Sunday, 29 March 2015

Weather guide Monday 30th March to Sunday 12th April 2015

This guide will be looking ahead at the next fortnight's weather, obviously the second week is much less defined and nebulous weather model- wise, therefore entailing more general a prediction and as such is more likely to be incorrect!

Last weeks highlights

A rather cool and showery start to last week, however some areas missed the showers and stayed largely dry and bright and hence temperatures not far off the late March average, much of the Midlands and the sheltered south coast of Wales reached 9 or 10c on Tuesday while showery West Wales (WW) only managed a chilly 7 or 8c with plentiful hail showers and limited sunshine. Quite a sharp frost for the parts of the Midlands Tuesday night, Pershore, Worcerstershire coldest at -3.5c, but a dry Wednesday with sunny spells and a touch below average generally, although still decidedly cool on the Cardigan Bay coast, Aberporth max 7.9c cf 11.1c inland here at Llanwnnen.

Wednesday night then wet, half an inch of rain for parts of WW, with a covering of snow over the Peak District and highest parts of Wales first thing Thursday. Thursday became largely dry and bright once more, but windy, with gale force gusts during the afternoon across the Midlands. Temperatures recovered to average by the end of the week Hereford top spot Friday at 13.1c with all locations away from high ground attaining 10c. This weekend has been milder still although with some spells of rain and quite windy, 15.5c at Pershore on Saturday while the high of 12.6c here at Llanwnnen was the highest reading of what has been a  disappointing month regards early warmth.

Week One: Monday 30th March to Easter Sunday 2015

Headline: Often cool and unsettled, showers or longer spells of rain and some hill snow; dry weekend with frosty nights

Heavy rain and strong to gale force winds across Wales on Sunday morning, parts of Snowdonia getting over an inch of rain in the past 24 hours, while winds have reached 46mph inland here at Llanwnnen and 69mph on the coast at Aberporth. An unsettled week to come with further rain and showers at times, but with dry and bright interludes. It will often be cool too, with even the chance of wintriness for higher ground.

The rain turning to sunny intervals and scattered showers this Sunday afternoon with winds easing, temperatures at their highest early this afternoon at 11 to 13c. Most of the showers dying out tonight and clear spells leading to a ground frost in some places but the breeze keeps up to prevent this for many. A dry and in places bright start to Monday, but the next Atlantic system will quickly bring over cloud and wind by midday with WW turning wet. Spells of rain then afternoon accompanied by a fresh to strong SW to west wind, with gusts perhaps to 60mph on exposed coasts and hills. WW may also see particularly heavy rain at times through the afternoon into the evening. Highs Monday an academic 11 to 13c which is about the average for the very end of March. The rain turns more showery during Monday night, still a strong NW wind driving in some showers though after midnight, and this preventing any frost.

Low pressure away to the NE on Tuesday, a cool, windy and showery day, some of the showers heavy with hail and thunder in places, a chance of sleet or snow above 300m especially during the evening.  As ever with showery days, some sheltered spots escaping with a dry bright day! Highs Tuesday between 8 and 11c (best for sheltered parts of the South Midlands and some South Wales coasts). Showers keep going during Tuesday night for Cardigan Bay, NW Wales and the NW Midlands perhaps with hail quite a feature, and some high ground such as Snowdonia may be waking to a covering of snow on Wednesday morning. The fresh NW wind restricting frost to some extent but there may well be a widespread ground frost, generally temperatures down between plus 1 and 3c. March goes out like a lion somewhat!

Cool and quite showery on Wednesday too, these still wintry on higher hills, however they should be dying down as we go through the afternoon, also sunny intervals and breezy with cool April highs of 7 to 10c. We should see an attempt at a ridge during Wednesday night, so that it should be dry with a touch of frost. This ridge may hold for much of Thursday but some doubt over this as further fronts may be coming through with showery rain at some stage during the day? However a reasonable chance of a mostly dry, bright Thursday, and certainly less in the way of wind, and highs up closer to average at 10 to 13c.

An active trough or even low seems set to sink SE across the UK during Thursday night into Good Friday so showers or longer periods of rain, heavy at times make for a generally wet start to the holiday period, although we may see a ridge drying things out eventually through the afternoon or evening. There may well be some cold air from the north drawn into Friday's sytem so that hill snow is a distinct possibilty, with even an albeit slight risk that the rain turns to sleet or snow for a time on Friday at lower levels too in places? Temperatures on the southern side of this low may be in double figures celsius, say 10 to 12c over South Wales and South Midlands on Friday morning, but with the colder air infiltrating from the north during the day and never much above 6c for Snowdonia and the Peak District where potentially it could be a snowy day, at least over the hills.

