91Èȱ¬

UPDATE 07:00HRS, FRI. 19 FEB. 2010:
It's a final update for this particular blog entry - and I suspect there'll be some further lively (and potentially disruptive)Ìýweather toÌýforecast and discussÌýat times next week, too, especially Wednesday but perhaps through Monday, too.

Meanwhile - I thought I'd share with you some moreÌýphotos sent to us here at 91Èȱ¬ West of yesterday's snowfall. Thanks very much to those of you who took time to send these to us!

The first (below) shows treacherous road conditions at Wiveliscombe in Somerset, taken by Anna Corbett.Ìý

The second - taken by Linda Atkins - shows the depth of snow near herÌýhome in Cutcombe/Wheddon Cross on Exmoor - "about 5 inches", she tells us, asÌýher photo quite clearly testifies!

Picture 3 is from Cam, near Dursley, Gloucestershire - taken by ´³´Ç³ó²ÔÌý²Ñ²¹³¦±ð of the snow that fell in his back garden yesterday.

The 4th photo, from Alison Napier, clearly shows the amount of heavy snow that draped the Brendon Hills of Somerset throughout yesterday. A Winter Wonderland indeed!

Photo 5, taken by Frances Ring, illustrates very well how much snow fell yesterday across the Forest of Dean in Gloucestershire. Her photo - taken this morning at daybreakÌýin Shortstanding - looks over Joyford, towards Edge End. "We had about six inches of snow here," Frances tells us.

UPDATE 12:30HRS, THURS. 18 FEB. 2010:
The snow is falling thick and fast here in Bradley Stoke, South Gloucestershire, as I write - and it's now quite readily settling after a somewhat hesitant start. However, it will take a fairly prolonged spell of similar intensity to really stick with any longevity -Ìýnot least on the main roads, where this wet snow is quickly turning to slush (and creating a lot of standing water on some routes).

Our expectation is for further snow to fall on-and-offÌýbetween now and mid-evening for a number of areas in West Somerset (Exmoor), Bristol, B&NES, South Glos.,Ìýmuch of GloucestershireÌýand North Wiltshire.Ìý However, for a while the snow prospect will very much depend on the intensity of the precipitation (i.e., heavierÌýspells helping bring the Wet Bulb Freezing Level down to low level, through a process of evaporational cooling).Ìý Towards the evening rush-hour, snow could prove more widespread - certainly across Gloucestershire - and I'd imagine the return journey home for many commutersÌýon various routes such as the A417 across the Cotswolds couldÌýbecome decidely tricky in places.

The graphic below shows the UKMO's expectations of snowfall by 6pm this evening. Those of you who have followed this blog entry since the start will note how little the overall geographic story and timelineÌýhas changed from original forecast predictions; indeed the Met Office's pinpointing and warningÌýof this event has been very good, in my opinion.

UPDATE 10:00HRS, THURS. 18 FEB. 2010:
Many thanks to Chris Binding of Luxborough, Exmoor, who just sent me this photo showing the amount of snow already settled in his district - he estimates around 10cm (4 inches) in places already!

UPDATE 09:00HRS, THURS. 18 FEB. 2010:
The snow is now falling thick and fast in Bristol, Bath and environs... but whether it will readily settle is another matter! We shall see... I'm sure it will settle in S. Glos and Gloucestershire.


UPDATE 08:10HRS, THURS. 18 FEB. 2010:
A quick update in between radio broadcasts!Ìý The forecast evolution today follows largely the pattern already outlined below - perhaps somewhat less in terms of snow totals expected but essentiallyÌýthe same story, soÌýthe early warnings remain in force.

We've just had reliable reports of snow falling in Exmoor (already 3-4cm in places); ditto Porlock, West Somerset - causing some traffic problems there - plus parts of the Forest of Dean and around Bath. So the process of seeing rain turn to sleet and snow is already underway for some areas.

If you can report on any snowfall in your own areas today, please feel free to do so hereÌýon the blog - I'm ensuring these reliable reports are fed back to colleagues at 91Èȱ¬ Weather Centre and to the Chief Forecaster at the Met Office Operations Centre in Exeter. It's all very helpful in honing the forecast detail!

Ìý

UPDATE 19:40HRS, WED. 17 FEB. 2010:
At this stage we can startÌýto offer a bit more forecast detail on the likely snow amounts expected during Thursday across the region...

These synthesised estimates (and I stress estimates)Ìýare based on the Met Office's high-resolution modelling (UKPP) of fresh snow depths by 9pm tomorrow evening. It'll be a rather narrow band ofÌýheavy / disruptiveÌýsnow developingÌý- hence many areas across the West CountryÌýwill see little or nothing from this; others, converselyÌý(especially, I suspect, parts of W. Glos) will see quite a bit. I'm still leaning towards this being a predominantly Gloucestershire / NW of M4 corridor event in terms of truly disruptive snow.... there's still time to be proven wholly wrong, however!Ìý Anyway, here's those estimates:

Somerset: Lowland areas seeing predominantly rain to a dusting of snowÌý(0.1cm). Exmoor: 5-10cm. Quantocks: Up to 5cm. Mendips: 2-5cm but variable (UKPP suggests very little here and over Blackdowns, surprisingly).

