to alter the path until Hanna finally starts the northwestward turn. Only after the turn begins will landfall points even begin to get a smidgen clearer. One thing to notice is that the updated track is a bit slower (for the moment, at least), pegging landfall now for later on Friday night versus in the afternoon. This is definitely something that could fluctuate depending on when Hanna starts moving and how fast it’s accelerated.

Tropical Storm Hanna at 11PM 09/02: Forecast Models

The computer models want to tell a different tale, though. After a brief jog to the west, they’ve since started trending rightward again, likely as a result of Hanna’s eastward movement during the evening. The models bear out a variety of scenarios; some, like HWRF, favor the southerly track, while GFDL, which has consistently veered more to the north, currently likes Isle of Palms. There’s significant agreement, though, for a landfall near Myrtle Beach. Some consensus is also building for an alternate clipping of the Outer Banks, though I’m not sure if that would come to pass as the HWRF and GFDL models have been exceptionally reliable. It’ll be interesting what will come out of the models when the recon data is taken into account. (NHC lists the next recon plane as going in at roughly 2 AM EDT.)


It’s still too early to tell — besides pretty decent amounts of rain and some elevated winds, probably to tropical storm force at times — what impacts Hanna will have on the area as the landfall location is still anybody’s guess. Using the current landfall location, though, I’m able to use an experimental wind field forecast product to give a general idea of what windspeeds to expect.

Tropical Storm Hanna at 11PM 09/02: Estimated Wind Field

The gray field is tropical storm force winds; the purple field are stronger tropical storm force winds up to 73 MPH. No hurricane force winds are depicted yet; if in fact Hanna makes landfall as a Category 1, expect those hurricane force winds (74 MPH or greater) to be concentrated about 20-25 miles to the northeast of the center. Intensity, storm size, etc. are still very touch and go at this point, so don’t read too terribly much into this; however, the estimation does show that a great deal of the state, including points as far west as Columbia and Augusta, could see tropical storm force winds for a time. Again, this should be interpreted as a general idea, and it’s quite possible a lot could change.

Closures, etc.

No word on any closures yet. The Charleston County School District has established a Hanna information page which will update as schedule decisions are made. Dorchester District 2 posted an inclement weather policy, but no closing information as of yet. I’ve not seen anything similar for Berkeley or Dorchester 4. Keep tuned to the local media outlets for up-to-the-minute closures and cancellations information.

More in the morning when the recon data is in; hoping that my getting some sleep will persuade Hanna to make a decision one way or the other so we can start trying to figure her out with some effectiveness. :)