Model Output Discussion - What does April have in store?

[ANYWEATHER]

6 minutes ago, Mapantz said:

Could you elaborate?

I see nothing pointing towards 'violent' 

CAPE values look extreme in some parts, but one convective factor doesn't paint the full picture.

Just wait you will find out tomorrow 

[Frosty.]

4 minutes ago, Mapantz said:

Could you elaborate?

I see nothing pointing towards 'violent' 

CAPE values look extreme in some parts, but one convective factor doesn't paint the full picture.

I'm still waiting for that snow he promised my back yard would get and a record cold april.

Anyway I agree, nothing violent, this isn't some epic plume event, it's a change back to typical spring weather with sunshine and heavy showers and a risk of thunder.

[Alexis]

Stav Danaos described Wednesday's showers as "torrential" on his last shift. Just saying.

Edited April 22, 2019 by Alexis

[Mike Poole]

11 minutes ago, Mapantz said:

Could you elaborate?

I see nothing pointing towards 'violent' 

CAPE values look extreme in some parts, but one convective factor doesn't paint the full picture.

CAPE Tuesday late afternoon, but I'm not sure what will trigger any significant storms.

Thursday looks of more interest to me, although lower CAPE, with the unsettled weather pushed in by now?  

[Methuselah]

3 minutes ago, Mike Poole said:

CAPE Tuesday late afternoon, but I'm not sure what will trigger any significant storms.

Thursday looks of more interest to me, although lower CAPE, with the unsettled weather pushed in by now?  

You're right enough, Mike: apart from a few storms along the trough, the best chances ought be once the unstable conditions fully take over? A whole day's insolation to play with?

[MATTWOLVES 3]

19 minutes ago, Alexis said:

Stav Danaos described Wednesday's showers as "torrential" on his last shift. Just saying.

Scattered thundery showers spreading North, its possible some of them could be torrential in places, while other places largely miss them... Like others have said this hasn't been a major heat plume with humidity through the roof, but I stand to be corrected. But I agree some of the showers could pack a punch. 

[MATTWOLVES 3]

30 minutes ago, Mike Poole said:

 

Sorry Mike couldn't resist, them charts are more far out than the spaghetti plots Karl posted recently.... Im suffering from a bout of vertigo now.

[Mike Poole]

We appear to be headed towards an odd place...here's the ICON 18z at T120 (end of run)...

Like the earlier runs low sandwiched between highs, here's the NH view:

High lat blocking and Azores forcing?  Wouldn't believe a model past T96 at the moment. 

[damianslaw]

After a lengthy dry and sunny period that started off preety cool, with some notably cold nights but more recently warm, we are about to see a marked pattern change - a trough dominated scene, trending much wetter and cooler everywhere. 

As we end the month and enter May, I don't see any immediate change, signs as we approach the next bank holiday weekend things may settle down again, but not clear whether this will be courtesy of heights nosing in from the SW, or heights building in from the NW.

Ensembles show a strong high pressure cell to our NW which is not conducive to the azores high building sufficiently NE, a messy set up, the trough may simply be squeezed in situ by these forces, however, with the PV lobe setting up shop over Russia, yes a weak affair, but it could portend a northerly flow eventually.

 

[Frosty.]

1 hour ago, ANYWEATHER said:

Just wait you will find out tomorrow 

Shirley you mean wednesday?..tomorrow looks dry, sunny and warm / very warm again bar some wispy high cloud and a dash of Saharan dust.

[MATTWOLVES 3]

19 minutes ago, Frosty. said:

Shirley you mean wednesday?..tomorrow looks dry, sunny and warm / very warm again bar some wispy high cloud and a dash of Saharan dust.

Shirley?? Who is she.. Yes very warm and mainly sunny tomorrow, then according to some who can't be named much colder Conditions on the way.... Brrrrrr...... Possible Nthly!!!! It's coming folks..... You've been warned.... 

[Frosty.]

1 minute ago, Mattwolves said:

Shirley?? Who is she..  

 

From that movie airplane when he says Shirley you can't be serious and the other guy says, I am serious and don't call me Shirley..anyway..putting it mildly, the second half of this week looks different to the first but temps still decent in the mid teens celsius range so not too bad really, ok for the time of year.

[knocker]

Outlook - The UK under the influence of the upper trough over the next few days as the high pressure migrates west. Thus unsettled, sometimes very, with temps back to varying around the average

The NH 500mb profile and the Atlantic surface analysis for midnight and the 0400 UTC UK chart

A varying amount of cloud this morning with some showers around in the south west and western areas and quite mild,whilst cooler in the north east with some mist and fog patches. The odd shower may persist through the day but generally warm again, particularly in wales and central southern England. But the dreaded onshore winds are back in north east and end eastern coastal regions and some stratus may drift in from the North Sea

Through this evening and overnight some showery rain will effect the south west as the trough and cold front just SW of Cornwall start to track north east

The showery rain will follow the fronts north during the day and evening on Wednesday with some heavier outbursts and thunder in the mix with clearer showery weather in the wake but more persistent rain may effect the south later as an occlusion slips into the Channel. Much cooler than of late, particularly in the north east which may well be under a blanket of stratus.

The rain and the occlusion will track north through Thursday but there is a lot of instability around now and a day of heavy showers will follow and again thunder will be in the mix. And temps are back to earth with vengeance

Friday another day of sunny intervals and heavy showers but a wave is forming to the south west of Ireland

The wave tracks across the UK of Saturday accompanied by persistent rain and strong winds and a decidedly chilly day.

Edited April 23, 2019 by knocker

[knocker]

Not to get too wrapped up with the detail from this point but continuing unsettled with temps varying around the average. The NH overview for the next three days illustrates the pattern change to a more fluid Atlantic.

[knocker]

Looking at the possible temps for next weekend with the ecm. some difference to the one just gone

Edited April 23, 2019 by knocker

[Methuselah]

The GFS 00Z is not good: 

The FV3 not just as bad:  

And the ensemble:           

But how will the models handle the final stratospheric warming, one wonders!

[Blessed Weather]

The GEFS 2m temperature anomaly for the last 7 days versus the trend for the next 7 days highlights the change on the way:

 

Although taking the month to date and forecast for the last week of April the month overall likely to end not too far off normal for the UK, but some cooler temps for folk taking a Spring break in holiday destinations such as Spain and Cyprus.

 

[Jonathan Rhodri Roberts]

10 hours ago, Mike Poole said:

CAPE Tuesday late afternoon, but I'm not sure what will trigger any significant storms.

Thursday looks of more interest to me, although lower CAPE, with the unsettled weather pushed in by now?  

For that big area of high CAPE across Wales, high ground as Met Office suggests a chance of a few isolated thundery showers today, mainly over the hills 

[Frosty.]

Looking at the Ecm 00z ensemble mean longer term the trough(s) are filling and temperatures are recovering from the south.

[northwestsnow]

Spell of cold wet and windy weather now inevitable looking at the 00z runs.

Must not grumble as its been a glorious Easter ..

Hopefully the upcoming phase will not be a long one.

[Frosty.]

Actually the longer term GEFS 00z mean looks encouraging and might suggest high pressure building in during early may.

Edited April 23, 2019 by Frosty.

[Methuselah]

Friday looks like being a rather convective day, as the entire UK is under a trough:

 

[Methuselah]

We're still on for a short-lived warm-up for Sunday?

 

[Frosty.]

6 minutes ago, Ed Stone said:

We're still on for a short-lived warm-up for Sunday?

 

I just blinked and missed that Ed

[Frosty.]

May starts very cool, cyclonic and showery according to the 6z operational