Good signs after the inauspicious start to the Easter period that things will actually turn out nice as with high pressure looking set to settle down very close by or over the UK next weekend! Some inherently cool air within this expected high though means the potential for sharp, damaging frosts on both Friday and Saturday night, -5c cannot be ruled out in places, so possibly some very cold nights for April to come. Both Saturday and Sunday look like being pleasant days with plentiful sunshine and maxima near normal in the  10 to 14c range - depending on whether a cool NE breeze occurs or not, at the cooler end if so, milder if not.

Week two: Easter Monday to Sunday 12th April 2015

Headline: Often dry, just the odd shower/ bout of rain; potentially warm and sunny around mid week

The latest GFS model run brings some weak weather fronts across the UK thus spoiling Easter Monday which would in this event be turning cloudy with light rain in places, the ECM model on the other hand keeps it fine and dry. On the whole though, week two is getting a reasonable signals for high pressure to be over or close to the UK for much of the week, bar the occasional weak front from time to time. Thus we can expect a largely dry week with sunny spells. Temperatures and cloud amounts likely to be variable from day to day and region to region, dependent on exact positioning of the highs and attendant wind directions. 

Some of the recent model output has shown high pressure locating over the Continent by the middle of week two, this would be good, as we would be getting warm SE winds and potentially temperatures into the low 20's celsius (above 70f)! Obviously a long way off this hope, and other options are there for cooler, rather cloudy anticyclonic conditions in which temperatures would struggle to reach 15c, and even some decidedly cool days for the Midlands should the high set up to our north (lucky to get max 10c). 

Of course, there is also the possibilty, and this too is suggested by some model output, and given the sheer variety of options they show at 10 to 14 days hence (such a timespan referred to by weather buffs as Fantasy Island), that it turns cool and unsettled by the end of week two! Basically by this stage (almost) anything could happen, but at least there is some prospect of fine, dry weather in the early to middle part of the week at least!

Sunday, 22 March 2015

Weather guide Monday 23rd to Sunday 29th March 2015

Headline: Rather cool with frosty nights; some rain or showers at times

Last weeks highlights

Showery rain more persistent than anticipated in last week's guide over much of the South and West Midlands during Monday with many places receiving 3 or 4mm, with a Solihull PWS recording 11mm. Few showers affecting West Wales (WW) nor the NE Midlands however on Monday. Tuesday still an isolated shower in places but overall it was a dry week, the majority of rain gauges collecting less than 5mm and with next to nothing across much of WW, a mere 0.2mm in total for the past 7 days at Mumbles, Swansea for example.  Many nights were frosty last week, both Tuesday and Wednesday nights down to -4.6c here at Llanwnnen, the former colder than any official UK Met station, with nearby Trawsgoed at -3.7c and -3.5c respectively. Then on Thursday night Swyddfynnon, Ceredigion the coldest spot in the UK at -3.2c, with Saturday night (last night) the coldest of the week across WW,  -5.0c at Llanwnnen.

Thick fog greeted last Wednesday which did though turn out nice with sunny spells. A beautiful sunny mild Thursday across WW and eventually the Marches contrasting with supressed temperatures, murk, and polluted air over most of the Midlands, 12.8c the high at Milford Haven, Pembrokeshire on Thursday contrasting with 6.2c at Little Rissington in the Cotswolds. Friday was mild with sunny spells with 15.5c (60f) at Pershore the warmest place in the UK, but cooler and cloudier for Cardigan Bay and NW Wales, max just 8.3c Aberporth. Saturday another of those days when much of the the Midlands was  plagued by North Sea cloud keeping it quite cool while Wales and the Marches were sunny and relatively mild.

The week ahead

We are in a rather cool airmass for much of the coming week, and although there will be some showers and longer spells of rain some days will be mostly dry and bright, Wednesday looks one such day. As ever some places miss out on the showers in any event and end up having a mostly dry week. After a sharp Spring frost Sunday morning is again sunny over WW but more cloudy over the Midlands, during this afternoon we should see some sunny breaks for the Midlands while WW gets more in the way of cloud, highs Sunday 9c where overcast and 13c where brightest with light winds. Clear spells and a slight frost tonight, this lifting after midnight at least over Wales where it clouds over. The weakening cold front slowly sinks SE during Monday, a largely cloudy and cool day for WW with mainly light rain on and off, it stays dry with sunny intervals for the Midlands before patchy rain arrives later in the day. Max temperatures Monday 8 or 9c WW and 11 or 12c Midlands, it may brighten for WW just before dusk.

