ATL: KATIA - Post Tropical - Discussion

[AJC3]

A total of 72 units of ACE was generated that season well below the 1968-2010 mean. There was little significant activity in the MDR after September 5th; most of the storms that did exist were murdered by a powerful central Atlantic upper trough. Yes, I call that a pathetic season by +AMO standards.

72 is about average...not well below.

Average ACE is a little over 100. An ace of 72 ranks 41st out of the last 62 years (1950-2011)

[HurrMark]

A total of 72 units of ACE was generated that season well below the 1968-2010 mean. There was little significant activity in the MDR after September 5th; most of the storms that did exist were murdered by a powerful central Atlantic upper trough. Yes, I call that a pathetic season by +AMO standards.

72 is about average...not well below.

Average ACE is a little over 100. An ace of 72 ranks 41st out of the last 62 years (1950-2011)

You are right...I thought the average was closer to 80. Still, I wouldn't call it much below normal (although for a 15 storm season, it was certainly well below what you would expect...2011 is very similar in that regard).

[crimi481]

Katia missing next forecast point - a good deal south of it?
http://www.ssd.noaa.gov/goes/flt/t2/flash-vis.html

[Steve H.]

Something is wrong with that image. Katia S/B at 28N at least!!!

[TYNI]

Katia missing next forecast point - a good deal south of it?
http://www.ssd.noaa.gov/goes/flt/t2/flash-vis.html

Appears to be on a more NW track at the moment. Don't want to get into wobble watching, so we'll see how she tracks over the next 8 or so hours.

[AmanziUK]

Keeping an eye on this girl... could get to fly my kite if she visits (well what will be left of her anyway).

[clfenwi]

Flight plan for the research mission being flown today.



Comment from the HRD blog"No arc clouds were seen on yesterdays mission. This morning’s 85 Ghz TMI shows the dry air wrapping around the storm so perhaps there will be some arc cloud formation. The purpose of this mission is to sample the environment around Hurricane Katia and target arc clouds."

In addition to the pages I mentioned above, arc clouds and research thereof are discussed in pages 58-62 of the Hurricane Field Program manual (PDF)

[HenkL]

Mission WB12A KATIA from NOAA9.
Dropsondes at 500 hPa level; wind and T/TD (°C):




Idem at 250 hPa level:

[westwind]

After being compleatly wrong about the eye yesterday, it looks Katia is finaly sorting out her inner core and a large eye appers to be forming on visible imagery, with weak convection reterning to the western side of the core. I don't know how to post images in the required format so here is the vis loop.
http://www.ssd.noaa.gov/goes/flt/t2/flash-vis.html
What do you guys think? eye or dry air?

[crimi481]

Just few thoughts.
Katia has moved W.N.W. for several hours now -and missed forecast point by large distance
The north to south alighnment of Lee's remains over N.E states "may" allow ridge north of Katia to build in and send her more west than current forecast. (and fact Katia now weaker system -may tend more west)
Anyone agree - or are still just wobbling?
Thanks

[JtSmarts]

Just few thoughts.
Katia has moved W.N.W. for several hours now -and missed forecast point by large distance
The north to south alighnment of Lee's remains over N.E states "may" allow ridge north of Katia to build in and send her more west than current forecast. (and fact Katia now weaker system -may tend more west)
Anyone agree - or are still just wobbling?
Thanks

Still looks basically on track in my opinion maybe slightly to the left.

[somethingfunny]

From the 5PM NHC Forecast Discussion on Katia:

OVERALL...LITTLE CHANGE IN STRENGTH IS FORECAST
DURING THE NEXT COUPLE OF DAYS. KATIA IS EXPECTED TO BECOME A
LARGE AND POWERFUL EXTRATROPICAL CYCLONE IN ABOUT 72 HOURS.

