Sunday, 6 December 2015

Weather guide Monday 7th to Sunday 13th December 2015

Last weeks review: very mild, unsettled and often windy

Last Sunday was mild (Pembrey 13.2c, Pershore 13.1c) and very windy, gusts above 80mph for some exposed parts of Wales (Capel Curig gust 93mph). There was also rain at times, heavy in places afternoon, although it was patchy and some places had only a little (Aberdaron 0.4mm). Dull, wet and windy for Wales throughout much of Monday with some rain and drizzle on and off for the Midlands also. Large totals across Wales with many places a few miles inland getting over an inch (25mm) - highest for WW being Capel Curig 53.8mm by midnight (also Lake Vyrnwy, Powys 58mm). It was though a very mild end to a very mild November (Pershore 14.8c, Milford Haven 12.9c).

Very mild over Mid and South Wales Monday night (min Pembrey 12.1c) with less mild air over other areas (min Nottingham 4.0c), drizzle in many places but still quite wet for North Wales. Some most welcome sunny spells for the Midlands on Tuesday and where it was dry. Mostly cloudy still for WW however with rain or drizzle in places which tended to die out afternoon, very mild in all areas (Pershore College 14.9c, Trawsgoed 13.3c) in stark contrast to northern Scotland where it snowed in places on Monday and Tuesday! Very mild again Wednesday, rain for WW afternoon but the Midlands stayed largely dry with a few sunny intervals with a little rain here by evening (Hereford 14.2c, Milford Haven & Pembrey 12.8c).

Mild with some rain in many places during Wednesday night, very mild indeed over much of the Midlands above 10c all night (min Pershore 11.7c, Mona 5.0c). Another very mild day Thursday, heavy rain and strong to gale force winds for WW with rain reaching most of the Midlands too later (Gogerddan 13.9c, Pershore 13.8c). Over an inch of rain for parts of Wales during Thursday (Capel Curig 42.2mm). Cooler Thursday night when it became largely dry (Llanwnnen 2.4c). Sunny intervals over the Midlands but a lot of cloud yet again for WW Friday, only a few showers and mild or very mild (Hereford 13.1c, Milford Haven 12.8c). Strong winds Friday pm with gales for exposed places.

Friday night saw strong to gale force winds in many areas (Capel Curig gusts to 89mph), wet for NW Wales and it was very mild staying above 10c for many (Pembrey min 12.1c, Hereford 11.3c) bearing in mind average maxima in early December are 8 or 9c. Named storm Desmond brought severe gales across WW during Saturday and a lot rain for the NW. Little if any rain for the rest of Wales and it was mostly dry for the Midlands but cloudy. A phenomenal amount of rain fell over Snowdonia during Saturday with 131mm at Capel Curig in the 24 hours to midnight, this though much less than what fell over Cumbria (Shap 201mm/ 8 inches) and it is likely that parts of the Lake District exceeded 350mm rain in 36 hours! Mild everywhere if not a great deal higher than the previous night (Shawbury 12.6, Pembrey & Trawsgoed 12.4c).

November review: very dull, very mild and unsettled; rather wet in most places, very wet parts of Wales

Record breaking warmth across West Wales on the first 2 days as Trawsgoed reached 22.4c (72f) with unbroken sunshine - unprecedented for November, but for much of East Wales and the Midlands it was foggy and quite cool especially 2nd. The rest of the month then unsettled and very dull. It was one of the mildest Novembers on record with temperatures 2 or 3c above average. Snowdonia was exceptionally wet as moist SW winds were frequently forced to deposit their contents on the massiff. There was data loss at Capel Curig during one wet spell over a couple of days and so the estimated total quoted would be at least 40mm higher and so the monthly total likely approached 750mm (almost 30 inches) - more than the average for a whole year for places such as Coventry in the Midlands!

