ATL: KATIA - Post Tropical - Discussion

[sponger]

That is a lot of ridging on the UK Met run! Combined with the Euro indicating more as well leads me to believe there are some changes afoot.

[sponger]

Looking very healthy this morning!

[Extratropical94]

The eye is clearing out.

Visible from 1345 UTC


Uploaded with ImageShack.us

[KWT]

Katia is looking far better then it ever has done, the inner core has finally sorted itself out after several days of plusing and waning.

NHC next forecast will probably call for a major hurricane again, maybe in the next 24hrs given the current trend.

[cycloneye]

BULLETIN
HURRICANE KATIA ADVISORY NUMBER 26
NWS NATIONAL HURRICANE CENTER MIAMI FL AL122011
1100 AM AST SUN SEP 04 2011

...KATIA RAPIDLY INTENSIFIES TO A CATEGORY 2 HURRICANE...


SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...21.9N 59.2W
ABOUT 360 MI...580 KM NE OF THE NORTHERN LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...100 MPH...160 KM/H
PRESENT MOVEMENT...NW OR 305 DEGREES AT 12 MPH...19 KM/H
MINIMUM CENTRAL PRESSURE...966 MB...28.53 INCHES


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


DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
AT 1100 AM AST...1500 UTC...THE CENTER OF HURRICANE KATIA WAS
LOCATED NEAR LATITUDE 21.9 NORTH...LONGITUDE 59.2 WEST. KATIA IS
MOVING TOWARD THE NORTHWEST NEAR 12 MPH...19 KM/H...AND THIS GENERAL
MOTION IS EXPECTED TO CONTINUE THROUGH TUESDAY. ON THE FORECAST
TRACK...KATIA WILL REMAIN NORTH OF THE NORTHERN LEEWARD ISLANDS.

MAXIMUM SUSTAINED WINDS HAVE INCREASED TO NEAR 100 MPH...160 KM/H...
WITH HIGHER GUSTS. KATIA IS A CATEGORY TWO HURRICANE ON THE
SAFFIR-SIMPSON HURRICANE WIND SCALE. ADDITIONAL STRENGTHENING IS
FORECAST DURING THE NEXT COUPLE OF DAYS...AND KATIA COULD BECOME A
MAJOR HURRICANE BY MONDAY.

HURRICANE-FORCE WINDS EXTEND OUTWARD UP TO 45 MILES...75 KM...FROM
THE CENTER...AND TROPICAL-STORM-FORCE WINDS EXTEND OUTWARD UP TO
175 MILES...280 KM. NOAA BUOY 41044 LOCATED JUST NORTH OF THE
CENTER OF KATIA RECENTLY REPORTED A SUSTAINED WIND OF 90 MPH...144
KM/H AND A GUST TO 107 MPH...173 KM/H.

THE ESTIMATED MINIMUM CENTRAL PRESSURE BASED ON RECENT PRESSURE
REPORTS FROM NOAA BUOY 41044 IS 966 MB...28.53 INCHES.


HAZARDS AFFECTING LAND
----------------------
SURF...SWELLS GENERATED BY KATIA ARE PRIMARILY AFFECTING THE
NORTHERN LESSER ANTILLES BUT SHOULD BEGIN TO SUBSIDE TONIGHT OR
MONDAY. SWELLS COULD BEGIN TO AFFECT BERMUDA BY EARLY NEXT WEEK.
THESE SWELLS ARE LIKELY TO CAUSE LIFE-THREATENING SURF AND RIP
CURRENT CONDITIONS. PLEASE CONSULT PRODUCTS FROM YOUR LOCAL WEATHER
OFFICE.


NEXT ADVISORY
-------------
NEXT COMPLETE ADVISORY...500 PM AST.

$$
FORECASTER BERG


HURRICANE KATIA DISCUSSION NUMBER 26
NWS NATIONAL HURRICANE CENTER MIAMI FL AL122011
1100 AM AST SUN SEP 04 2011

EARLIER THIS MORNING...THE CENTER OF KATIA MOVED JUST TO THE SOUTH
OF NOAA BUOY 41044...WHICH MEASURED A PEAK 1-MINUTE WIND OF 78
KT...A GUST TO 93 KT...AND A MINIMUM PRESSURE OF 968.3 MB.
SUBJECTIVE DVORAK INTENSITY ESTIMATES HAVE RISEN TO BETWEEN 65 AND
77 KT FROM TAFB AND SAB...BUT THE LATEST UW-CIMSS ADT ESTIMATES
HAVE BEEN HOVERING AROUND 85 KT. BASED ON THESE DATA...KATIA IS
INITIALIZED AS AN 85-KT HURRICANE. AN EYE IS BECOMING APPARENT IN
VISIBLE SATELLITE IMAGERY...YET THE INFRARED IMAGERY DOES NOT SHOW
THE DEEP CONVECTION VERY SYMMETRICAL.

