Sunday, 31 May 2015

Weather guide Monday 1st to Sunday 7th June 2015

Headline: Cool with rain and strong winds Monday/ Tuesday; then mostly dry becoming very warm, perhaps even hot briefly; thunderstorms in places Friday/ Saturday; turns cooler weekend

Last week's highlights

Last Sunday turned out surprisingly warm over Herefordshire, presumably due to sunny intervals ahead of the weak front that was giving cloud and a little rain over some other parts of the Midlands?Hereford itself managed 20.6c, but with most of the Midlands under cloud and maxima more like 17c; it a rather cool day over Cardigan Bay and North Wales behind the front, max just 12.7c Aberporth inspite of afternoon sunshine.  Bank Holiday Monday was at least largely dry, if rather cool again as well as quite cloudy, temperatures for most reaching between 13 and 16c (high max Pershore 17.1c, Pembrey 16.6c, low max Aberporth 12.0c). It turned fairly sunny for all areas during Tuesday afternoon and generally a touch warmer (Hereford 18.8c, Pembrey 16.3c) although some areas still on the cool side (as at Aberporth 12.9c and Shawbury 14.6c).

Clear spells led to a widespread grass frost Tuesday night - the latest at Coventry since the one on 29th June 2011 (min Tirabad, Powys 1.5c, Llanwnnen 1.7c, Pershore 2.1c). Pleasant sunny spells for a while on Wednesday but some rain arrived across WW eventually afternoon (max Hereford 18.7c, Llanwnnen 16.7c). These fronts failed though to bring significant rain during Wednesday or the overnight period away from Snowdonia, and following them very few showers about on Thursday, many places dry and bright if rather cool and breezy (max Capel Curig 11.9c, Pershore 17.0c). 

A spell of heavy rain for many early on Friday (although barely a drop at Little Rissington) cleared to a few showers and sunny spells, but a cool and breezy day (max Pershore 15c, Capel Curig 11.2c, wettest Swyddfynnon, Ceredigion 18mm, Pershore 10mm). Some pleasant sunny spells Saturday as a ridge gave a dry day, however for most quite cool yet again, especially along coasts (max Hereford 16.5c, Llanwnnen 16.1c, Aberdaron 11.2c) . Some rain did reach WW during the evening with some, though not large amounts everywhere last night as well.

(Note:  warmest/ coldest/ wettest quoted places may be for both West Wales and Midlands or combined regions)

The week ahead

A disturbed start to the coming week as a deep low crosses Scotland bringing wet and wild weather from Monday pm lasting into Tuesday, then convincing signs in the models that there will be a short-lived very warm or even hot spell by the end of the week!

Bits and pieces of rain mostly cleared during this Sunday morning to leave sunny intervals and the odd shower this afternoon, quite cool again, highs 13 to 15c with the WNW breeze. Becoming mostly dry with clear spells tonight with the 3 to 6c minima cool enough for very localised ground frost even if it is June 1st! A bright dawn to Monday flatters to deceive as the cloud thickens and wind strengthens through the morning with rain moving into WW by lunchtime. A wet and windy afternoon for most, the SW wind gusting to at least gale force inland and as high as 70mph for exposed coasts and hills, so with trees in full leaf there could be some travel problems. Particularly wet on Monday across Wales where an inch or more may fall in many areas, although most of the rain quite light for the Midlands. Maxima ranging from 15c over brighter East Midlands, to a very poor 11 or 12c for West Wales (WW), so a truly awful start to Summer here = very cool, very windy and wet! 

