Looking for a satelitte/IR/WV pic

[Jim Cantore]

does anybody have one at about the moment Katrina was downgraded from a cat 5 (2am)?

I'd appreciate it deeply

[wxmann_91]

[JonathanBelles]

awesome pic

[StormScanWx]

I think Katrina was a 4 at landfall but IMO, this is another (out of many) that Katrina was downgraded. Look at the appearance, the storm is becoming lopsided, plus dry air is seeping into the storm.

[SouthFloridawx]

[SouthFloridawx]

I just realized what a freak of nature that was... it's huge!!!!

[Jim Cantore]

Thanks those pics have been scarce considering between 3:15 and 6:15UTC, the satelittes jumped and no pics were in in between that period

if someone has a freak pic in between that area I will worship them for a day

[f5]

[wxmann_91]

Do not worship me Floyd but...

4:00Z

4:30Z

5:00Z

5:30Z

6:00Z

[Jim Cantore]

thats a beauty

[wxman57]

I think that the satellite may have gone into eclipse mode during that period you're looking for. The GOES site lists the eclipse period starting right near that time. I have an animation and it skips from 3:45 to 6:15Z.

[Jim Cantore]

Do not worship me Floyd but...

4:00Z

4:30Z

5:00Z

5:30Z

6:00Z

thanks a ton

how far ahead of Eastern time are Z's again?

[wxman57]

Here, I edited a microwave animation that covers the period in question. I removed the 36 hours prior to the morning in question:

http://myweb.cableone.net/nolasue/Katrinamicro.gif

The microwave animation seems to show an eyewall replacement cycle beginning near landfall.

[JonathanBelles]

I think that the satellite may have gone into eclipse mode during that period you're looking for. The GOES site lists the eclipse period starting right near that time. I have an animation and it skips from 3:45 to 6:15Z.

eclipse mode???

[wxman57]

I think that the satellite may have gone into eclipse mode during that period you're looking for. The GOES site lists the eclipse period starting right near that time. I have an animation and it skips from 3:45 to 6:15Z.

eclipse mode???

At certain times of the year, generally surrounding the autumnal and vernal (fall and spring) equinox, the Earth's shadow passes across the satellite for a few hours in the late night/early morning (around 06Z-08Z or so). When the satellte is eclipsed by the Earth's shadow, it has no power to transmit imagery.

Here's the explanation from the GOES satellite FAQs:
http://www.srh.noaa.gov/srh/ssd/html/goesfaqs.htm

What is a satellite eclipse period?
Since GOES is in a geosynchronous orbit, the sun will yearly traverse a +/- 23.5 degree angle perpendicular to the Earth's equator (GOES orbit plane). As a result, near the Vernal and Autumnal Equinoxes the Earth disk will periodically occult the sun, from a GOES perspective. Essentially, there are two eclipse seasons for each GOES spacecraft. Each eclipse season spans a 48-day period, symmetric around the equinox and the sun occultation lasts for a maximum of 72 minutes/day during the equinox. Each GOES spacecraft utilizes a solar array that converts sunlight into electricity in order to power the satellite. Each day during the eclipse season the sun is blocked by the Earth and sunlight is not available to the GOES solar array. Therefore, the energy needed to power the instruments is not available and the instruments are powered off. There is typically a 0-3 hour outage of imagery each day as GOES progresses through eclipse season. The maximum outage of 3 hours will occur at or near the equinox.

[wxman57]

I went through all the Katrina loops I saved, and they're all missing that period between 0345Z and 06Z. August 29-30 was listed as the start of the autumnal eclipse cycle, so that may be it. The only problem, though, is that the Fall 2005 schedule has the eclipse periods closer to 08Z and not from 0315Z to 0615Z:

http://www.ssd.noaa.gov/PS/SATS/GOES/WE ... -Rout.html

[JonathanBelles]

ok thanx i have never heard that before

[wxmann_91]

Do not worship me Floyd but...

4:00Z

4:30Z

5:00Z

5:30Z

6:00Z

thanks a ton

how far ahead of Eastern time are Z's again?

4Z is midnight for you during Daylight Savings.

Whenever converting from Zulu to regular time, just remember this time:

0Z=8:00 PM EDT or 7:00 PM EST

Then just do math. So for example, 14:33Z would be 0+14:33, 8+14:33=22:33/10:33 AM EDT, or 9:33 AM EST.

[Aslkahuna]

The time of 08Z for the eclipse period time would be more likely for GOES-10 (GOES-West) since 08Z equals midnight PST. Since GOES-East is located somewhat to the east of the US East Coast, the eclipse period would be a function of when LOCAL midnight occurs at the satellite longitude (which is not the same as Zone time).

Steve

[f5]

thats a beauty

she is also a classic monster.you don't see a hurricane look like that very often.she is a perfect round circle not the spiral type you see with Mitch,Ivan or Rita