Ex Katia storm thread - TECHNICAL DISCUSSION, FORECASTS AND OBSERVATIONS ONLY!

Pangea · 11-09-2011 12:50am

Pretty Stormy here at the moment.
Time to call it a night, hopefully M.T. will have a few surprises in the forecast tomorrow (wishful thinking eh)

maquiladora · 11-09-2011 12:52am

Ex-Katia starting to come into view on this loop.

http://www.sat24.com/en/eu?ir=true

mickger844posts · 11-09-2011 12:57am

maquiladora wrote: »

Ex-Katia starting to come into view on this loop.

http://www.sat24.com/en/eu?ir=true

Is it in the position that was expected or a little further North in your opinion Maq?

sdanseo · 11-09-2011 1:03am

M.T. Cranium wrote: »

Dunno about that, Lee was mainly falling apart over eastern U.S. as Katia went by on Thursday, some of the remnant energy may have fed around in the jet stream to energize this current low, but it really has little if anything to do with Lee.

But Sunday night is all Katia, no doubt about that.

Previous posters were right, Katia had almost no effect on the U.S. except for some big swells on east coast beaches, the TV folk were no doubt thinking of Irene.

To those asking, how bad? Bear with us, the general consensus is that it won't be too bad a storm except possibly in a few northwest coastal locations, but opinions could change in a hurry if the next round of guidance changes the storm track closer to Ireland.

It won't quite be a case of waiting to find out, but I don't expect a really definitive forecast on this until mid-day Sunday.

I got the impression the pressure differential from Lee was what kept Katia from barrelling into the USA, as per Irene, by forcing it out to sea and in that sense, it was at least partially responsible for deflecting the storm our way. Am I reading that right?

Also on the topic of different systems interacting, will the fact that ex-Katia seems to be running right into the back of the existing low currently centred over the Rockall area serve to weaken it, or divert it off its plotted course?

maquiladora · 11-09-2011 1:04am

mickger844posts wrote: »

Is it in the position that was expected or a little further North in your opinion Maq?

It looked on track to me last time I looked but I'm sure MT and WC will be checking for any deviations.

Have to snooze now, early start for the rugby!

pauldry · 11-09-2011 1:06am

Sounds real windy out now so brought out the wind yokey and turned on the wind reader on my weather station. WIND yokey handheld read 33knots but had to stand out on main road and cars were beeping and wind reader read 28 knots so I think you have to wait a long time for a good gust. Seemed really strong the wind but checked Finner and its only reading 30knot too. hope tomorrow brings more excitement than this:mad:

delw · 11-09-2011 1:16am

maquiladora wrote: »

Ex-Katia starting to come into view on this loop.

http://www.sat24.com/en/eu?ir=true

sorry for stupid question but is Ex-Katia a high pressure system?
reason i ask,low pressure anticlockwise but this system clockwise or is that the extra-tropical storm?

cherryghost · 11-09-2011 1:19am

delw wrote: »

sorry for stupid question but is Ex-Katia a high pressure system?

No.

High Pressure = less cloudy/sunny days
Low pressure = heavy/cloudy/rain/wind

In Lehman's lehman's terms!

thecretinhop · 11-09-2011 1:25am

delw wrote: »

maquiladora wrote: »

Ex-Katia starting to come into view on this loop.

http://www.sat24.com/en/eu?ir=true

sorry for stupid question but is Ex-Katia a high pressure system?

Yep 7 am start c u 2mrw

delw · 11-09-2011 1:33am

cherryghost wrote: »

No.

High Pressure = less cloudy/sunny days
Low pressure = heavy/cloudy/rain/wind

In Lehman's lehman's terms!

i understand what you are saying cherrygoast(or do i

) but reason i ask was on sat it looks to be coming clockwise but i though highs went clockwise

nacho libre · 11-09-2011 2:14am

fairly good explanations about low pressure and high pressure here:

http://geography.about.com/od/climate/a/highlowpressure.htm

http://www.weatherquestions.com/What_causes_low_pressure.htm

monster1 · 11-09-2011 4:37am

well lads, the auld lad has to go up to galway for treatment in the hospital monday morning.. will it be ok to travel in the morning or should we organise accommodation sunday nite? thanks in advance, ye doing a good job

sdanseo · 11-09-2011 4:52am

Can't see it stopping you driving once you're not on an exposed cliffside road :rolleyes: - but if whoever is going to be driving is not that confident driving when it's a bit windy then maybe best to organise something in advance.