During Monday night the deep low with a central pressure around 980mbar is crossing Scotland, further rain at times as a warm sector comes through which may raise temperatures after midnight to above 12c for most areas, some of the rain still heavy at times for Wales in particular, so that by Tuesday morning some spots may have had 50mm (2 inches) in the 24 hours. The rain should finally be clearing the Midlands by early Tuesday afternoon to leave sunny intervals and a few scattered showers and with the wind decreasing.  Highs afternoon between 14 and 18c, best for the Midlands and South Wales. Becoming largely dry overnight with improvements for Wednesday as pressure builds over southern UK, a mostly dry day, bar the odd light shower for North Wales and the North Midlands, sunny intervals and maxima between 15 and 19c (coolest for western coasts due to onshore breezes). Clear spells and cool for Wednesday night down to 5c in places. 

High pressure likely to be centred to our east on Thursday which sees warm air advecting our way from off the Continent. A nice dry, warm and quite sunny day then at last, maxima between 20 and 23c, but cooler sea breezes for some coasts. Uncertainties with developments from Friday into the weekend but we should experience a very warm, even quite hot day on Friday but with thunderstorms in places. The latest GFS run supporting this evolution with highs widely of 24 to 27c (81f). The model consensus does seem that this will be a hot blip however and as soon as Saturday we see things cool down! At some stage in the day a cold front is likely to progress east, this perhaps setting off further thundery downpours across the Midlands, with scattered lighter showers for Wales. Wales likely to see maxima back down to just 16c, with 20c perhaps the best for the Midlands but this a long way off and it is not out of the question that the heat hangs on for one more day here? Sunday and a new but most likely cool high is closeby so it should be pleasant enough with sunny spells and temperatures reaching say 16 to 20c. Looking further out into the middle of June, plenty of generally dry and bright weather showing up although with temperatures only around average for June ( 17 to 20c).

Sunday, 24 May 2015

Weather guide Spring Bank Holiday Monday to Sunday 31st May 2015

Headline: Mostly dry with some sun to midweek, turning cool and unsettled with rain or showers

Last week's highlights

Wet last Sunday night and Monday morning, many parts of Wales had 20mm or more (wettest 30mm at Capel Curig) while parts of the Midlands received over 10mm (Hereford 14mm). Squally winds caused some structural damage and brought trees down in the Swansea area on Monday morning. Cool for much of last week especially on Wednesday when all locations failed to reach 14c, parts of WW coolest with max just 8.1c Capel Curig (persistent showers) and 10.4c Trawsgoed (only a few showers) and with a cold wind. Showery then on Wednesday with hail and thunder in places, parts of the Midlands, such as Coventry, caught a succession of hail showers through the day. Some coasts missed most the showers and had decent sunny spells, as at Milford Haven which had no measurable rain on Tuesday. Ground frost formed over the Welsh Marches and Vale of Evesham on Tuesday night as the showers died out, localised grass frost for some other parts of the Midlands as well.

Only a few showers on Wednesday, most of WW dry and bright, but still on the cool side everwhere but with the NW winds lessening. Another ground frost in places Wednesday night, lowest air temperatures Pembrey Sands and Llanwnnen min +1.7c. Thursday mostly dry and warmer with sunny periods, much of the Midlands above 18c, warmest Pershore and Coventry on 19.4c. Unfortunately with the wind off a still quite cold sea most of WW still pretty cool, decidedly so at Aberdaron near the tip of the Lleyn Peninsular max 12.3c, though Llanwnnen inland enough to attain the late May average at 16.4c. Some warm sunny intervals developed during Friday, although with light showers in places, max 20.4c Pershore and Hereford, 20.3c Llanwnnen, however most of WW did not better 18c and some coasts struggled yet again with onshore breezes and low cloud, Mumbles, Swansea at only max 13.0c the cool spot.

Contrasting fortunes Saturday, with WW away from Anglesey and Snowdonia having a rather warm sunny day, while most of the Midlands was rather cloudy with just a few sunny intervals, an exception being Herefordshire which was quite sunny and warm. Max temperatures Tirabad, Powys 19.8c, Hereford 18.9c, Pembrey Sands 18.5c,with Aberporth 13.4c coolest inspite of the sunshine, followed by Valley 15c, while the cloudier parts of the Midlands such as Coventry were around 16c. Coventry yet to break the 20c barrier this year which could end up the latest 'first 20c date' in the city's history, with June 1st 1983 to beat (please see the excellent )!

