Jamiewx
Storm Tracker
Reged: Wed
Posts: 371
Loc: Orlando, Florida
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Here is another interesting link, with reference to T-numbers and strength.
http://www.tropicalupdate.com/atlantic_tropic_watch_guide_to_d.htm
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danielw
Moderator
Reged: Wed
Posts: 3525
Loc: Hattiesburg,MS (31.3N 89.3W)
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Jamie, I like that link better
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Jamiewx
Storm Tracker
Reged: Wed
Posts: 371
Loc: Orlando, Florida
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Quote:
Jamie, I like that link better
its, always been one of my favorite links for , i actually printed a chart for future reference, i had some post a question about telling strength once and i gave this link, should have posted it a while ago for anyone one the board that has not seen it.
Am noticing quite a few people giving praise to and noting how much they have learned. I have to say i have learned a lot myself from this board, and my library of useful tropical links has grown dramatically this season. The site is like a big online weather/tropical community and its a great place to come for information and education especially with the proffesional meterologists like Ed and Jason. Sorry to be off topic, back on topic as of now, just a pause to praise the site and its admin for making it available.
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wxman007
Meteorologist
Reged: Sat
Posts: 617
Loc: Tuscaloosa, AL
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Thanks Jamie....
Earl is REALLY getting his groove on tonight...at this rate, Cat one by tomorrow is likely....
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Jason Kelley
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GuppieGrouper
Weather Master
Reged: Fri
Posts: 596
Loc: Polk County, Florida
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This is a hypothetical question. With the path so similar to , is there anything that will prohibit Earl from taking the path that was once predicted for , such as coming in to Tampa Bay. Even a Cat 1 at the wrong angle at high tide would be a flood and catastrophic event for Tampa Bay. Just hoping that this is impossible for this season.
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God commands. Laymen guess. Scientists record.
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danielw
Moderator
Reged: Wed
Posts: 3525
Loc: Hattiesburg,MS (31.3N 89.3W)
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8/12/04 1200Z model runs:
Going back and looking. At which models came the closest to Punta Gorda.
The GFDI came closest, followed by DSNS (disney?), and the OFCI model. The others were north of Tampa/St. Petersburg.
Not bad for 30 hours in advance!
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BillD
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Posts: 398
Loc: Miami
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Nothing is impossible and anything is possible, but this far out we don't even know that Earl will make it into the GOM, much less hit Florida. Way too early to tell whether Earl will follow Bonnie, or go anywhere from SE Florida to Texas.
Bill
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danielw
Moderator
Reged: Wed
Posts: 3525
Loc: Hattiesburg,MS (31.3N 89.3W)
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Yeah he could be real nice to everyone and dissipate.
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BillD
User
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Loc: Miami
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I hope so, but I don't think he will.
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Clark
Meteorologist
Reged: Wed
Posts: 1710
Loc:
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javlin - yes, somewhat. Midlatitude (cold-core systems) tend to be of a more baroclinic nature, while tropical systems are closer to barotropic. Deals with how the systems grow, in laymans terms. It's tough to explain without going into atmospheric dynamics and could take 20 pages, neither of which I'm about to do! 
BillD - I agree, though I'd tend to believe the models right now just because they are so tightly clustered. I'll buy recurvature; I don't know that I'll buy it within the next few degrees of longitude. By 50°W, sure; just after 40°W, I'm not so sure. Ultimately though, I think it's a fish spinner, leaving the intensity question to be the last unanswered question.
Also saw a question about the technique. Not sure how much depth the links went into, but in a quick summary, the technique was established many years ago to classify tropical systems and their intensities based upon observed satellite patterns. It splits tropical cyclones into a few major cloud-organization categories - I don't recall the exact ones, but there's a spiral band category, a category, and I *think* a sheared category - and allows an intensity for each to be obtained based upon how well a given system matches the expected cloud organization structure for that type of storm. It's a good estimator of intensity, but as we've seen not necessarily an accurate one. It is not good with rapidly developing storms, for instance, as we saw with (highest estimate of T5.0, or 90kt).
A couple of observances on the tropics...
