Hurricane Katia Part 2, TS Watch for Bermuda

[OSUmetstud]

Katia has weakened to a 75 kt category one hurricane. It expected to pass between the US and Bermuda and merge with the westerlies.

[k***]

we havent had a good truck tire in the ATL in a while...

[OSUmetstud]

newest microwave at 1224z.

[OKpowdah]

That microwave imagery, along with zoomed in satellite definitely shows at least one mesovort along the eyewall, which would be encouraging mixing, and the development of a more annular appearance at least with the inner core.

Last few IR frames have been improving in leaps and bounds

[OSUmetstud]

That microwave imagery, along with zoomed in satellite definitely shows at least one mesovort along the eyewall, which would be encouraging mixing, and the development of a more annular appearance at least with the inner core.

Last few IR frames have been improving in leaps and bounds

I'm having difficult understand the thought process here.

[OKpowdah]

I'm having difficult understand the thought process here.

Mesovortices in the eye are a common feature (and precursor) in annular hurricanes, because they mix low PV air in the eye with high PV air in the eyewall, to support the larger eye

[OSUmetstud]

Mesovortices in the eye are a common feature (and precursor) in annular hurricanes, because they mix low PV air in the eye with high PV air in the eyewall, to support the larger eye

cool...thanks. Where did you find that?

[OKpowdah]

cool...thanks. Where did you find that?

I did some reading on it a few years ago. I'll see if I can find the paper

[k***]

I did some reading on it a few years ago. I'll see if I can find the paper

http://rammb.cira.colostate.edu/resources/docs/annular_knaff.pdf

p. 211 has the relevant mesovortices stuff

[Riptide]

Katia appears to be strengthening this morning and may become a major hurricane soon by Dvorak estimates. No recon is scheduled to investigate the storm at this time due to it's low threat of landfall.

A thorough recon investigation would be preferred. It's not like we are experts on annular hurricanes. Honestly, it looks like it wants to make a run at Cat 5, very isabelish.

[k***]

A thorough recon investigation would be preferred. It's not like we are experts on annular hurricanes. Honestly, it looks like it wants to make a run at Cat 5, very isabelish.

lol...let's give it 12 hours and then see if its running at cat 5.

[OKpowdah]

Here's the main one from Knaff: http://journals.ametsoc.org/doi/pdf/10.1175/1520-0434%282003%29018%3C0204%3AAH%3E2.0.CO%3B2

Another from Wang: http://journals.ametsoc.org/doi/pdf/10.1175/2007JAS2528.1

[Srain]

NOUS42 KNHC 051445
WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1045 AM EDT MON 05 SEPTEMBER 2011
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
        VALID 06/1100Z TO 07/1100Z SEPTEMBER 2011
        TCPOD NUMBER.....11-097

I.  ATLANTIC REQUIREMENTS
   1. HURRICANE KATIA
   FLIGHT ONE -- TEAL 70
   A. 06/17Z
   B. AFXXX 0112A KATIA
   C. 06/1415Z
   D. 27.5N 66.5W
   E. 06/1615Z-06/1830Z
   F. SFC TO 10,000 FT
   2. OUTLOOK FOR SUCCEEDING DAY: PSBL 07/17Z FIX
   3. REMARK: NOAA G-IV RESEARCH MISSIONS
      FOR HURRICANE KATIA TAKING OFF 06/11Z AND 07/11Z.

[OKpowdah]

A thorough recon investigation would be preferred. It's not like we are experts on annular hurricanes. Honestly, it looks like it wants to make a run at Cat 5, very isabelish.

Usually annular hurricanes are characterized by relatively steady intensity. So while it's definitely organizing nicely right now, we're not going to see any crazy intensification. Only way it could have a shot at much above 115kt is if it had more time over warmer waters, but that is a significant limiting factor

[Srain]

A thorough recon investigation would be preferred. It's not like we are experts on annular hurricanes. Honestly, it looks like it wants to make a run at Cat 5, very isabelish.

