Storm Brian : Orange Wind Warning Sat 21 -10-17

Longboard

http://www.inchydoneyisland.com/en/beach-cam/

jumpjack wrote: »

I can't find any working webcam in whole Ireland seaside!
Any link?

gozunda

Absolute no wind early morning - took opportunity to move a couple of tons of animal bedding undercover.

By 12.30 wind had started to rise and first belts of rain. Wind WSW going now to WNW but variable. Currently gusting to 24.1 km/h. Rainfall currently 2.29 mm/hr. Current pressure reading of 977 hpa and falling.

Local rivers full to bank level . Land saturated.

East Limerick Cork border

fraxinus1

Gloomy but dry in South Donegal. Breezy with swirling gusts that are blowing the leaves into mini tornado like features in the garden. Love this type of weather.

Not expecting anything more than a gale here.

gozunda

jumpjack wrote: »

I can't find any working webcam in whole Ireland seaside!
Any link?

Mace Head webcam



http://140.203.204.247:8650/

circadian

fraxinus1 wrote: »

Gloomy but dry in South Donegal. Breezy with swirling gusts that are blowing the leaves into mini tornado like features in the garden. Love this type of weather.

Not expecting anything more than a gale here.

I would have expected some heavy rainfall around.

teelinboy

Its pouring down here now in SW Donegal, has been for for half an hour now

spookwoman

hit 5.1mm already in Waterford

http://www.waterfordcityweather.com/

uck51js9zml2yt

jumpjack wrote: »

I can't find any working webcam in whole Ireland seaside!
Any link?

try
http://www.onitsurf.com/surf-cameras/inch_surf_cam.html

My friend has a few web cams around the south west.

Rulmeq

spookwoman wrote: »

hit 5.1mm already in Waterford

http://www.waterfordcityweather.com/

I see the bunting finally broke.

gozunda

spookwoman wrote: »

hit 5.1mm already in Waterford

http://www.waterfordcityweather.com/

Waterford - increase to 7.1 mm for previous 24 hrs

Similar reading of 7.8 mm here for same period

Still raining ...

Lumi

Satellite view of Storm Brian



Image courtesy DSRS
http://www.sat.dundee.ac.uk

froog

sun out in cork city. that band of rain looks to have past. it's heading across the country now i guess. traffic is really bad all over the city, avoid if you can.

piuswal

MJohnston wrote: »

It is a storm, but a storm is a very broad definition.

Anyway, here's a quick noobs guide to reading the model charts (and I'm writing this as a total novice myself, so I hope this doesn't come across as condescending or useless!).

Looking at Meteorite's post above, the first graphic shows the forecast for wind - specifically 'mean' winds (in the 'average' sense of the word). The blue text in the top left is in French, but you can tell that it indicates the date of each frame of the animation, and the time too. The next blue line of text tells you what the chart shows - in this case "Mean wind speeds at 10m" (10m above the surface I believe), as well as the units of measurement shown - in this case km/h.

In plain English, this means it shows what the highest constant ('sustained') wind speed will be, and the scale of the colours at the bottom are in km/h. The graphics are actually commonly colour coded so that "angrier" colours are the top end of the scales, so the angrier it looks, the worse it will be! You can also see the wind direction indicated on the lines (I'm not sure what the lines indicate exactly, they might be isobars, but it isn't really essential to understand the chart).

The second chart shows wind speed again, but in this case it's showing the strongest gusts of wind at the surface - so there's a big difference between gusts and sustained winds, gusts can be way stronger, but they can also be very brief. The scale for gusts vs sustained winds is usually different too.

The third chart shows how much rain (or more accurately precipitation, but we're not expecting snow!) will fall between now ("depuis +0h" just means "since 0 hours from now") and the date indicated in the top left, in this case Sunday 1am. There's no units shown on this chart, but as it's a European chart, I'm guessing that it's in millimetres. So parts of the Southwest might see something like 90mm of rainfall over the next few days, which is quite a lot (especially as a couple of the days will be dry).

