ATL GUSTAV: Tropical Depression - Discussion

[srainhoutx]

For those interested, I used the latest recon data to work out it's current trajectory (for the past 98 minutes):

I used 25'51''N, 86'33''W to 26'2''N, 86'54'' and used the FCC website to account for differences in heading dependent upon latitude to get a precise value of:

300.3 degrees at 21.9 knots.

Note that the heading for the previous six hours was an average of 315 degrees at 15 knots.

So it has sped up a little and for the past 1.5 hours has been heading on a more westerly track than prior.

Are you sure of the speed calculation? That seems high to me, especially since Gustav is probably starting push up against the ridge and slow down some(though probably not a lot). The heading is believable and if it holds true will miss the NHC points to the west somewhat. I certainly don't have the tools to check your work, but just expressing my concerns. IE if it held on your heading we could be talking a SW LA landfall vs. the current projected landfall. Thanks for you work and posting this for discussion.

I just measured a 2 hour movement to 301 degrees at 19 kts. I just put my mouse cursor in the center of the eye at 1745Z and advanced the satellite loop 2 hours forward and read a distance of 38nm. Landfall by 9am tomorrow, maybe earlier. That's allowing for a significant slow-down.

Thanks wxman57. Looks as SW LA if in play if not SE TX.

[NC George]

Dumb question perhaps, but does the forward speed have anything to do with the destructive potential in the right front quadrant?

Yes foward speed adds to wind speed in RFQ

However, this is already accounted for in the wind speeds reported by the NHC. In other words, the wind speed reported by the NHC is the actual highest wind speed measured, all potential modifications have been factored in.

[rtd2]

Movement between VDMs was 304 at 15.2 kt.

VDM's ?? thanks

[stormie]

Anyone know what the winds are here in the Tampa Bay area? Specifically along the beach of Pinellas County. Both peak wind gust and sustained. I'm surprised at how strong they've been.

The winds surprised me, too. I'm in NW Hillsborough County. I just checked the weather station in my backyard, and it had recorded a 55 mph gust.

Yeah, we've got some branches and limbs down. What are we 200 miles away?

I'm guessing it's more like 300 to 400 miles away. I'm just wondering if weather conditions near here will improve or deteriorate as the storm is moving NW. Maybe we'll just split the difference and the weather effects we're getting will stay about the same. Either way, on radar it looks to me like we're going to be feeling a hefty rain band here soon. That is one large TC!

[vbhoutex]

Dumb question perhaps, but does the forward speed have anything to do with the destructive potential in the right front quadrant?

I think one beneficial effect will be a lot less time for the easterly winds to pile water into the lake and canals.

You already have almost the whole E GOM as a fetch for some very strong winds which are likely already piling water into the MRGO and the Lake among other places. If the forecast track verifies it is much more a Hurricane Betsy type scenario which is worse for SE LA and the NO area than the track that Katrina was on.

I sure hope they are wrong on the estimates of people staying behind in the lower parishes!!!! Even if this is "ONLY"(SARCASM) a CAT3 landfall it will not be a good situation for anyone in those areas due to the surge.

[tolakram]

This buoy near NO. Winds already increasing.

http://www.ndbc.noaa.gov/station_page.php?station=42040

[KWT]

Exactly Windy, if they are going to get out there they must do it now or stay put and hope for the best, the time for acting is probably only another 6-9hrs after that conditions will be going rapidly downhill.

[chadtm80]

[Cape Verde]

We're seeing fringe effects in the Houston area. Small clouds are moving to the west, which they never do except when a tropical system is in the Gulf.

I'm no longer the least concerned that we'll get a major impact from the storm other than rain after it makes landfall somewhere to the east of us and has to dump its moisture somewhere.

But I'm impressed that I'm seeing any effects of the storm here now at all.

[ROCK]

quote="hiflyer"]

Anyone know what the winds are here in the Tampa Bay area? Specifically along the beach of Pinellas County. Both peak wind gust and sustained. I'm surprised at how strong they've been.

The winds surprised me, too. I'm in NW Hillsborough County. I just checked the weather station in my backyard, and it had recorded a 55 mph gust.

Yeah, we've got some branches and limbs down. What are we 200 miles away?