THE INITIAL MOTION ESTIMATE IS 320/9. THE MODELS REMAIN IN VERY
GOOD AGREEMENT MOVING KATIA AROUND THE WEST SIDE OF A
MID/UPPER-LEVEL RIDGE OVER THE CENTRAL ATLANTIC DURING THE NEXT
24-36 HOURS. AFTER 48 HOURS...THE CYCLONE IS EXPECTED TO
ACCELERATE NORTHEASTWARD AHEAD OF A BROAD TROUGH MOVING ACROSS
THE CANADIAN MARITIMES. THE GFS AND ECMWF MODELS ARE STILL IN
REMARKABLY GOOD AGREEMENT ON THE EXTRATROPICAL PORTION OF THE
TRACK. THE OFFICIAL FORECAST HAS BEEN NUDGED NORTHWARD AT 36 HOURS
AND BEYOND AND IS NEAR THE MIDDLE OF THE GUIDANCE ENVELOPE.

FORECAST POSITIONS AND MAX WINDS

INIT 07/2100Z 29.9N 69.7W 70 KT 80 MPH
12H 08/0600Z 31.3N 70.1W 70 KT 80 MPH
24H 08/1800Z 33.8N 70.0W 70 KT 80 MPH
36H 09/0600Z 36.6N 68.5W 70 KT 80 MPH
48H 09/1800Z 39.2N 64.5W 70 KT 80 MPH
72H 10/1800Z 44.5N 46.0W 65 KT 75 MPH...POST-TROP/EXTRATROP
96H 11/1800Z 53.0N 26.0W 65 KT 75 MPH...POST-TROP/EXTRATROP
120H 12/1800Z 60.0N 7.0W 60 KT 70 MPH...POST-TROP/EXTRATROP

In essence, Katia may retain its' identity rather than merge with a trough, and race upon England as a powerful extratropical storm. It wouldn't be anything they haven't seen before, but it could be among the stronger ones they've seen over there.

[KWT]

Looks like Katia's inner core is still fairly well organised and whilst the shear and dry air has weakened its holding itself together fairly well for now...

[westwind]

buoy 41048 recently reported 10 min sustained winds of 46.6kt with max 1 min sustained winds at 50.5kt and a relatively high pressure of 1004mb.

I suspect that this is considerably stronger that 70kt based on these buoy observations as the buoy is still quite far from the centre. here is a link to the buoy.
http://www.ndbc.noaa.gov/station_page.php?station=41048&unit=M&tz=STN

The eastern eyewall (which is where the strongest winds should be) should pass over the buoy in the next 12 hours which should give a good estimate of the max winds.

[chrisjslucia]

8-) Keeping an eye on this girl... could get to fly my kite if she visits (well what will be left of her anyway).

Looks like she is after you and KWT or maybe just your Scottish relatives!

[tobol.7uno]

000
WTNT32 KNHC 072341
TCPAT2

BULLETIN
HURRICANE KATIA INTERMEDIATE ADVISORY NUMBER 39A
NWS NATIONAL HURRICANE CENTER MIAMI FL AL122011
800 PM AST WED SEP 07 2011

...KATIA GENERATING LARGE SWELLS ON BERMUDA AND THE EAST COAST OF
THE UNITED STATES...


SUMMARY OF 800 PM AST...0000 UTC...INFORMATION
----------------------------------------------
LOCATION...30.2N 69.9W
ABOUT 335 MI...535 KM WSW OF BERMUDA
MAXIMUM SUSTAINED WINDS...80 MPH...130 KM/H
PRESENT MOVEMENT...NW OR 325 DEGREES AT 10 MPH...17 KM/H
MINIMUM CENTRAL PRESSURE...982 MB...29.00 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES IN WATCHES AND WARNINGS WITH THIS ADVISORY...

NONE.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

A TROPICAL STORM WATCH IS IN EFFECT FOR...
* BERMUDA

FOR ADDITIONAL STORM INFORMATION...PLEASE MONITOR PRODUCTS ISSUED BY
THE BERMUDA WEATHER SERVICE.

DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
AT 800 PM AST...0000 UTC...THE CENTER OF HURRICANE KATIA WAS LOCATED
NEAR LATITUDE 30.2 NORTH...LONGITUDE 69.9 WEST. KATIA IS MOVING
TOWARD THE NORTHWEST NEAR 10 MPH...17 KM/H. THE HURRICANE IS
EXPECTED TO TURN TOWARD THE NORTH BY EARLY THURSDAY...FOLLOWED BY
NORTH-NORTHEASTWARD MOTION WITH AN INCREASE IN FORWARD SPEED
THURSDAY NIGHT AND FRIDAY. ON THE FORECAST TRACK...THE CENTER OF
KATIA WILL MOVE BETWEEN THE EAST COAST OF THE UNITED STATES AND
BERMUDA TONIGHT AND THURSDAY.

MAXIMUM SUSTAINED WINDS REMAIN NEAR 80 MPH...130 KM/H...WITH HIGHER
GUSTS. KATIA IS A CATEGORY ONE HURRICANE ON THE SAFFIR-SIMPSON
HURRICANE WIND SCALE. LITTLE CHANGE IN STRENGTH IS FORECAST DURING
THE NEXT 48 HOURS.

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 70 MILES...110 KM...FROM
THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 205
MILES...335 KM. A NOAA BUOY LOCATED ABOUT 125 MILES NORTH OF THE
CENTER OF KATIA RECENTLY REPORTED A SUSTAINED WIND OF 54 MPH WITH
A GUST TO 65 MPH.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 982 MB...29.00 INCHES.


HAZARDS AFFECTING LAND
----------------------
SURF...LARGE SWELLS GENERATED BY KATIA WILL CONTINUE TO AFFECT MOST
OF THE EAST COAST OF THE UNITED STATES...BERMUDA...AND EAST-FACING
BEACHES OF THE BAHAMAS DURING THE NEXT COUPLE OF DAYS. THESE SWELLS
ARE LIKELY TO CAUSE LIFE-THREATENING SURF AND RIP CURRENT
CONDITIONS. PLEASE CONSULT PRODUCTS FROM YOUR LOCAL WEATHER SERVICE
OFFICE FOR ADDITIONAL INFORMATION.

WIND...TROPICAL-STORM-FORCE WINDS...ESPECIALLY IN GUSTS...ARE
POSSIBLE IN BERMUDA THROUGH THURSDAY.

RAINFALL...KATIA IS EXPECTED TO PRODUCE TOTAL RAIN ACCUMULATIONS OF
1 TO 2 INCHES ACROSS BERMUDA.


NEXT ADVISORY
-------------
NEXT COMPLETE ADVISORY...1100 PM AST.

$$
FORECASTER CANGIALOSI/BEVEN

[dwsqos2]

At 250Z, buoy 41048 reported 10-minute winds of 60.2 knots with a gust of 75.2 knots. In the supplemental obs the peak 1-minute wind was 66 knots reported at 244Z. A pressure of 29.39 in. was also reported.

http://www.ndbc.noaa.gov/station_page.php?station=41048

[toto]

At 250Z, buoy 41048 reported 10-minute winds of 60.2 knots with a gust of 75.2 knots. In the supplemental obs the peak 1-minute wind was 66 knots reported at 244Z. A pressure of 29.39 in. was also reported.

http://www.ndbc.noaa.gov/station_page.php?station=41048

Thanks for the link.

How close is the hurricane to this buoy ?

Highest 1-minute Wind Speed... Time (EDT) 11:21 pm... 75.8 kts


.


.

[tobol.7uno]

Looks like the UK or Norway may get TS force winds from Katia!

[leanne_uk]

I am gonna go with katia/remenants of katia making a bee line for North west Scotland. Just my opinion tho and it is by no means one to pay attention to lol

8-) Keeping an eye on this girl... could get to fly my kite if she visits (well what will be left of her anyway).

Looks like she is after you and KWT or maybe just your Scottish relatives!