Anyway, these are charts from a particular model called the ARPEGE. There are various different computer forecasting models created by the various forecasting services, so there's the GFS which was created by the American's national weather service, ECMWF model created by a group of European countries working together, ARPEGE is the French model, etc. There are lots of others like GEM, AROME, HARMONIE, HIRLAM and many more. You can usually identify which model created any chart because it will be labelled on the chart somewhere (in the case of the ones I explained above, it's mentioned in the black bar at the top right), or the poster will mention it.

These computer models at a very simplified level are programmed with a lot of knowledge about how weather systems are expected to work and interact, and then they run simulations starting from the current day and time and extrapolating what weather might be like in the future. Different models are run at different frequencies, but it's usually something like every 6 hours. You can usually tell the time and date that a model was run by looking at the charts created, for example the third chart above was created by an ARPEGE model run at 0Z (0 hours Zulu Time, which is essentially 00:00 GMT, which is 1am Irish time until the clocks go back) on 18th October 2017.

As you can imagine these computer models aren't perfect (because the actual weather systems are unimaginably complex), and the imperfections can add up over time. So a chart for 24 hours away is probably quite accurate, but one for 48 is less so. Beyond a point (120 hours from now) the models are so far away that the certainty that they will be accurate has dropped enough that they're unlikely to be true, you'll see many posters call charts from beyond this timeline "Fantasy Island" because they're so unlikely (but not impossible!).

This is why having multiple models to consult is important, because if they all show very different outcomes, you can say that confidence is low that any individual one of them is going to be accurate. If they are all showing very similar outcomes however, you can be very confident that they are going to be accurate - this is what happened a few days out with Ophelia, where various different models were starting to converge on a very similar outcome.

Unfortunately, even when the models seem to agree, sometimes they can vary by what on global scales seem like very tiny distances, say 40-50 miles worth of different on where the heaviest rain might happen. On an human scale though, 40-50 miles of difference can actually be quite
important, particular in such a small island as Ireland. With Ophelia, we had that kind of uncertainty about the exact path of the storm, and therefore where the worst winds might be - and that 40-50 mile variation was the difference between the West coast getting the worst of it and the East coast getting the worst of it (or somewhere in between as seemed to actually happen this time).

And to bring it back to this weekend's storm, we're talking about the models predicting the passage of an area of low pressure that is currently somewhere just off the East coast of the USA, so think of the thousands of miles it has to travel before reaching us. The various models seem to be in agreement that the system will pass close to Ireland, but the uncertainty is still at the point where the path hasn't narrowed enough to say where with any exactness (a 100 mile variation at this point is the difference between nobody feeling any effects, and it directly passing over the middle of the island).

Anyway, this got way, way longer than I intended, but hopefully it's helpful to some of our newer weather forum watchers! There are loads of other chart types available that are more complex and show stuff like air pressure, which is a whole other level of difficulty (I don't really understand these yet myself beyond the very broadest strokes like low pressure = unsettled weather, high pressure = settled weather).

Great article. Just an additional point which I may have missed;

ECMWF address the issue of small variations building up by their ensemble forecasts;

they rerun, 50 or 51 times- not sure exactly, their global model, with small variations built into the initial observations in critical areas and so produce an ensemble of forecasts. These can then be compared to calculate confidence in any particular situation.

Im sure someone can display such info, of not already dome.

jumpjack

I know it's a heavy requirement but... are realtime streaming  and/or HD webcams available? Wind and rain are quite invisible at low res and 1 FPS. :ermm:

Harry Palmr

It's a bit wet. Seriously though at 3 pm the first drops hit the ground in Waterford City and now it's a total windy deluge. The growHQ gardens have dealt with the rain so far this Autumn, be interesting to see how they look on Monday morning after this weekend.

