cieldumort
Moderator
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Posts: 1047
Loc: Texas 30.40N 97.80W
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Helene has really gotten her act together overnight. As of this comment (about 3AM CDT) she appears to have all but completely pushed out and away any remaining detrimental SAL, and has blossomed a very pronounced deep convective core roughly right on top of her center. Additionally, it also *appears* that she has been making an attempt to develop some embryonic buzzsaw-like banding. Really ramping up. Good thing for us for her to ramp up quicker than anticipated, as there have been some subtle hints among a few models that the ridge may be a little too strong for a weak southerly track Helene to punch. Even now it would seem that Helene is a bit west and south of where she was forecast to be, such that it might already be too late to expect her to be captured and whisked away for 100% certain.
Sure looks like Helene is headed to become our next hurricane - I would go out on a limb and say she wants to cane today, and might even just do it.
For entertainment purposes, take a look at the piece of energy that has broken off of early Helene and has been trailing behind to her east. This would be really something if it pulls a Gordon - or even close to pulling a Gordon.
Hmm 5AM is out.
Edited by danielw (Fri Sep 15 2006 06:08 AM)
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Lee-Delray
Weather Master
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Helena bearly made the news this AM in West Palm Beach. But, he did say that some of the models showed it might head west after Tuesday (which would hit S, FL) and to stay tuned. I think he must have been sniffing the model glue.
Other than an "iffy" I don't see it.
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typhoon_tip
Meteorologist
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Posts: 551
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Quote:
...Other than an "iffy" I don't see it.
A partial explanation as to why the has this W bias is likely related to the model having a weaker system, such that it is not as vertically integrated within the predominant steering levels as the stronger versions of the cluster (which includes the s in this latter sense).
A shallower system, as it is often referred....will subject the system to steering levels that are lower in the troposphere..
Currently, if you look at the satellite on water vapor and infrared channels http://www.ssd.noaa.gov/goes/east/catl/loop-avn.html
...you can see a fairly concerted motion toward the W and even WSW in the vicinity of Helena and points W... There are other levels that we cannot infer from these vantages...But, what is apparent here when looping is a general motion toward the W and WSW along 15-20N. This is < 700mb stuff.
I would suggest comparing the first 12 to 18 hours off the 00Z run, against what has verified since then for starters. Compare also intensity profiles for each interval. This would be to get an initial impression of where, if any, errors the model is already commiting... If there are a few, anything that takes place subsequently down wind (out in time) would have to be suspect.
John
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allan
Weather Master
Reged: Thu
Posts: 468
Loc: Palm Coast, Florida 29.55N 81.20W
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Wow I never thought i'd see the this far south on the new run.. Shows it just miles north of the Lesser Antilles. Another shock is how the models are now moving it more westward to and there strengthening the ridge more tahn they did earlier. Bermuda may be another target yet maybe the USA now has bumped up to a good 10 to 15% chance of strike. Not putting any bets on it right now but interesting to see the models really jump south and move it more westward. It was supposed to curve NW today which did'nt happen. is not a bad model because it has really helped us out with and Jeanne. This is all something to watch for the coming week. 
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Allan Reed - 18,9,5
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Lee-Delray
Weather Master
Reged: Thu
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I noticed a bit of a shift too, but we are still too far out to have any certainty. Problably won't be until one of the Saturday runs until we have a clearer picture.
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Cat 5orBust
Weather Hobbyist
Reged: Tue
Posts: 90
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still way too early to see if this will be a threat or not, but there has been a little consistancy with every run of shifting the track just a touch to the left. regardless of any shifts in the track in the coming days, there wont be a solid feel for what the ridge will be like for several more days after. it is historically unlikely of a landfall along the coast but if that ridge builds in where the weakness was supposed to be then all bets are off. will be an interesting feature to see unfold over the next week.
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Solak
Verified CFHC User
Reged: Mon
Posts: 11
Loc: Raleigh, NC
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No one's brought it up yet... I'm curious to see what that mid-level Low dropping SE out of Virginia will have to do with the Atlantic steering currents over the next few days. That, and the fact that Gordon has barely moved today. What effect will that have on the Atlantic High pressure ridge? Certainly getting stacked up out there at the time being.
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typhoon_tip
Meteorologist
Reged: Wed
Posts: 551
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Quote:
still way too early to see if this will be a threat or not, but there has been a little consistancy with every run of shifting the track just a touch to the left....
Oh I'd say the shift has been more than just a touch... Problem is likely that we are seeing such a large amount of room to spare that large correction may appear minimal at first impression.
However, for what it is worth, the 18Z has trended a little more than 500km SW of its 12Z position... Not bad for a 6-hour difference.
