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Hurricane Katia


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All of you weenies need to look at hour 216 of the Euro. Yes, it's far out, but it also shows consistency in terms of a recurve. This is not a significantly further west recurve... this is pretty much the same except just before hour 216, she gets bumped a little to the west before being recurved by that gigantic trough of no escape coming off the east coast.

I'm not trying to defend anyone, but it is a marginal situation with the trough, is very far off and will change several times over. Obviously a recurve is very likely in this circumstance based on climo in the direction Katia is moving (WNW at current Lattitude), but any change in the strength/orientation of the trough, if at all, even assuming any accuracy in the 7-8 day timeframe, could result in drastically different tracks.

Wavelength also seems a bit long for early Sept but that could be decieving.

12zeurotropical500mbSLP192.gif

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All of you weenies need to look at hour 216 of the Euro. Yes, it's far out, but it also shows consistency in terms of a recurve. This is not a significantly further west recurve... this is pretty much the same except just before hour 216, she gets bumped a little to the west before being recurved by that gigantic trough of no escape coming off the east coast.

Not trying to wishcast but just a question - The recurve depends on either 1. the trough being positively tilted? and 2. interaction with Katia in a way that it doesn't pass her by? I can tell by looking at the model that this trough is certainly oriented in a way to pick Katia up move it away before it threatens the east coast as currently modeled. Just trying to get a better handle on how these larger hurricanes move in the overall flow.

Would this storm start to look more like an EC threat if either A. the trough trended from a positive to a negative tilt (does that even happen very often this time of year?) so that it slings the storm more north/NNW rather than NNE when the storm gets picked up? OR if the trough was much weaker and "misses" picking up Katia allowing the atlantic ridge to build in and steer the storm more west as we saw with Irene?

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All of you weenies need to look at hour 216 of the Euro. Yes, it's far out, but it also shows consistency in terms of a recurve. This is not a significantly further west recurve... this is pretty much the same except just before hour 216, she gets bumped a little to the west before being recurved by that gigantic trough of no escape coming off the east coast.

What they DON'T need to look at is the 240 hour prog off the FIM! :devilsmiley:

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Well obviously now I have to go check.

It shows nothing cool. I've been meterologically rick-rolled. lightning.gif

Try this... http://fim.noaa.gov/FIMscp/jsloop.cgi?dsKeys=fimy:&runTime=2011083112&plotName=wind_10m&fcstInc=360&numFcsts=41&model=fim&ptitle=Experimental%20FIM%20Model%20Fields&maxFcstLen=240&fcstStrLen=-1&resizePlot=1&domain=236&wjet=1

I think the normal FIM is from yesterday. This is some variation.

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Try this... http://fim.noaa.gov/...main=236&wjet=1

I think the normal FIM is from yesterday. This is some variation.

Sorry, yes, I meant the experimental FIM-Y. While I think we are probably at 90% for a recurve east of the CONUS, as someone pointed out looking at a different model yesterday, the fact that a model can construct a solution like this helps show there are still a few low probability outliers out there.

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More on the use of the heading between 25W and 30W. I looked at 79 1851-2010 storms that are recorded as having become a TD by 28W:

1) Headings of 270 deg. or less:

- 18 TC’s.

- Avg. furthest west they got: 72W

- % that made it to 70W: 61%

- CONUS hit %: 50%

2) Headings of 271-280 deg.:

- 33 TC’s

- Avg. furthest west they got: 68W

- % that made it to 70W: 39%

- CONUS hit %: 27%

3) Headings of 281-290 deg.:

- 18 TC’s

- Avg. furthest west they got: 56W

- % that made it to 70W: 6%

- CONUS hit %: 0%

4) Headings of 291+ (Katia is in this category since its heading was at ~293 deg. Between 25 and 30W):

- 10 TC’s

- Avg. furthest west they got: 53W

- % that made it to 70W: 0%

- CONUS hit %: 0%

5) All headings combined:

- 79 TC’s

- Avg. furthest west they got: 64W

- % that made it to 70W: 32%

- CONUS hit %: 23%

So, this indicator, alone, suggests that Katia, which had a heading of ~293 deg. between 25 and 30W, has only a very minimal chance of hitting the CONUS. The 12Z GFS and Euro both have it making it almost to 70W, which would in itself be a notable accomplishment considering that only one of 28 TC's with a heading of 281+ made it past 70W (Faith of 1966).

Despite models getting it pretty close to 70W, I'm maintaining a 90% chance of Katia missing the CONUS based on how it headed between 25 and 30W since that appears to be a strong climo indicator of the future track as well as based on the fact that the GFS and Euro are still not hitting the CONUS.

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IMO, find out what climo says the % is for a recurve for a TC at Katia's current location and then add about 5-8% as of right now.......just my own way to roughly ascertain the uncertainty at these still, fairly long leads......

So that gives it 100% to 108% chance of recurve.

Obviously the further SW it gets the better cance it has wen the troff finally dous pick it up. Also if the first troff misses it and moves into the central atlantic it shifts the shifts the center of the ridge back toward the western atlantic. and may turn the storm back west. It has a lot of shear to contend with this time too.

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So that gives it 100% to 108% chance of recurve.

Obviously the further SW it gets the better cance it has wen the troff finally dous pick it up. Also if the first troff misses it and moves into the central atlantic it shifts the shifts the center of the ridge back toward the western atlantic. and may turn the storm back west. It has a lot of shear to contend with this time too.

I was talking about location only....Larry broke it down further to current heading, which obviously would suggest a further increase in recurve, but looking into the very short term, there is a good chance that we have will have a heading close to 270, and a recalculation based on historical data would most likely lead to a pretty good increase in LF chances with the new samples (maybe back to 20% or so....just guessing)

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Average model position error for Katia through 18z model runs I only plotted the top 6 performing models through 18z plus the GFS=AVNO. GFS isn't doing so hot. Obviously we will see a change in which models have the lowest error as time progresses but I think this is worth viewing to at least see which models are doing well handling it's position in the deep tropics. It can at least give us some insight into where it may be positioned in the next 48-72 hours which will in turn translates into comparing that position with what the globals are indicating post-3697-0-71830400-1314839715.jpg

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Dry air has been keeping Katia in check, but its not stopping it from slowly intensifying... The most recent convective burst has wrapped almost all the way across the center, and there are hints of a weak echo area near the center starting to form. Whether or not Katia undergoes RI in the next 24 hours will be determined if it can close off that NW quadrant from dry air entrainment.

2dsgwhd.jpg

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I would find it very hard to imagine that the 11:00 pm advisory will not classify this as a hurricane now, given the improved presentation.

Not sure if this means anything, but they call it "Hurricane Katia" for the early track guidance map...

http://www.ral.ucar.edu/guidance/realtime/plots/northatlantic/2011/al122011/track_early/aal12_2011090100_track_early.png

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Interestingly enough all 6 of them have a slight bend back to WNW too at the end of the model run. Of course it's one run so take it for what its worth which is not a whole lot.

If that thing bows back to the west at that point , we are in deep dodo baby. Isabelle track familiar? Good God !

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