Atlantic Storm Watch: December 2013

maquiladora

Weathercheck wrote: »

UKM going for a less developed feature but still develops a reasonable low at t60hrs.

I think there will be some support for a less developed low taking a slightly further south track.

Just one GFS Ensemble to show what is possible..

Looks like about 8 members go for a bigger impact than the op and about 10 are weaker. Could go either way, I thought there was better ensemble support for a strong low on the previous runs though, so maybe leaning towards a downgrade.

ECM will be interesting.

Iancar29

GFS ens 11 as above...




Estimated pressure pattern on the night of ' THE BIG WIND' Jan 7-8 1839



http://www.met.ie/climate-ireland/weather-events/Jan1839_Storm.PDF

Oneiric 3

The NAE, while taking the low track similar to UKMO, develops a very small secondary which passes over the NW. Could have bring equally high winds but on a more localised scale.

UKMO 12z fax has low slightly more south on Wed noon that what they forecast at 00z. This is good as it will scoop up more energy, but I can't seem to get myself excited about this one as looks too similar to the lame efforts of the last few winters.



(gif shows 12z and 00z comparison fax for Wed noon.

ninebeanrows

ECMWF has a small tight cored low of 965hPa @ 48hrs, probably heading further north than the GFS run.

M.T. Cranium

To convert the map above for 7 Jan 1839, note that pressure intervals are 0.25" Hg which equate to 8.3 mbs. You could almost double the gradient to get a sense of how it might compare to model output. The central pressure on the map is within the 27.25" contour and that equates to 922.8 mb so the other contours would be around 931, 939, 948 etc while the central pressure as per this map is about 916. From what I recall reading, the lowest verified station pressure on land was something like 930 mbs in northern Scotland.

There is a comparison to be made, with some of the current model output, although I would say the worst looking GFS perturbation or slight twist of the GME would be something like an 80% solution of this historic storm. Still, you don't want to be dealing with 80% of the intensity of that damaging storm. My current estimate is more like two-thirds. In the Big Wind, I have to imagine an hourly from Belmullet something like this

Temp 8 Dew point 5 Wind W 82 kt gusting 123 SLP 940.5

so a two-thirds solution of that would be 55 kt gusting 81 SLP 955.

JanuarySnowstor

ECM says what storm!!
Weaker and further North.
Another con job by the models

ninebeanrows

JanuarySnowstor wrote: »

ECM says what storm!!
Weaker and further North.
Another con job by the models

You joking? You haven't seen the charts between 48-72hrs!

Would hit Ireland hard, northwest and north obviously most at risk.
But you are very wrong with your assessment, broadly similar to the GFS.

Oneiric 3

JanuarySnowstor wrote: »

ECM says what storm!!
Weaker and further North.
Another con job by the models

Storm is set to peak at around 10 pm Wed so 24hr 12z frames may not show too much detail

maquiladora

Weathercheck wrote: »

ECMWF has a small tight cored low of 965hPa @ 48hrs, probably heading further north than the GFS run.

It's 958mb at 48 hours on the hi-res.

Yeah it looks to be going further north. It's very similar to the 12Z GEM between 48 and 72, and looking at the frames between those times on the GEM you can see its mostly a swing and a miss for us.

ninebeanrows

Lots of uncertainty when you compare the UKM, GFS and ECMWF so!

All at 48-60hrs.

JanuarySnowstor

Weathercheck wrote: »

You joking? You haven't seen the charts between 48-72hrs!

Would hit Ireland hard, northwest and north obviously most at risk.
But you are very wrong with your assessment, broadly similar to the GFS.

I disagree, its clearly further North than the GFS and it's own 0z run from earlier.
A slight nudge North in the morning runs and it will miss altogether
That's my assesment anyway:)

maquiladora

Weathercheck wrote: »

Lots of uncertainty when you compare the UKM, GFS and ECMWF so!

All at 48-60hrs.

Yeah. I was thinking a blend between GFS and UKMO but then ECM/GEM have a third option. Can't all be right.

Hard one to call.

Oneiric 3

JanuarySnowstor wrote: »

I disagree, its clearly further North than the GFS and it's own 0z run from earlier.
A slight nudge North in the morning runs and it will miss altogether
That's my assesment anyway:)

on the plus side, a nudge north would bring a better chance of squall zones developing near Ireland.

ninebeanrows

maquiladora wrote: »

Yeah. I was thinking a blend between GFS and UKMO but then ECM/GEM have a third option. Can't all be right.

Hard one to call.

Yea, not long until we find out. I'd probably call a version of the GFS with the highest winds a touch further northwest.

ninebeanrows

ECMWF has the low near 952hPa off the northwest coast at 60hrs.

