Hanna had another trick for us up her sleeve: She accelerated her forward speed to 20 MPH, still heading northwest, and thus the track has shifted left a bit. We’re now looking at a landfall from anywhere from northern Charleston County to Myrtle Beach again, roughly 2am Saturday (though if Hanna continues to accelerate, this timeframe may also speed up).

The model consensus bears out a landfall spread roughly from Beaufort back to the NC/SC border, but interestingly enough, the Wilmington landfall that was fairly certain yesterday is no longer even in the cards, according to this run. The 8am runs should shed more light.

The Shift’s Impacts

We can now expect fairly sustained tropical storm force winds in the afternoon through midnight, including winds over 60 MPH at times with gusts near hurricane force, with the worst of the weather coming when it’s dark. The NWS forecast for today calls for 50-60 MPH sustained winds through the night, especially along the coast; those winds can cause power outages, so now’s the time to make sure you’ve got your batteries in place for your flashlight, because it’s a fairly safe bet you’ll need it. The leftward shift also means inland impacts through South and North Carolina will be increased, with the possibility of sustained tropical storm force winds spreading very close to even Greenville, SC now.

Vitals

Hanna’s still a 65 MPH tropical storm, but it’s pressure has dropped to 989 millibars, suggesting that it has strengthened slightly and could continue to do so. The possibility still exists for it to become a minimal hurricane by landfall, though that’s a matter of semantics when dealing with the differences between a minimal hurricane and a strong tropical storm. Its satellite appearance is still not wonderful, but there is a bit of a flareup of storms on the leftward edge, which is captured well by Melbourne’s radar site.

Continuing Coverage

Coverage continues throughout the day. Stick close to here and Twitter for updates, including on-air times (which may be fairly soon as conditions begin to deteriorate).

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Cautious optimism is the word in Charleston; however, preparedness needs to become the word in Wilmington and the Outer Banks. The 5PM track shifted well eastward and now points to a landfall very close to Wilmington as a medium Category 1 hurricane. Despite this shift, Charleston could still see tropical storm force winds and some heavy rain at times on Friday into Saturday morning.

11:00 is about to come out — I’ll have more then. Regardless of Hanna’s track, I’ll do another briefing tomorrow night at 9:15 when more should become clear about what Charleston will face.

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Hanna also appears to be making the turn to the north and northwest; once motion resumes, we’ll have a better idea of what’s happening. It’s still too early to judge exact landfall points.

Winds are still 60 MPH; pressure’s at 997 millibars. The NHC noted in the public advisory Hanna’s size; tropical storm force winds now extend almost 300 miles north of the center. It’s expected to organize a bit more as the day goes on and should strengthen back to a hurricane sometime tomorrow. Keep an eye out, and there will be more at 2…

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The forecast track has shifted eastward and now predicts a landfall Friday afternoon around the Charleston metro or just a teeny bit north. I must reiterate that this scenario is very uncertain and could all change by the time we wake up tomorrow morning.

I’ve noticed this eastward trend progressing throughout the day; this morning, landfall was projected south of Savannah; at 5PM, landfall was shifted to the border with a hard turn right up through the gut of SC; now, another eastward shift takes it into Charleston. This is a curious development; I’ll get into that in a moment. First, here’s some explanation from the NHC discussion (links to models added by me, where appropriate):

AS HIGH PRESSURE DEVELOPS
OVER THE WESTERN ATLANTIC OVER THE NEXT 2 TO 3 DAYS…A
NORTHWESTWARD TRACK FOR HANNA IS EXPECTED TO DEVELOP. WITH THE
EXCEPTION OF THE UKMET…THE MODEL GUIDANCE IS REMARKABLY WELL
CLUSTERED. THE OFFICIAL FORECAST IS ADJUSTED SLIGHTLY TO THE EAST
OF THE PREVIOUS ADVISORY AND IS ONLY SLIGHTLY TO THE LEFT OF THE
GFS…GFDL…AND HWRF.

Here are the latest spaghetti plots for those of you who are into meteorological pasta:

And a close-in view of the plots as they cross over Charleston:

I do find it interesting that they’re leaning on the GFS, GFDL, and HWRF so much; as the spaghetti indicates, there’s still plenty of support for the more leftward solution. It probably has to do with the reliability of GFDL lately, and the fact that GFS trended more leftward to match up with it; but this is still an interesting development. The morning runs will be good to watch to see if more things come into alignment with this rightward track. Again, the cone of uncertainty is quite wide, and it’s still important for everyone from Miami to Norfolk to keep close tabs on this one.

