Storm Ciara - Strong Winds & Potential Snow **TECHNICAL DISCUSSION**

M.T. Cranium wrote: »

A thread is coming about storm Ciara. Check back in a few minutes and I will have this introductory post somewhat more filled out with an overview of what looks like being a long-duration and complex event. I have posted a LEVEL 1 tag for the storm now because I am about 99.9% certain it will get at least that and most likely a LEVEL 2 designation eventually.

There will be three phases to this storm.

A rather brief but intense period of strong winds seems likely by late Saturday as a leading wave hits the west coast. Winds may peak at about 70 to 120 km/hr during this phase with a brief interval of heavy rain possible.

The "main event" will arrive on Sunday as the depression actually tagged as storm "Ciara" moves east to the north of Ulster towards northwest Scotland. This will involve a fairly long-duration blast of strong winds from the west, but perhaps a more severe impact in terms of elevated sea states leading to battering waves and coastal inundations (as usual Galway Bay in the firing line for this but generally all parts of the west and possibly south coasts). I could imagine this phase being mainly 70 to 110 km/hr winds with some intervals as strong as 90 to 130 km/hr locally, but it's more about the long duration than the peak gusts with Ciara.

A third phase will be falling temperatures and continued strong winds with a trailing wave likely to pass to our north on Monday, allowing the squally showers already in progress to become increasingly wintry through the day on Monday. This may actually continue for much of Tuesday with some chance for heavy snowfall accumulations on some higher terrain in Connacht and west Ulster and on hills elsewhere too. Once again this phase may involve mainly 70 to 110 km/hr speeds but could ramp up towards Monday evening to 80 to 130 km/hr.

I may expand this post but feel free to "have at it" and I will rely on moderators to change the tag (LEVEL "x") in sync with the Met service who have an excellent commentary available in their forecast section. There is such widespread model consensus that I think the discussion will be mainly about details and inevitably the red/orange debate will probably arise, I would say even at this early stage, red might verify in terms of coastal impacts not so much from the intensity of the winds as the long duration combined with the coastal flooding factor. But for now we'll be conservative and start off with a LEVEL ONE tag so that Boards readers know something bad cometh this way.

Note: There may be a yellow (LEVEL ONE) warning associated with a weaker system timed to move through on Friday afternoon and evening. This will be separate from the above complex storm event and may briefly get its own little discussion thread, but if not, just in general be aware that Friday's outcome will be independent of the evolution of storm Ciara and if it fizzles or gets stronger, not likely to be a "trend" in terms of how Ciara might perform.

I have added in some wind speed thoughts to my first posting above, otherwise this will have to do to get us started, Meteorite and some others are the pros at posting graphics so rather than having me fumbling around with that, I imagine they will go for the jugular as soon as some good solid guidance becomes available.