* The models I have seen lately take Earl a bit further south than . The storm does continue to become better organized and I do not think it will be a storm that struggles to get it's act together over the Caribbean. The current steering flow should keep it on a west to west-northwest motion throughout the forecast period, albeit I think probably at a faster rate initially than the is calling for. The strength of the next East coast trough will determine it's ultimate fate - Mexico/Texas or eastern Gulf. Current projections say it may well be weak enough to not have much of an influence on Earl, but that's five days away. The G-IV will be headed out to Earl in a day or two, which should help to refine things. No sense in predicting a track beyond saying it should be somewhere near Jamaica in about four days. Intensity? All factors seem to be favorable, save for the fast motion, for some strengthening. Hurricane status is almost assured; wouldn't be shocked to see a cat 2 or 3 in four days.
* Danielle continues to become better organized and, while this may sound like a broken record, major hurricane status is not out of the question for this one either. The next day or so will be critical; the further west it gets before recurving, the stronger it gets. Imagine the eye will pop out on the first few visible images of the day in the east Atlantic - it's a classic Cape Verde storm, but also a classic fish spinner.
* Wave train over Africa is well established, but we may see a brief lull of a wave or two after Danielle moves away. Waters out there aren't *that* warm yet and the strengthening of Danielle is going to churn them up just a bit. It's folly trying to predict storm formation (or no formation) from something over the middle of Africa, but I think we'll have a few days' respite before the next waves get cranking in the east Atlantic.
* Those of you in the Tallahassee area interested in seeing some Bonnie or video in a couple of weeks, feel free to PM me and I'll fill you in on the details. Our local AMS chapter should be showing some video of Bonnie's onslaught and 's aftermath later this month.
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Current Tropical Model Output Plots
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Clark
Meteorologist
Reged: Wed
Posts: 1710
Loc:
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For those interested in a more comprehensive view of the technique, including how all storms are broken down into four categories (I was close before - there's also a curved band pattern), the Australian Bureau of Meteorology has an excellent resource available online:
http://www.bom.gov.au/bmrc/pubs/tcguide/ch2/ch2_3.htm
Specifically, read through section 2.3.2 while keeping their figures 2.4(a,b) and 2.5(a,b) open in a separate window.
It may be more information that you ever wanted to know about the technique, but it gives you a comprehensive view of what an analyst goes through when assigning a subjective T-number. It's worthwhile to note that objective analyses go through the same process without the human constraints/enhancements (depending on how you want to view it!).
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Current Tropical Model Output Plots
(or view them on the main page for any active Atlantic storms!)
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HanKFranK
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Reged: Mon
Posts: 1841
Loc: Graniteville, SC
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late, winded from mountain biking this afternoon.. keeping it terse.
charley heading out, going the way of bonnie. end of story.
danielle strengthening, likely to recurve far out to sea. SSTs out 2-3 days aren't terribly warm, southwesterly shear ahead.. but as the storm makes it's right turn the relative shear should drop and SSTs up near 25-30N in the east atlantic are warmer. dependent on how dramatic a recurvature takes place.. a significant remnant cyclone may make a run toward the iberian peninsula later on.
not likely at this point, though. storm has some potential to be major.
earl. jk's assessment on the strengthening this evening looks valid.. feature trying to assert itself. should be going through the islands tomorrow afternoon/evening. if we have a hurricane out of earl before midweek look for a track to the right of the guidance envelope.. and potential interaction with the greater antilles. if it gets to hurricane after midweek expect it to be to the left and nearing the yucatan. i'm siding with the stronger earl, getting into the gulf around next saturday. already posted earlier a quote from the hpc discussion.. the later solution at this time is a recurvature into the central gulf coast around monday.. grand isle to apalachicola. bonnie redux. i suppose keeps indicating a shortwave lifting out of texas around then.. it was yesterday. not very specific, but i'll go with the consensus on all that.
old trough boundary hanging in the central gulf deserves a glance but not much more. another piece of the old trough drifting nw near bermuda.. very limited convection and almost no chance. wave that was tailing danielle is lapping it and being mostly entrained (note the mid-level vortex devoid of convection NE of danielle's center).. follow on wave around 10w looks well-defined at this point. watcher when it comes off monday behind danielle.
gfs wants to develop more systems in the future.. the further west they start up (closer to 50w off the ).. the more likely they are to be players and not fish spinners. earlier noted that we are strangely in positive and basin convection should be inhibited.. signal seems to be masked and not running the show right now. very negative last few days as noted by steve... shots of strongly negative phase will contribute to the onset of an el nino warm phase. we're getting there.