12z 144 hour had Helene ~52.5W/29N,
18z 138 hour has her ~56.0W/26.5N
This trend is also a continuance between the 06Z and 18Z run, or 12 hour difference... That differential is:
06z, ~52.0W/34.0N
18z, ~56.0W/26.5N and plugging those values in gives a little over 940kms for a 12hour model differential...
You can see for your self:
http://moe.met.fsu.edu/cgi-bin/gfstc2.cgi?...&hour=132hr
http://moe.met.fsu.edu/cgi-bin/gfstc2.cgi?...&hour=144hr
This is bordering on a demonstrative trend... That's obviously ~475km per 6-hour run and fairly large run to run corrections now over the last 12-18 hours. Meanwhile, the has persisted left, almost due west between 108 and 144 hours across 2 cycles of its own runs. Interesting...
John
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GuppieGrouper
Weather Master
Reged: Fri
Posts: 596
Loc: Polk County, Florida
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Just saw a local report showing the prediction of Helena turning out to sea even sooner than Gordon. The way it was presented is that Florence Turned out at a more western longitude, with Gordon more Eastward at turn and Helena more eastward than that. At this rate the AZORES will get pounded by the next forming storm.
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God commands. Laymen guess. Scientists record.
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Storm Cooper
Moderator
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Loc: Panama City Beach, FL 30.22N 85.86W
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The models are not certain right now for the most part. Plenty of time if anything were to really change...
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Hurricane Season 2012 11/5/2
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scottsvb
Weather Master
Reged: Mon
Posts: 1088
Loc: fl
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models have been certain for a month out there!!! nothing will make it west of 65W...too much troughiness...only chance is something near the bahamas dropping off a front..or in the gulf or carribean....there is no bermuda high and this time of year..its usually the azores high... I mention the bahamas cause a weak ridging off the east coast might push a system back...but it matters on how strong a ridge will form this time of year....usually they last only a day or 2 before the next trough comes down from the midwest. Helene chance is less then 10%
(While I tend to agree with your thinking, when the switches from western New England to east of Bermuda on the same day, I would not suggest that the models have been 'certain'. Try a lump of diplomacy in your cup of response - it goes a long way.)
Edited by Ed Dunham (Mon Sep 18 2006 08:55 PM)
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Cat 5orBust
Weather Hobbyist
Reged: Tue
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i noticed in the latest runs some models move west to wsw over time before the turn to the northwest begins. if this happens it obviously would take longer for it to get caught in the flow and pushed back into the atlantic. if this process takes longer is there anything down the line that shows a high building back in and maybe pushing it closer to t he u.s. than what is forecast? http://euler.atmos.colostate.edu/~vigh/guidance/atlantic/early1.png
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Wingman51
Weather Guru
Reged: Tue
Posts: 122
Loc: Orlando, FL 28.41N 81.24W
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The 11 indicates that Helene is now a Cat 1 storm and is continuing the NW motion - - will the Cold front the passed through the southeast this week keep her to the south and moving west or is there not enough strength to allow that to happen - - Just asking 
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allan
Weather Master
Reged: Thu
Posts: 468
Loc: Palm Coast, Florida 29.55N 81.20W
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Well looking at more models shift west and head it to Bermuda or even close to the USA. Very interesting but I knew that this would soon occur. The high is just too strong to pull it northward that quick. No bets yet... still needs to be watched and the East Coast should moniter it. Bermuda is the target though for now. model takes it dramatically close to the NE coastline of the USA. Wonder if it will shift near or far next run? This is certainly a westward shifting day for the models. still shows the high weakening and turning Helene northward. I clearly don't see it happening anytime soon. Bermuda has another storm to watch.. Maybe the USA.. too soon yet.
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Allan Reed - 18,9,5
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Clark
Meteorologist
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Posts: 1710
Loc: Great Lakes 45.95N 84.55W
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I wouldn't say "dramatically" close to the NE in the 12Z -- it has it getting caught up in a frontal boundary and ultimately heading to Nova Scotia. That's 9 days out in the model, though, and a LOT can and will change between then. We have enough trouble figuring out a 3-5 day track before speculating on a 9 day track.
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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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Loc: Graniteville, SC 33.56N 81.82W
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i wouldn't worry about helene making it that far to the west. much of the modeling has a sort of blocking type ridge east of the canadian maritimes that kind of pulses up and down and causes the storm to wiggle west as shortwaves go by.. but once it gets southwest of the ridge max and through the subtropical ridge axis, up it goes. the longwave pattern just isn't right for a longtrack hurricane to get to the u.s. unless it stayed at extremely low latitude and weak enough to not feel the passing systems in the westerlies.