Hmmm...not so sure about that...

THE UPPER-LEVEL ENVIRONMENT NEAR KATIA APPEARS CONDUCIVE FOR FURTHER

STRENGTHENING OVER THE NEXT SEVERAL DAYS. HOWEVER...WITHIN THE NEXT

24 HOURS OR SO...THE HURRICANE WILL BE MOVING OVER OCEAN HEAT

CONTENT VALUES THAT DO NOT NORMALLY SUPPORT SIGNIFICANT

INTENSIFICATION. THE OFFICIAL FORECAST THEREFORE INDICATES GRADUAL

STRENGTHENING OVER THE NEXT 24 HOURS AND THEN MAINTAINS THE

INTENSITY THROUGH DAYS 2 AND 3. WEAKENING IS FORECAST ON DAYS 4

AND 5 AS VERTICAL SHEAR INCREASES...AND AS KATIA MOVES OVER EVEN

LESS CONDUCIVE OCEAN WATERS.

[Riptide]

Hmmm...not so sure about that... THE UPPER-LEVEL ENVIRONMENT NEAR KATIA APPEARS CONDUCIVE FOR FURTHER STRENGTHENING OVER THE NEXT SEVERAL DAYS. HOWEVER...WITHIN THE NEXT 24 HOURS OR SO...THE HURRICANE WILL BE MOVING OVER OCEAN HEAT CONTENT VALUES THAT DO NOT NORMALLY SUPPORT SIGNIFICANT INTENSIFICATION. THE OFFICIAL FORECAST THEREFORE INDICATES GRADUAL STRENGTHENING OVER THE NEXT 24 HOURS AND THEN MAINTAINS THE INTENSITY THROUGH DAYS 2 AND 3. WEAKENING IS FORECAST ON DAYS 4 AND 5 AS VERTICAL SHEAR INCREASES...AND AS KATIA MOVES OVER EVEN LESS CONDUCIVE OCEAN WATERS.

Here are the maximum surface pressure and intensity maps, assuming optimal conditions, which is very unlikely hmm?

[k***]

Here are the maximum surface pressure and intensity maps, assuming optimal conditions, which is very unlikely hmm?

posting the clown MPI maps won't help you...just back away from the cat 5 and isabel talk and return to lurking plz

[Riptide]

posting the clown MPI maps won't help you...just back away from the cat 5 and isabel talk and return to lurking plz

I was simply stating that it could make a run at Cat 5, which is completely possible. What did you hope to accomplish?

[k***]

Here's the SHIPS output...shows some of the potential intensity issues as we move forward that the NHC was talking about

[k***]

I was simply stating that it could make a run at Cat 5, which is completely possible. What did you hope to accomplish?

Bringing up a cat 5 or Isabel is exceptionally silly right now...no one is forecasting anything close to that. Like I said,if in 12 hours it is a mid level 4 and still improving we can discuss...but it's hard to get something to wrap up that quickly given the size of the eye and environmental factors.

[Riptide]

Bringing up a cat 5 or Isabel is exceptionally silly right now...no one is forecasting anything close to that.

I'm not forecasting that either, only stating that it could happen. You did bring up some good points (epic chart) and I agree with the NHC. If Katia is going to go for Cat 5, it needs to do it within 24 hours which would support rapid intensification.

[k***]

I'm not forecasting that either, only stating that it could happen. You did bring up some good points (epic chart) and I agree with the NHC. If Katia is going to go for Cat 5, it needs to do it within 24 hours which would support rapid intensification.

Stating "what could happen" is oftentimes an excuse for just making stuff up or talking about an overly-dramatic solution. I thought your cat 5 reference and the Isabel stuff was premature and didn't add much to what was a good discussion about what the storm is actually doing.

[Ellinwood]

I'm not forecasting that either, only stating that it could happen. You did bring up some good points (epic chart) and I agree with the NHC. If Katia is going to go for Cat 5, it needs to do it within 24 hours which would support rapid intensification.

