Tag Archives: forecast

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:

THE CLOUD
PATTERN HAS CONTINUED TO DEGRADE…AND IT IS POSSIBLE THAT HANNA
HAS WEAKENED EVEN MORE. HOWEVER…WE WILL KEEP THE INITIAL
INTENSITY AT 55 KT SINCE ANOTHER AIRCRAFT IS SCHEDULED TO
INVESTIGATE THE STORM AROUND 0600 UTC.

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.)

Impacts

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. :)

2PM: Hanna The Meanderer…for now

Apologies for the later post; the day job has been hectic with storm stuff as well.

Tropical Storm Hanna’s been caught in something of a steering purgatory this afternoon; it continues to rain very heavily on the Turks and Caicos. As of the 2PM advisory, it’s moving SE at 2 MPH. We’re all awaiting the ridge of high pressure to build in and take it away — but it’s all a wait and see, still.

Intensity Rollercoaster

Hanna’s also been in a weakening trend; Gustav’s outflow has been negatively affecting it most of the day, having a great deal of its northwestern quadrant sheared off, helping to weaken the storm to tropical storm status earlier in the day. It’s held on as a 70 MPH tropical storm, so when the shear lets up, there won’t be much inhibiting it to becoming at least a minimal hurricane again.

This weakening has thrown a wrench in a lot of the forecast, though. The 11AM forecast discussion demonstrates significant uncertainty in the intensity forecast — it could barely hang on as a Category 1, or break free from the shear and blossom into a Category 3:

HOWEVER…GIVEN THE PRESENT LACK OF
ORGANIZATION…IT IS DIFFICULT TO KNOW HOW MUCH STRENGTHENING IS
POSSIBLE. THE NEW OFFICIAL FORECAST IS LOWER THAN THE PREVIOUS
ADVISORY BUT SHOWS HANNA BECOMING A CATEGORY ONE HURRICANE IN ABOUT
36 HOURS. IT SHOULD BE NOTED THAT THIS IS A LOW CONFIDENCE
FORECAST. IN FACT…IF ONE CONSULTS THE WIND SPEED PROBABILITY
PRODUCT INCLUDED IN THIS PACKAGE…IT CAN BE SEEN THAT THERE IS
NEARLY AN EQUAL PROBABILITY OF HANNA BEING A TROPICAL STORM OR
HURRICANE AT DAY 3.

A recon flight should shed much more light on Hanna’s structure; a flight’s scheduled for this afternoon and it probably is on the way in as I type. Here’s hoping that information is reflected in the 5PM.

Track Thoughts

The 11am advisory shifted the track back westward a little bit. Here’s the NHC’s map:

The NHC forecast track splits two groupings of model guidance down the middle. Here’s the high-carb meteorological pasta as of 3:15:

Computer Models at 3:00 Tuesday

One camp — with tighter agreement, I may add — takes an even more westward tack, bringing the center of Hanna onshore to central Georgia. Notably, the GFDL and HWRF models favor this scenario, with the GFDL taking a Category 3 just north of Jacksonville Friday. HWRF is a bit weaker, expecting a Category 2 storm. The other camp favors a Charleston-to-Myrtle Beach swath primarily. It’s a bit more divergent than the other two camps in terms of exact points, but remember, it’s still too early to get caught up in little jogs here and there. NHC has not adjusted the track much in part because Hanna’s size and intensity, as well as where it begins its movement from — remember, the storm has been meandering aimlessly southeast — has some bearing on how much and how quickly the expected high pressure will influence it.

Emergency Preparation

I caught Raymond from News 2’s tweets from the Charleston County EOC meeting. EOC has switched to OPCON 3, which activates the emergency operations center and indicates that an emergency situation is imminent. Mayor Riley is giving a press conference at 3:30 this afternoon; I recommend keeping an eye on News2’s Twitter. I’ll be watching that and will retweet big nuggets of information accordingly on both @chswx and @jaredwsmith.

Don’t forget about the video briefing tonight, tentatively scheduled for 9:15 PM. Sorry it’s so late in the night; I have obligations (read: class) to attend to from 7:00 to 8:15. This will give me an opportunity to review the 8PM advisory and break things down a bit better.

A special hello to those of you who came from The State — thanks for stopping in, and thanks to The State for syndicating this blog on their Web site! I hope folks are finding this useful; I know I’m enjoying doing it. :)

Hanna at 11am: Strengthening

Tropical Storm Hanna 11am track and intensity

As Hurricane Gustav makes landfall on Louisiana as a Category 2 storm — far weaker than the Category 4 monster that it was two days ago, thankfully, but still an intense hurricane — Tropical Storm Hanna is emerging into some more favorable conditions for strengthening. As of 11am, the winds are 60 MPH (and could be higher, but NHC is staying conservative with intensity fixes at this point). It’s started that west-southwest motion at about 4 to 5 MPH, and is expected to be a hurricane by Wednesday.

