91Èȱ¬

UPDATE: 09:00HRS, MONDAY 22 FEB. 2010:
So, further snow being reported quite widely across our districts - from as far afield as Burnham-on-Sea and Weston-super-Mare acrossÌýto Avebury in Wiltshire; albeit in most lowland areas it'll be a transient feature and unlikely to settleÌýto any great degree.Ìý

Different story into the NE areas of Gloucestershire and Wiltshire, where the snow will readily accumulate for a while this morning and indeed into the afternoon, before gradually easing-away eastwards around mid-afternoon.Ìý

Worth adding that tomorrow (Tuesday) could yield similar weather in many of the same areas. I'm expecting to see snow over Exmoor early on Tuesday - possibly quite heavy - with a broad swathe ofÌýrain again at lower levels but this turning progressively to snow from around the M4 corridor northwards. The risk of heavy snow tomorrow for the Forest of Dean is greater than today; definitely a situation we'll need to monitor closely. For what it's worth, the rest of the week promises further spells of distinctly inclement weather and the accumulation of rainfall could well cause localised (surface water) flooding problems for some areas.

UPDATE: 07:00HRS, MONDAY 22 FEB. 2010:
We now have snow falling in parts of Gloucestershire (Forest of Dean and Cotswolds), plus along stretches of the M4 corridor in Wiltshire, especially near Swindon and Marlborough.Ìý I'm expecting snowfall over Exmoor too and albeit rain for most other districts this morning, a sleety mix and sporadic wet snowÌýisÌýquite possible even at lower levels. The risk of snow should vacate the Forest of Dean quite readily this morning, but conversely it will remain across the northern Cotswolds for a more protracted period into the mid-afternoon. Here, you might see 5cm or more falling in some areas.

Ìý

UPDATE: 04:00HRS, MONDAY 22 FEB. 2010:
Well, the new model run again flips-back to the original idea of a possible snow threat for Gloucestershire this morning - hence Ìý Still looks like rain elsewhere in our region - with the possible exception of the most northerly districts of Wiltshire. I suspect Gloucestershire will be on the very cusp of the rain-to-snow transition, but once again the upland areas will have the greatest chance of seeing snow.

UPDATE: 10:00HRS, SUNDAY 21 FEB. 2010:
The latest modelling for MondayÌýfrom the Met OfficeÌýwill bring a major sigh of relief for Gloucestershire commuters growing weary of negotiating snowbound roads.

The risk of significant snow for Monday morningÌýhas been drastically reduced on the new NAE run, albeit with some still signalled into the Midlands and across to The Wash - Ìýhopefully leaving Gloucestershire free of a further disruptive event.

The next model runs will be critical in confirming the positioning of the areaÌýwhere rain could change to snow (if any)Ìý- it's stillÌýa tadÌýknife-edge for extreme north and north-east Gloucestershire, but for all our other counties, rain willÌýsurely beÌýthe result rather than snow.

Indeed, the entire West Country - and for that matter, all of southern England - looks set for a very wet spell during the early morning tomorrow, with some heavy rain developing at times across many districts but clearing steadily eastwards towards midday. By early afternoon, all of our region - with the possible exception of east Wiltshire - should be dry, with cloudy and cold, breezy weather then prevailing for the remainder of the daylight hours.

Further wet (and rather windy)Ìýweather will affect us all on Wednesday and on Thursday; byÌýFriday, there's hints of colder air seeping back southwards again.Ìý But for now at least, any threat of significant snow looks effectively minimal for the West Country, whereas the rainfall willÌýcertainly grab our atttention!

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(ORIGINAL ENTRY FOLLOWS)

It's likely some of you, especially in more northern districts,Ìýwill see some snow tomorrow (Sunday) morning at least falling, if not settling.

We expect a band of showery outbreaks of rain, sleet and some snow to cross eastwards, but it's the risk of widespread ice that causes us most concern, ratherÌýthan any snow per se.

However, the likelihood of seeing some lying snow tomorrow in the West CountryÌýisÌýgreatest in Gloucestershire.

And yet again, it's Gloucestershire in the crosshairs for potentially more wintry weather at the start of the working week...

As if it doesn't need repeating, 'uncertainty' is yet again the watchwordÌýto stress forÌýthis early blog stab at the forecast but -Ìýwith the risk of snow now at 40% -Ìýthe .

In many respects, the broader set-up is similar to last Thursday and the resultant snow this time - if indeed we see any - may follow a geographic spread that's much the same.

The models indicate a risk of snowfall up to 10cm in places and I'm again focused on Gloucestershire as the area at highest - or perhaps only -Ìýrisk of anything disruptive in the West Country. I suspect most areas will see a day of (sometimes heavy) rain and windy conditions rather than snow, but the extreme north of Gloucestershire and Wiltshire might experience something much whiter than wetter.

The timings are currently a tad unclear, but snow could fall over upland areas of the countyÌýby Monday morning's rush-hour onwards and then perhaps to lower levels as the morning progresses.

It's very important to stress some key differences between various models in their handling of Monday's evolution and associated snow potential. Some paint little or no snow whatsoever across southern England; whereas others - including the latest Met Office NAE and - suggest otherwise.

Between these two, there are differences in the regional bias of snow risk, albeit cruciallyÌýthe actual variance is not significant if considering the resolution of the models.

Below, I've annotated a graphic showing how the NAE, as interpreted through 91Èȱ¬ graphics,Ìýoffers snow at 12pm on Monday from SE Wales up into the Midlands (with 5+cm snow contour in blue).

Further south, including into London and the 91Èȱ¬ Counties, the GFS solution for the same timeÌý- outlined in red - suggests similar snow totals but affecting a different swathe of the country. Tricky, huh?

This sort of key difference in bias, over fairly small distances in forecasting terms, speaks volumes about just how difficult it can be to judge snow risk at this sort of lead time and to makeÌýinformed, timelyÌýdecisions when issuing public advisories and warnings.

Last Thursday the Met Office got things pretty much spot-on; let's see how things develop for Monday....Ìý Groundhog Day?