It could also weaken, but no one's brought that up yet. If you agree with the NHC that it won't become a Cat. 5 and that it is unlikely to occur, then there's no real reason to bring it up.

[Riptide]

It could also weaken, but no one's brought that up yet. If you agree with the NHC that it won't become a Cat. 5 and that it is unlikely to occur, then there's no real reason to bring it up.

There are alot of reasons to highlight the potential, mostly for the sake of personal accuracy. More importantly, if Katia does obtain Category 5 status, we won't be bashing the NHC or other forecasters because we knew that it was unlikely.

[k***]

There are alot of reasons to highlight the potential, mostly for the sake of personal accuracy.

How would this impact your personal accuracy since you aren't actually saying that it will do anything besides what the NHC said?

[OKpowdah]

I'm not forecasting that either, only stating that it could happen. You did bring up some good points (epic chart) and I agree with the NHC. If Katia is going to go for Cat 5, it needs to do it within 24 hours which would support rapid intensification.

Just stop

[Srain]

There are alot of reasons to highlight the potential, mostly for the sake of personal accuracy. More importantly, if Katia does obtain Category 5 status, we won't be bashing the NHC or other forecasters because we knew that it was unlikely.

This type of personal accuracy discussion is probably better suited for the banter thread than a pinned thread. Just a hint...

[winterymix]

I was simply stating that it could make a run at Cat 5, which is completely possible. What did you hope to accomplish?

It can't. It can attain an upper-end Cat. III but in reality, it is

rushing towards extra-tropical status. The SSTs are borderline

and shear + dry air intrusion are lurking throughout the future path

of Katia.

Primary impacts on the Continental US are increased tides/high surf.

Factor in subsidence on the west side of the storm as well.

NHC removes much realistic hope for the wish-casting crowd.

[OKpowdah]

It can't. It can attain an upper-end Cat. III but in reality, it is

rushing towards extra-tropical status. The SSTs are borderline

and shear + dry air intrusion are lurking throughout the future path

of Katia.

Primary impacts on the Continental US are increased tides/high surf.

Factor in subsidence on the west side of the storm as well.

NHC removes much realistic hope for the wish-casting crowd.

No, it really isn't

[donsutherland1]

Here are the maximum surface pressure and intensity maps...

My personal experience with those maps suggests that they are not a very useful tool for forecasting intensity. For example, Katrina exploded into a Category 5 hurricane in a region where the maps did not suggest Category 5 potential. In most cases, even when the environment is conducive for maximum intensification, the storms have lagged what the maps suggest.

Where I do believe the maps add value is illustrating where heat potential exists. But that is just one component of many other factors in trying to forecast hurricane intensity. Such forecasting has not advanced nearly as far as track forecasting. Wind shear forecasting can be inaccurate at times (early experience with Katia is one example).

With respect to Katia, early on the modeling suggested Category 4 potential (a few even briefly took it to Category 5). Then the modeling backed off dramatically, with a consensus forming as low as Category 1. Now the modeling has again grown bullish on major hurricane status. It seems to me that the modeling takes into too much consideration a storm's current intensity/recent intensity history and then builds from there. However, erratic development e.g., along the lines of Gladys (1975)--seemingly a good analog for Katia's intensity--does not preclude significant intensification later on. In contrast, early fairly rapid intensification does not assure continued strengthening. The often quirky SHIPS/DSHPs models sometimes intensify tropical cyclones after they have been forecast to have progressed well inland.

Finally, in contrast to the modeling, historic climatology suggested that Katia would likely peak as a major hurricane, possibly Category 4. The same climatology also suggested that Irene would not rapidly intensify given its trajectory toward NC, something I noted in the Irene thread at a time when, if I recall correctly, the ECMWF was going crazy forecasting rapid intensification. My point on this is that much research still needs to be done to better forecast hurricane intensity. Right now, especially for the overall life cycle of a storm, historic climatology is arguably at least as good as the modeling.