DOCARCH

jumpjack wrote: »

I know it's a heavy requirement but... are realtime streaming  and/or HD webcams available? Wind and rain are quite invisible at low res and 1 FPS. :ermm:

Unless your a pig, wind is not very visible...generally.

M.T. Cranium

Always walk on the lower side of alerts. (doo doo, doo doo doo doo doo doo)

Villain

jumpjack wrote: »

I know it's a heavy requirement but... are realtime streaming  and/or HD webcams available? Wind and rain are quite invisible at low res and 1 FPS. :ermm:

I have two in Carlow if they are of any interest.

Emme

Lashing rain and very windy in Kildare

dave1982

Sun trying to break through clouds in cobh. All clear no wind or brian

nagdefy

M.T. Cranium wrote: »

Always walk on the lower side of alerts. (doo doo, doo doo doo doo doo doo)

The Daily Express has to be 'Biggus Dickus'

jumpjack

DOCARCH wrote: »

jumpjack wrote: »

I know it's a heavy requirement but... are realtime streaming  and/or HD webcams available? Wind and rain are quite invisible at low res and 1 FPS. :ermm:

Unless your a pig, wind is not very visible...generally.

yes it is:
http://www.carlowweather.com/wxwebcam.php

M.T. Cranium

LOL at B.D. two posts back, yeah, why is everybody laughing? etc

Oddly the actual orange level situation is the combined rainfall of Thursday plus today, it doesn't appear very likely that winds with Brian will gust above 110 km/hr anywhere except possibly outer coasts tonight and Mace Head tomorrow when the westerlies kick in. This is good because some weakened trees no doubt after Ophelia plus all this recent rain. For that reason probably a good thing to have an orange wind alert because there could be those sorts of impacts on the weakened trees and also you have to consider possibly structural problems left over for any minor windstorm to exploit.

Anyway, it's a bit of a three dressed up as a nine.

Meteorite58

ARPEGE 12Z

Mean



Gust



WRF- NMM

WRF / GFS Showing a track crossing the country further than the ARPEGE / ECMWF







ECMWF

squarecircles

Thundery rain moving in later with violent gusts possible tonight - Siobhan Ryan

Are squall lines possible???

tayto lover

Does high wind effect aircraft much?
I'm flying early tomorrow, something i really dread, and just wondering if this will make it worse for me.

Irish Steve

tayto lover wrote: »

Does high wind effect aircraft much?
I'm flying early tomorrow, something i really dread, and just wondering if this will make it worse for me.

there may be some disruption to flights from the smaller regional airports, and also Cork & Shannon, but in the overall scale of things, the winds are not outrageous for aircraft operation, and on the present showing, Dublin should not be too much affected in the morning, there's a possibility of some issues with gust strengths later in the day, but most flights should get in and out without too many issues.

Drumpot

Feels like east coast keeps dodging bullets. Is it luck combined with wind direction and Wicklow mountains?

Iancar29

Drumpot wrote: »

Feels like east coast keeps dodging bullets. Is it luck combined with wind direction and Wicklow mountains?

Wicklow mountains.. winds are from the SW so most of Dublin in the Shadow/

JanuarySnowstor

M.T. Cranium wrote: »

LOL at B.D. two posts back, yeah, why is everybody laughing? etc

Oddly the actual orange level situation is the combined rainfall of Thursday plus today, it doesn't appear very likely that winds with Brian will gust above 110 km/hr anywhere except possibly outer coasts tonight and Mace Head tomorrow when the westerlies kick in. This is good because some weakened trees no doubt after Ophelia plus all this recent rain. For that reason probably a good thing to have an orange wind alert because there could be those sorts of impacts on the weakened trees and also you have to consider possibly structural problems left over for any minor windstorm to exploit.

Anyway, it's a bit of a three dressed up as a nine.

I disagree along the south coast looks poised to see 130km gusts and after all Irelands largest city outside Dublin is right on the coast. I see plenty disruption from this for Cork/kerry