Some November rainfall totals:

Capel Curig >690mm  (>240%)
Trawsgoed c. 210mm 
Llanwnnen 238.9 (160%)
Aberporth c. 150mm 
Pembrey Sands c. 170mm
Llanelli 165.6mm

Nottingham c. 80mm
Coleshill c. 60mm
Coventry 78.4mm 125%
Church Lawford 73.2mm 112%
Long Lawford 64.9mm 105%
Hereford 74.4mm 116%
Pershore 69.8mm 123%
Cirencester  PWS 94mm 

Some November sunshine totals:

Valley 35.2 hrs
Llanwnnen est 38 hrs (70%) - 16 hours of which first 2 days
Aberporth 32.7
Coventry, Bablake School 37.8 hrs = dullest Nov since 1884 (36.3)
Shobdon 28.4 

Autumn 2015: rather average overall

Temperatures close to or a little above average overall in spite of the very mild November; likewise rainfall in many places was quite close to average in spite of a wet November in most places, Hereford though had a dry Autumn.

Some Autumn rainfall totals:

Trawsgoed c. 370mm (96%)
Llanwnnen 403.9mm (103%)

Long Lawford 161.6mm (96%)
Church Lawford c. 188mm (103%)
Coventry, Bablake 201.6mm (106%)
Hereford c. 142mm (74%)

and sunshine:

Llanwnnen est 303 hrs (112%)
Coventry 280.4 hrs (91%)

The week ahead: changeable with rain at times (chiefly WW) and some drier brighter days; often mild but perhaps colder Friday/ Saturday

November and the start of December has been very mild and very dull, less than 2 hours sun in the past fortnight here at Llanwnnen. Capel Curig has has 263mm rain in the first 5 days of this month and Long Lawford just 8.4mm such are the variety of conditions these Isles provide us with! Better prospects of getting a brighter day or two in the coming week as things dry out somewhat over Wales. Sunday night saw some further rain over WW with the Midlands again staying largely dry, it was another very mild December night (Pembrey min 12.1c). Still residual bits and pieces of rain in places lasting into Sunday afternoon but for many a dry afternoon in prospect with a few sunny intervals, maxima at 12 to 15c but cooling across North and Mid Wales afternoon, and much less wind. The next weather front associated with a mid Atlantic low will bring further spells of rain across Wales later this evening, but should only be light and patchy over the Midlands tonight, it could drop down to 5c in the north of our regions this evening but will be back into double figures celsius by dawn.

We are in yet another warm sector during Monday so very mild with a lot of cloud and a little rain or drizzle, chiefly for Wales, while the Midlands may see a few chinks of brightness. Maxima again 12 to 15c and well above the December average, there will be a freshening SSW wind but not gales on Monday. The cold front then brings a more general band of rain across all parts during Monday evening and night, some of this heavy and a mild night no lower than 6c even behind the cold front, a windy night too. Tuesday and its hopeful of a bright, breezy showery day, so most places getting a couple of hours sunshine at last! Hardly any showers making it to the Midlands, max here 12c in the morning, while WW reaches 8 to 10c in somewhat cooler air.

Clear spells Tuesday night could give a ground frost in places under a ridge, close to 0c then locally although freshening winds should have lifted this by dawn as the next fronts arrive. Although there will be quite an intense high over France during Wednesday weak fronts will bring plenty of cloud again, although after sunny intervals for a time over the Midlands. Light rain and drizzle quite likely to develop over WW as we go through the day, mild at 10 or 11c but the SW wind increases strong to gale by evening. More active fronts seem likely to be strung out overnight Wednesday close to WW where it may well be wet in places, and with gales in exposed areas, but mostly dry Midlands.

The slow- moving strung out front scenario may last well into Thursday, so this is another day when Snowdonia in particular could get an awful lot of rain, wet in other parts as well but this cannot be ascertained at this stage, and it may not pan out this way as the fronts could clear though more quickly Thursday. It should be another mild day but may cool down later if the cold front does manage to clear through. Uncertainty expands come the end of the week but it may end up rather colder but remain changeable, although some options do keep it generally on the mild side still. Friday into Saturday then again hopeful of sunny intervals and scattered showers type conditions with temperatures down to around average (max 7 to 9c). However indications are that it could turn wet again eventually next weekend as a low trundles our way from the SW with at this stage Saturday night into Sunday seeming the more likely timespan for this.

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