Greatest gradient just off coast, if this occurred it would be just the northwest bearing the brunt.

dopolahpec

Met Eireann won't be making a call on this yet on the basis of the current output. Still seems to be a range of solutions running from intense storm affecting much of the north to an increasing trend toward a more northerly track which even the 12z GFS was hinting at with severe winds only affecting the north west coast

snowstorm2013

As much as I enjoy the watching the power of these winter storms, I am hoping that this event wont be severe. Last saturday a large tree got knocked near my garage and a second is weakened. I have a tree surgeon booked for Friday but if this tree falls it will hit either the garage or the fuel shed. Am I right in saying that things are looking less likely for a major wind storm for Ireland? Im in North co. Sligo near the coast

ninebeanrows

snowstorm2013 wrote: »

As much as I enjoy the watching the power of these winter storms, I am hoping that this event wont be severe. Last saturday a large tree got knocked near my garage and a second is weakened. I have a tree surgeon booked for Friday but if this tree falls it will hit either the garage or the fuel shed. Am I right in saying that things are looking less likely for a major wind storm for Ireland? Im in North co. Sligo near the coast

No, you seem in a very vulnerable location. I would say there is a high chance of you receiving some 60kt gusts at least with a moderate risk of 70kts.

(That is knots, multiply by 1.9 for kilometers)

maquiladora

Latest NWS chart for 48 hours. 958mb deepening to 942mb north of Scotland 24 hours later. Track takes a slight bend towards the northwest coast.

A small enough margin between a standard windy winter night on the west coast, or something more severe.

http://www.opc.ncep.noaa.gov/shtml/A_48hrbw.gif

Weathering

Unable to access charts all day(phone screen is cracked) and I'm kind of lost as to what's happening. Lots of mixed messages reading through this thread.

whitebriar

Weathering wrote: »

Unable to access charts all day(phone screen is cracked) and I'm kind of lost as to what's happening. Lots of mixed messages reading through this thread.

Basically..
If you have a shed roof in the west/northwest with loose timbers,I'd be down to the hardware store first thing tomorrow for enough rope to secure it.

Oneiric 3

A grim hope remaining with the latest WRF. Like NAE, has smaller, mesoscale features developing around main circulation though that is where similarity between the two ends.



(from meteogalica)

What does it take to get a half decent storm these days?

snowstorm2013

Weathercheck wrote: »

No, you seem in a very vulnerable location. I would say there is a high chance of you receiving some 60kt gusts at least with a moderate risk of 70kts.

(That is knots, multiply by 1.9 for kilometers)

Ok thanks. I spoke with a neighbour and he had heard it was going to be windy but met eireann arent really saying much about it. The tree surgeon cant get to me until Friday but he said he hadnt heard of any big wind event... I spoke to hm ten minutes ago. So I hoping that we will be spared wind on Wednesday night. I could get another crew in tomorrow but they way more expensive and I cant risk using the Christmas money on the seemingly small chance of strong winds. Dreading the next 48 hours

ninebeanrows

Oneiric 3 wrote: »

A grim hope remaining with the latest WRF. Like NAE, has smaller, mesoscale features developing around main circulation though that is where similarity between the two ends.


(from meteogalica)

What does it take to get a half decent storm these days?

I really would not write this storm off.

Best case scenario is that it hits the northwest coastal districts only, but if it did, it would hit here hard because it would have to have went under exceptionally rapid deepening to take this curve north.

ECMWF Ensembles will be interesting, as i think you'll find, a large % will take a more southerly route.

ninebeanrows

snowstorm2013 wrote: »

Ok thanks. I spoke with a neighbour and he had heard it was going to be windy but met eireann arent really saying much about it. The tree surgeon cant get to me until Friday but he said he hadnt heard of any big wind event... I spoke to hm ten minutes ago. So I hoping that we will be spared wind on Wednesday night. I could get another crew in tomorrow but they way more expensive and I cant risk using the Christmas money on the seemingly small chance of strong winds. Dreading the next 48 hours

Well it was made clear on the 6.1 Weather Bulletin that the northwest was a risk of Storm winds during Wednesday night.

Tactical

Oneiric 3 wrote: »

What does it take to get a half decent storm these days?

Probably the same thing it takes to get decent snow event!

patneve2

As always, only the nowcasting will reveal the precise position of the low. However, I doubt that it will track any more south than its forecast to at the moment, and to be honest I hope it doesn't.

Oscar Bravo

Siobhan Ryan gave a very good forecast after the 6 news. She had a line marked out for connaught and most of Ulster for Wednesday evening/night and a symbol saying 100km/hr+ gusts. Have a look after the 9 news. It will be a stormy night in the W/NW ,of course we who live there are well use to that kind of thing.

snowstorm2013

Oscar Bravo wrote: »

Siobhan Ryan gave a very good forecast after the 6 news. She had a line marked out for connaught and most of Ulster for Wednesday evening/night and a symbol saying 100km/hr+ gusts. Have a look after the 9 news. It will be a stormy night in the W/NW ,of course we who live there are well use to that kind of thing.[/QUOTE

Saw her forecast on rte+1 and she mentioned gusts well in excess of 100kmph so I gonna get the other guys in tomorrow. Not taking the chance.

ninebeanrows

ECMWF mean is further south than the Op.

Will take a look at stamps in next hour. Of course we miss the crucial 60hr charts.