The track hasn’t changed, and model guidance is surprisingly confident about the track taking a recurvature into Georgia or South Carolina. The next day or so is critical; it all depends on when and how strongly an area of high pressure builds over Bermuda. There’s still significant uncertainty in the track as a result; again, it’s a wait and see. It’s too early to muse about wobbles or small jumps in track; there’s too much uncertainty to do that and a lot can change from day to day.

Because of the uncertainty, it’s good to start preparation now. NWS Charleston issued a public information statement about 10 minutes ago (as of this writing) imploring the public to begin their preparations for a potential Hanna impact later this week. Take heed!

As a reminder, I’ll be doing an update on Ustream tonight at 8:30 to talk more about Hanna after the 8PM information comes in. The next new track comes at 5PM.

Update: NHC just issued a special advisory: Hanna is now Hurricane Hanna as of 1:30 PM, packing maximum sustained winds of 75 MPH.

Gustav continues to plow to NOLA; Hanna struggles

Before I hit the sack, I wanted to bring folks up to speed about my latest thoughts on Gustav and Hanna. First, Gustav.

Eyewall Replacement Cycle?

Gustav emerged off the coast of Cuba at roughly 11:30 or so and promptly started trying to get its act back together. It looks like it’s in the middle of an eyewall replacement cycle, which basically means it’s reorganizing a bit at the core and should be ready to start strengthening again. Cuba knocked it down to a 140 MPH system, which is still nothing to sneeze at. I suspect we’ll wake up to Gustav as a Category 5 tomorrow morning.

Official Track and Computer Models, 11PM

The official track takes the center of the storm roughly 50 miles or so west of New Orleans, which is likely to cause tremendous problems not only for the city itself, but for a fairly wide swath of real estate, as the current scenario could push surge up the Mississippi. It’s a matter of wobbles — again, as I’ve said before, five miles to the east or west could be a world of difference. The computer models continue to show a cone of uncertainty stretching roughly from the LA-MS border to the LA-TX border. The track has continued to go eastward as Gustav wobbled right several times during the day. The landfall point is still very uncertain, and we probably won’t really know where it will end up until the hours immediately leading up to the point of landfall.

The good news is that New Orleans is being evacuated. Here’s hoping they can get everybody out this time — I have a bad feeling that because of the position of the center, this could be worse for NOLA. We’ll see what the next day bears out.

Hanna’s future becoming a smidgen clearer…maybe

Hanna’s still struggling in the face of wind shear and some interference from Gustav. It’s hanging in there at 50 MPH, as it has for much of the day. The wind shear is expected to back off just enough to let it strengthen a bit more, but the NHC discussion forecasts the shear to return Tuesday, which should inhibit development.

Model runs on Hanna run the gamut from a landfall at the Florida/Georgia border (NGP) to a brushing of the Outer Banks and eventual recurvature to sea (GFS). I’m seeing some consensus between the GFDL and HWRF models, specifically designed for forecasting tropical cyclones, in a scenario bringing the center onshore in South Carolina; likely somewhere like Bulls Bay, Georgetown, or Myrtle Beach. However, two models does not a forecast make. Keep in mind it’s still very early — a week away — and that there is still plenty of divergence in the other atmospheric models. The GFDL is being weird about Hanna, too, somehow developing it into a Category 3 despite forecasted moderate wind shear.

As always, it behooves anybody from Florida to North Carolina to keep a close eye to Hanna as it meanders around in the Atlantic. I suspect Hanna is going to become quite a thorn in our side as the week progresses.

Gustav knocking on Category 5’s door

Hurricane Gustav radar fix in Cuba

Major Hurricane Gustav is closing in on Category 5 status very quickly, raking Cuba and giving Key West quite a blustery time in the process. As of the 5 PM advisory, Gustav’s packing 150 MPH sustained winds, making it an intense Category 4, and is moving to the northwest at 15 MPH. This puts the storm somewhere along the Gulf Coast roughly Monday night. Model guidance agrees well on Gustav’s track at this point; it’s now a matter of wobbles — five miles east or west could change the prognosis for New Orleans, Houston, Biloxi, and other cities along the coast pretty substantially. As it stands, New Orleans may see sustained hurricane force winds on the eastern side of the storm, which is where the worst storm surge will occur. However, a lot can change between now and Monday.