KATIA APPEARS TO BE ON TRACK WITH AN INITIAL MOTION OF 305/10 KT.
ALTHOUGH A LOT OF UNCERTAINTY REMAINS IN THE 3 TO 5 DAY FORECAST
PERIOD...LITTLE CHANGE WAS MADE ON THIS FORECAST RELATIVE TO THE
PREVIOUS ONE. THE ECMWF...UKMET...AND HWRF MODELS REMAIN ON THE
SOUTHWESTERN SIDE OF THE GUIDANCE WHILE THE GFS AND GFDL ARE A
LITTLE FASTER AND FARTHER NORTH BY DAY 5. MUCH OF THIS DIFFERENCE
APPEARS TO BE DUE TO THE POSITIONING OF THE CLOSED MID- TO
UPPER-LEVEL LOW FORECAST TO DEVELOP OVER THE EASTERN UNITED STATES
IN 4-5 DAYS...WHICH THE GFS SHOWS ABOUT 300 N MI FARTHER TO THE
EAST AND DEEPER THAN IN THE ECMWF AND UKMET AT DAY 5. THE OFFICIAL
FORECAST IS VERY CLOSE TO THE MULTI-MODEL CONSENSUS AND STILL KEEPS
THE HURRICANE AT OR EAST OF 72W.

DESPITE THE QUICK STRENGTHENING OVER THE PAST 6 TO 12 HOURS...ADT
ESTIMATES HAVE LEVELED OFF AT 85 KT...AND IT IS HARD TO TELL IF THE
CYCLE OF RAPID INTENSIFICATION IS GOING TO CONTINUE DURING THE DAY.
THE SHIPS MODEL IS STILL DIAGNOSING ABOUT 15 KT OF SOUTH TO
SOUTHWESTERLY VERTICAL SHEAR OVER KATIA...BUT THE HURRICANE MAY BE
BENEFITING FROM UPPER-LEVEL DIVERGENCE ASSOCIATED WITH OUTFLOW
JETS TO ITS NORTH AND NORTHEAST. THE OFFICIAL INTENSITY FORECAST
IS AT THE HIGHER RANGE OF THE INTENSITY GUIDANCE...FOLLOWING CLOSE
TO THE GFDL AND HWRF MODELS. HOWEVER...THE ENVIRONMENT APPEARS
SUFFICIENTLY CONDUCIVE FOR INTENSIFICATION...AND KATIA COULD STILL
STRENGTHEN MORE THAN INDICATED HERE.

FORECAST POSITIONS AND MAX WINDS

INIT 04/1500Z 21.9N 59.2W 85 KT 100 MPH
12H 05/0000Z 22.9N 60.6W 95 KT 110 MPH
24H 05/1200Z 24.1N 62.4W 100 KT 115 MPH
36H 06/0000Z 25.2N 64.0W 100 KT 115 MPH
48H 06/1200Z 26.2N 65.6W 105 KT 120 MPH
72H 07/1200Z 28.0N 68.5W 105 KT 120 MPH
96H 08/1200Z 30.0N 71.5W 105 KT 120 MPH
120H 09/1200Z 33.0N 72.0W 95 KT 110 MPH

$$
FORECASTER BERG

[cycloneye]

...KATIA RAPIDLY INTENSIFIES TO A CATEGORY 2 HURRICANE...


SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...21.9N 59.2W
ABOUT 360 MI...580 KM NE OF THE NORTHERN LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...100 MPH...160 KM/H
PRESENT MOVEMENT...NW OR 305 DEGREES AT 12 MPH...19 KM/H
MINIMUM CENTRAL PRESSURE...966 MB...28.53 INCHES

[clfenwi]

I was somewhat expecting recon and G-IV dropsonde drops to start on Tuesday, but that appears to not be the case for the time-being. Possible research mission, though.

NOUS42 KNHC 041500
WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1100 AM EDT SUN 04 SEPTEMBER 2011
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.
II. PACIFIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. SUCCEEDING DAY OUTLOOK.....NEGATIVE.
VJH

[SouthernBreeze]

That is a lot of ridging on the UK Met run! Combined with the Euro indicating more as well leads me to believe there are some changes afoot.

Hopefully by Tue they'll get some fresh data to feed into their models -- No Recon scheduled yet!

3. REMARK: POSSIBLE NOAA G-IV RESEARCH MISSION
FOR HURRICANE KATIA TAKING OFF 06/1100Z.

[TheEuropean]

From the discussion:

HURRICANE KATIA DISCUSSION NUMBER 26
NWS NATIONAL HURRICANE CENTER MIAMI FL AL122011
1100 AM AST SUN SEP 04 2011
...

