South West & Central Southern Regional Discussion 2nd August 2013 >

[AWD]

Looking very wet across much of the region tonight, more particularly Cornwall & South Devon.

Bodmin Moor could be the "hotspot" so to say.

Will put across a forecast after the 12z output, but for those of you down in the South West, stay tuned to the more professional Met Office forecasts and warnings. Could be quite soggy for rush hour tomorrow morning.

[SunnySouthCoast]

Nice day today, mostly sunny.Hopefully that rain will edge a bit further eastwards as we could do with it

[Andy Bown]

Today is the coolest day since 2nd July! Still managed 21.7c though with sunny spells and drizzly showers this afternoon blowing through quickly on a strong WSW wind.

[gottolovethisweather]

Looking very wet across much of the region tonight, more particularly Cornwall & South Devon.Bodmin Moor could be the "hotspot" so to say.Will put across a forecast after the 12z output, but for those of you down in the South West, stay tuned to the more professional Met Office forecasts and warnings. Could be quite soggy for rush hour tomorrow morning.

 

 

Indeed AWD, Bodmin Moor was quoted yesterday by Helen Willetts as to the probability of getting an inch today and a further 75mm (3 inches) out into Monday.

Edited August 4, 2013 by gottolovethisweather

[gottolovethisweather]

Today is the coolest day since 2nd July! Still managed 21.7c though with sunny spells and drizzly showers this afternoon blowing through quickly on a strong WSW wind.

 

Similar to you as with my Maximum was 21c today, bar the 30th July when I managed only 20.8c, my records stretch back to the 3rd July when I last failed to exceed 20c.

 

I must say, it is a pleasure to be able to keep the house cool by opening all the windows and let the breeze blow through.

 

After July's prolonged warmth I still see August being above average by day and by night. We are currently at 1.9c above the long-term mean and I can't see that dropping much in the first half of August at least.

Edited August 4, 2013 by gottolovethisweather

[gottolovethisweather]

Whilst this is not specific to our region, it may effect some of us, the below is taken from the Convective thread, courtesy of Supacell.

 

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At first glance I cannot see the potential for today but then I remembered it's not all about CAPE. Having said that, although GFS are forecasting only a small amount of CAPE - the values shown by NMM and WRF are more substantial.

 

However, we then have the fact that we have 30-40 knts of deep layer shear, 30knts of 0-1km shear which increases to 40-45knts overnight, strong helicity (with some very strong helicity moving through Wales and into NW England overnight) and you can see why the storm forecasting's clever people think there is the risk of something this evening and overnight. A lot of rain to come too, so flooding may be of biggest concern.

 

Although storms are by no means guaranteed, IF they do form they will likely become organised with the possibility of supercells, large hail, 40-50mph wind gusts and possibly a tornado. I don't see this being a widespread lightning fest though, but clearly lightning and thunder would be present.

 

Low risk but moderate to high impact I would say.

[Freddie123]

Warnings updated - http://www.metoffice.gov.uk/public/weather/warnings/#?regionName=sw&from=rss&sn=4D8E521B-BA35-49AC-0630-48A9C5169B0E_5_SW&utm_source=twitterfeed&utm_medium=twitter&tab=map&map=Warnings&zoom=5&lon=-3.50&lat=55.50&fcTime=1375570800

 

Ian Fergusson @fergieweather (from Twitter)

W COUNTRY Rain arriving later this eve will continue tonight & Monday, turning heavy & potentially thundery in places. 20-40mm widely with 60+mm possible locally. A @metoffice yellow warning in force; potential for disruption. Re timings, wet all night/AM; latest @metoffice model then brings v heavy rain up M5 corridor into Mon afternoon to clear slowly N.

[dec10snow]

From Ian:

W COUNTRY Likelihood of heavy (poss disruptive) rain developing frm SW tonight & into Mon for some areas (e.g. #Somerset, #Bristol, #B&NES).

W COUNTRY Rain arriving later this eve will continue tonight & Monday, turning heavy & potentially thundery in places. 20-40mm widely (contd

W COUNTRY CONTD..with 60+mm possible locally. A @metoffice yellow warning in force; potential for disruption. Stay tuned for further updates

W COUNTRY Re timings, wet all night/AM; latest @metoffice model then brings v heavy rain up M5 corridor into Mon afternoon to clear slowly N

*Edit* Freddie seems to have beat me to it by a matter of seconds!!

Edited August 4, 2013 by dec10snow

[ARTDEMOLE]

Nasty weather......Coming then...  

[AWD]

Right, here goes with another difficult but important forecast.

I've split it into 3 sections. The first map is for tonight, the second is for tomorrow and the third is a map representative of the total rainfall accumulations I expect between 21:00 tonight and 18:00 tomorrow evening.

Onto tonight first then and here is tonight's forecast map;

As you've probably heard by now, it's forecast to be a rather wet night across the South West, with Devon & Cornwall taking the brunt of this rainfall.

As daylight fades and the night sky rolls in, an area of heavy, locally torrential rainfall is expected to enter Cornwall, moving steadily northeast. The area in blue, which includes high ground of Cornwall such as Bodmin Moor could have some torrential falls of rain overnight causing localised flash flooding. It's worth bearing in mind that this rainfall will quickly flow downhill towards the coast too so something to consider for local towns and villages on the north Cornwall coast such as Looe, Padstow and Mevagissey. Along with the torrential rainfall, some localised thunder and lightning is possible over Devon & Cornwall.

The area in red will also see periods of moderate to heavy rainfall, although nothing as torrential is expected here. This area includes the remainder of Cornwall, Devon, west Dorset and West Somerset up into the Bristol Channel. There will be some heavy falls of rain within this area, interspersed though by lighter falls of rain.