Clear spells and a touch of frost on Monday night, once any cloud and rain has cleared the Midlands that is, lows around zero. Meanwhile showers will be affecting parts of WW later in the night, these with hail and becoming wintry over high ground. Tuesday and we are in a rather cold NW flow, sunny intervals but also a fair crop of showers, some heavy downpours with hail and perhaps thunder, even a little sleet or snow possible for highest ground. As ever though a few places could miss all the showers and have a rather pleasant albeit chilly, dry day with sunny spells! Maxima Tuesday rather cold at 7 to 9c, with a cool and quite fresh NW breeze. Most of the showers die out on Tuesday night to leave clear periods and a frost, -3c locally.

A weak ridge of high pressure gives a mostly dry but cool Wednesday, although still a few showers scattered about most places should be dry with sunny spells. Rather cool again though at max 8 to 10c. Clear spells and frost forming during Wednesday evening getting down to below zero across the Midlands, but cloud and rain arrives for WW after midnight, although timings of this rain front are uncertain. This front is proving not straightforward for the models, it may hold together and give quite a wet day, particularly for Wales, or it may fizzle out so that after some early rain it becomes mostly dry afternoon. Another rather cool day maxima between 8 and 11c depending on varying degrees of dampness/ brightness. We should be seeing another ridge and attendant frost for Thursday night.

Mixed signals, as is often the case by the end of the week, most models bringing in an Atlantic low with rain and strong winds during Friday, while with some we scrape a dry day, temperatures though no better than the average of 10 to 12c. Next weekend too looking unsettled with some rain at times, and by Sunday it may well be milder but windy as well as rather wet!

Sunday, 15 March 2015

Weather guide Monday 16th to Sunday 22nd March 2015

Headline: Mostly dry with sunny intervals and just the odd shower; some frost but temperatures around average 

Last weeks highlights

Frosty last Sunday night, -3c or -4c in places, and the coldest night of the week with further slight frosts through to midweek and again this weekend more locally.  Some rain on most days last week, with parts of the Midlands tending to escape mostly dry. Tuesday though was fine, sunny and rather mild max 10 to 12c, although Cardigan Bay coasts cooler with onshore breezes, Aberporth reaching just 7.9c. Heavier rain over West Wales on Thursday particularly for Pembrokeshire, Anglesey and the Llŷn Peninsular where the rain band stalled for much of the day, highest official total being 26mm at RAF Mona, although a Personal Weather Station (PWS) near Caernarfon reported above 50mm (2 inches) for the day.

Thursday was the mildest day of the week for the Midlands where it stayed dry until late in the day, highest reading 13.7c Pershore with most places getting above 12c. Thursday night into Friday it was the turn of the West Midlands for the heavy rain - the 24 hours to 0900 Friday having 16.2mm at Bablake, Coventry making it their wettest March day since 2008, while the east Birmingham area had over 20mm. The rain band only reached as far as Northampton though during Thursday night before deciding to nudge back west as it fizzled out on Friday! There was a little snow over some Welsh hills as colder air dug in from the east beneath the decaying front. This weekend is turning out mainly cloudy and cool, Tirabad in Powys reached just 4.0c Saturday.

The week ahead

With high pressure always close by a reasonably dry week can be expected, bar the odd light shower (especially during Monday and again by the end of the week perhaps). Temperatures never straying far from the mid March average (9 to 11c) although any sunnier days are likely to be milder, and any clearances overnight will readily see a slight frost forming.

Sunday and the ENE winds are bringing a lot of cloud again from off the North Sea, so quite cool and although largely dry, there will be some drizzle or light showers in places, particularly the Midlands. West Wales (WW) may brighten from time to time but for many quite a dull, cheerless afternoon  max 7 to 9c. With all the cloud tonight frost is unlikely, although any clear intervals would readily produce temporary grass frost locally. The large Scandinavian high is still there into the start of the coming week, so another chilly day Monday with east to SE winds, plenty of cloud, a few sunny intervals and a scattering of mostly light showers, these mainly over the North Midlands above Coventry. Maxima Monday rather cool again at 7 to 9c. Cloud still stubborn on Monday night, although clear breaks are more likely over Wales where there will be a widespread ground frost at least, down to -1c in places.