The week ahead

Plenty of dry if rather cloudy weather to the middle of the week, though some sunny spells, but then it turns cooler and unsettled quite appropriately to see out this rather cool and unsettled May! Sunday seeing a lot of cloud with a little rain or drizzle in places as as weakening front slowly crosses the country. Most of this dying out/ clears afternoon with some late sunny intervals for WW and the NW Midlands in particular, maxima Sunday 14c WW and 16c Midlands. Dry with clear intervals tonight. Bank Holiday Monday will be mostly dry, a light shower cannot be ruled out entirely however, with sunny intervals developing, but highs quite cool at between 13 and 17c.  Dry overnight too bar the odd spot of drizzle for WW.

The omnipresent Atlantic high to our WSW attempts to exert a ridge over the UK once more during Tuesday and Wednesday which will be largely dry as a result. Troublesome weak fronts keep tracking SE though in the NW flow bringing areas of cloud if little in the way of rain at all. Tuesday then and one such frontal sytem means a lot of cloud with spits of drizzle in places, hopeful though that sunny intervals develop afternoon. Maxima Tuesday generally 15 to 18c, but 20c is just about possible where better sunny spells occur, fairly light breezes from the NW. Clear spells and calming air during Tuesday night could lead to a grass frost in places. The ridge declines during Wednesday but still a mostly dry and bright day, highs again in the 15 to 20c bracket dependent on cloud/ sea breeze, etc. Rain fronts could well arrive into Wales during the evening with quite a wet night everywhere.

A low passes close to Scotland during Thursday which sees early rain clearing to sunny intervals and showers, some heavy with hail and thunder possible. Cool and windy too for Thursday, gale force NW gusts in places and poor maxima of  12 to 15c (worst over a very showery Snowdonia).  An unsettled mobile pattern likely come the end of the week, so although a transient ridge dries things out Thursday night into Friday, even with some sunshine for a time,  further rain fronts (perhaps even a small low system) look set to cross Wales and England eventually during the day, although perhaps not until late on.  Next weekend too continues in a similarly unsettled vein, bouts of rain and strong winds coming through, with drier brighter intervals between, and generally on the cool side. Let's see what Summer will bring?

Sunday, 17 May 2015

Weather guide Monday 18th May to Spring Bank Holiday Monday 2015

Headline: Cool and showery to midweek then becoming drier & brighter; tentatively a fine & rather warmer Holiday weekend?

Last week's highlights

In spite of a weak cold front passing over Monday was largely dry, bright and quite warm, a few spots in the Midlands scraped 20c such as Nottingham at 20.1c, more generally though max temperatures of 15 to 18c Monday. Tuesday mostly dry too with sunny spells, but temperatures back down close to average or slightly below, Pershore warmest at max 17.5c. A touch of ground frost in places on Tuesday night, coldest spots down around 2c in the air. Wednesday for most saw around average maxima but some areas were quite warm with sunny spells with most of West Wales (WW) having a nice sunny day. Llanwnnen had its warmest day of May to date, max 19.3c, this a fair bit higher though than the warmest official weather station across our regions, namely Pershore and Hereford at max 17.5c, with coastal areas of Wales, although sunny, affected by sea breezes pegging temperatures down below 16c (Aberporth just 13.0c).

While the UK struggles to find much in the way of warm weather this month, Iberia (Spain and Portugal) in contrast saw record May heat last week as 40c was exceeded on several days. Cordoba, Spain had a maximum temperature of 41.2c on Wednesday breaking the European record for heat in May. This record lasted just 24 hours as on Thursday Xativa reached a staggering 42.9c (109f) and 30c hotter than most of Wales and the Midlands! Thursday's low ended up a southerly tracking one, the centre crossing the tip of Cornwall, with the worst of the wet weather over South Wales and the South Midlands, wettest being Pembrey Sands, 13.8mm, although some places saw very little rain, and it did not quite reach Nottingham which had a dry day. Very cool over the Midlands as well as rather wet on Thursday, many places no higher than 10c, Little Rissington (Cotswolds) only managing max 8.0c,  most of WW  was  12 to 14c however.

