ATL: KATIA - Post Tropical - Discussion

[RL3AO]

Lets get on topic guys.

[Swimdude]

^ My fault--I apologize.

Regarding Katia (whatever form she may take!), I've been seeing an increasingly symmetical system over the course of the last 24 hours. What I find a little strange is that given the next-to-ideal conditions, no RI has occurred. I suppose this isn't too uncommon, but what I'm finding especially strange is that the eye keeps attempting to emerge--and then disappearing. Thus, slower intensification is taking place--we've never seen the eye for more than an hour or so. This probably won't mean much in the long run, but it does mean that something is less than ideal for this system, or we would see more rapid intensification... I believe.

Hurricane at 11:00? I say yes.

[Disclaimer: I am as meteorologically intelligent as the bicycle seat sitting next to me. Ok, maybe slightly better than that--but not much.]

[Weather Watcher]

It still looks like some dry air penetrating the center, but I could be wrong. I think it still will be a TS at 11

[Meteorcane]

Significant Fujiwara effects are quite rare in the Atlantic, but I suppose if Lee actually developed into a deep system and moved to the eastern Gulf, there could be a possibility of a minor Fujiwara interaction.

[Annie Oakley]

Swimdude...your disclaimer is false to me. You are a great asset to this site for us amateurs. You know a lot more than I do and I learn from you.
That really is odd about her eye opening and closing.
Some people have talked about her becoming an annular. What do you think?

[cycloneye]

HURRICANE KATIA FORECAST/ADVISORY NUMBER 12
NWS NATIONAL HURRICANE CENTER MIAMI FL AL122011
0300 UTC THU SEP 01 2011

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

HURRICANE CENTER LOCATED NEAR 15.0N 44.4W AT 01/0300Z
POSITION ACCURATE WITHIN 20 NM

PRESENT MOVEMENT TOWARD THE WEST-NORTHWEST OR 285 DEGREES AT 17 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 987 MB
MAX SUSTAINED WINDS 65 KT WITH GUSTS TO 80 KT.
64 KT....... 20NE 0SE 0SW 20NW.
50 KT....... 50NE 40SE 0SW 50NW.
34 KT.......110NE 90SE 45SW 110NW.
12 FT SEAS..200NE 30SE 90SW 120NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 15.0N 44.4W AT 01/0300Z
AT 01/0000Z CENTER WAS LOCATED NEAR 14.8N 43.6W

FORECAST VALID 01/1200Z 15.6N 46.7W
MAX WIND 75 KT...GUSTS 90 KT.
64 KT... 20NE 0SE 0SW 20NW.
50 KT... 50NE 40SE 0SW 50NW.
34 KT...110NE 90SE 45SW 110NW.

FORECAST VALID 02/0000Z 16.3N 49.1W
MAX WIND 85 KT...GUSTS 105 KT.
64 KT... 40NE 30SE 20SW 40NW.
50 KT... 60NE 50SE 40SW 60NW.
34 KT...120NE 100SE 60SW 120NW.

FORECAST VALID 02/1200Z 17.3N 51.3W
MAX WIND 90 KT...GUSTS 110 KT.
64 KT... 40NE 30SE 20SW 40NW.
50 KT... 60NE 50SE 40SW 60NW.
34 KT...120NE 100SE 60SW 120NW.

FORECAST VALID 03/0000Z 18.4N 53.1W
MAX WIND 95 KT...GUSTS 115 KT.
50 KT... 75NE 60SE 40SW 75NW.
34 KT...150NE 125SE 75SW 150NW.

FORECAST VALID 04/0000Z 20.5N 56.0W
MAX WIND 100 KT...GUSTS 120 KT.
50 KT... 80NE 70SE 45SW 80NW.
34 KT...160NE 140SE 90SW 160NW.

EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 175 NM
ON DAY 4 AND 225 NM ON DAY 5...AND FOR INTENSITY NEAR 20 KT EACH DAY

OUTLOOK VALID 05/0000Z 22.5N 59.0W
MAX WIND 105 KT...GUSTS 130 KT.

OUTLOOK VALID 06/0000Z 24.0N 61.5W
MAX WIND 105 KT...GUSTS 130 KT.

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 15.0N 44.4W

NEXT ADVISORY AT 01/0900Z

$$
FORECASTER BROWN


BULLETIN
HURRICANE KATIA ADVISORY NUMBER 12
NWS NATIONAL HURRICANE CENTER MIAMI FL AL122011
1100 PM AST WED AUG 31 2011

...KATIA BECOMES THE SECOND HURRICANE OF THE SEASON...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...15.0N 44.4W
ABOUT 1165 MI...1875 KM E OF THE LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...75 MPH...120 KM/H
PRESENT MOVEMENT...WNW OR 285 DEGREES AT 20 MPH...32 KM/H
MINIMUM CENTRAL PRESSURE...987 MB...29.15 INCHES


WATCHES AND WARNINGS
--------------------
THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.


DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
AT 1100 PM AST...0300 UTC...THE CENTER OF HURRICANE KATIA WAS
LOCATED NEAR LATITUDE 15.0 NORTH...LONGITUDE 44.4 WEST. KATIA IS
MOVING TOWARD THE WEST-NORTHWEST NEAR 20 MPH...32 KM/H...AND THIS
MOTION WITH A GRADUAL SLOWING OF FORWARD SPEED IS EXPECTED OVER
THE NEXT 48 HOURS.

MAXIMUM SUSTAINED WINDS HAVE INCREASED TO NEAR 75 MPH...120
KM/H...WITH HIGHER GUSTS. KATIA IS A CATEGORY ONE HURRICANE ON THE
SAFFIR-SIMPSON HURRICANE WIND SCALE. ADDITIONAL STRENGTHENING IS
FORECAST DURING THE NEXT 48 HOURS AND KATIA COULD BECOME A MAJOR
HURRICANE BY THE WEEKEND.

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 25 MILES...35 KM...FROM
THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 125
MILES...205 KM.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 987 MB...29.15 INCHES.


HAZARDS AFFECTING LAND
----------------------
NONE.


NEXT ADVISORY
-------------
NEXT COMPLETE ADVISORY...500 AM AST.

$$
FORECASTER BROWN


HURRICANE KATIA DISCUSSION NUMBER 12
NWS NATIONAL HURRICANE CENTER MIAMI FL AL122011
1100 PM AST WED AUG 31 2011

THE CLOUD PATTERN ASSOCIATED WITH KATIA CONTINUES TO GRADUALLY
IMPROVE. THE CENTER IS LOCATED NEAR THE MIDDLE OF AN EXPANDING
CENTRAL DENSE OVERCAST AND THERE IS A LARGE CURVED BAND OF DEEP
CONVECTION OVER THE SOUTHERN SEMICIRCLE OF THE CYCLONE. RECENT
SSMIS MICROWAVE DATA SHOWED THE BEGINNINGS OF A BANDING EYE
FEATURE...HOWEVER THE CONVECTION OVER THE SOUTHERN PORTION OF THE
EYE IS STILL A BIT THIN. SUBJECTIVE AND OBJECTIVE DVORAK SATELLITE
INTENSITY ESTIMATES HAVE INCREASED TO 65 KT...AND THE INITIAL
INTENSITY HAS BEEN RAISED ACCORDINGLY. KATIA IS THE SECOND
HURRICANE OF THE 2011 ATLANTIC HURRICANE SEASON.

THE HURRICANE IS EXPECTED TO REMAIN IN A LOW SHEAR ENVIRONMENT
AND OVER WARM WATER DURING THE NEXT DAY OR SO...WHICH SHOULD FAVOR
ADDITIONAL STRENGTHENING. AFTER THAT TIME...A MID- TO UPPER-LEVEL
TROUGH SEEN IN WATER VAPOR IMAGERY BETWEEN 50W AND 60W IS FORECAST
BY THE GLOBAL MODELS TO WEAKEN. THIS SHOULD KEEP THE HURRICANE IN
A FAVORABLE UPPER-LEVEL WIND PATTERN AND KATIA IS FORECAST TO
BECOME A MAJOR HURRICANE WITHIN 72 HOURS. THE NEW NHC INTENSITY
FORECAST SHOWS A SLIGHTLY FASTER RATE OF INTENSIFICATION DURING THE
FIRST 2-3 DAYS THAN INDICATED IN THE PREVIOUS ADVISORY...AND IS A
BLEND OF THE STATISTICAL AND DYNAMICAL GUIDANCE.

THE INITIAL MOTION ESTIMATE IS 285/17 KT. THE HURRICANE IS
EXPECTED TO CONTINUE MOVING WEST-NORTHWESTWARD TO THE SOUTH OF A
SUBTROPICAL RIDGE DURING THE NEXT 2-3 DAYS. AFTER 72 HOURS...
KATIA WILL BE NEARING THE SOUTHWESTERN PORTION OF THE RIDGE. THIS
SHOULD RESULT IN A REDUCTION IN FORWARD SPEED AND A GRADUAL TURN
TOWARD THE NORTHWEST. THE NEW TRACK FORECAST IS ESSENTIALLY AN
UPDATE OF THE PREVIOUS NHC FORECAST AND LIES BETWEEN THE
MULTI-MODEL CONSENSUS AND THE RELIABLE GFS AND ECMWF MODELS.

THE WIND RADII HAVE BEEN ADJUSTED SLIGHTLY ON THE BASIS OF RECENT
ASCAT DATA.

