Wednesday Storm (15/08):MOD WARNING #626 High Winds + Heavy Rain/Flooding Likely

JanuarySnowstor · 13-08-2012 7:37pm

Was going to write off this system until I saw the Hirlam above.
Interesting, and of course after so much rain lately the ground is well and truly saturated

Iancar29 · 13-08-2012 7:51pm

JanuarySnowstor wrote: »

Was going to write off this system until I saw the Hirlam above.
Interesting, and of course after so much rain lately the ground is well and truly saturated

Me too!!... hmmm possible photo day out at the coast so!

Su Campu · 13-08-2012 9:26pm

Hirlam shows up to 55-knot sustained winds off the south and southeast coasts by Wednesday evening (8 pm). It's looking like one feckin filty durty day!

Redsunset · 13-08-2012 9:37pm

Hirlam doesn't seem right. System takes a right turn instead of left.

Redsunset · 13-08-2012 10:01pm

12z model comparison 48hrs

cherryghost · 13-08-2012 10:38pm

18Z is rolling out. Looks about the same thus far.

EDIT: Also sorry, but I have to post this :P

ninebeanrows · 13-08-2012 10:45pm

GFS 18z more inline with meso models.

Obviously it won't have the power to resolve the centre of this properly, but it sure does look interesting.

Could be a powerful storm for the southeast coast.

http://www.wetterzentrale.de/pics/Rtavn421.png

Redsunset · 13-08-2012 11:24pm

Latest NAE singing with HirLam.

HirLam

davidsr20 · 13-08-2012 11:52pm

Looks interesting. I wonder will we see much impact in the west?

sunbabe08 · 14-08-2012 12:10am

well that's me stuck down in youghal than.

any chance of any thunderstorms coming from this. my head is fit to burst from the tension in the air.

M.T. Cranium · 14-08-2012 1:21am

Unreal, the latest official forecast skips right over Wednesday ... the general idea at present time seems to be that the low will deepen rapidly south of Valentia, move N then NNW and this could bring in very strong SSE winds through aligned topography in south-central to southwest counties.

My morning forecast will consider all available guidance. At the moment I think this is too delicate a situation to be very confident, we are basically talking about a severe storm with a 24-36 hour life cycle that has not yet begun. Forecast users must be patient and realistic, we have nothing much more than theory to work with -- a strong trough and strong wind shear aloft spells trouble. It is a time in the lunar cycle (northern max) that I have long associated with severe weather. No reason to downplay this potential yet.

Rougies · 14-08-2012 1:45am

M.T. Cranium wrote: »

Unreal, the latest official forecast skips right over Wednesday ...

I've seen 24 hr periods omitted from forecasts before from met eireann in times of uncertainty, most recent being their forecast for Sunday 5th August (thunderstorms). On that Friday evening their forecast skipped Sunday and went straight from Saturday night onto Sunday night.

Redsunset · 14-08-2012 2:59am

I think this is the way it will go too.
NOAA

Sponge Bob · 14-08-2012 3:54am

M.T. Cranium wrote: »

Unreal, the latest official forecast skips right over Wednesday

I'd say that a longish meeting was held today and that the collective wisdom of those present was well versed on Bombs. I expected something today myself apart from the rather risible "wet and windy" but tomorrow morning is soon enough for a warning (as well as a bit late for one).

cherryghost · 14-08-2012 6:36am

ME have updated their forecast now:

Wednesday will be a very wet and very windy day. A band of heavy and persistent rain will reach the south early in the morning and this rain will spread northwards across the country during the morning, together with strong and gusty easterly winds. The rain will cause some localised flooding. In the afternoon, the rain will ease for a time, but another spell of heavy rain will follow quickly from the southwest, with winds veering southerly and increasing further to gale force in coastal districts of Munster and Leinster with the risk of some severe gusts. The wet and very windy weather will continue throughout Wednesday evening. Highest temperatures of 17 or 18 degrees.

M.T. Cranium · 14-08-2012 8:01am

This is likely to become an explosive deepening situation. The models may not be catching the full severity of the storm because it will reach a lower central pressure on almost a meso-scale basis when the vortex interacts with the warm, humid air now present. I have worded the forecast more dramatically than may be heard elsewhere because I don't want Boards users to be caught unaware of what might be a very severe outcome especially in the south. As there is some uncertainty on track people should get frequent updates from midnight on ... we'll be watching very carefully here.

As I've stressed in other situations, central pressure is important but so is rate of pressure change. That will be unusually large for a summer season low and this storm may become similar to the gale that hit the southwest in January 2010. I think this was almost concurrent with the Haiti earthquake. Very strong winds and a continuous roaring sound were reported by several of our observers with that one. But now the trees are all in full leaf and that could greatly increase the potential for wind damage. Also we now have August sea surface temperatures and humidity levels which would increase the rainfall potential as well as the wind potential in similar energy regimes.

Although the track might make it appear that the west is most at risk, there will be impacts all around the country with the possible exception of sheltered parts of east Ulster.

Now, here's the over-under on predictable comments:

where is the storm, I don't see anything yet ... 0230h

this is coming in faster than anyone said it would ... 0630h

there goes the first trampoline ... 0822h

nobody said this was going to happen ... 0930h

wasn't it supposed to last all day? ... 1245h

as usual, nothing happened here ... 1530h

Despite that moment of levity, I hope that folks across Munster in particular are or will be prepared for a rather eventful day, things are looking rather ominous on the charts.

sunbabe08 · 14-08-2012 9:38am

well this should be fun day in youghal tomorrow

ninebeanrows · 14-08-2012 9:56am

6z NAE churning out.