Another grass frost locally on Thursday night, lowest air temp 1.2c at Trawsgoed but Friday and Saturday were milder with decent sunny spells and mostly dry, although some areas still on the cool side for mid May, Aberporth sunniest place in the UK Saturday with 13 hours.

The week ahead

After a bright morning in places a rather cloudy and breezy Sunday afernoon to come with drizzle for some, chiefly over NW Wales, highs a rather cool 13 to 15c. A frontal system crossing southern Britain turns it rather wet everywhere after midnight, some fairly heavy rain in places, no lower than 7c. The rain may linger across the SE Midlands through Monday morning but then all areas seeing sunny intervals and showers, some heavy. A cool day, max 12 to 15c with quite a fresh WNW wind. Most showers dying overnight, chilly but too much wind for frost risk.  Low pressure slow moving close to Scotland on Tuesday means another cool and showery day, more in the way of heavy showers about, hail and thunder in places, with few places escaping a downpour or two.  Poor maxima Tuesday of 11 to 14c, perhaps just 10c at best over a rather wet Snowdonia, and with a fresh NW wind. Showers dying out away from windward coasts and hills overnight, down to 2c in coldest spots with a grass frost possible very locally.

High pressure still anchored to our SW is edging closer during Wednesday so that most of the showers die out over Wales but still occurring over the Midlands, some still heavy ones scattered around. Sunny intervals but still that keen NW breeze so cool once more, maxima 13 to 15c. Clear spells and cool overnight down to 3 to 5c. We could be fortunate to have a ridge over us Thursday which may be a mostly dry day with sunny spells, especially over the Midlands where it will be a warmer day, 18c in places, more like 13 to 16c elsewhere though. Clouding over perhaps afternoon as weak fronts may be arriving to bring light rain or drizzle into NW Wales and the North Midlands in particular by the end of the day.

Support in the models for reasonably strong ridging over Wales and the Midlands continuing over much of the Holiday weekend although things may break on the Monday itself. Friday though perhaps a 'fly in the ointment' weak frontal sector loitering with light rain or drizzle in places, which should eventually be drying out and even brightening. Saturday and Sunday most favourable for some fine conditions with decent sunny spells, although the odd shower cannot be ruled out entirely, especially over the Midlands, essentially though it is hopeful for a dry and bright weekend.  Most models have it somewhat warmer over the weekend but by no means all, so expect maxima in the 14 to 19c range, sheltered spots could scrape a 20c, and not a bad weekend in prospect with plentiful dry weather. Just about possible that the airmass is cool enough to permit local ground frost overnights, 1c minima probably at lowest in hollows. If fortunate, this dry, fine weather may stick into Monday too, equally weather fronts could arrive with cloud and some rain during the day.

Sunday, 10 May 2015

Weather guide Monday 11th to Sunday 17th May 2015

Headline: Often dry and bright bar the odd shower; Thursday though cool with rain and showers and perhaps windy

Last week's highlights

A disappointing start to May, often cool and showery, with some longer spells of wet weather, although parts of the Midlands did have some decent dry, brighter spells and temperatures closer to normal (which for that region in early May is around 16c). It has also been a dull and wet start to May, parts of North Wales have already reached the average rainfall due in a whole month of May! Last Sunday alone 15.8mm fell on the city of Coventry, more than during the preceding 4 weeks, while at Nottingham 19mm was almost as much as the total for whole of April (20.2mm). Quite warm after the rain cleared last Sunday over the Midlands up to 19c although there were some heavy downpours and even a few thunderstorms scattered about. In contrast it was a cool day along parts of the Welsh coast (Aberdaron max 11.7c, Pembrey 12.2c) and Snowdonia (Capel Curig 11.4c) though with plenty of cloud and fresh winds.