FORECAST POSITIONS AND MAX WINDS

INIT 01/0300Z 15.0N 44.4W 65 KT 75 MPH
12H 01/1200Z 15.6N 46.7W 75 KT 85 MPH
24H 02/0000Z 16.3N 49.1W 85 KT 100 MPH
36H 02/1200Z 17.3N 51.3W 90 KT 105 MPH
48H 03/0000Z 18.4N 53.1W 95 KT 110 MPH
72H 04/0000Z 20.5N 56.0W 100 KT 115 MPH
96H 05/0000Z 22.5N 59.0W 105 KT 120 MPH
120H 06/0000Z 24.0N 61.5W 105 KT 120 MPH

$$
FORECASTER BROWN

[Buck]

11pm - Hurricane Katia. 75 mph, 987 mb.

[Fyzn94]

BULLETIN
HURRICANE KATIA ADVISORY NUMBER 12
NWS NATIONAL HURRICANE CENTER MIAMI FL AL122011
1100 PM AST WED AUG 31 2011

...KATIA BECOMES THE SECOND HURRICANE OF THE SEASON...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...15.0N 44.4W
ABOUT 1165 MI...1875 KM E OF THE LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...75 MPH...120 KM/H
PRESENT MOVEMENT...WNW OR 285 DEGREES AT 20 MPH...32 KM/H
MINIMUM CENTRAL PRESSURE...987 MB...29.15 INCHES

[locke]

Significant Fujiwara effects are quite rare in the Atlantic, but I suppose if Lee actually developed into a deep system and moved to the eastern Gulf, there could be a possibility of a minor Fujiwara interaction.

Actually, with Neville and Olga in 2010, Neville had pretty much degraded to a tropical depression whilst interacting with Olga which would at best have been classified as Cat 1 hurricane on the US scale. I actually chased Olga and ended up very frustrated as she veered North away from my location to circle around Neville to her East. Neville ended up a doing a a complete circle around Olga and crossed the coast below her.

Still I agree the fujiwharra effect in this instance is a very minor possibility. I doubt the 2 storms will get close enough together to interact and formation of Lee in the GOM whilst likely is not yet guaranteed.

[Swimdude]

Swimdude...your disclaimer is false to me. You are a great asset to this site for us amateurs. You know a lot more than I do and I learn from you.
That really is odd about her eye opening and closing.
Some people have talked about her becoming an annular. What do you think?

I appreciate the praise, but truly--the only reason you're learning from me is that I'm not informed enough to speak in technical terms about these storms and therefore make my input based on MUCH less information than the experts. Anyone listed as a Professional Met on this site has advanced degrees and knows infinitely more than I ever will about the tropics.

(Sorry mods for off topic, but I felt that needed clarifying publicly.)

- - -

Annular is a rare characteristic of a storm, I'm pretty sure of that. Many storms have been known to have had "annular characteristics" without being fully annular. Could Katia become annular in the future? My best guess is yes, given the perfect conditions, it is possible. Simply search Google images for "annular hurricane" and you'll see how far Katia has to go yet.

[CrazyC83]

If that eyewall closes completely, look out I would think.

[StarmanHDB]

....Some people have talked about her becoming an annular. What do you think?

From Wikipedia, so please take this with a grain of salt:

ON "FORMATION" OF ANNULAR HURRICANES....

"Research into the characteristics and formation of annular hurricanes is still in its infancy. First classified and categorized in 2002, little is known about how they form, or why some are able to maintain their intensity in hostile conditions.

What meteorologists do know is that a normal hurricane, after undergoing an eyewall replacement cycle, fails to re-establish the standard hurricane appearance. The new eyewall thickens, and rainbands dissipate, and the hurricane takes on an annular structure. As compared to the formation of normal hurricanes, this happens under weaker wind shear and, surprisingly, cooler sea surface temperatures.

Some of the conditions associated with annular hurricanes are:

An intensity 85% or greater from their theoretical maximum potential intensity,
Weak wind shear from the east or southeast,
A cold east wind at a high altitude (the 200 mbar pressure level),
Near-constant sea surface temperatures between 25.4 °C and 28.5 °C, and
Lack of relative eddy flux convergence at the 200 mbar pressure level, relative to the storm."

[geomindspin]

Thank you everyone that responded to my question. It is much clearer now. Thank you for the help.

[floridasun78]

i look at new cone it more to left i have link from nhc that you can see past cone as more to left a bit so nhc looking shift models to left on cone but their dont talk about at 11pm about models shift to lefthttp://www.nhc.noaa.gov/archive/201 ... p_5W.shtml

[meriland23]

Wow Katie, had us all fooled. Was almost certain you would do your biz yesterday... lol

[meriland23]

"Just keep swimming, just keep swimming..what do we do, we swim swim"

[LeeNess87]

NHC had Katia at 15.0N and 44.4W during the last public advisory. It looks a little bit more south to me??? Am I seeing things?

[USTropics]

The 00z GFS is running. Out to 72 hours and not seeing much of a difference from the 18z run:

[meriland23]

New GFS model runs, 00z. will post per 24 hour period for whomever it may interest.

24 hr


48 hr



72 hr

[MGC]

Giant ULL awaits Katia. Katia had better build up some ACE because unless the ULL moves it is going to wind whip Katia......MGC