This Week's Storms - FORECAST, MODEL DISCUSSION ONLY

Deep Easterly

125 years ago yesterday a particularly powerful storm bore down on our wee Isle:



Now that is what I call a low!

leahyl

So am I right in saying that the lower the number is on the chart (in the centre of the storm) the stronger the storm is??

Deep Easterly

leahyl wrote: »

So am I right in saying that the lower the number is on the chart (in the centre of the storm) the stronger the storm is??

The general rule of thumb is yes, but not always. Amongst other factors it depends on what the actual pressure gradient is between the low pressure center and any given point away from it. The tighter the pressure (or isobaric) gradient is, the better chance you have a stronger winds.

The ECMWF ensemble mean run seems to be pretty much aligned with its deterministic run this morning on the actual track and position of potential storm depression prognosed for early next week:


if not quite as intense but the ens tend not to focus on specific detail beyond a sub-synoptic scale so overall, the trend is looking good so far.

ECMWF 00z windspeed chart for Tuesday 12z:

Image: yr.no

Narrow but intense zone of winds off the west coast. Will be interesting to watch how (if) this wavers on the models over the weekend.

maquiladora

It's only early Friday, but the UK Met Office already have a Yellow Alert for this.

Issued at - 09 Dec 2011, 11:31
Valid from - 12 Dec 2011, 18:00
Valid to - 13 Dec 2011, 18:00

Western and southern areas of the UK are at greatest risk of very windy weather on Monday evening and during Tuesday which could lead to disruption. At this stage there is a good deal of uncertainty and the public are advised to monitor forecasts over the weekend to keep up to date with this warning.

Interesting that they are putting an advance warning out so early and also interesting that they say "western and southern" areas most at risk...

leahyl

maquiladora wrote: »

It's only early Friday, but the UK Met Office already have a Yellow Alert for this.



Interesting that they are putting an advance warning out so early and also interesting that they say "western and southern" areas most at risk...

Exciting stuff:)

Birdnuts

Just had a look at the 06Z run!! - next week looks like Armageddon in terms of wind:eek:. If it pans out like that it will the most severe spell in wind terms for at least a decade!!

only one

What mph winds could we be getting from this and what part of the country could be worst affected? I know it's still early but it's worth a shot

maquiladora

only one wrote: »

What mph winds could we be getting from this and what part of the country could be worst affected? I know it's still early but it's worth a shot

Have a look at the gust charts I posted on the previous page.

Remember though that it could change a lot by Tuesday.

ninebeanrows

12z GFS very similar track to 6z.

Not much change still tracking just to our north.

Looks slightly more worrisome though.

maquiladora

Yeah some expected changes here and there with timing and track but the end result for Tuesday looks pretty much the same on the 12Z GFS.

More fun then again later in this run... :rolleyes:

ninebeanrows

Later in the week we get pounded by a bomber of a system that really interacts with a extreme jetstream.

Now that would cause serious disruption.

It is influenced by a much stronger jetstream than the system on Tuesday.

WolfeIRE

http://www.accuweather.com/en/weather-news/hurricane-force-winds-batter-u/58843
Being an unusually strong storm, the system will rough up seas in the north Atlantic. Wave swells of over 40 feet are forecast off the coast of western Ireland early Tuesday morning.

Harps

Some crazy storms showing up this week, three major storms in the space of a week??

Highly unlikely to come off but the one on the 16th would be disastrous :eek:



Tuesday still looking bad for us in the north in particular

Deep Easterly

Weathercheck wrote: »

Later in the week we get pounded by a bomber of a system that really interacts with a extreme jetstream.

Now that would cause serious disruption.

It is influenced by a much stronger jetstream than the system on Tuesday.

Looking increasingly like a case of 'meet the family'. Models have been showing for this 2nd potential later next week alright for a while now. Seems to have a steeper thermal gradient than storm no.1 as well.

Harps wrote: »

Some crazy storms showing up this week, three major storms in the space of a week??

Highly unlikely to come off but the one on the 16th would be disastrous



Tuesday still looking bad for us in the north in particular

That's it. I am moving to Donegal!

rhonin

WolfeIRE wrote: »

http://www.accuweather.com/en/weather-news/hurricane-force-winds-batter-u/58843
Being an unusually strong storm, the system will rough up seas in the north Atlantic. Wave swells of over 40 feet are forecast off the coast of western Ireland early Tuesday morning.

Now that would be worth a trip home to Belmullet. There was some serious swells last weekend.

pauldry

by next week it will have moved north hitting scotland again

leahyl

pauldry wrote: »

by next week it will have moved north hitting scotland again

Will it? You mean you don't think it will hit us in the South?

Deep Easterly

pauldry wrote: »

by next week it will have moved north hitting scotland again

Another general rule of thumb is that when a family of depressions develop, each one tends to follow a slightly more southerly track than the previous one. Simplistic maybe but something to hold onto.

gothwalk

Deep Easterly wrote: »

Another general rule of thumb is that when a family of depressions develop, each one tends to follow a slightly more southerly track than the previous one. Simplistic maybe but something to hold onto.

That's interesting. Any idea what the physics behind it is?

maquiladora

UKMO at 144 has the same idea as the GFS?

patneve2

:O look at this one

still a week away but looks very stormy

redsteveireland

I don't want to sound pedantic but don't we have a thread for FI and other model discussion, It's just that I thought this thread was dedicated to Monday/Tuesday event and the place is getting overloaded with charts.

All the info about Mon/Tuesday event is great and I may need to take a trip to Salthill if this one comes off.


Iancar do you still have my anemometer? It would be handy for this event.

Deep Easterly

gothwalk wrote: »

That's interesting. Any idea what the physics behind it is?

Depressions like this tend to form along the polar front, which uninterrupted has a tendency to move south or southeastwards over time before weakening. Add in a strong jet stream, intense troughing in the upper atmosphere to initiate big surface depressions forming if the temperature gradient at the surface is steep enough. If a 'family' of depressions develop, these will actual help slow down the overall movement south of the polar front but in general not prevent it. Hence why each subsequent depression within a family has a tendency to take on a slightly more southerly track than the previous one.

Badly explained I admit and only assumes an idealized scenario. Of course, actual specific weather has a tendency to blow general rules to bits whenever it takes it fancy.

Just to add, this is the more favoured scenario in winter. During the summer months, the opposite tends to apply.

WolfeIRE

If this system was to shift further south it would raise the prospect of snowfall for many.

A Dub in Glasgo

I don't think people should be hoping for a storm like this. Whilst good to get the odd photo and experience it, it is essentially destructive

maquiladora

Some disagreement between the main 12Z models on the handling of Tuesdays low.

Tactical

A Dub in Glasgo wrote: »

I don't think people should be hoping for a storm like this. Whilst good to get the odd photo and experience it, it is essentially destructive

A decent wind event is well overdue Naturally without any wish of injury to persons or destruction of property.

The odd tree down here and there as long as no one gets hurt is ok though;)

I love the wind, the stronger the better.

(Before anyone chastises me too badly for hoping for a decent bit of bad weather, I'm someone who has to go out and work in it when it does get bad.)

whiteandlight

This is a lot of storms in one week?! I'm due to get married on the 17th so forgive me for hoping that tue is the last one for about a week!!

only one

WolfeIRE wrote: »

If this system was to shift further south it would raise the prospect of snowfall for many.

God I hope so! Never get snow in the south east.

Winger_PL

redsteveireland wrote: »

Iancar do you still have my anemometer? It would be handy for this event.

I still have it in Maynooth, wondering what's the best way to pass it on to you?