Includes all higher summits in the southern half of Wales: the Bannau Brycheiniog / Brecon Beacons National Park, southern Cambrian Mountains and highest Preseli hills.
Brecon Beacons
Wednesday 6th December 2023
Last updated
Tue 5th Dec 23 at
4:28PM
After a hard frost, mostly dry and bright, but feeling increasingly bitterly cold as southeasterly winds strengthen and cloud thicken through the day ahead of a front, which will bring and increasing risk of upland snowfall, in across western mountains toward evening, and then spreading to all parts overnight.
Early sun, then overcast. Bitter chill as winds strengthen. Rain/snow tops later.
Southeasterly, strengthening from southwest from around 30-35mph after dawn to 40 to locally 50mph afternoon.
Walking increasingly difficult, in places on lower slopes, and feeling bitterly cold as wind chill becomes significant.
Dry until late afternoon, then periods of rain, temporarily snow.
Dry for much of daylight, but fronts will bring persistent rain, although particularly mid Wales, initially snow., from mid to late afternoon. The change to rain will tend to occur fairly abruptly into the evening.
Persistent fog from most lower slopes up
Summits likely to start cloud free in the morning. Will deteriorate in afternoon with cloud base lowering extensively to 300m or lower as rain/snow arrives, although breaks above 450 Cambrian mountains.
70% lowering later in afternoon to 10%
Early sun, but soon overcast as cloud thickens. Appalling or near zero visibility in the upland snow that arrives late in the afternoon.
0 or -1C (only a degree or so warmer in valleys) post dawn; rising to 1C from southwest. Will feel as cold as minus 15C directly in the wind.
450 to 700m; a transition to above the summits will extend slowly from southwest.
Brecon Beacons
Thursday 7th December 2023
Last updated
Tue 5th Dec 23 at
4:28PM
Very turbulent conditions developing. Southeasterly, later southerly, winds; lifting through day to 50 to 70mph.
Be prepared for increasingly very difficult conditions, as turbulent and very powerful winds accelerate over the mountains.
Frequent rain, heavy at times.
Frequent spells of rain and drizzle through the day. May become heavy or intense later in the day as an active front moves in, perhaps with local thunder.
Very extensive
Hills widely shrouded in fog all day from lowest slopes upwards.
Less than 10%
Overcast. Poor or very poor visibilities.
4C, Feeling closer to -14C in exposure to the wind.
Above the summits, but ground from mid slopes up, still partially frozen, with slow-continued thaw.
Brecon Beacons
Friday 8th December 2023
Last updated
Tue 5th Dec 23 at
4:28PM
Southerly 45 to 65mph at first, but as low tracks in, winds will veer southwesterly and ease 25 to 40mph, maybe less.
Be prepared for difficult conditions with significant wind chill and buffeting. Slowly moderate into the afternoon.
Frequent, at times heavy, rainfall.
Low pressure will drive frequent, and at times heavy, rainfall into the area through the day. Setting in at times in the west.
Extensive
Extensive hill fog through the day, and at times forming from lower slopes upwards.
20%
Little if any sun. Visibility often poor due to rain.
Around 4C, but feeling more like -10C or below in direct exposure to the strongest winds.
Above the summits, with upper level terrain continuing to thaw out. windy
Unsettled conditions will prevail over the next week to 10 days, with periods of upland gales or severe gales with precipitation frequent, mostly rain, although intermittently snow Scottish Highlands, more rarely elsewhere. Driest conditions (relative to the average) will likely be in the northwest Highlands, given the often backed flow, as the low pressure areas track in.