April 2009 Rainfall Stats

[damianslaw]

Like February this year, this month is turning out to be another very dry one for Cumbria, I don't have any statistics, but we really have seen little in the way of rain this month.

I suspect much of Yorkshire, Lancashire and NE England will also be recording a very dry April so far and probably much of Scotland aswell, whereas more southern parts thanks to lasts weeks rain may be nearer average, again very reminicent of Feb..

Yes there is still 9 days to go, but I don't foresee a great deal of rain for the rest of the month...

Does anyone have any stats to back up my impression of this month so far.. will be interesting comparing differences region by region... Everyone seems to talk about temps and sunshine rather than amounts of rain, as we approach summer it is rainfall that is more critical than temps or sunshine..

[SP1986]

16.2mm so far this month the average is around 30-40mm, 69mm for the year so far

[Cheese Rice]

We (amazingly) havent really seen any rain, the odd light shower but thats it

[Bottesford]

12mm this month so very dry indeed. A dry start to this year that's for sure but after the rain of the past couple of years I'm not complaining! So long as it doesn't turn sour in May/June/July I'm happy.

[damianslaw]

12mm this month so very dry indeed. A dry start to this year that's for sure but after the rain of the past couple of years I'm not complaining! So long as it doesn't turn sour in May/June/July I'm happy.

Yes thats my worry, that the summer will make up for the dry start to the year.. I wish I was an optimist!

[Terminal Moraine]

Very dry so far this month here with just over 18mm recorded, against a 30 year average of just over 76 mm for the month.

[J07]

Is there any way this links to the weather down under? I'm not very familiar with the multitude of teleconnections unfortunately.

But 12mm so far here this month, and 20mm in March.

[Osbourne One-Nil]

Like February this year, this month is turning out to be another very dry one for Cumbria

Have you always been in Windermere?! Anyway, just 22mm so far 18 miles northeast of you.

[The PIT]

What rain ???

11.6mm so far and after other dry months this summer could be very interesting if and a big if it stays that way.

[damianslaw]

Have you always been in Windermere?! Anyway, just 22mm so far 18 miles northeast of you.

No I used to live in Newcastle upon Tyne and work in Sunderland, however I moved back to Windermere in November last year, and work in Kendal.

Great Asby although only 18 miles away in weather terms is a world away from here.. Windermere after Ambleside is statistically the wettest town in England, rainfall patterns decrease markedly from the centre of the lakes outwards and from sw cumbria to ne cumbria, however, the 22mm seems quite a large total to me.

[Nick L]

Some people are hoping for a hot and dry summer, but with a dry or very dry spring so far, I say be careful what you wish for. I would prefer to have a wet summer if it means avoiding water shortages.

[stormchaser1]

Another dry month {so Far} with only 10.3mm rain being recorded up to 22nd april

March was 14.0mm

we need rain lots of rain

[morfius]

I would prefer to have a wet summer if it means avoiding water shortages.

Thames water seem to have the definition of a water shortage as reservoirs at 96% capacity.

Well at least they did in 2006 when they seemed to think that this level necessitated a hose ban....

[Nick L]

Thames water seem to have the definition of a water shortage as reservoirs at 96% capacity.

Well at least they did in 2006 when they seemed to think that this level necessitated a hose ban....

I think the reservoirs were considerably lower than 96% in 2006...

[Costa Del Fal]

Not sure of exact figures but i think our rainfall is only about 10-15mm so far. It has been very dry for February, March and probably April now.

[Andy Bown]

My sig was updated before last Friday's 3.5mm so we're now at 13mm for April, this added to just 10mm from 10-31 March means less than an inch in well over a month. Places fairly nearby had that much in last week's thundery out breaks that managed to avoid Westbury.

[Button Up]

Very dry April so far with only 10.8mm and most of that was last week in the thundery outbreak / unsettled few days we had

[Nick L]

I have had 22mm so far this month, which is a deluge compared to some!

[Costa Del Fal]

I have had 22mm so far this month, which is a deluge compared to some!

We just missed the deluge from last weeks storm therefore our rainfall totals are much lower than those to our North.

[SteveB]

Only 13.4mm so far this month.

And we only got 18mm last month. Very dry, hope we get some more rain soon.

[morfius]

I think the reservoirs were considerably lower than 96% in 2006...

http://news.bbc.co.uk/1/hi/england/4799446.stm

"The ban comes despite the latest figures for water storage showing Thames Water reservoirs to be 96% full - the second fullest in the country."

[HighPressure]

http://news.bbc.co.uk/1/hi/england/4799446.stm

"The ban comes despite the latest figures for water storage showing Thames Water reservoirs to be 96% full - the second fullest in the country."

I don't work for TW anymore but the principle has not changed in the last 100 yrs so I doubt it has much in the last 4. 96% res storage is only @190,000 Ml (million litres). London Uses @2000 Ml of that water per day every day in theory a 95 day store, however the law of hydraulics means that these are only efficient at above 50% as they are on a gravity system and below that flow reduces as does quality (which reduces treatability) with depth. What this means is that in reality London has @50 days of reserves if river abstraction drops to zero, nowhere near enough to sustain a long summer period. The key figure is that of the remaining flow over Teddington weir the last weir in the Thames if this drops to zero the upper tidal reaches will become stagnant and there are legal requirements on TW to maintain a min flow. What is left in the river after that min flow can be abstracted but in the summer when there is little rain it is only sustained by ground water being released and if the previous winter was poor for that then TW will know early if it needs to impose any restrictions.

To give you an example the min flow over Teddington can drop to 200Ml/d in the summer TW need to abstract 1000-1500 Ml/d to get through until October, so it is not easy or as straight forward as some would suggest. TW need to sustain 95% storage until the end of July to be entirely safe for the period

[Osbourne One-Nil]

Great Asby although only 18 miles away in weather terms is a world away from here.. Windermere after Ambleside is statistically the wettest town in England, rainfall patterns decrease markedly from the centre of the lakes outwards and from sw cumbria to ne cumbria, however, the 22mm seems quite a large total to me.

Aye, but the vast majority of it fell on over just two days.

[damianslaw]

Rain was at bay again from us today, it just doesn't want to come near us it seems this month, we had spits and spots this morning hardly dampened the ground... tomorrow may bring a proper dose if we manage to catch a heavy downpour later in the day as some of the models are suggesting.

[morfius]

I don't work for TW anymore but the principle has not changed in the last 100 yrs so I doubt it has much in the last 4. 96% res storage is only @190,000 Ml (million litres). London Uses @2000 Ml of that water per day every day in theory a 95 day store, however the law of hydraulics means that these are only efficient at above 50% as they are on a gravity system and below that flow reduces as does quality (which reduces treatability) with depth. What this means is that in reality London has @50 days of reserves if river abstraction drops to zero, nowhere near enough to sustain a long summer period. The key figure is that of the remaining flow over Teddington weir the last weir in the Thames if this drops to zero the upper tidal reaches will become stagnant and there are legal requirements on TW to maintain a min flow. What is left in the river after that min flow can be abstracted but in the summer when there is little rain it is only sustained by ground water being released and if the previous winter was poor for that then TW will know early if it needs to impose any restrictions.

To give you an example the min flow over Teddington can drop to 200Ml/d in the summer TW need to abstract 1000-1500 Ml/d to get through until October, so it is not easy or as straight forward as some would suggest. TW need to sustain 95% storage until the end of July to be entirely safe for the period

Thanks for that, I didn't realise quite how complex the water management was.