Monday was dry with temperatures around average but rain arrived during the evening with quite a wet night, various places getting around half an inch. Unusually windy for May on Tuesday, a 60mph squall at Coventry Airport, a 52mph gust recorded on the roof here at Llanwnnen, and with almost 70mph for some more exposed parts of Wales such as Capel Curig (67mph) and Mumbles (69mph). Tuesday to Thursday were all essentially cool and showery days, but there were some longer spells of wet weather on Tuesday for Wales, only a few places missing out.  Maxima quite poor for May on Tuesday with all the cloud and showers nowhere higher than 14c, worst of all max 9.2c at Capel Curig which was also the wettest spot in the UK with 35mm. Still some showers about on Election Day although more places tended to miss them, not Trawsgoed however which was one of the wettest spots in the UK catching 8.6mm. Cool again Thursday, although parts of the Midlands saw more reasonable temperatures of 15 or 16c.

 Tuesday 5th May 2015 wind gusts:

A few places had a grass frost Thursday night, then Friday saw more general rain in most areas, NW Wales particularly wet again getting around 25mm (one inch). Capel Curig ending up with 35.6mm in the 24 hours to 0700 Saturday and was the wettest spot in the UK for the second time in a week, hardly any rain though for the South Midlands on Friday. Saturday saw an improvement to generally dry, brighter and, at least for some, milder conditions too, here at Llanwnnen at 14.4c it was almost 3c warmer than Friday.

The week ahead

On Sunday and Monday we are between low pressure west of Ireland and high pressure over the Continent to our east and south. A deep moist, mild SSW flow on Sunday means a rather windy and mostly cloudy day with the odd spit of drizzle for WW, with the sun perhaps poking through at times afternoon. Better chances of some sunny spells for the Midlands with less wind here too so feeling quite warm this afternoon. Highs Sunday 16 to 18c WW and 20c for parts of the Midlands. Generally dry overnight and mild no lower than 9c or 10c. Rain arriving across WW before dawn. Patchy rain across WW during Monday morning, this front tending to fizzle as it edges east into the Midlands but still giving some showery rain in places there afternoon. Sunny intervals too during Monday and quite warm for the Midlands with some places again touching 20c, nearer 15 to 17c WW with a fresh SW wind. Monday night largely dry and fairly mild.

High pressure building close to our SW on Tuesday but perhaps not enough to prevent a scattering of showers, and a fresher feeling day with a moderate to fresh WNW breeze. Some pleasant sunny intervals too Tuesday with temperatures close to average at 14 to 17c, and any showers dying out come evening leading to a clear, calming and cold night with quite a widespread ground frost, down close to 0c locally. High pressure crossing the UK Wednesday should just about give a dry, fine day with sunny spells and highs between 16 and 19c. Fronts from the SW though perhaps introducing cloud and showery rain in places come evening.

Low pressure in some form or other will be crossing the UK during Thursday which will be a cooler and very unsettled day. Probably we will be seeing early rain, heavy in places that should turn to showers afternoon, a chance of thunder in these showers. A cool day with all the cloud, rain or showers no better than 13 or 14c. Potential for strong to gale force winds Thursday as well, this dependent on actual form and postioning of the low come the day. Some showers or longer spells of rain may linger well into Thursday night.

For Friday and next weekend high pressure will be attempting to influence our weather from the SW but with low pressure still close to northern Britain at times. Plenty of reasonably dry and bright weather then seems likely come next weekend, although often with a cool NW to west breeze so never feeling especially warm. We could be affected by the odd passing weak front producing a spell of light rain or shower but the weather should be predominantly dry. Expect maximum temperatures Friday and through the weekend to be in the 13 to 17c range with a ground frost risk should skies clear and winds drop enough by night.