A rather slack SE flow for Tuesday, a better chance of some sunny intervals, just an isolated light shower in places, but most parts remain dry, highs milder at 10 to 13c with a light SE breeze, so feeling pleasant enough in any sunshine Some clear spells during Tuesday night give a more widespread ground frost although this may come and go as cloud amounts vary, generally no lower than 1c.

The Scandinavian high has moved away by Wednesday only to be replaced by a new high centred near Northern Ireland. A dry day with sunny intervals, a cool NE breeze although highs of 10 to 13c are not so bad. Clear spells and a widespread frost for Wednesday night, down to -2c locally especially WW. A similarly dry, bright day for Thursday, extensive cloud at times but decent sunny spells for some areas and maxima 10 to 13c, but still that nagging cool NE breeze.

Model differences by the end of the week revolve around the positioning of the high, GFS keeps it close by while ECM has been consistent with the idea of pulling it further west which would allow a colder northerly flow across the country later Friday into next weekend. In any event Friday should be another largely dry and bright day, perhaps turning colder later in the day with a few showers into the North Midlands? Saturday too, overall, is looking mostly dry with sunny intervals although perhaps chilly, and IF the colder scenario comes off wintry showers will be a possibilty.  Sunday could be the start of a more unsettled end to March. Still the risk of frost in places by night next weekend.

Sunday, 8 March 2015

Weather guide Monday 9th to Sunday 15th March 2015

Headline: Changeable: rain and wind at times with dry bright spells too, some frost

Last weeks highlights

A chilly if not so cold start to last week, with some wintry showers, snow reported across parts the West Midlands on Monday morning, and with inch or two lying over the Brecon Beacons and Peak District on Tuesday morning, nothing out of the ordinary though for March in the UK! There were decent dry, sunny spells too early in the week, but it did feel cold in the wind.  Wednesday saw plentiful sunshine and was largely dry and although still a bit chilly in the wind a few spots did manage 10c. Slight frosts by night too last week at times but from Thursday it became milder. Mild but windy on Friday, Hereford 15c, most places getting above 11c. Even warmer on Saturday for the Midlands at least and sunny too, Hereford again top spot at 17.2c (63f) with many places above 15c, a mostly cloudy and windy day for West Wales (WW) however. A dry week overall, with virtually no precipitation anywhere from Wednesday to Saturday.

The week ahead

A wet Sunday morning across WW, this (by then) light rain progressing across the Midlands during the afternoon, but clearing WW to leave a mainly dry, bright afternoon here. Maxima Sunday 10c this morning for WW and 13c for the East Midlands this afternoon. Any rain dies out this evening over the Midlands then to clear spells with a slight frost down to -2c in places, although this will have lifted from Wales by dawn as it clouds over.  All change again Monday as a rather nasty little low passes close to Scotland. A mostly cloudy and windy day with rain at times, especially over Wales, maxima 10 to 12c.  This rain clears away by evening from most places although some could still be affecting the South Midlands to around midnight. Clear spells with a fairly widespread ground frost on Monday night, but probably too much cloud hanging on across the South Midlands below Coventry.

High pressure then temporarily resides over us for Tuesday which will be quite a pleasant dry and bright day with sunny spells and gentle breezes, highs of 10 to 12c which is fairly mild for March. There could be a ground frost for the Midlands on Tuesday night but too much cloud for this over WW as weak fronts eventually push in bringing some rain and drizzle by dawn. After a dry morning for much of the Midlands Wednesday is mostly cloudy and breezy with rain at times, this mostly quite light though, but perhaps little if any for the East Midlands, temperatures again reaching between 10 and 12c. There should then be another dry interlude overnight Wednesday as the rain clears through.

Further rain fronts coming through during the course of Thursday, so although it may flatter to deceive first thing it will cloud over with more rain at times afternoon into the evening, and probably another rather mild day if quite windy. Friday sees a return of high pressure, so dry and bright with temperatures close to average (9 to 11c). There may well be a frost for Friday night.

Next weekend strong signs that blocking high pressure sets up over Scandinavia, so a dry weekend is in prospect. Hard to predict cloud amounts as winds look like being between ENE and SE, the more SE then the better prospects for sunshine, in any event WW most favoured to see the brightest conditions next weekend, with the Midland getting duller skies at times. There will be a chilly breeze as an easterly is coming from off a cold North Sea, and where dull it will be rather cold (say max 7c), but where bright temperatures up to the average (max 10 or 11c). If clearances permit then slight overnight frosts are a possibilty.