Tag Archives: projections

And ’round and ’round we go…

Tropical Storm Hanna: 5am

Hanna continues to frustrate folks here in Charleston from just northwest of Haiti as it does a little loop-de-loop (it’s already completed one) over the water, waiting for the high pressure system to build in, pick it up and whisk it off to the northwest. The good news is that it’s still on a slow weakening trend; this morning’s satellite image, depicted above, has her looking like a flat-out mess. The thunderstorms are fairly well-separated from the center; it’s amazing it’s maintaining 60 MPH winds as it interacts with Hispaniola.

Because The Turn hasn’t happened yet, we still are stuck in a wait-and-see pattern. This is frustrating because as NHC’s stated before, we won’t have any idea of exactly where landfall will happen until this thing starts to get going.

The 8am model runs showed a wild rightward shift in almost every model, probably as a result of Hanna’s eastern motion. Time will tell if this shift is anomalous or shows more of a permanent rightward trend. The 2am models started to demonstrate more rightward movement, but the 8am ones are the first time that I’ve seen the HWRF and GFDL models tack as significantly northward as they have.

Tropical Storm Hanna: 5am

The official forecast should look pretty familiar to you at this point, if not a smidge more rightward than previous tracks. Will be interesting to see what 11am brings.

I won’t be blogging all that often today; keep an eye to the Charleston Weather Twitter for updates throughout the day. I’m going to do a video briefing at 9:30 tonight; it won’t last too terribly long unless there are significant changes to discuss (and I’m willing to bet there might be). Back to waiting!

5am: Hanna Still Drifting

Not much on Hanna has changed since the 11PM advisory; it’s still at 80 MPH drifting west at 2. What we’re waiting for is that turn to start, and that’s not expected to happen until tomorrow. The sooner it begins turning, the more northward the track will likely go.

One thing that bothers me from this morning’s advisory is this passage from the NHC discussion:

It is important to note that
Hanna is expected to continue to intensify…or at least remain
steady…until landfall occurs between 84 and 96 hours…rather
than appear to be weakening like some automatic intensity plotting
software may show. In fact…by 84 hours Hanna could be a major

The GFDL model has indicated for the past several days that this could hit minimal Category 3 strength before landfall, and for the first time it appears NHC is supporting this theory. Intensity is a struggle to predict; this deserves further watch as a potential Category 3 strike changes the game dramatically in terms of evacuations and other preparedness steps.

Here’s the full run of model plots from overnight. You’ll see two clusters; one favoring the Savannah track, and one favoring the northerly track into Charleston. GFDL also seems to want to target Myrtle Beach:

All Forecast Models -- Hanna -- 6am

Here’s one that focuses on the more tropical-oriented models; call it the “low-carb” spaghetti plot if you will. Note a bit more spread with these on the orders of hundreds of miles — this is significant, and why the cone of uncertainty is still so wide:

Significant Model Runs -- Hanna -- 09/02/2008 5am

And, for completeness’ sake, the largely unchanged official forecast, which still targets a Category 2 landfall now over Hollywood/Ravenel (but this is still minutia; still a long way to go to determine specifics):

Hanna Projected Path, 5am Advisory 09/02/2008

I’m hoping later today we’ll start to see what a projected wind field may look like over Charleston (and also hoping that maybe this thing will jog out to sea, but that’s not looking too likely at this point). Today is a good day to commence your preparations; my advice is to prepare as if it’s a medium Cat 3 at landfall. While that might not end up being the case, it’s best to over-prepare at this point. If in fact the higher intensity does begin to bear out, you may need to start thinking of evacuation plans depending on where you are.

I’ll be doing a video chat with the 5PM track and 8PM information at about 9:15 tonight. Stay tuned…it’s just now getting interesting.