ATL: KATIA - Post Tropical - Discussion

[Extratropical94]

Just a question:
If Katia is moving towards the NE at 65 mph and her sustained winds are 80 mph, does that mean that if you are in the SE quad, you feel 145 mph winds, and only 15 mph winds in the NW quad?

Nope. 80 MPH MSW are ground relative, not storm relative.

Thanks for the quick reply.

[CrazyC83]

Large field of near-hurricane winds, with a ship reporting winds to 55 kt (I think those are 10-min sustained too).

http://www.ndbc.noaa.gov/radial_search. ... =A&time=12

[HenkL]

MetOffice is forecasting winds up to 9 or 10 Bft (40-55 kt) around Scotland and the northern North Sea, perhaps 11 Bft (56-63 kt) in the area between Iceland and the FarOer.
See: http://www.metoffice.gov.uk/weather/mar ... tlook.html

Not exceptional for extratropical storms in autumn and winter in those areas. In fact, there were winds (nearly) like those around the North Sea in the last week.

[CrazyC83]

MetOffice is forecasting winds up to 9 or 10 Bft (40-55 kt) around Scotland and the northern North Sea, perhaps 11 Bft (56-63 kt) in the area between Iceland and the FarOer.
See: http://www.metoffice.gov.uk/weather/mar ... tlook.html

Not exceptional for extratropical storms in autumn and winter in those areas. In fact, there were winds (nearly) like those around the North Sea in the last week.

At those times of year, trees are not in full leaf like they are now? So tree and power line damage would be magnified.

[Cryomaniac]

MetOffice is forecasting winds up to 9 or 10 Bft (40-55 kt) around Scotland and the northern North Sea, perhaps 11 Bft (56-63 kt) in the area between Iceland and the FarOer.
See: http://www.metoffice.gov.uk/weather/mar ... tlook.html

Not exceptional for extratropical storms in autumn and winter in those areas. In fact, there were winds (nearly) like those around the North Sea in the last week.

At those times of year, trees are not in full leaf like they are now? So tree and power line damage would be magnified.

I think the last major storm we had was in January 2009, and that brought down a lot of trees, so this time of year it's likely to worse.

[Chacor]

FQNT21 EGRR 110800
SECURITE

HIGH SEAS BULLETIN FOR METAREA 1
ISSUED AT 0800 UTC ON SUNDAY 11 SEPTEMBER 2011
BY THE MET OFFICE, EXETER, UNITED KINGDOM
FOR THE PERIOD 0800 UTC ON SUNDAY 11 SEPTEMBER UNTIL 0800
UTC ON MONDAY 12 SEPTEMBER 2011

STORM WARNING
AT 110000UTC, LOW 47 NORTH 38 WEST 958 EXPECTED 55 NORTH
18 WEST 959 BY 120000UTC. WINDS WILL REACH STORM FORCE 10
IN THE SOUTHERN QUADRANT BETWEEN 50 AND 300 MILES FROM
THE CENTRE THROUGHOUT THE NEXT 24 HOURS, AND IN THE
WESTERN QUADRANT BETWEEN 50 AND 100 MILES FROM THE CENTRE
UNTIL 111800UTC. WINDS MAY ALSO REACH VIOLENT STORM FORCE
11 IN THE SOUTHERN QUADRANT BETWEEN 100 AND 200 MILES
FROM THE CENTRE AFTER 120300UTC

AREA FORECASTS FOR THE NEXT 24 HOURS

EAST CENTRAL SECTION
IN NORTH, SOUTHWESTERLY AT FIRST IN NORTHEAST, OTHERWISE
CYCLONIC BECOMING WESTERLY, 6 TO GALE 8, INCREASING
SEVERE GALE 9 OR STORM 10 FOR A TIME, PERHAPS VIOLENT
STORM 11 FOR A TIME LATER. VERY ROUGH OR HIGH, BECOMING
ROUGH FOR A TIME, BUT BECOMING HIGH OR VERY HIGH LATER.
RAIN, CLEARING TO SQUALLY SHOWERS EXCEPT IN FAR
NORTHEAST. MODERATE OR POOR.

