Hurricane Katia

[Rainshadow]

We know that the UKMET has been on the left side of guidance with its forecast tracks of katia.

What's interesting about its 0z run is that its further south again after shifting north on the 12z

run yesterday.This looks like the UKMET has moved into the Euro Op and Ensemble camp.

12z

0z

I know past performance is not necessarily an indication of future trends, but the ukmet, nogaps and gfdn have had some of the largest southward bias(es) with Katia during the past 48 hours. Conversely the gfs has had some of the largest track errors with Katia so far, it has had a slow bias. The web site does or can not verify the Euro.

[donsutherland1]

So basically what support did Avila have for the following statement below? I know this is stupid to be arguing over, but now they are going to have a 85 knot storm at 11am that will be considered a rapid intensification case from 60 knots (25 knot increase in intensity in 12 hours) when in reality the storm was likely already 65-70 knots at 11pm and underwent more modest intensification (15 knots). Hopefully this is corrected in the post-analysis.

I agree with you, Phil. This is an interesting issue. I'm really curious what additional guidance NHC uses.

At 11 pm, I could see NHC's being cautious about fluctuations to see if Katia would sustain its apparently regained hurricane strength and holding it at 60 knots at 11 pm, but at 5 am, the satellite data still showed a hurricane (CIMSS had improved since 11 pm). My guess is that this is an issue that will ultimately be corrected in the re-analysis.

[WeSuck]

Looks like an "Eye" is visible

http://www.ssd.noaa.gov/goes/flt/t2/flash-vis.html

[phil882]

best track updated with the initial intensity set at 85 knots.

[battlebrick]

http://www.ndbc.noaa...p?station=41044

this buoy was right in the middle of the storm.. 77.7 kts sustained at 7:39 am AST, 93 kts gust at 8:55 am AST.

Pressure was 28.60 at 7:48 am AST, 968 mb.

Those wave heights are pretty massive too, ~33 ft.

Nice RI.

[donsutherland1]

Katia regained hurricane strength overnight and has been steadily intensifying since then, reaching Category 2 by 11 am (maximum sustained winds of 100 mph). My guess remains that Katia will peak as a major hurricane, possibly reaching Category 4 status.

Over the past 6 hours, Katia tracked at a 302° bearing. Since 11 pm, its track has been northwestward at 310°. I expect that motion to continue through the day today.

In terms of analogs, there have been some changes since I last listed my analogs on Friday. My ten analogs at this point would be: H4 (1893), H1 (1927), H13 (1933), H13 (1936), H7 (1944), Carol (1953), Gladys (1975), Gloria (1985), Edouard (1996), and Floyd (1999). 6/10 (60%) of my analogs from 9/2 (Post #561) remain relevant. The top analog right now is Hurricane #1 (1927).

In contrast, the FSU-generated analogs have retained only 2 (20%) from 9/2 18z. Curiously, one of those two analogs is Irene (1981), which recurved after reaching 57.2W. Katia is already west of that position and continues to track ever farther away from where Irene recurved.

When one takes into consideration the likely 500 mb pattern (GFS ensembles), the odds of landfall are not as great as might be implied by my analogs. Indeed, I believe a worst-case scenario would be a track close to either Hurricane #7 (1944) or Floyd (1999), but those would be low probability scenarios. Right now, I still believe odds of recurvature without landfall are around 60%. Were landfall to occur, North Carolina’s Outer Banks would probably be the best candidate.

With the 9/4 0z and 6z GFS considerably farther east than the 9/4 0z ECMWF, I will leave my estimated track unchanged. I am leaning toward revising some of the positions from 30.0N and northward somewhat to the left, but the GFS argues for caution. I do believe that once the storm reaches 40°N +/- 2.5°N, it will be turning more aggressively toward the east.

Estimated Track:

17.5N 52.8W; Actual: 17.5N 52.4; Error: 26 miles--1.5 hours in advance

20.0N 56.8W; Actual: 20.0N 57.0W; Error: 13 miles--33.0 hours in advance

25.0N 63.9W

30.0N 72.0W

35.0N 69.6W

40.0N 63.5W

[k***]

If she wants to go annular her structure certainly provides a nice jumpstart to the process

[Nikolai]

Rather gorgeous eye now apparent on satellite... definitely looks like a Cat 2+. Eagerly anticipating the 12z EURO and any surprises it may have in store--not to mention the GGEM et al.

It may just be the emergence of the eye, but Katia also appears to be taking a due W jog at the moment as well.

[bluewave]

It did shift west with Lee's remnants and now has more ridging along the coast than at 0z.

0z

12z

[donsutherland1]

Some quick model links:

AmericanWx (RaleighWx/Allan's Links): http://raleighwx.americanwx.com/models.html

NCAR (Hurricane Models): http://www.ral.ucar.edu/hurricanes/realtime/current/

NCEP: http://mag.ncep.noaa.gov/NCOMAGWEB/appcontroller

[usedtobe]

It did shift west with Lee's remnants and now has more ridging along the coast than at 0z.

