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

maquiladora

Am I missing something or does the 12Z GFS take 42 hours to get Katia to the same pressure that the NHC she is already at right now?

cherryghost

You're not missing anything. I'm completely boggled by that run

Sponge Bob

GFS has moved it sort of generally north by around 50 miles with that 12z run. I'd be happy enough if they were right

Mc Love

So are we safe from the winds now? Is there a potential for power outages?

Waves now in Waterford

ninebeanrows

GFS has the storm well to the north with the impact much lessened.

darkman2

maquiladora wrote: »

A considerable difference in position at only 36 hours between the 12Z and 06Z GFS.

Similar to the UKMO 00z evolution. When the Euro models both differ with their North American counterparts at this stage it's best to back our own. Will post the 12z UKMO in a minute.













A significant downgrade on wind strength and the timing has shifted to Monday afternoon for strongest winds. Although it would be stretching it to describe it as a "storm" at this stage for Ireland. Still very strong winds though and potential for severe gusts in the far North and exposed Atlantic coasts. All could change on the later model runs though. ECM is out from around 7pm.

maquiladora

Weathercheck wrote: »

GFS has the storm well to the north with the impact much lessened.

WC, what do you make of the 12Z having Katia initialised at 970 when the NHC say its already down to 954, but the 12Z doesn't deepen it that much for another 42 hours or so?

ninebeanrows

UKM very similar has storm well out to sea.

Keeping a fish Hurricane a fish Extratropical storm.

JanuarySnowstor

UKMO follows gfs.
It's looking like another damp squib.
In fact it doesn't look wet either so the whole thing is becoming a bit of a joke tbh.
Tonight will be the much windier of the two imo

nacho libre

Parts of Scotland are in for a hammering either way. I hope the latest GFS is just a wobble. This country is crying out for a proper storm. Ok, maybe not :pac:

maquiladora

Katia appears to be a stronger system than what the models are showing at the start of their runs. If anything this could lead to a track even further to the north, or it could mean that it will peak and weaken sooner than expected which might end up taking it on a more southerly track later.

Interested to see what MT says.

Pangea

Shame to see things go pear shaped.
But isnt this an upgrade for wind strength?
Appears to have moved further east

Iancar29

Pangea wrote: »

Shame to see things go pear shaped.
But isnt this an upgrade for wind strength?
Appears to have moved further east

*SCRATCHES HEAD*....

VERY ODD.... never seen this kind of ODD disagreement before.

ninebeanrows

It is hard to disagree with the models at this stage.

Although their initial pressure does seem incorrect. There is strong consensus that the low will be centred well to the northwest of Ireland.

Of course this can change but increasingly unlikely to do so.

I would suggest gusts to 70 knots still likely in the northwest.

40knots widely across the country.

dsmythy

Iancar29 wrote: »

*SCRATCHES HEAD*....

VERY ODD.... never seen this kind of ODD disagreement before.

As already said I think it would be better to believe the European modelling over the American for the region when there's a big difference.

ninebeanrows

Consider today we are seeing widespread gusts above 35 knots and upto 55 in Belmullet.

Pangea

Weathercheck wrote: »

I would suggest gusts to 70 knots still likely in the northwest.

40knots widely across the country.

Weathercheck wrote: »

Consider today we are seeing widespread gusts above 35 knots and upto 55 in Belmullet.

That puts things into perspective

M.T. Cranium

The reported central pressure is the wild card in this deck, basically the only thing we can do at this point is to assume the track forecast is valid and watch hourly positions for any signs of trend deviation. A storm this tightly wound and moving this fast has at least a 2 deg position error at 36h which explains why we shouldn't just write off the threat of very strong winds at this stage. Also you have to wonder how well initialized the 12z models were given that pressure reading and when it came to light. Anyway, I have taken a close look at the progress of the storm from 12z to 1630z on satellite imagery and don't see anything suspicious about the track, it seems to be heading ENE and gaining latitude about one degree for every four that it moves east. Current position (17z) estimate is 45N 44W.

Basically we are very close to the "nowcasting" stage and once the current disturbance moves past tonight, the next big item of interest will be the frontal system that is likely to spin out ahead of Katia to see what potential there is for thunderstorms or locally strong winds moving through Sunday evening to early morning Monday.