Elsewhere it's looking like a quiet night with just patchy, light, showery bursts of rain here and there. This includes Hampshire, Wiltshire, Gloucestershire, Berkshire, east Dorset and Oxfordshire.

Into tomorrow then, here is tomorrow's forecast map;

Behind the band of rain moving up from the south west overnight tonight will be further pulses of heavy rainfall. We look to start tomorrow on a cloudy and sporadically wet note for much of the region. A rather messy picture will ensue, with heavy pulses of rainfall moving west - east through the day. In the blue area is where I expect the heaviest showers/rainfall to be with some locally torrential downpours possible here tomorrow. This area includes much of Wiltshire, north Hampshire, Bristol, BANES, North Somerset and South Gloucestershire.

The red area will also see heavy rainfall/showers too, but slightly more scattered and interspersed with drier phases here though. This area includes Dorset, Gloucestershire, Oxfordshire, Devon and South Hampshire. It's unclear whether the rainfall in both the red and blue areas will fall in a showery nature or as a more prolonged rainfall event.

Elsewhere, although still with scattered showers, things shouldn't be as wet and there should be some decent drier, although still rather cloudy periods about. This includes Cornwall where after the overnight and early morning rainfall, things should dry up into the afternoon.

Temperatures tomorrow look to be around average for many on the thermometer, with high teens - low twenties widely. However, with the rainfall and windchill, it probably won't feel all too pleasent out and about.

Onto what sort of rainfall accumulations we can come to expect by tomorrow evening then. Here is the third, PPN accumulation map up to 18:00 tomorrow evening;

In the red circle, which covers high ground of north Cornwall including Bodmin Moor, I expect totals to reach 40mm - 50mm.

In the blue circle which includes much of the rest of Cornwall and Southernmost Devon I expect totals to reach 20mm - 30mm.

In the green circle, which includes Devon and Bristol Channel coasts up towards Bristol. I expect totals to be between 15mm - 25mm.

In the yellow circle, this area I expect to see the least rainfall and what does fall here will fall tomorrow afternoon in a more showery form. No more than 5mm expected here. This area is primarily for parts of Oxfordshire and Berkshire.

Elsewhere, most of the rainfall that will fall over Dorset, inland Somerset, Gloucestershire, BANES, Wiltshire and Hampshire will fall tomorrow daytime (a little may fall tonight, but the majority tomorrow). I expect totals typically around 5mm - 15mm in these areas although with the rainfall falling in a more showery nature here, some local variances may apply.

To recap then, heavy, locally torrential rainfall spreading into Cornwall tonight, moving steadily northeastwards. Tomorrow the rainfall turns more showery in nature, with perhaps a squall line developing over Wiltshire later tomorrow, with some heavy pulses of rainfall possible for the West Country and parts of Central Southern England. The highest rainfall totals expected over Cornwall though.

Edited August 4, 2013 by AWD

[AWD]

To add to the forecast above, it's quite possible for a couple of thunderstorms to develop tomorrow afternoon with the benefit of diurnal heating and weak CAPE too.

[Zephyr]

Lots and lots of rain tonight for the south west and other parts of the country waiting for the raw 18z NAE! 

[samster]

Thanks AWD for another comprehensive and detailed forecast and for taking the time to do it!! I rely on you and Gibby so may for unbiased, informative and relevant info re the weather x 😃

[Bristawl Si]

Brilliant insight, as usual, AWD.

[Rinse The Raindrops]

Interesting reading hoping for some summer sunshine again after that currently visiting Bude for two weeks so a guest on here from SE thread

[124alex]

Tweet from Ian:

 

W COUNTRY Local rainfall detail nxt 24hrs tricky (no model is wholly reliable) but S Devon, up M5 via #Somerset/#Bristol, poss v wet indeed.

[Snowangel-MK]

Seen more butterflies and dragonflies this last few weeks than I can recall seeing for years too.

 

Mr P and I were saying the same thing last weekend when I took this...

 

 

.....the hot and dry weather is brilliant for insects and has given numbers a real boost, butterflies, bats and bumblebees are all benefiting from the weather and many birds have been laying a second breed of eggs as they take advantage of the warm weather. However, less desirable insects such as biting midges are also on the rise but our wildlife really needed this summer because rain over the last couple of years has been a big problem for them.

[Zephyr]

raw NAE 18z +48 Accumulation

 

Edited August 4, 2013 by Zephyr

[Mark Parsons]

Looks as if the groccles will get a battering on the coastline of Dorset today when the wind picks up, that will make the tents flap and the caravans wobble!!!

[Evening thunder]

Looks like another fail at significant rain here - 2.0mm so far today lol and nothing coming this way on radar. Only 0.2mm of rain since 1:30am too.

[ARTDEMOLE]

1.5mm Rain today...More later...18c. Humidity 91%.

[Nights King]

Where is the rain?? I don't see any here and forecast even locally says heavy rain most of the day...

[AWD]

1.5mm Rain today...More later...18c. Humidity 91%.

Indeed. Heavy pulses of rain/showers will spread west - east today into the areas that have had little rain so far.The overnight spell of rain was probably 30miles or so further west than expected, but still affected Cornwall and parts of Devon mostly, which was the main theme overnight.It's a case of seeing how it rotates and develops now as to what other counties further east get later.

[georgiedre]

I've popped in from Wales thread and I think my area has been severely affected by rain with reports of 86mm being recorded since 1am!

[AWD]

I've popped in from Wales thread and I think my area has been severely affected by rain with reports of 86mm being recorded since 1am!

Yes. Wales and NW England could see some worryingly large rainfall accumulations today.