Very strong winds developing south, east; storm watch late Tuesday

Let's keep in mind that the storm is rapidly occluding and the front, which is likely to become very active, will race eastward across Ireland during Friday morning (west) to mid-day (east) with the possibility of some squally showers or even thunderstorms, with hail. The gradient winds at that time are only around 40-70 km/hr but convection may double that locally, south coast and inland south may be most at risk (as far northeast as Kildare-Laois). This feature will be long gone before the main storm winds appear on the west coast, so that there may be a fairly long quieter interval for many lasting from mid-day Friday (west) to early morning Saturday.

As of 1800h the Canadian met service map shows a 967 mb low at 54.3N 30.8W and more recent satellite imagery gives a fix near 55N 29W. The occluding front is already east of 20W and may begin to show up on Shannon radar by midnight.

Strongest winds in the developing warm sector of this storm or near the cold front, from ship reports, are in the 50 knot range, there are several well-placed ships to sample the winds around the part of the circulation heading for southwest Ireland, we may get some interesting reports in the next hour as ships tend to report more frequently every 3h (more so every 6h).

With most reliable guidance showing minimum central pressures near 940 mb for a good part of the 24h before landfall, we cannot overstate the potential for coastal flooding and I think this storm could produce seas that are generally at least half if not one metre higher than the worst of the January events, in almost all the same places. So this may involve a bit more than shoreline installation damage, it may extend into severe flooding of near-shore communities and I would advise everyone in those areas to be on a level 3 alert despite the more widespread level 2 theme.

Moderators please note, I have passed the time limit on editing the original post, if you feel at any point that a level 3 heading is required, that will need moderator intervention. I would say level 3 applies to all coastal regions from about Westport around to Waterford, possibly Wexford, level 2 applies to all exposed locations south of a Mayo to Louth line, level 1 applies to less exposed locations and just to be on the safe side the rest of the north although realistically from Donegal to Antrim there would likely be rather subdued effects, certainly from wind, the tidal increase could be more of an issue. As to the east coast, I would speculate that the tidal increases might be similar to January because of the less favourable wind directions this time, as opposed to the larger volume of water coming at the south coast that has to move into the Irish Sea. So that will be interesting to compare, and caveat emptor that I am not very experienced at making tidal surge forecasts anyway (or I wasn't before this year).

This map will outline the areas of high, moderate, low and negligible risk from the incoming storm system.



In level 3 areas, winds could gust above 130 km/hr causing severe local damage and storm surges especially at the Saturday morning high tides could cause moderate to severe flooding and damage.

In level 2 areas, winds are likely to peak at 120 km/hr in gusts, causing some instances of moderate damage. Most level 2 areas are inland but where they reach coasts, expect isolated or less severe coastal damage from considerably above normal high tides.

In level 1 areas, winds are likely to peak at 110 km/hr in gusts and damage should be minor. Coastal areas could be impacted by moderate storm surges.

In the "watch" area largely confined to Ulster, the current indications suggest that winds will not exceed 100 km/hr in gusts and coastal impacts should be slight or moderate at worst.

In all cases some very exposed locations could see more severe conditions than their position on the map indicates. Conversely, some sheltered locations within each zone would experience a lower level of impacts. The key point in assessing your location is exposure to the southwest through west, as that will be the prevailing wind direction.

If I feel that the storm is changing significantly from this outlook I will update this warning / alert / watch map. A "watch" basically means that conditions may favour an alert in the future and at the present time no warning is imminently likely.

As discussed in a previous post, some rather active weather extends out well in advance of the main core of storm winds and will move through on Friday morning, mainly in the level 1 to isolated level 2 category at that time. Some spot flooding on roads may develop as this front moves through. The depicted map zones apply to expected conditions on Saturday 1 Feb from about 0300h to about 1500h with peak stormy conditions 0600h to 1100h.