WEST CENTRAL SECTION
IN SOUTHEAST, CYCLONIC GALE 8 TO STORM 10 BECOMING
WESTERLY OR NORTHWESTERLY 5 TO 7. VERY ROUGH OR HIGH,
OCCASIONALLY VERY HIGH AT FIRST. RAIN OR DRIZZLE THEN
SQUALLY SHOWERS. MODERATE OR POOR, OCCASIONALLY GOOD
LATER.

OUTLOOK FOR FOLLOWING 24 HOURS:
VIOLENT STORM FORCE WINDS EXPECTED IN ROCKALL. STORM
FORCE WINDS EXPECTED IN SHANNON. SEVERE GALES EXPECTED IN
SOUTHEAST ICELAND, EAST NORTHERN SECTION AND EAST CENTRAL
SECTION. GALES EXPECTED IN BAILEY, FAEROES, WEST NORTHERN
SECTION, WEST CENTRAL SECTION AND DENMARK STRAIT, WITH A
RISK OF GALES IN SOLE AND NORTH ICELAND

[tropicana]

2130hrs, Sunday Sep 11 2011:

Excerpt from the Irish Weather Office on KATIA:


Pressure update from iWeather Online Senior Forecaster Peter O’Donnell – I’m estimating 964 mbs at 53N 21W for the central pressure, or about 400 miles west of Ireland...but plotting a few available buoys and ship reports shows that the gradient is tighter around 51-52 N than either side if you assume that central pressure, for a stronger gradient near the centre you need to drop the pressure to 960 mbs.

No classic look yet because colder air has not caught up to the centre, it is still overlain by tropical air mass but that should change soon and the extensive warm sector (which is just now pushing into Kerry) should begin to get lifted as it comes in over Ireland tonight. Lift may be rather feeble until about 0300-0600hrs. Would watch satellite imagery for weak cold front now only discernible as slight change in I.R. temperature signal, probably a band of low scud if you were out there on a ship. This should begin to show stronger signal after midnight curving in ahead of the low towards southwest Ireland. The warm front is very clearly marked and from the buoy at 49N 13W the warm sector air mass temperature/dew point over the ocean is 18/16. Further southwest it is 22/17. Pressures at the M6 buoy next 3-6 hours should reveal the actual central pressure of the low because the centre is going to pass just to the north of that location around 0300hrs.

[CrazyC83]

Even when extratropical, with a pressure near the center, 1 mb drop per 10 kt of wind?

[Chacor]

Strong winds from the tail-end of Hurricane Katia are battering much of the UK, with Met Office severe weather warnings in place for many areas.

Southern and central parts of Scotland, Northern Ireland, and northern England and Wales have been experiencing winds of up to 80mph (129km/h).

Flood alerts have been issued, with road, rail and ferry travel disrupted.

The weather caused the cancellation of stage two of cycling's Tour of Britain, through Lancashire and Cumbria.

"We've had to take the decision based on the advice we've had from the police and highways [officials] that it is unsafe," a tour spokesman said.

The Met Office issued an amber warning covering several areas, meaning the public should be prepared for the risk of transport disruption and the possibility of damage to trees and structures.

It said an 82mph (132km/h) gust had been recorded at Capel Curig in North Wales, with strong winds expected to continue into Monday evening.

http://www.bbc.co.uk/news/uk-14883670

[HenkL]

Dutch coast last hours: winds up to 45 kt (10 minutes mean), gusts 55 kt.
Lowest pressure at 15Z: 975 hPa in Scotland.

[Cookie]

highest gust from this was 87 mph, I was down in blackpool at the weekend where a gust of 57 mph was recorded,

1 person was killed further south by a falling tree.