The upcoming ‘warm spell’ which has been forecasted here since last week is now well advertised as it becomes more and more obvious on the models but while many jump on the idea that it’s going to warm up, i’ve been trying to determine the finer details of this weekend, such as timing, how much sun and just how warm will it get. Remember that this has been on the cards since LATE MARCH, given the indexes would flip back around during the second week of April and I stated, once those indexes start going up, let’s watch for the jet lifting back north which would bring the return of lower pressure and the chance of seeing some ridging. I tweeted back on Saturday that 21-23C is a good bet for the South of England during Sunday, perhaps Monday and those numbers are still looking good to me.

[s2If current_user_can(access_s2member_level1)]

In terms of sunny weather, expect eastern parts to see the best of the brightness because it’s with the help of a deep Atlantic low, which will transport Azores air into the UK and western areas are sure to be cloudy but will be mild, perhaps muggy.

As for tonight through Friday and into Saturday, there will be pulses of rain with two fairly heavy bands pushing across southern England and Ireland tonight, accompanied by a stiff wind. Both bands will weaken as they lift north into a drier atmosphere. The northern half of the UK certainly needs some rain as it’s been dry for the best part of a month now. It’s going to be interesting to see how much appreciable rain falls through the rest of April and May and right now, I stand by the idea that we’re going to see a dry spring.

However dry doesn’t mean particularly warm and both NAO and AO look to go back negative later which would suggest more cool but dry and settled weather into May. The good thing is, a negative NAO/AO during May won’t bring anything like the cold we’ve just seen. What it should do is bring us bright or sunny days with mild temperatures and clear, chilly nights with perhaps some rural frost. The focus will be on the continued lack of rain.

Two Warm Spells Over The Next 10 Days

As I see it, the next 8 weeks looks to see ‘come and go’ warm spells and while they may be relatively short lived, this month will be much better than last April when it was wettest on record.

Here’s the ECMWF upper chart and 850s. Nice ridge and SW flow on Sunday will bring us the warmest air of the year, wouldn’t be hard right?

This Sunday…

Monday is looking less good but I suspect this might change with future runs and we may get another nice and warm day before cooler and more unsettled weather returns.

The pattern is becoming more progressive with the NAO now up nearer neutral and with little blocking over the North Atlantic, there’s little to stop the west-east flow. However, while we see the return to unsettled and cool into next week following a very nice couple of days, the models are now showing another ridge and warm spell towards NEXT WEEKEND.

Here’s the chart for next Friday (19th)

Next Saturday

Given the NAO/AO flirting with neutral, this supports just as much chance for ridging as troughiness and so I very much buy this idea.

Although the upper flow is becoming more fluid, the warm spells will come and they will go but I strongly believe we will remain in a DRIER THAN NORMAL pattern over the next 8 weeks and this will have effect on our summer.

As you well know, the ensembles are showing the return to a negative NAO/AO which promotes a cooler end to April but nowhere near as cold as what this month started out and as for May, it’s looking cooler and drier than normal.

[/s2If][s2If current_user_is(s2member_level0)]

Join a subscription plan, [s2Get constant=”S2MEMBER_CURRENT_USER_DISPLAY_NAME” /]!

[warning]You do not have a valid subscription to access premium content exclusive to members. You will need to join a subscription plan if you would like to continue.[/warning][/s2If][s2If !is_user_logged_in()]

Sign in to read the full forecast…

Not yet a member? Start your 7 day free trial

Create your free markvoganweather.com account today to get unlimited access to Mark Vogan’s premium articles, video forecasts and expert analysis for 7 days.
[/s2If]