Sunday, 20 September 2015

Weather guide Monday 21st to Sunday 27th September 2015

Last weeks review: Rather cool and unsettled but became mostly dry

Mostly dry and bright last Sunday, Ceredigion doing best for temperatures which were a touch above the September average here (Gogerddan 19.2c), elsewhere temperatures near or slightly below average (Nottingham 18.4c, Aberdaron 16.9c, Little Rissington 15.8c). Mostly cloudy and showery Monday, some heavy and thundery showers over the Midlands and weak tornadoes were reported from various places including Tewkesbury, Leamington Spa and near Northampton.  South Wales saw longer periods of rain during Monday (wettest Milford Haven 55.2mm). A cool day in most places only Llanwnnen (17.8c) reaching average (Wellesbourne 17.2c, Mumbles 16.6c, Shobdon max 12.9c, Capel Curig 11.8c).

A lot of cloud with showers in places Tuesday, these less widespread than on Monday but still some heavy downpours in places, such as Coventry during the early evening (13mm). Rather cool for most (Pershore 18.4c, Milford Haven 17.5c, Shawbury 16.9c, Tirabad, Powys 14.0c). A chilly night for WW followed with a ground frost for parts of the NW (Capel Curig air min +0.9c). The deep low that was anticipated in last weeks guide to give us a wet and windy Wednesday merely side swiped us in actuality. The rain missed most of Wales and the NW Midlands which had a dry day with sunny intervals, but it did turn wet later in the afternoon into the evening across the south and east Midlands, with the edge through Coventry and Leicester. On the cool side almost everwhere again (Porthmadog 18.3c, Pershore 16.8c) and especially cool for mid Wales (Tirabad max 12.6c).

Sunny intervals and a few showers on Thursday, South Wales catching most of them with some heavy, temperatures average to rather cool (Pershore 18.7c, Mumbles 17.9c, Capel Curig 14.5c). Heavy downpours over parts of WW and the South Midlands during Thursday night (Aberdaron 22mm) then Friday mostly dry with sunny intervals and just the odd shower scattered about, a few heavy ones over the Marches in particular.  Temperatures just about exceeded the average in places (Church Lawford 19.3c, Mumbles 18.5c) while others were still quite cool (Aberporth 14.8c, Shawbury 17.1c).

A foggy start to Saturday in places, dense fog shrouded Draycote Reservoir near Rugby, in contrast to the sunshine in Coventry just 10 miles away (see below). At least some pleasantly warm sunshine for most places during Saturday, much of the the Midlands had a sunny afternoon and Anglesey had 10 hours sun (Newport, Salop 20.3c, Llanwnnen 19.7c,) but cooling sea breezes for Cardigan Bay coasts (Aberdaron 15.6c).
Draycote webcam

The week ahead: Rather cool and changeable; fine, dry weekend

Thick fog over much of the Midlands this Sunday morning (even Coventry city centre), most of us seeing some sunshine this afternoon courtesy of a ridge, although WW may have a lot of cloud. Highs around 16c max WW and 18c Midlands, close to average for mid/ late September. Weather fronts bring patchy light rain and drizzle to WW eventually this evening. More organised rain overnight across Wales, possibly with some rather heavy bursts, this progressing into the West Midlands by dawn Monday, lows 10 to 12c. Monday then a rather cloudy and damp for the Midlands with some mostly light rain at times, the cold front clearing the rain from WW by lunchtime. Just a few showers affecting Wales during the afternoon with sunny intervals, it should be a bright end to the afternoon for most of the Midlands too. Highs rather cool at 14 to 16c.

A frontal disturbance moves across bringing showers and some longer spells of rain for Wales during Monday evening, heavy in places, this then onto the Midlands overnight, Sunny intervals and scattered showers on Tuesday, some heavy with thunder, these especially over the Midlands, highs 13 to 15c as the breeze turns into the north. Most of the showers dying out in the evening, lows 6 to 8c inland. Wednesday sees a transient weak ridge of high pressure quickly displaced by weak fronts so a mostly dry day with some sunshine over the Midlands, but it clouds over for WW with drizzle in places eventually, highs 15 to 17c. A little rain or drizzle in places then for Wednesday night which is quite mild remaining  above 10c.

Low pressure NW of Scotland on Thursday, we are in a rather cool WSW flow bringing some showers and sunny intervals. WW catching most of the showers where a few could be heavy, much of the Midlands on the other hand escapes largely dry and bright, maxima Thursday ranging from 13c for shower prone Snowdonia to 17c for brighter spots of the Midlands. Friday looks a rather cool and breezy day but bright with only a few showers expected.

Next weekend it is likely that high pressure will be over southern Britain, we should be seeing plenty of dry and rather warm Autumn weather with pleasant sunny spells, temperatures perhaps close to 21c 70f come Sunday.  The ECM model goes on to bring us a proper plume of warmth for the last couple of days of September which would see temperatures in the high 70's f (25c) should this scenario come to fruition. Fine and warm conditions may even hold into the beginning of October!

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