TheMilkyPirate · 11-09-2011 5:20am

Katia can suck my hairy balls.

monster1 · 11-09-2011 5:51am

ah right,as long as there wont be trees and mobile homes in the middle of the road on the way il be grand. was just making sure it wasn't going to be dangerous on the way up.. although I want it to be a proper storm all the same.. cheers

monster1 · 11-09-2011 5:55am

so its only going to be a bit windy? ah fack it..

M.T. Cranium · 11-09-2011 7:28am

The guidance continues to give mixed reviews for Katia but I am leaning towards the stronger winds as well as stressing that overnight (tonight) there may be strong frontal showers and thunderstorms moving very quickly, in this scenario strong gusts can develop rapidly too, not just in the coastal regions but scattered around other regions depending on where the storms are stronger. That part will pretty much have to come from very short-term forecasts and radar interpretation.

My impression was that the two European models have stronger wind potential for the northwest than the various North American models, and also, I have been watching hourly positions for the storm and noticed that after a jog north 21-23z the motion has returned more to ENE and now the centre seems to be close to 50N 28W. This seems to be a bit south of what the models would suggest even in a 6-hour time frame. So now the wait begins to see exactly how strong this storm will become.

I have maintained the alerts in the Boards forecast and added this comment ... a point I would like to stress is that the west and north coast winds are not the only story of this storm, the potential for overnight frontal storms must be watched closely as well. And those could affect more populated areas all over the country.

MiNdGaM3 · 11-09-2011 7:45am

Looks to me like Monday night will be worse in the north than tonight.

irish1967 · 11-09-2011 8:45am

1 Hour.... No Posts.... Ah this is what is meant by the Calm Before The Storm !

MiNdGaM3 · 11-09-2011 8:52am

irish1967 wrote: »

1 Hour.... No Posts.... Ah this is what is meant by the Calm Before The Storm !

Busy watching Ireland fart about against the USA maybe?

nacho libre · 11-09-2011 8:53am

MiNdGaM3 wrote: »

Busy watching Ireland fart about against the USA maybe?

I was, anyway. I fear we are going to get hammered next week:(

nacho libre · 11-09-2011 9:00am

Parts of Scotland, and the very north west of Ireland gets the worst of the wind on this guidance

MiNdGaM3 · 11-09-2011 9:14am

nacho libre wrote: »

I was, anyway. I fear we are going to get hammered next week:(

Yeah, don't want to watch the match next week but I know I will in the end!

I wonder how long the storms will keep tracking up towards us? Maria goes on a similar path to Katia but gets rapidly absorbed into a low around Iceland before it arrives.

maquiladora · 11-09-2011 9:25am

I think Australia will be hammering Ireland a lot stronger than ex-Katia ever will! :rolleyes:

Anyway, here is the latest warning from Met Eireann. I can't remember the previous one, so not sure what if anything has been added here.

Issued at 11 September 2011 - 07:21

Weather Warning

Later Sunday night and continuing through Monday, southwest winds will increase to mean speeds of 50 to 80km/h, with gusts ranging 90 to 130 km/h. The most sustained and severe winds are expected across Connaught and Ulster.

Exceptionaliy high seas along the western seaboard, in conjunction with high spring tides, may cause coastal flooding in prone locations during Monday also.

Redsunset · 11-09-2011 9:42am

Here is the previous warning,

Severe weather warning
Warning Stormy weather is likely to develop late Sunday night and continue much of Monday with coastal counties of Connaught and Ulster most at risk. Connaught and Ulster most at risk Southwest winds could gust between 100 and 130 km/ hr in exposed areas. Very high waves expected on west, northwest and north coasts on Monday with wave heights between 6 and 10 metres

maquiladora · 11-09-2011 9:52am

http://www.ssd.noaa.gov/eumet/neatl/flash-wv.html

Looks to be more or less on track up to 06:00 UTC anyway.

Deep Easterly · 11-09-2011 10:00am

Satellite animation of Katia between 12.15utc 8th Sept through to 0615utc 11th Sept in 6 hour increments:

Amazing to see how as a hurricane, Katia was slow moving but once she got caught up in the jet, there was no stopping her.

ronnie3585 · 11-09-2011 10:08am

It's incredible to see how fast she crossed the Atlantic!

maquiladora · 11-09-2011 10:11am

The global models still have the pressure wrong for ex-Katia.

Look at the Fax compared to the UKMO.

John.Icy · 11-09-2011 10:16am

Seeing the first few slides of that satelite image sequence would make you think katia is going to plough straight through us. Nex time for us Southies

Deep Easterly · 11-09-2011 10:27am

maquiladora wrote: »

The global models still have the pressure wrong for ex-Katia.

Look at the Fax compared to the UKMO.

