SE, London & EA - Weather Discussion

[MAF]

1 hour ago, Snowangel-MK said:

Now that’s what I call a long range forecast ! 

well i always live in hope  

[Eagle Eye]

Me and Jayy's forecast for tomorrow (I once again wrote the discussion and he did the map)

"

Convective outlook  

Friday 00:00 - Saturday 00:00

An occluded front moves across Ireland early morning on Friday sparking a few showers capable of a strike or two of lightning. Though that's a very conditional risk for lightning at about a 5% risk of even 1 strike.

However, in the afternoon across western Ireland the risk ramps up behind the front with fairly buoyant air and latent heat release from surface heating. The air remains moist up until around the 500MB parcel layer. Given good kinematics storms could reach to around 20,000 feet. Though shearing is unlikely to be that strong, 500-700+J/KG of MUCAPE may be able to overcome that and storms can become relatively tall.

There's also backing from the lapse-rates for hail given fairly cold but moist upper air. A lot of moisture has the potential to be condensed in the atmosphere given the time of year and the models suggest quite a lot of the PWAT will be saturated. The forecasted high relative vorticity along a lobe on the west coast suggests horizontal convergence and upper-level divergence, a sign of ascending motion or convection  that forms thunderstorms. Thus, a slight risk has been added at a 35% chance of lightning within a 25 mile radius.

In the UK the risk is similar but strong WAA after a clearing cold front in the morning will give rise to temperatures strong enough to break any of the CIN and vertical motion increases. Similar lifting especially surface based to the west Ireland risk, even better lapse-rates and better supportive shearing but drier air in the mid Troposphere and the boundary layer dynamics are much less good may limit potential. Depending on the timing of the cold front, MUCAPE could be anywhere between 300 J/KG max or 800+ J/KG max so we decided to limit the slight risk to a low-end slight risk to the main area (around 30% chance of lightning within 25 miles).

Later on in the evening, showers could fire up along the southern edge of the advancing occluded front along the southern/southeast coasts and the risk for a strike or two in the channel/coasts is possible given 200-300 J/KG of MUCAPE. Update will follow on this rather early hours Friday or in the afternoon.

These will come with the risks of heavy rainfall, some hail and sporadic to some organised lightning.

"

[Tn9]

Partly cloudy at  first  light ..now cloud level down to 400ft with light rain ..but 9c which is or feels summery if that's a word 

Up date low cloud  proberbly sea level now or near on ..dropped totally 

Edited March 17, 2023 by TN9

[Freeze]

Warmest day of the year here at 13c feels nice in the sun.

[Eagle Eye]

Fantastic sunset I have to say.

 

 

[lottiekent]

Bit of a miserable day, brief glimpse of sun towards end of afternoon and warmish at 10c

[Eagle Eye]

Me and Jayy's forecast for tomorrow
Convective Discussion 

Friday 23:59 - Saturday 21:00

Showery rain pushes across the South and south east in the morning with an occluded front providing some instability for a strike or two of lightning possibly but shallow cloud heights should limit that.

Behind that occluded front and surface heating with any cloud breaks should allow for 700-800+ J/KG of SBCAPE and hefty showers and thunderstorms could form. Kinematics such as high positive vorticity promotes convergence and better storm formation but it looks like the shearing will be fairly limited with the best in the SE/London area (with slightly limited CAPE though) and up to the Midlands and parts of the eastern coast where the slight risk has been added due to taller Storms and therefore theoretically better lightning chances.

There may be favourable kinematics elsewhere such as strong moisture flux in areas along the west coast of Wales and northern England but the latent heat release is likely to be weaker there and forecasted soundings in the area suggest a warm dry nose at the 600MB and the air is less buoyant there especially towards the mid-levels.

Compare that to the slight risk and though there's some weak dry air at the 700MB layer, that should erode given the buoyancy and amount of energy and the moisture looks better (when in conjunction with temperature) above that till about 22,000 feet so given very good kinematics Storms could reach that that but its unlikely. I think a more realistic height is around 18,000 feet in the slight risk area.