Latest hourly showing gusts 30-35 kts on the coast around TPA....ouch!
http://www.srh.noaa.gov/tbw/html/tbw/Ta ... ather.htm#[/quote]

Ridge is building near Tampa so the Pressure Gradient is really tightening up. Probably why the winds are increasing.

http://cimss.ssec.wisc.edu/tropic/real- ... 8dlm6.html[/quote]


Stormcenter- not being nick picky but your using the wrong heights. ....Gus is around 958.....so adjust your heights and see the current steering layers....

http://cimss.ssec.wisc.edu/tropic/real- ... 8dlm4.html

[funster]

What? Hurricane winds in NE Texas?

[HouTXmetro]

Dumb question perhaps, but does the forward speed have anything to do with the destructive potential in the right front quadrant?

I think one beneficial effect will be a lot less time for the easterly winds to pile water into the lake and canals.

You already have almost the whole E GOM as a fetch for some very strong winds which are likely already piling water into the MRGO and the Lake among other places. If the forecast track verifies it is much more a Hurricane Betsy type scenario which is worse for SE LA and the NO area than the track that Katrina was on.

I sure hope they are wrong on the estimates of people staying behind in the lower parishes!!!! Even if this is "ONLY"(SARCASM) a CAT3 landfall it will not be a good situation for anyone in those areas due to the surge.

I have relatives who refuse to leave Coastal Vermilion Bay around Morgan City, Franklin and Jeanerette. I hope the surge isn't to bad there.

[Category 5]

A piece of good news.




Category 2 at landfall IMO.

[HarlequinBoy]

Well I think he is dumb for staying. It's just Schriever is northwest of Houma and should be safe from any surge. But the winds still worry me.

Tonight: Tropical storm conditions expected, with hurricane conditions possible. Scattered showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Some of the storms could produce gusty winds and heavy rain. Mostly cloudy, with a low around 75. North wind 15 to 20 mph increasing to between 25 and 30 mph. Winds could gust as high as 45 mph. Chance of precipitation is 60%.

Labor Day: Hurricane conditions expected. Showers and possibly a thunderstorm. Some of the storms could produce gusty winds and heavy rain. High near 82. North wind 45 to 55 mph becoming east between 60 and 80 mph. Winds could gust as high as 100 mph. Chance of precipitation is 100%.

[storms in NC]

Did it slow up some? They had it this morning going in around 7 AM

[xironman]

That is what I was wondering, if the building ridge could pick up the winds by simply adding a stronger pressure gradient, especially on the NE side where the ridge is building.

[soonertwister]

Would someone mind educating me on this. I see people referring to direction of movement as 280, 300, 275, etc. I know 270-300 is in the WNW to NW but can someone tell me what number signifies W and what number signifies N so I can know what the inbetween numbers mean?

The 16 points on the compass

Diirection, Bearing (in degrees)

N 0
NNE 22.5
NE 45
ENE 67.5
E 90
ESE 112.5
SE 135
SSE 157.5
S 180
SSW 202.5
SW 225
WSW 247.5
W 270
WNW 292.5
NW 315
NNW 337.5

When a bearing is near the middle between the two closest bearing numbers, you can say NW by WNW, or SSE by S, or whatever else fits. Use the bearing identifier that is closest to the actual bearing. If it's within about 6-7 degrees of one of the above direction points, just say that's where it is. No need to get too techical about it.

[senorpepr]

Movement between VDMs was 304 at 15.2 kt.

VDM's ?? thanks

Vortex Data Message.

It's the center fix from the recon plane.

[KWT]

Category 5, notice shear however is decreasing near Gustav and that should continue as that region of shear moves out of the way, though with Gus moving faster its possible it will not get much better shear conditions that some models were epxecting, its hard to say what will happen.

Eye still looks pretty decent right now and the eyewall is also still bursting in a fairly impressive fashion.

[HouTXmetro]

quote="hiflyer"]

Stormcenter- not being nick picky but your using the wrong heights. ....Gus is around 958.....so adjust your heights and see the current steering layers....

http://cimss.ssec.wisc.edu/tropic/real- ... 8dlm4.html

How do you determine the appropriate steering layer?