B Ozanne
EF5
What about Pacific typhoons? They sustain themselves at CAT 5 for days.
Satellite indicates that Frances is becoming more symmetrical again.
8/27/04 FCST: Frances (Atlantic)
- Thread starter Scott A. Kampas
- Start date
What about Pacific typhoons? They sustain themselves at CAT 5 for days.
Satellite indicates that Frances is becoming more symmetrical again.
Mike Hollingshead
Yeah that strong drying/sinking looked possibly enhanced by the land of Florida as it outlined it pretty well to the east. Whatever the case, that problem seems to be out of the way now.
Mike Peregrine
EF5
It also looks like the track may be straightening itself out a bit ... looks to be turning more to the west now. The last frame shows what may the re-emergence of an eye as well. This will be an interesting show to watch this afternoon -
B Ozanne
EF5
This is intersting, but soooo slow to play out. I'm keeping an eye on satellite. I don't know about the storm's center, but the central dense overcast just took a wobble to the west.
Bob Schafer
EF5
I won't try to analyze, but I thought there were some interesting differences between the KMIA sounding from Wednesday night...
http://weather.unisys.com/upper_air/skew/p...kew_KMIA-3.html
...and from this morning...
http://weather.unisys.com/upper_air/skew/s.../skew_KMIA.html
The dew depressions this morning, compared to Wed, are just screaming for attention. Also, note the difference in the upper level wind directions and speeds.
Huge thanks to everyone posting in here for all the insights the last few days. I feel like I've learned more this week than in a long time.
Bob
Oh, also, I noticed Unisys is really bogged down. Must be unprecedented numbers of people accessing wx data online on all the popular sites. No such problem on CoD attm, though. I've quit using everything but CoD for radar (Miami is back up) and sat imagery.
[edit again:] Oh, I didn't mean to imply that CoD is an "unpopular" site, LOL. Just not as well known to the "Great Unwashed!"
http://weather.unisys.com/upper_air/skew/p...kew_KMIA-3.html
...and from this morning...
http://weather.unisys.com/upper_air/skew/s.../skew_KMIA.html
The dew depressions this morning, compared to Wed, are just screaming for attention. Also, note the difference in the upper level wind directions and speeds.
Huge thanks to everyone posting in here for all the insights the last few days. I feel like I've learned more this week than in a long time.
Bob
Oh, also, I noticed Unisys is really bogged down. Must be unprecedented numbers of people accessing wx data online on all the popular sites. No such problem on CoD attm, though. I've quit using everything but CoD for radar (Miami is back up) and sat imagery.
[edit again:] Oh, I didn't mean to imply that CoD is an "unpopular" site, LOL. Just not as well known to the "Great Unwashed!"
Mike Peregrine
EF5
Definitely a big thanks for helping us learn about this incredible display. What a difference from weather in the plains! - Completely different worlds ... I can see after this that there is just a ton for me to learn about hurricanes. Sorry if my newbie attempts to analyze this stuff is irritating to anyone ... it's been a great learning experience.
COD is also experiencing high traffic, and the website will ask to close your browser window after a few minutes. There are probably people everywhere attempting to follow this storm.
Here are the latest strike probabilities as of an hour ago ... looks like W. Palm Beach is currently still being watched intently:
http://hurricane.terrapin.com/text/1094237...1US.TXT.html.en
Latest forecast advisory:
http://hurricane.terrapin.com/text/1094237...1US.TXT.html.en
Latest public advisory:
http://hurricane.terrapin.com/text/1094248...1US.TXT.html.en
Latest discussion:
http://hurricane.terrapin.com/text/1094237...1US.TXT.html.en
B Ozanne
EF5
Nassau just reported a 110mph gust! 45 miles from the center of circulation.
David Wolfson
EF5
The radar seems to show an outer eyewall that would be just about through Nassau. I think that obs may confirm that?
David Schuttler
EF5
Curiously I've wondered why the effects of Francis going over islands hasn't been discussed as another part in helping Francis lose strentgh.
Wouldn't getting less energy because it wasn't completly over water have an effect also?
Wouldn't getting less energy because it wasn't completly over water have an effect also?
David Wolfson
EF5
Land coverage is only a few percent. For the sake of discussion I'd expect even that small effect would be "balanced off" by orographic/turbulent lifting.
B Ozanne
EF5
I think the Bahamas are just too small to have a significant effect. They also have no significant terrain like the volcanic islands around the Carribean.