Dorset: Lowland areas only rain or a dusting; upland areas of West Dorset up to 5cm

North Somerset: 1-2cm; but very variable with some areas seeing only a dusting

Bristol & environs: 1-5cm (greatest in northern districts and potential for >5cm)

Bath & NE Somerset: 1-5cm (greatest in northwest districts)

Wiltshire: Very patchy coverage; rain and sleet for many but up to 2cm in northwest

South Gloucestershire: 2-5cm, possiblyÌý>5cm locally to north and across highest ground

Gloucestershire: Forest of Dean especially prone; 5-10cm or more possible here and across towards Gloucester, Tewkesbury and Cheltenham. South Cotswolds: 2-5cm; North Cotswolds: 5cm fairly widely; 5-10cm in NE districts.

The images below shows how the latest Met Office NAE model - shown here in 91Èȱ¬ graphics representation - takes the risk of snowfall across aÌýnumber of districts up into the Midlands into the evening rush-hour and towards 9pm:

UPDATE 15.45HRS, WED. 17 FEB. 2010:
There's growing continuity in the general weather developments tomorrow, if the midday NAE run is to be believed. However, some uncertainty existsÌýover just how cold (orÌý not)Ìýthe air will be at lower levels during the earlier part of morning. The idea of snow starting to fall much later in the morning - towards midday - is still the most likely outcome.

The Met Office early warnings cover a fair swathe of the West Country's more northerly districts, albeit I'm yet to be wholly convinced about the risk of any significant snow for North Somerset (Mendips aside), Bristol and lowland adjacent areas... I wouldn't be at allÌýsurprised if the transition from rain to snow lies somewhere a bit further north, such as across the Forest of Dean and southern Cotswolds, but I'll keep you updated on any views - divergent or otherwise -Ìýfrom the Met Office!

In any event, as I'm broadcasting our breakfast TV and local radio weather output throughout tomorrow morning, it'll be my ownÌýforecasting headache to tackle!

Ìý

UPDATE 11:00HRS, WED. 17 FEB. 2010:
The latest NAE assessment this morningÌý-ÌýcompletedÌýsince I wrote the original blog below -Ìýrepeats the snow risk across broadly the same districts and suggests tomorrow's events could prove quite disruptive and noteworthy.Ìý

Consequently, early warnings (>60% chance of severe weather)Ìýhave now been issued by the Met Office for the following parts of the West Country: N. Somerset, B&NES, Bristol, S. Glos. and Glos.Ìý

Advisories remain in force for Somerset and Wiltshire.

.

Ìý

(ORIGINAL ENTRY FOLLOWS)

The second half of this week is a forecasting headache - not least the next 48 hours, as we keep a close eye on the potential for further snow.

And possibly quite a lot... at least for some areas.

Today's wet weather also has theÌýpotential to turn wintry as it spreads northwards across upland Gloucestershire, albeit we're expecting any significant snowfall duringÌýthis afternoonÌýto appear largely up into East Wales, the Marches, parts of the West Midlands and towards Manchester. So for most of the West Country, bar some rather fleeting spells of wet snow and sleet,Ìýit's effectivelyÌýa wet Wednesday...

But what about a white Thursday? Tricky for the detail, this one!

'On paper'Ìýat least, the ingredients areÌýin place to bring a swathe of snowfall - potentially significant amounts - into areas from around Bristol, Bath & CardiffÌýnorthwards into Gloucestershire, the West Midlands and across to LincolnshireÌýas a frontÌýpivots itself across England, associated with an area of low pressure centred - by around midday Thursday - somewhere around Lyme Bay.

It's important to note that different forecast models handle the associated snow risk to varying degrees.ÌýSome underplay it considerably.

The Met Office's NAE (North Atlantic Evolution) modelÌý- - offers a distinctly pessimistic outcome (unless you are a snow aficionado!) compared to various other computer solutions.

The chart below, generated from our bespokeÌýÌýbroadcast graphics system, replicates how the Met Office model paints a snowy story developing across a number of districts by 6pm on Thursday.Ìý

It actually begins to turn rain to snow from around late morning onwards in the same broad area, aided by a distinctly chilly - and foggy -Ìýstart to the day, as temperatures fall readily tonight toÌý0C even in the centre of Bristol and other large urban areasÌýand more like -1 to -3C out in the countryside.Ìý

I've annotated the zone where heaviest (and perhaps newsworthy)Ìýsnowfall is possible; with over 10cm signalled in a few spots but stress this is highly speculative - we're awaiting further runs of the model to see what level of continuity it provides (or not).Ìý As you'd rightly expect, the Met Office will not upgrade the for this potential event to an early warnings until we're seeing the 'whites of it's eyes' -Ìýliterally!

And yes - as ever - I'll update you later today based on any new analysis and forecast expectations... will this one become a damp squib or a whiteout?