I don't expect there to be any "new" information until the 12z ECM run shows up but perhaps it's a foregone conclusion that there would be a similar track forecast there, so really the 18z model run is probably our next really new insight unless the storm appears off course on satellite imagery before then.

For interests in Mayo and Donegal, I would caution against downgrading wind estimates very much because the storm's strongest winds will tend to spread out over a much larger area and there could be some squally showers in the circulation giving brief bursts of very strong winds. The term "damp squib" may also give the wrong impression because once the fronts blast through there could be clearing across parts of the south so perhaps some people expecting a horrible day will be surprised on Monday by bright sunshine and in sheltered locations not all that much wind (thinking of the southeast in particular).

Anyway, it looks to me like the real workload on this storm forecast will fall much later so I may plan to be around more continuously from about 2300h on. Heading out soon to enjoy a warm, sunny day here.

maquiladora

I think that the very fast motion of ex-Katia (53 mph) combined with models having the pressure considerably higher than what it actually is right now make the final track and intensity still uncertain, one way or the other.

I think considerable further downgrades or upgrades are still very much possible.

I'm not going to write it off just yet considering the latest NHC public advisory does say :

GALE- TO STORM-FORCE WINDS ARE EXPECTED TO AFFECT MUCH OF
THE BRITISH ISLES ON MONDAY...AND COULD CAUSE DAMAGE TO TREES AND
DISRUPT TRANSPORTATION AND OTHER PUBLIC SERVICES

http://www.nhc.noaa.gov/text/refresh/MIATCPAT2+shtml/101454.shtml?

maquiladora

12Z HIRLAM (model Met Eireann use) has the storm further south and east than the GFS/UKMO at 48 hours.

vonbarracuda

How are we looking for Dublin North east? Im in a third floor apartment :eek:

blinksarah182

God I wonder how Ireland can deal with a hurricane? It just seems like a foreign Idea to me!

Pangea

NHC are no longer giving Katia advisorys.

Pangea

I know it's not Katia but Evelyn map showed gusts of 90km this evening in NW and 80km in SE .

TeddyTedson

I get the impression people will be killed during this storm.
Not too often that happens here.

Not

vonbarracuda wrote: »

How are we looking for Dublin North east? Im in a third floor apartment :eek:

Don't panic !! Don't panic !!

Unless the apartment block was built by Mr Blobby you'll be fine ! *
On the other hand, if it was.. well.. good luck

*Going on current models verifying which indicate nothing particularly extraordinary for Dublin. These could change.

maquiladora

http://www.ssd.noaa.gov/goes/flt/t2/flash-rgb.html

Toggle the Trop points option above the loop to see if she is tracking as forecast.

Pangea

"at this stage we are really getting concerned especially for Scotland and NI for some very strong winds"

http://news.bbc.co.uk/weather/forecast/10209

gozunda

Outlook from Met Eireann


Current situation

Meteorological situation at 1500: A depression of 970 hPa c. 280 miles west of Belmullet is tracking northeastwards as strong southerly airflow covers Ireland. The flow will veer southwesterly for Sunday, but another developing storm depression will approach Ireland later Sunday.

Sunday / Monday

Sunday night and Monday will be extremely windy countrywide with stormy conditions through parts of Connaught and Ulster. Gale force South to southwest winds will gust 100 to 130km/hr in exposed places, especially in coastal counties of Connacht and Ulster. Widespread rain for a time on Sunday night will give way to squally showers for Monday and winds will veer southwest to west. There will also be very high waves on western and northern coasts, possibly reaching 6 to 9 metres in height. Winds won’t be as strong on Tuesday. But it will still be a blustery day with a mixture of sunshine and showers, some heavy. Wednesday will be bright with sunny spells, well scattered showers and light to moderate southwest breezes.

A concern here is for the potential strenght of the incoming weather system is the relatively warm sea temperatures currently of the south and west coasts and similar warmm temperatures over land. Normally such storms start to run out of energy when hitting colder landmasses - dont think that this will be the case atm...

See Table of air & sea Temperatures LINK

delw

maquiladora wrote: »

http://www.ssd.noaa.gov/goes/flt/t2/flash-rgb.html

Toggle the Trop points option above the loop to see if she is tracking as forecast.

how often is that updated maq?