John Bacsa
Because a hurricane has an organised structure I think that even slight disturbances in convection and small obstacles could have a large effect (in a way that is difficult to predict)?
Tim Vasquez
EF5
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Jeff Snyder
EF5
Ugh... I hate tropical storm forecasting... Isidore, Lili, Floyd, Frances, etc etc etc are all examples that demonstrate how unpredictable this is. I mean, even at 11pm Wednesday (when the downward trend began), NHC forecast discussion mentioned: "GIVEN THE ALREADY IMPRESSIVE
OUTFLOW PATTERN...SOME ADDITIONAL STRENGTHENING SEEMS PLAUSIBLE. ALSO...THE VERY DRY MID-LEVEL AIR...30-40 PERCENT HUMIDITY...THAT FRANCES HAS BEEN TRAVERSING THROUGH AND INGESTING OVER THE PAST 5 DAYS IS FORECAST TO INCREASE TO MORE THAN 60 PERCENT IN 36-60HR...WHICH MAY ALSO HELP WITH THE INTENSIFICATION PROCESS." Oddly enough, this is almost opposite of what happened, as it appears that at least some dry air has been getting entrained. The 0z sounding from Tampa shows relative humidity of 15% at 500mb. The hurricane is getting close enough to MIA that upper-level clouds are beginning to move over the area, so it's not really characteristic perfectly of the pre-storm environment...
Winds are down to 105mph on the 8pm public advisory, making it a Category 2 storm now. There was a very intense convective burst an hour or so ago, but shear on the westside remains evident. In addition, nearby upper air obs from 0z do not look good for Frances. MIA shows some pretty dry air at the upper-levels, with relatively strong winds in the upper levels as well (32kts at 200mb). Additionally, Tampa and Key West show some dry air at the upper levels, instead of the typical semi-saturated soundings that are more associated tropical systems. A high south of Cuba is progged by the ETA to shift westward will continue to provide signficant shear over atleast the western edge of the storm. That said, the ocean temps are about as warm as they get so who knows...
OUTFLOW PATTERN...SOME ADDITIONAL STRENGTHENING SEEMS PLAUSIBLE. ALSO...THE VERY DRY MID-LEVEL AIR...30-40 PERCENT HUMIDITY...THAT FRANCES HAS BEEN TRAVERSING THROUGH AND INGESTING OVER THE PAST 5 DAYS IS FORECAST TO INCREASE TO MORE THAN 60 PERCENT IN 36-60HR...WHICH MAY ALSO HELP WITH THE INTENSIFICATION PROCESS." Oddly enough, this is almost opposite of what happened, as it appears that at least some dry air has been getting entrained. The 0z sounding from Tampa shows relative humidity of 15% at 500mb. The hurricane is getting close enough to MIA that upper-level clouds are beginning to move over the area, so it's not really characteristic perfectly of the pre-storm environment...
Winds are down to 105mph on the 8pm public advisory, making it a Category 2 storm now. There was a very intense convective burst an hour or so ago, but shear on the westside remains evident. In addition, nearby upper air obs from 0z do not look good for Frances. MIA shows some pretty dry air at the upper-levels, with relatively strong winds in the upper levels as well (32kts at 200mb). Additionally, Tampa and Key West show some dry air at the upper levels, instead of the typical semi-saturated soundings that are more associated tropical systems. A high south of Cuba is progged by the ETA to shift westward will continue to provide signficant shear over atleast the western edge of the storm. That said, the ocean temps are about as warm as they get so who knows...
Mike Peregrine
EF5
Unless there is some dramatic intensifying, it appears that the primary threat from Frances is quickly becoming the flooding rainfall it will likely produce as it inches its way along rather than wind.
Down to Cat 2. I'm starting to feel like Jeff ... these things are just impossible to accurately predict. Hurricanes are naturally impressive but it seems like every little thing that comes along has some dramatic impact ... the butterfly effect. I'm certainly not disappointed that the people of Florida could be spared from the full wrath this storm was capable of at one time ... but have to scratch my head with these things ... at this point it almost feels like a bust chase ... when we're all standing around asking ourselves what happened -
Down to Cat 2. I'm starting to feel like Jeff ... these things are just impossible to accurately predict. Hurricanes are naturally impressive but it seems like every little thing that comes along has some dramatic impact ... the butterfly effect. I'm certainly not disappointed that the people of Florida could be spared from the full wrath this storm was capable of at one time ... but have to scratch my head with these things ... at this point it almost feels like a bust chase ... when we're all standing around asking ourselves what happened -