HF 0555z15august
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LI Phil
User
Reged: Fri
Posts: 2637
Loc: Long Island (40.7N 73.6W)
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You two gentlemen are more than welcome to post any time any where on these boards. Lord knows I (and I am sure many others) are quite thankful for your insightful posts, and I am learning everytime I log on. Keep up the great posts!
Sorry to anyone if I overreacted (much) earlier this evening, but we cannot have posters who treated this storm as a summer shower. Enuf said.
Peace & best to all affected by (which is actually dumping on me right now...just rain & a bit of wind-nothing like SFL residents faced...prayers for them)
LI Phil
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2005 Forecast: 14/7/4
BUCKLE UP!
"If your topic ain't tropic, your post will be toast"
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Clark
Meteorologist
Reged: Wed
Posts: 1710
Loc:
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Lending credence to the recurvature of Earl is the latest run of the UKMET model. Of course, the UKMet didn't do so hot at times with Bonnie and , but it's still interesting to note.
It is a bit faster than the , calling for landfall in about 6 days. The path is almost redux - interaction over Jamaica, passing over the western tip of Cuba - up until what it does in the Gulf, where it takes the system into the Florida panhandle just west of Apalachicola. It makes it a strong system, though the guidance I have just says "STRONG" as opposed to saying how strong. The doesn't really initialize Earl in the last run I saw (18z yesterday), but the midlatitude features are ominous for the eastern & central Gulf. The last I've seen (12z yesterday) takes this system into the Ft. Myers area - sound familiar?
In any case, it's one to watch over the coming days, and I'll buy the stronger Earl and the resulting track as well. The saving grace would be some significant interaction with Cuba - I'm not sure it'll gain enough latitude to really be affected by the Dominican Republic. Only time will tell.
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danielw
Moderator
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Loc: Hattiesburg,MS (31.3N 89.3W)
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I believe you or one of the other mets on the board said something the other day/night about the pressures being higher than normal this year. Would this be part of the reason the models are Not picking up the storms. Pressure differential and gradient are out of the norm? I know I set myself up for that one, but I'm used to getting better data from buoys and such. This year I haven't been able to tell that a storm was anywhere around the buoys.
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HanKFranK
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Reged: Mon
Posts: 1841
Loc: Graniteville, SC
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bonnie and were tight, compact systems. with a tight inner core the pgf (pressure gradient force) is higher, which tends to accelerate the winds higher than you would normally see with a large-envelope storm of the same pressure. you get less widespread damage than say a hugo type storm, but more bang for your buck in the zone.
HF 0626z15august
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danielw
Moderator
Reged: Wed
Posts: 3525
Loc: Hattiesburg,MS (31.3N 89.3W)
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Thanks HF. Have any of you seen the PSU loop?It shows Earl sitting over Cozumel at 126hrs from 18Z yesterday. That would be 00Z on the 20th if i calculate that right. Thursday night at sundown. Another weekend landfalling storm!
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Clark
Meteorologist
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Posts: 1710
Loc:
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HF took care of most of the question (very well, I might add), but I'd also like to add a thing or two.
The pressures being higher on average won't affect the models picking up the storm, just that a higher pressure than normal inside the storm can result in higher wind speeds than one might expect from climatology. This goes into the PGF stuff HF mentioned - the gradient wind.
Models can't initialize a tropical cyclone well at all, though they tend to be able to pick up on a vortex once it is well-defined or if it is large enough. The resolution in many of these global models is not very high - 12 to 40km - meaning that smaller systems may have additional troubles being captured in the model analyses.
The buoy system is very useful, but there aren't terribly many buoys out there. With these small systems, it's tough to find many impacts unless the center passes near or over a buoy. Bonnie passed very near buoy 42001 in the northern Gulf and some impacts were measured there; I believe the used it as justification for some intensity changes.
GFDL 12Z on Earl did not really even capture the storm, so I'd like to see some more run-to-run consistency with capturing the storm before latching on to where it may head. I did see the 18Z to the Yucutan, however, and it certainly is one possibility out there...can't really discount anything right now, unfortunately.
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danielw
Moderator
Reged: Wed
Posts: 3525
Loc: Hattiesburg,MS (31.3N 89.3W)
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I seem to remember the taking one of the other storms to the same area. Just looking at the previous weather patterns most could probably pick that location out.
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danielw
Moderator
Reged: Wed
Posts: 3525
Loc: Hattiesburg,MS (31.3N 89.3W)
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Post deleted by danielw
Edited by danielw (Sun Aug 15 2004 04:35 AM)
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