Looking interesting at T30

Redsunset · 14-08-2012 9:59am

I think we'll have to up the warning to level 3 High Risk seek shelter because that is what we will be doing.

ninebeanrows · 14-08-2012 10:06am

Looks like the storm peaks before landfall.

Hits 970mb at around T+24hr

Before filling to near 980mb as it moves inland at T+42hrs

eskimocat · 14-08-2012 10:07am

Stormy Weather.... this is an interesting one. I noticed that all the models seem to agree on the pressure even if there are differences in the track.

I was wondering if anyone here remembers the website that has the wave height recorded by the buoys that are around Ireland. Could they assist in tracking the storm as it approaches and give clues to which track its taking? Or was it ships that were reporting wave height??? (anyone there able to figure out what I am trying to remember, tired over here and brain on strike! ) We tracked a storm someway like this before, (didn't we?) :eek: <Yawn

Clamball · 14-08-2012 10:07am

I have travelled from Cork to Midleton to Fermoy via Castlelyons yesterday and today and the ground is saturated from very heavy rain over the last several days. Yesterday morning there was deep flooding between Midleton and East Cork Gold course and this morning there was surface water on the road from Dungourney to Castlelyons in locations I had not seen before. The edges of the roads are all very broken.

A lot of rain tomorrow should cause a lot of flooding as everything is so saturated and on back roads travelling by car will be in very poor conditions.

ninebeanrows · 14-08-2012 10:10am

Redsunset wrote: »

I think we'll have to up the warning to level 3 High Risk seek shelter because that is what we will be doing.

Spoke too soon! Will be an interesting watch for sure.

Maybe keep this at Level 2 for the time being?

Sponge Bob · 14-08-2012 10:13am

Clamball wrote: »

A lot of rain tomorrow should cause a lot of flooding as everything is so saturated and on back roads travelling by car will be in very poor conditions.

A lot of rain and accompanying WIND , striking an area with already wet ground, and with the leaves still on the trees, could cause a fair bit of damage if a load of trees are knocked.

The same scenario applied to the famous London 'hurricane' in 1987.

Redsunset · 14-08-2012 10:20am

Weathercheck wrote: »

Spoke too soon! Will be an interesting watch for sure.

Maybe keep this at Level 2 for the time being?

Yeah I suppose nothing is concrete yet.

nbar12 · 14-08-2012 10:37am

really like this thread guys, keep up the good work. I've always had an interest in the weather! What I would do to be in Cork tomorrow, love a bit of stormy weather!

M.T. Cranium · 14-08-2012 10:44am

If that NAE map verifies and then the storm tracks as per most of the global models a bit further west then it won't fill and you would be justified in going to level 3. Have been tracking closely past 3 hours and continues to look like early-stage explosive deepening. Ship reports west of the centre are indicating a 30-40 knot NNW gradient. Air temperatures seem very close to lowest seasonal values around 25W indicating that deepening will soon begin once the energy max rounds the base of the trough around 15-18z.

The website requested for marine data is

http://ndbc.noaa.gov

click on "recent" to get maps, you have the option on each selected buoy of reviewing all marine reports within specified distance, would recommend taking K1 buoy west of Brittany and going 500 miles to get all relevant ship reports. Longitude west of Greenwich is negative to avoid confusion.

Nothing much will happen before about 18-21h (except for a gradual eastward motion of the developing complex low) then it should start to deepen rapidly southwest of that K1 buoy, run right over it around midnight and head towards Valentia by 0900h to 1100h. The GEM upper air panels are jaw-dropping almost, for me at least, and I have seen a lot of upper air maps. If those verify, it's like having a November storm with summer dynamics basically and that could spell trouble. What catches my eye is the tight gradient at 500 mbs and the rapid height falls from about 576 dm to 532 dm west of Valentia next 24h. You can already see a lot of energy streaming north into the warm sector of this storm on satellite imagery around 40N 18W and ship reports from that region will be available (there's a ship heading into that zone on the hourlies now with a rising westerly wind).

leahyl · 14-08-2012 10:46am

I know there's a lot of concentration on the wind but is the rain going to be just as bad? Met Eireann are saying the rain will cause some localised flooding but aren't indicating how much in mm.

Sponge Bob · 14-08-2012 10:55am

Strikes me that the track of the centre is forecast a bit further east ( over Connacht rather than off Connacht and that the Irish Sea quadrant will get more of a battering than the south coast will.

As there will be a continual easterly quadrant wind for quite some time the possibility of coastal flooding in Dublin at High Tide should not be discounted and preparations for same should be undertaken today...closing low lying car parks along the coast etc etc as soon as today.

The main risk would seem to be the 11pm Weds and 11am Thursday high tides, dumping of as much water as is possible out of that Leixlip dam should be underway now so that they can close the gates for the 2 hours or so before high tide.

Item 1 on the Corpos agenda this morning should be. WHO has the Keys. ??? and Item 2 should be to put some Petrol in them Chainsaws and lubricate the teeth.

maquiladora · 14-08-2012 10:57am

06Z GFS is a bit more intense than the 0Z. Strong gales for the southwest coast.

Overall, I'm not really sure about this one. It's quite different from the usual Atlantic lows were used to watching late in the Autumn/Winter. Will be interesting to see how it develops.

Wednesday Storm (15/08):MOD WARNING #626 High Winds + Heavy Rain/Flooding Likely

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