ADVANCE ALERT (NO: 3, 7 Dec 2012) - Wintry Weather Mid-Week Next Week

ADVANCE ALERT continued for the risk of (moderately) severe wintry weather arriving around Tuesday night (11th-12th) and lasting several days towards the following weekend. Confidence in such an eventuality is now at 65%, up from 60% yesterday (6 Dec).

There will be slight recovery in daytime temperatures over the weekend before the next cold spell arrives. It will be mostly cloudy with some mist (fog over hills) on Tuesday. Later on in the day some sleet or wet snow may develop in the east with the precipitation falling as cold rain further south and west. It will feel much colder than the temperatures of 3-6c would suggest as the winds will be blustery northeast (30-50 km/hr) Overnight temperatures on Tuesday night will be -2 to +2 C.

It will start off cloudy in the east and partly cloudy to sunny in the west on Wednesday but it will feel bitterly cold everywhere with daytime temperatures ranging 0c to 4c. Morning lows will dip to between -5 and -2c. The risk of snowfall is generally very light but isolated snow or hail showers in streamers are likely near Irish Sea coasts and some parts of Derry, Donegal and North Mayo.

Thursday will be partly to mostly cloudy with some outbreaks of light snow, mainly near eastern and southern coasts, and in parts of northwest. Accumulations of 1-3 cms are possible in most cases. Snow could turn to sleet or rain near sea level. Lows -5 to -2 C and highs 0-5 C.  Friday and Saturday of next week will be cloudy with sleet changing to rain at times in the southwest, but snow accumulating on hills here (potential for some moderately heavy amounts). Overnight lows -3 to +2 C and daytime highs 2-6 C.

The weekend of 15th-16th is likely to see a slight rise in temperatures and rain rather than snow, especially by Sunday. The next few days are likely to be foggy and rather chilly as milder air moves in mostly aloft, highs from Sunday to mid-week are likely to remain 4-7 C.

NOTE: ALERT for slippery or icy roads in many rural and some higher urban areas tonight and repeating for the next few nights, as temperatures drop well below freezing, leading to freezing fog and frost.

Peter O'Donnell is a Vancouver-based climatologist who specialises in providing long-range forecasts for Ireland and Britain.