HIRLAM has it at 965mb at the same time frame on the 06 run. I think it is fairly typical for actual LP values in a deepening depression to be slight lower than what is indicated by quality NWP models and I reckon the guys at Exceter are probably taking that into account, but it is a tricky one for sure to try and estimate.

Pangea · 11-09-2011 10:30am

Looks iike the storm had lots of potential but will turn out out to be a relativley normal very windy event. High seas should be nice to look at it.

maquiladora · 11-09-2011 10:33am

Deep Easterly wrote: »

HIRLAM has it at 965mb at the same time frame on the 06 run. I think it is fairly typical for actual LP values in a deepening depression to be slight lower than what is indicated by quality NWP models and I reckon the guys at Exceter are probably taking that into account, but it is a tricky one for sure to try and estimate.

Yep, the NHC on their last advisory for the storm had it about 20mb lower than the models based on the last buoy it passed near to yesterday. The models corrected a bit but not enough and thats why I think there is still that difference now.

maquiladora · 11-09-2011 10:35am

Pangea wrote: »

Looks iike the storm had lots of potential but will turn out out to be a relativley normal very windy event. High seas should be nice to look at it.

The powerful jet has taken its toll on it but it should get in better shape again later.

Discodog · 11-09-2011 10:40am

I wonder if it will just appear to be a continuation of what we have now. Very unusual to have three really windy days together.

maquiladora · 11-09-2011 10:41am

Slightly further southeast at 24 hours on the 06Z GFS.

Pangea · 11-09-2011 11:01am

Ive been hearing Katia has turned back into a hurricane, is this true?

maquiladora · 11-09-2011 11:02am

Pangea wrote: »

Ive been hearing Katia has turned back into a hurricane, is this true?

Nope. It's tropical days are over.

fryup · 11-09-2011 11:11am

so what time will it hit ireland?

km79 · 11-09-2011 11:14am

Maquiladora can u give a quick synopsis of how things look now please ? Is it still likely to hit...how hard...where ?

maquiladora · 11-09-2011 11:19am

km79 wrote: »

Maquiladora can u give a quick synopsis of how things look now please ? Is it still likely to hit...how hard...where ?

No big changes either way that I can see but MT is the man for this so let's wait and see what he says. :pac:

The Met Eireann warning is a good synopsis I think :

Later Sunday night and continuing through Monday, southwest winds will increase to mean speeds of 50 to 80km/h, with gusts ranging 90 to 130 km/h. The most sustained and severe winds are expected across Connaught and Ulster.
Exceptionaliy high seas along the western seaboard, in conjunction with high spring tides, may cause coastal flooding in prone locations during Monday also.

km79 · 11-09-2011 11:22am

Just similar to the one last year so

fryup · 11-09-2011 11:23am

its getting fairly gusty right now in east-clare

vonbarracuda · 11-09-2011 11:24am

Anyone got a link to weather cams along the west which would show the waves?

maquiladora · 11-09-2011 11:27am

km79 wrote: »

Just similar to the one last year so

If the models are right, it won't be as intense for Ireland as the storm last year. There could still be some surprises but we'll have to wait and see.

Su Campu · 11-09-2011 11:35am

89 GHz AMSU imagery suggests that this system is taking the form of a Shapiro-Keyser cyclone, with the cold front detached and perpendicular to the warm front.

M.T., what do you think the consequences of this are for track and intensity? The UKMO haven't shown this in their FAX charts, going more with the traditional norwegian model. The cold front seems to be showing increased intensity in the last few hours.

EDIT: Actually the UKMO analysis does depict this structure, with the cold frontogenesis showing up, but it switches to a norwegian structure as it reaches Ireland.

maquiladora · 11-09-2011 11:44am

Latest warning from the UKMO

Issued at - 11 Sep 2011, 11:24
Valid from - 12 Sep 2011, 03:00
Valid to - 12 Sep 2011, 23:59

The remains of Hurricane Katia will move eastwards across northern Scotland during Monday, bringing a spell of very windy weather to the UK and also heavy rain to western Scotland. The strongest winds are expected to affect parts of Northern Ireland during the morning, before moving east across central and southern Scotland and into northeast England by evening. However, areas further south will not be immune, with the potential for strong gusts, particularly to the east of high ground.

The public should be prepared for the risk of disruption to transport and of the possibility of damage to trees and structures.

Sponge Bob · 11-09-2011 11:57am

UKMO severe weather warning monday

2011-9-12

cherryghost · 11-09-2011 12:09pm

06Z a bit closer to Ireland than yesterday's models.

maquiladora · 11-09-2011 12:12pm

06Z HIRLAM at 24 hours has the centre further east than the GFS.

Ex Katia storm thread - TECHNICAL DISCUSSION, FORECASTS AND OBSERVATIONS ONLY!

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