Update: Here’s a map of the official NHC forecast track along with the spaghetti models to demonstrate variability in the landfall locations. Models look roughly at the Texas/Louisiana border all the way to right next to New Orleans, which is a disastrous scenario if that’s the one that comes to pass.

Track and models for Gustav

How I’m Following Gustav

Social media has mobilized throughout the day for getting the word out about Gustav. Twitter is figuring heavily into the mix, as one might expect: I’m following Mark Mayhew, who’s on the ground in New Orleans, as well as The Interdictor Project, one of the several aggregators of information about Gustav being made available this afternoon. (Interdictor may sound familiar to those who followed the Interdictor LiveJournal during Katrina; it was one of the best blogs that was actually on the ground through the duration of the storm.) I’ve also begun following Vanessa (aka iThinkMedia), who’s on the ground in Alexandra, LA, and James Wheeler, who lists his location as the Mississippi Gulf Coast. You can get the big picture using this Twitter search. A centralized Gustav Ning site has been set up for disseminating information and also for coordinate efforts to help folks who may be displaced by the storm. Finally, for you FriendFeeders out there, Wayne Sutton is compiling a list of resources for following Gustav.

Gustav is captivating me not just because of the obvious meteorological aspect, but also how folks are mobilizing so quickly using social media tools to disseminate information. This will be quite a study in social media’s maturity, and it’ll be interesting to see how things turn out.

Fay strengthens over land, confounds forecasters

Every year or so, we get a reminder of just how unpredictable tropical systems can be. Tropical Storm Fay is proving to be that storm. It’s done very little to plan at this point; it surged more westward than expected; came onshore weaker than expected, and now it’s done what is usually unthinkable — it’s strengthened over land. Continue reading

92L Becomes Fay

Invest 92L has become Tropical Storm Fay, spinning right over Hispaniola right now tracking to the west at 40 MPH. The current track — which, given the history of this storm, has the potential to be incredibly variable — takes it over Hispaniola and into Cuba, and then out just south of the Keys in the next three days. If it stays over the islands, this is a good thing in terms of strengthening, because the mountains will generally tear the storm apart and prohibit it from becoming too incredibly strong. Indeed, the three-day forecast sees Fay maintaining tropical storm status.

The newest model runs are starting to come in, as well. Most of these, so far at least, agree on a track that recurves it northward into the Gulf of Mexico. This could still be problematic for us if Fay becomes a fairly significant storm; it could bring considerable rain.

However, it’s worth noting that the models just this morning had this thing tracking up the gut into Charleston; it’s still too early to tell. A lot depends on when the northward turn happens. The sooner the turn happens, the higher the probability of rapid strengthening, too. As I say a lot, much akin to a broken record, this is one to watch for the next several days.

Hurricane Hunters headed into 92L

The National Hurricane Center reports that Hurricane Hunter aircraft are currently investigating Invest 92. NHC’s boosted the chances of development in that area of disturbed weather to over 50%. Despite its disorganization, I’ve seen lesser storms classified as tropical depressions, and I think this one will be classified before the day is out. More later.

A scorcher in store

Charleston’s got another scorcher in store for today, with a heat advisory in effect once again from noon until 9 PM for heat indices over 105 degrees. With such heat and humidity, thunderstorms are a distinct possibility, much in the way they fired up over Charleston yesterday. Keep an eye to the skies — preferably from indoors or in the shade with lemonade if you must be outside — it’s going to be a typical July day in Charleston.

Anemometer update and Tuesday

I got my replacement anemometer in yesterday…and of course, during the only real time that I’ll have to get it all set back up, the rain will be here. I’m going to try to see, weather permitting, if I can get things going again on Sunday. That’s going to be a fairly big job, though — we’ll see what happens.

The rain is definitely inbound. NWS has it pegged for “after midnight” — here’s hoping it holds off for at least a little while so I can get to work reasonably dry. I have an umbrella there, which is a plus. So far, the rain does not look like it’s moving all too quickly, but we’ll see what happens. Don’t think I’m going to activate the radar for this one — makes the main PC somewhat sluggish at times, especially when I need to dive in and do analysis of my own.

If you haven’t already, I urge you to read Brian Goode’s blog about the Tuesday weather non-event. It’s a great explanation of why broadcast meteorologists reacted the way they did to the threat — the data was pretty solid. I certainly appreciate the perspective and transparency Brian brings to the process through his blog time and time again. I do find it hilarious how people get all up in arms when the weather is less worse than predicted — isn’t that a good thing? As Brian put so well, the media did not tell the schools and cities and stuff to start closing up shop. They just reported what they saw as the situation, and the situation evolved and changed throughout the day to end up being very much in our favor.