0z

12z

But that's still not a pattern conducive to Katia making landfall over teh U.S. The big broad ridging over the western u.s pretty much means there will be n

rthwesterly flow over eastern canada and even maine. Which means unless Katia comes wwd enough to impact the outer banks, it should turn eastward rather sharply before getting to southern New England. My guess is the odds are about 80% or more for a fish storm. of course, 15 or 20 percent chance still does not completely rule out a hit, it just makes it unlikely.

[tmagan]

12Z UKMET Hour 144

[dan88]

Might get a research plane in there Tuesday Morning.

SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)

VALID 05/1100Z TO 06/1100Z SEPTEMBER 2011

TCPOD NUMBER.....11-096

I. ATLANTIC REQUIREMENTS

1. NEGATIVE RECONNAISSANCE REQUIREMENTS.

2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.

3. REMARK: POSSIBLE NOAA G-IV RESEARCH MISSION

FOR HURRICANE KATIA TAKING OFF 06/1100Z.

[bluewave]

But that's still not a pattern conducive to Katia making landfall over teh U.S. The big broad ridging over the western u.s pretty much means there will be n

rthwesterly flow over eastern canada and even maine. Which means unless Katia comes wwd enough to impact the outer banks, it should turn eastward rather sharply before getting to southern New England. My guess is the odds are about 80% or more for a fish storm. of course, 15 or 20 percent chance still does not completely rule out a hit, it just makes it unlikely.

So far I like a recurve closer to the Euro with the potential for bigger surf near the coast than the GFS is showing.

[k***]

[Clinch Leatherwood]

Very decent agreement between the GFS and Euro through 72 hours. I'd post the attachment but that still doesn't seem to be working.

Roughly translated the Euro isnt burying the system as far south as it did on the 0z, has shifted north early in the period.

[Amped]

0 East Coast landfalls on the latest GFS ensembles. I am upping my odds of an OTS storm from 99% to 100%.

http://www.meteo.psu.edu/~gadomski/ENSPRS_12z/ensloop.html

[atownwxwatcher]

12 Z ECM looks to me to be Southwest of the 12 Z GFS at 72 and 96 hrs

[atownwxwatcher]

120 hrs..its closer to the coast then the 12 Z GFS IMHO

[k***]

None of the globals have shown any real run to run consistency, its hard to say that one should be weighted more than the other at this point

So you wouldn't wager that the euro is more likely to be right than the UKMet?

[IsentropicLift]

Is that a true "pinhole" eye? There was a larger ragged eye on the last few frames before being replaced by this

[violinist]

Im glad u think u know more than everyone else then.....its does seem to be looking like a fish storm but to say that will such certainty is arrogant

I dont think its arrogant, rather confirming what almost everyone else in this thread seems to think, that Katia , in all probability , will not hit the coast. I would like to see what the EC indicates, since it was one of the models that showed a east coast hit. And considering that he is only raising his opinion by 1$, that is hardly much of a change. It's just his opinion. Mad cheese seems to know what he is talking about based on previous posts. I wouldn't argue with him but that is my opinion.

[IsentropicLift]

So you wouldn't wager that the euro is more likely to be right than the UKMet?

I personally favor the Euro every other model, but we have seen big run to run shifts over the past week, and the latest Euro has shifted somewhat offshore, with if you can believe a sub 930 low off the mid-atlantic coast

[Hoosier]

12z Euro violently recurves away from the east coast.

[Amped]

Okay I stand corrected.K*** do you think he's arrogant?? thanks

Sometimes I do. This time I think models ensembles are sending a clear signal unanimous signal.

But sometimes I make stupid calls like Hurricane Irene OTS based on the east trend and the west bias of models. It didn't happen. The east trend stopped and the Euro was only a little to far west.

[thewxmann]

12Z Euro solution is probably the most sensible one... I'd take that as my forecast track more or less thru 5 days.

[dan88]

SHIPS was initialized with 90kt, so baring any significant changes, probably what the 5pm advisory will go with.

[usedtobe]

12z Euro violently recurves away from the east coast.

I think a violent recurve is the most likely scenario tho exactly how quickly is still a little in doubt. Still the pattern shown on the GFS and Euro strongly favors and out to sea solution

[k***]

Now the eye is gone all together on IR, what's going on?

chill...it's common for the eye to wax and wane in size, shape, and clarity when a hurricane is starting to develop one.

[bluewave]

I think a violent recurve is the most likely scenario tho exactly how quickly is still a little in doubt. Still the pattern shown on the GFS and Euro strongly favors and out to sea solution

Yeah,beyond 120 hrs a sharp right would be in order with the trough digging over SE Canada and the westerlies dipping south.