Penellype's Weather Channel

[sandspider]

Cold north easterly wind here, but more sun than forecast, so not too bitter. Yet...

[Gillykat]

Very icy here in Alnwick today - I was cursing forgetting my gloves as I walked up to the allotment. The sun came out later tho' though and took the edge off the ice. We had a few light hail/sleet showers before midday.

[bikermike]

Well, we've had rain, snow, cold wind, and hail today...

Can we have the contrails back please...?

(It's my fault, I put a pic of my rhubarb on fb, and a german-based freind was impressed, and remarked on cold forecasts ( -3).I said there was nothing like that forecast for us...

[Penellype]

Thankfully the models have backed off an extended very cold spell at the start of April. It remains chilly for the next week or so, with a possible dip at the weekend, but after that it may become milder, and probably wetter too. However this is outside the more reliable timeframe.



There is a problem that the models have at the moment, which is that a lot of the atmospheric readings are taken by instruments carried by passenger airlines. Fewer or no aircraft means far fewer readings and a corresponding drop in accuracy. Therefore, do not be surprised if there are sudden changes even in relatively short-term forecasts, and expect the longer term ones to be even more inaccurate than usual.

[quanglewangle]

Coldest so far this winter

Beautiful weather - sunny and light winds. But very cold. In fact lowest temperature so far this year. Not usually this cold here this late in the spring.

0700 this morning

[Martin H]

It went down to -1 in my greenhouse by 7:00 this morning. Coldest night since January 20th.

[Penellype]

Bit warmer here last night due to a blanket of cloud, but further south with clear skies it has been unusually cold for the time of year. Things should warm up a bit, but further cold snaps can't be ruled out at this stage.

[Penellype]

A warm weekend coming up, and not bad next week either. Please remember that it is only early April and there is a possibility that cold northerly winds may return later in the month.

The models are all over the place by next weekend, with each run looking quite different. Spring is a difficult period to forecast anyway and as I mentioned before, the lack of aircraft measurements could well be adding uncertainty. This is this morning's GFS run:



Quite a few of those lines are really rather cold by next weekend. It may not happen, but be aware that it could!

Snow is more common at Easter than at Christmas.

[sandspider]

Seems a shame to ask given the lovely sun, but do you have an idea when we might get rain, Pen? I have little trees needing water! Thanks.

[sandspider]

One forecast says none for ages, another says rain on Monday. I suppose the models aren't in agreement?

[Greenleaves]

I note on local Hampshire forecasts they are predicting frosts Monday and Tuesday nights

[Penellype]

As I've hinted at recently, the models do seem to be struggling to pin things down at the moment, which could be due to reduced numbers of measurements from aircraft. Easter has proved particularly difficult with massive differences in the forecasts from different models and runs until very recently. The current thoughts are that the high pressure that has brought the warm and sunny weather to most of the UK (due to its position over and to the east of us) will weaken through the weekend allowing showers to become increasingly widespread. A trough of low pressure then sinks south through the country during Sunday/Monday possibly bringing more in the way of rain although this could be fragmented.

As this low moves south it pulls the wind in from the north east, with high pressure building again from the north and west. This will result in a considerable drop in temperatures and a return to chilly nights with frost possible under clear skies next week.

The degree of uncertainty is well illustrated by the latest GFS ensemble which shows massive differences in forecast rainfall and upper air temperatures as early as Monday:



If the coldest of these is correct there could be a severe frost on Monday night and it is not too late for some of that precipitation to fall as snow (about half of the members are predicting some snow for York, which could mean just a few flakes or sleet). As you can see from the graph, there are more in the way of rainfall spikes from mid-April, but these are not well co-ordinated and not particularly big. There are massive differences in temperature too, with some members going very cold indeed towards the end (very unreliable), which could again lead to frost and/or snow - it is much too early to say.

In general though the models are predicting predominantly higher pressure with brief incursions from somewhat weak lower pressure troughs which may be in a position to drag in colder air from the north or east at times. You can therefore expect mainly dry or showery weather, with little organized heavy rain (although showers in April can be locally heavy and thundery). Be prepared for the threat of frost at times for the remainder of April at least, particularly but not exclusively further north.

[sandspider]

Thank you. We shall see!

[Penellype]

WARNING - the temperatures are about to drop by about 10 degrees or more from the summer-like ones we have had over the past few days. There is a risk of significant night frost for the next 3 or 4 nights, particularly so on Monday night when widespread below zero temperatures are likely.

[Containergardener]

Thanks Pen