Weak low-level shear and decent lapse-rates keep up the risk for small hail but the lapse-rates are likely to be a lot weaker than Wednesday and Thursday. Main risks with these are heavy rain and small hail as well as sporadic lightning, some organised Storms are possible in the areas of highest shearing.

[Uxbridge90]

It might be wet but at least it's a lot warmer than the miserable cold sleety dross we had the other week! 

Here's hoping there's no more cold weather and Spring really kicks in to gear.

 

[MAF]

well at least we are into 12 hours of daylight now. In London that is. 

today - sunrise 0608 - sunset 1809

[Froze were the Days]

Another dismal day here...just the same as yesterday but rain probably somewhat lighter...we can all thank the SSW for this, but who knows maybe we'll need this rain come July.

[Methuselah]

29 minutes ago, MAF said:

well at least we are into 12 hours of daylight now. In London that is. 

today - sunrise 0608 - sunset 1809

The only drawback of increasing day lengths is that my boss (Cat) wakes me up earlier and earlier! 

[alexisj9]

1 hour ago, MAF said:

well at least we are into 12 hours of daylight now. In London that is. 

today - sunrise 0608 - sunset 1809

The equilux aparently 

Edited March 18, 2023 by alexisj9

[SunSean]

Some more stat digging for ya! From January 1990 up until this month so far, out of 399 months in total, March 2023 is currently the 6th dullest month out of all those 399 months. Sure, there is still another 13 days left after todays 100% overcast day but with the forecast looking absolutely dull as dish water, the month is still guaranteed to be in the bottom 20 at best. Truly woeful month.

[Freeze]

Lovely calm sunny day here and 11c 

[Eagle Eye]

A bit of a timelapse from this afternoon 

Distant convection

 

 

Edited March 18, 2023 by Eagle Eye

[chilly milly]

Finally brightened up this afternoon after a mainly dull and wet day. Can actually see blue sky which is nice.

[snowrye]

Just done my last job, and noticed this interesting cloudscape over northern france

[lawrenk]

It’s afternoons like this that make me look forward to those lovely balmy late afternoon/early evening May and June evenings in the garden, slightly the worse for wear, with some good music in the background. Won’t be long!

[alexisj9]

Does march have a fog index, and what does it stand for, good storms in summer?

Thick fog here tonight.

[snowrye]

10 minutes ago, alexisj9 said:

Does march have a fog index, and what does it stand for, good storms in summer?

Thick fog here tonight.

Is this like the October fog index

[Harry's House]

Very pleasant fine afternoon here with distant Cbs inland. Watched football match between Pagham and Christchurch in the sun. Unfortunately Pagham lost 3-2 because of a late penalty due to a foul, but it looked a fair tackle to me.

[m1chaels]

11 hours ago, SunSean said:

Some more stat digging for ya! From January 1990 up until this month so far, out of 399 months in total, March 2023 is currently the 6th dullest month out of all those 399 months. Sure, there is still another 13 days left after todays 100% overcast day but with the forecast looking absolutely dull as dish water, the month is still guaranteed to be in the bottom 20 at best. Truly woeful month.

2018 had a very dull March and April - and then a very sunny May, June and July.....

[SunSean]

9 minutes ago, m1chaels said:

2018 had a very dull March and April - and then a very sunny May, June and July.....

Yeah i know. Hopefully the same again but with a better April too!

[MAF]

Well regardless of what the weather wants to do, for me Spring is here. Confirmed by the knock-knock-knock of our local woodpecker

[Froze were the Days]

Another poor MeteoGroup (BBC) forecast for today...where's the sun? glimpses today but that's about it. Forecast for the week ahead and again a lot of cloud with drizzle/rain at times - oh joy! no doubt they'll get that right...