More in the morning…

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Here in Charleston, we may have a tropical issue of our own to deal with by the end of next week. I’ve been spending a showery morning in West Ashley playing with computer model runs for Tropical Storm Hanna and the end result has been a little heightened concern for our neck of the woods.

Before we dive into Speculationland, let’s first start with the official 5-day forecast track for Hanna as provided by the National Hurricane Center:

Hanna’s currently expected to do something unusual for tropical cyclones and actually take a southward dip toward the Bahamas. I need to reiterate just how weird that is — it doesn’t happen often. (This southward dip is actually much less pronounced than what was being forecast yesterday through 5am.) One thing to note is the gigantic cone of uncertainty, especially as we get into Days 4 and 5. A lot of it has to do with a high pressure system that’s built up over the Southeast. This high pressure is what’s likely to steer Gustav into the Gulf Coast. It’s also expected to move out more into the Atlantic during mid-week, breaking down Gustav’s steering (and stalling it out over Louisiana and Texas, making for a potentially catastrophic flooding event) and also starting Hanna on a northward trajectory. It’s the degree of the high’s movement that makes all the difference.

The long-range models show a variety of northward-turning scenarios. The GFDL has Hanna doing a loop-dee-loop before resuming a northwest motion about a week from now. The HWRF model shows a southward dip and then a resumption of northwest motion. The GFS shows, so far at least, a track that shows a Savannah landfall roughly Thursday night into Friday morning as a fairly deep area of low pressure. Conversely, the CMC shows a dip into Cuba before straddling Florida’s west coast by Friday. Those are just a few of the scenarios out there — it’s really anybody’s guess.

Another area of Hanna’s uncertainty is the intensity forecast. NHC’s official forecast keeps it at tropical storm strength thanks to some persistent upper-level shear; however, the models continue to try to make Hanna at least a Category 1. For a time, in fact, the GFDL shows Hanna touching Category 3 strength before backing off into a Category 2 over the Bahamas. The HWRF is a bit more conservative with intensification, but still makes Hanna a Category 1. The confidence in all intensity forecasts is fairly low and this is definitely a low-confidence forecast.

Needless to say, anywhere from both of Florida’s coasts up the Eastern Seaboard should keep an eye on this one. This has the chance to be even more unpredictable than Fay proved to be, so it’s definitely one to watch especially as the week wears on.

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Bertha’s slowing up in forward speed, too, which is a pretty good indication that it’ll start to turn northwest and more north in the next day or so. Bermuda will want to keep an eye on it because the exact time when it will turn changes their situation, but things are looking more like a U.S. landfall is less likely.

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Bertha’s a minimal hurricane right now, but it’s likely to strengthen a little bit more before running into some more unfavorable conditions down the road. See the 5am NHC discussion for the thinking behind this.

There is still a lot of uncertainty and variability with the forecast track. The official Hurricane Center forecast did begin to recurve the storm away at about 5:00 last night; however, the cone of uncertainty is a gigantically wide area four to five days out. The current track seems to put Bermuda square in line for a direct hit, but that can (and almost certainly will) change. A majority of the models now recurve the storm (the BAMM still thinks Bertha will not be steered away for the moment), but there is still so much variability on exactly where the storm will be recurved, hence a continued uncertain forecast from the Hurricane Center.

Oh, and here’s a fun tidbit: In a fun little coincidence, the last Hurricane Bertha formed on July 7, 1996. I guess 7/7 is a good day for Berthas or something.

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The track does look pretty ominous. Should you be getting ready? I don’t think it’s too early to start thinking about it, but it’s not time to panic, either. This forecast is really, really uncertain.

The variety of forecast models out there which try to predict storm movement have been disagreeing like the Hatfields and the McCoys. However, it seems as if more and more of the models are getting on board with a recurvature of Bertha as time goes on, though there are still a couple straggler models that keep it to the south. Dr. Jeff Masters at Weather Underground has an excellent writeup of what’s happening.

The forecast brings it to a minimal hurricane, but again, the state of the atmosphere is still so much in flux that a lot could change. A Cape Verde storm in the first week of July is uncharted territory for the Hurricane Center, so their confidence in their forecasts has been lower than most other times.

Is it time to panic? No way. It’s never time to panic. :) Is it time to prepare? Well, it’s always good to have some hurricane preparation done ahead of time. The storm is about a week away from approaching the coastline, if in fact it holds together and/or doesn’t recurve first. There’s plenty of time to be thinking and getting ready just in case Bertha should come knocking.

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