Weather
Anglesey weather is special
Expect rain - and Holyhead (in particular) may offer sun. Expect sun - and the Menai Strait (in particular) may offer drizzle. (Anglesey drizzle is like Irish mist - less than a half inch of torrential rain an hour !!).
Winds work the same way. It can be blowing a southwesterly hoolie off SouthStack, gusting heavily in Holyhead Bay - and Holyhead harbour will be calm. Even in the Menai Strait very local conditions exist. In easterlies, Beaumaris can be 'enjoying' a misty F5, whilst Port Dinorwic (the other side of the Swellies and the bridges) is basking in F1 and sun.
It is, therefore, necessary to take Met Office forecasts with a' pinch of salt'. Some of the newer weather sites (such as Theyr Net and XCWeather take land effects into consideration. Sometimes it works ....
| Holyhead Coastguard @ 0235UTC +4hr | North of Anglesey, Channel 84 (Gt. Orme aerial) South of Anglesey, Channel 73 (Mynedd Rhiw aerial) |
| Liverpool Coastguard @ 0210UTC +4hr | North of Anglesey, Channel 86 (Snaefell aerial) Liverpool Bay, Channel 73 (Liverpool & Blackpool aerials) |
Irish Coastguard @ |
Dublin, Wixklow Head, Roslare, Carlingford: select best reception from announcement on Channel 16. |
| RTE1 (Eire), 567 Khz, 88.2Mhz |
0602, 1255, 1957, 2355 |
| BBC Radio 4, 198 Khz, 103.6Mhz : |
0048, 0535, 1201, 1754 |
| Teletext | BBC p409: ITV p158 |
The reasons are many - and best understood by the met. people. From observation, however, it seems that the mountains of Snowdonia deflect winds from the southeast to southwest, and in the latter case, Holyhead Moutain adds its own special influence. Northwesterlies are funnelled by the North Channel, then focussed by the Pennines and the Snowdonia range. Southwest through Northwest winds will typically ease as you move away from Holyhead Bay and land, whilst along the north coast, those same breezes will pick up a force. As one would expect, easterlies are 'killed' along the west coast and in Holyhead Bay, leading to some unpleasant surprises at Carmel Head.
In the Menai Strait, southwesterlies are typically increased by about 1 force between F4 & F6 and by perhaps 2 forces at F7 and above. Those same winds will be decreased in Red Wharf Bay (Traeth Coch) by their passage over the Island. So an approach to Puffin Sound from Point Lynas in a forecast F6 may blow F3/4 across Red Wharf Bay ("They got it wrong AGAIN!") only to turn into 30 - 40 knots from Puffin Sound to Beaumaris!