HOWEVER...THE ENVIRONMENT APPEARS
SUFFICIENTLY CONDUCIVE FOR INTENSIFICATION...AND KATIA COULD STILL
STRENGTHEN MORE THAN INDICATED HERE.

FORECAST POSITIONS AND MAX WINDS

INIT 04/1500Z 21.9N 59.2W 85 KT 100 MPH
12H 05/0000Z 22.9N 60.6W 95 KT 110 MPH
24H 05/1200Z 24.1N 62.4W 100 KT 115 MPH
36H 06/0000Z 25.2N 64.0W 100 KT 115 MPH
48H 06/1200Z 26.2N 65.6W 105 KT 120 MPH
72H 07/1200Z 28.0N 68.5W 105 KT 120 MPH
96H 08/1200Z 30.0N 71.5W 105 KT 120 MPH
120H 09/1200Z 33.0N 72.0W 95 KT 110 MPH

FORECASTER BERG

[ronjon]

11 am NHC disc:

KATIA APPEARS TO BE ON TRACK WITH AN INITIAL MOTION OF 305/10 KT.
ALTHOUGH A LOT OF UNCERTAINTY REMAINS IN THE 3 TO 5 DAY FORECAST
PERIOD...LITTLE CHANGE WAS MADE ON THIS FORECAST RELATIVE TO THE
PREVIOUS ONE. THE ECMWF...UKMET...AND HWRF MODELS REMAIN ON THE
SOUTHWESTERN SIDE OF THE GUIDANCE WHILE THE GFS AND GFDL ARE A
LITTLE FASTER AND FARTHER NORTH BY DAY 5. MUCH OF THIS DIFFERENCE
APPEARS TO BE DUE TO THE POSITIONING OF THE CLOSED MID- TO
UPPER-LEVEL LOW FORECAST TO DEVELOP OVER THE EASTERN UNITED STATES
IN 4-5 DAYS...WHICH THE GFS SHOWS ABOUT 300 N MI FARTHER TO THE
EAST AND DEEPER THAN IN THE ECMWF AND UKMET AT DAY 5. THE OFFICIAL
FORECAST IS VERY CLOSE TO THE MULTI-MODEL CONSENSUS AND STILL KEEPS
THE HURRICANE AT OR EAST OF 72W.

It's all where the mid-to-upper level low cuts off and sets up shop - further west allows more SW Atlantic ridging which steers KAT closer toward the SE US.

[KWT]

Well as somewhat expected the NHC is more agressive with the forecast...

[cpdaman]

big euro run again imo. lets if shes consistent w position of the closed upper low. did any gfs ens members agree w euro closed ul position

[Jevo]

Did I call it or what.... Joe B jumped all over the W shifting Euro @ 0z when he woke up this morning.. BTW I am far from a JoeB Fanboi

@BigJoeBastardi Joe Bastardi: Big problems with US models, IMO as they try to hand off Katia to the north to quick. My track has problems for NC by weekend

Backing off a little 1 min later

@BigJoeBastardi Joe Bastardi: Storm may stay offshore, but large circulation and beaches already in bad shape means major potential problem if this gets within 100 m

[AdamFirst]

12z GFS is rolling. Someone else can post the plots.

http://raleighwx.americanwx.com/models/12zgfs.html

[Jevo]

12z GFS +72



12z GFS +96

[SouthFLTropics]

Looking at the 12z GFS I'm very suspect of the run...It appears to me that it slows Katia down to a crawl South of Bermuda with a decent high to her North. Based on what I'm think I'm seeing it would appear that she should be heading more west like the Ukie and Euro are showing if a high like the GFS depicts was there. I think the GFS is struggling somewhat with the evolution of the ridge and the trough over the Eastern CONUS. Today's 12z Euro promises to be very interesting...The battle rages on between the Euro and GFS. Who will win???

SFT

[Jevo]

AM I seeing this right..... is the GFS stalling/drifting it for almost 20 hours

12z GFS +120

[Jevo]

Looking at the 12z GFS I'm very suspect of the run...It appears to me that it slows Katia down to a crawl South of Bermuda with a decent high to her North. Based on what I'm think I'm seeing it would appear that she should be heading more west like the Ukie and Euro are showing if a high like the GFS depicts was there. I think the GFS is struggling somewhat with the evolution of the ridge and the trough over the Eastern CONUS. Today's 12z Euro promises to be very interesting...The battle rages on between the Euro and GFS. Who will win???

SFT

you beat me to it.. I had to look and make sure my screen was refreshing as i scrolled through the images

[Battlebrick]

moving due east after 120 hrs.. lol what?

[Jevo]

12z GFS +144 (After sitting and spinning for 28 hours off to the races)