Tag Archives: forecast track

5am: Leftward Shift

Tropical Storm Hanna, 5am Advisory:  Forecast Track

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).

Hanna 2am Forecast Models

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

5am:  Hanna estimated windfield

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

5am Hanna Satellite

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.

Hanna as seen by KMLB radar site, Melbourne, FL

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).

Hanna Briefing: Cautious Optimism in Charleston

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.

11am: Track shifts eastward

The 11am advisory is out and shifts the track of Hanna eastward toward a landfall in Georgetown and Myrtle Beach. This is in line with the tropical models I discussed in the previous post, which had shifted significantly rightward. The NHC doesn’t commit as much to the right turn as the models do but this is fairly huge for Charleston. It remains to be seen whether this will stick, though.

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…

Hanna trending rightward

The 11PM advisory is out on Hanna. She’s holding steady at 80 MPH; pressure’s down a couple millibars to 978, and this storm is very, very stationary, causing a lot of problems on the Turks and Caicos with the potential for deadly mudslides due to the copious amounts of rain being dumped on the area.

Hanna Forecast Track, 11PM 09/01

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
GFSGFDL…AND HWRF.

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

Hanna Models -- Overview -- 11PM 09/01

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

Hanna Model Plots - Close In on 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…

Hanna the Headache

There’s a lot of eyes on Hurricane Gustav this weekend, and rightfully so — it’s become a Category 3, 125 MPH beast, and the forecast just does not look good for Texas and Louisiana around, unfortunately, New Orleans. Gustav appears to be in position to make this Labor Day weekend a very memorable one for all the wrong reasons. Here’s hoping folks are heeding the call to leave the coast early; the last thing anybody wants to see is a duplication of the tragedy of Katrina three years ago yesterday.

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. Continue reading

Bertha intensifies rapidly; now a Cat 3!

Hurricane Bertha, a minimal hurricane earlier this morning, is now a major Category 3 storm, packing 115 MPH winds. It’s developed one heck of a satellite presentation — it looks pretty textbook to me. This intensification kind of outgunned what most of the thinking was with the computer models; again, predicting hurricanes is still a very inexact science, and they still do things that we don’t necessarily expect. Bertha’s not expected to be this strong for too terribly long; it’s moving into an uncertain environment with slightly cooler water and some wind shear, so it will probably start to lose steam in the next day or so.

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.

Bertha gets a little bigger

After largely holding steady in intensity over the weekend as it moved through less favorable conditions, Bertha was given a little more room to breathe last night, got pretty well organized (and is showing an eye-like feature now) and became the first hurricane of the 2008 season.

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.

Eyes on Bertha

It’s still too soon to tell what Tropical Storm Bertha, which is holding steady at 50 mph and 1000 millibars of pressure, will do in the next few days. A look at the forecast, though, certainly will raise a few eyebrows along the Eastern Seaboard.

TS Bertha, five day forecast track

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. Continue reading