globals are showing subsequent development from waves off africa into the next week or so. this is not likely to continue for much longer, as we're into the middle of september and that region tends to shut down during the last week of the month, from east to west. we're getting into the part of the year where the caribbean/SE 2/3 of the gulf becomes the focal area for threatening development (though development can still occur over much of the central atlantic as well). globals show generally zonal H50 ridging across the western atlantic/gulf near 25-27N being established in about a week, with rising heights in the western atlantic. also synoptically lowered pressures and a slowly progressive longwave trough in the west. makes me think the last week this month may try to send something up out of the caribbean, sort of as a parallel to the two hurricanes (john and currently lane) impacting the west coast of mexico. there is nothing apparent right now... just a good hunch. there will probably be at least one repeat of the pattern going into october... and more amplifications into the east. it's sort of the last remaining threat this season, as the september burst of activity arrived when the longwave pattern had that familiar early-2000s look that resulted in so little activity prior to the 2004-2005 run.
so far we've got alberto and (and i guess weak beryl on nantucket) to show for 2006. it's more than halfway over and this has been a mild hurricane season. barring any late surprises or sudden bursts of activity, this could be the first year with no US hurricanes since 2001. can't really put any money on that until around mid-october and the end of the caribbean to florida climatological window... but it's conceivable at this point.
HF 1751z16september
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Steve H1
Storm Tracker
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Loc: Palm Bay FL USA
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Wow, talk about a west trend, the 18Z is much further west than the 12Z , taking Helene into the Bahamas and about 75 miles east of Cocoa Beach! Not that I'm buying it yet, but it shows the trough lifting out quickly leaving strong ridging coming into/off the eastern seaboard at what, day 9. I want to see the 18Z . Be interesting to see the future runs. CHeers!!
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typhoon_tip
Meteorologist
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Posts: 551
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For what it is worth...the DGEX has a massive W shift too, and places Helene dangerously within 200m of the SE U.S. Coast in its 18Z run...
I would like to call it to folk's attention that special missions were flew to sample the surrounding atm environment during the day today... It was commented by TPC that these were done primarily for SAL purposes. I believe it was probably so they could more accurately get a handle on intensity prospects, as the last 24 hours have not shown what for all conventional wisdom should have been a better intensity behavior.
Be that as it may..the upshot of these missions is that there is a denser data field thus available for the 18Z ingest and initializations. That is intriguing because as I pointed out earlier in this thread, yesterday showed a very large trend W in the solutions spanning 12 hours... The 24 hour change, which I did not post, as of 06Z this morning had increased the SW position adjustment 1,300+kms! That is an interesting talking point that is being avoided by official agencies, and one that is of huge importance, particularly when we have a background +NAO signal out there... That signal would teleconnect to a 50/50 height rise tendency and now that we are seeing that in todays runs, the W motion thus gains plausibility in my mind.
Before we get to excited, there is still nearly 200 hours in the 18Z run before this would be a threat to anyone... That means there is a very large degree of uncertainty related to assessing details in the flow that will have effects. Tonights runs will be interesting...
John
Edited by typhoon_tip (Sat Sep 16 2006 08:25 PM)
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HanKFranK
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Loc: Graniteville, SC 33.56N 81.82W
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just saw the 18Z . we're talking a whole different ballgame if the other 00Z runs pick up on the huge westward shift it has shown. all that chaos in the guidance actually meant something earlier... later runs are increasing the ridging in the western atlantic and having the shortwave totally miss helene (it picks up the hybrid type system forming east of hatteras this evening). we've seen , florence, and gordon make funny recurvatures with little catches or bendbacks in them. could be this NAO positive thing tending to snap ridges back together to the northeast of systems, and blowing shortwaves out faster (as well as the longwave pattern with increasing troughing in the west/central u.s. and the tropical east pacific feeding amplification over there). helene still has very little chance of making it to the u.s. coast, but these recent westward trends may be on to a big switch in the expected height pattern off the east coast.
the western gulf may come of interest late next week as a tropical wave interacts with an amplifying trough. it would probably just break free and head west under rebuilt ridging anyway.
gfs is showing the eastern atlantic generate another storm this upcoming week, and is still trying to develop waves to the end of the month. i have a hunch they will develop slower than shown, as the season is getting later... it's possible some of that wave energy will be trying to develop closer in or perhaps play into a caribbean development near the turn of the month.
if anybody remembers kyle in 2002... the storm that kept swerving westward and meandered in the western/central atlantic for almost three weeks... this could be an analog pattern at least briefly and give helene a good lunge into the western atlantic.. provided it still doesn't just snag the first shortwave and wheel up to the north atlantic.
HF 0221z17september
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Cat 5orBust
Weather Hobbyist
Reged: Tue
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if you read the 11 discussion the states that with the latest run, it could be suggesting a significant change in the forecast track in the future, but until other models catch on they will adjust the track only slightly. seems like the potential of it affecting the U.S. keeps going up as each day progresses.
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