Storms and Convective discussion - 20th March 2023 onwards

[Supacell]

I was planning on waiting until April 1st to open a new thread as this is when I tend to become interested in all things convective again. However, considering there has already been some convective interest over the last few days and indeed more to come during the week ahead, I have brought forward those plans. It is a joy to be seeing decent opportunities ahead for thunderstorm risks as early as March. Welcome back all fellow storm fans.

So here we go. Old thread below.

https://community.netweather.tv/topic/97528-storms-and-convective-discussion-1st-august-2022-onwards/

And as for these opportunities. Well the forecasts on TV are already mentioning "thundery" in the forecasts for tomorrow, but my interest is further ahead with GFS, NMM and UKV all showing interest for Thursday onwards especially as an area of low pressure parks itself close by and generates lots of showers, some of which are likely to be thundery with hail. We are not talking intense summer heat and plumes of course, but some nice springlike thunderstorms with good convective skies and rainbows.

Admittedly I am more about chasing than forecasting, I sometimes try to forecast but I am best leaving that to the experts. I can though, see the opportunity. If I capture a thunderstorm within the next week, it will be the first time I have ever captured a thunderstorm in March and 2023 will be my 20th year of storm chasing.

MUCAPE charts from Thursday to Sunday from the NMM

  

  

[Raindrops]

On 20/03/2023 at 12:15, Supacell said:

I was planning on waiting until April 1st to open a new thread as this is when I tend to become interested in all things convective again. However, considering there has already been some convective interest over the last few days and indeed more to come during the week ahead, I have brought forward those plans. It is a joy to be seeing decent opportunities ahead for thunderstorm risks as early as March. Welcome back all fellow storm fans.

So here we go. Old thread below.

https://community.netweather.tv/topic/97528-storms-and-convective-discussion-1st-august-2022-onwards/

And as for these opportunities. Well the forecasts on TV are already mentioning "thundery" in the forecasts for tomorrow, but my interest is further ahead with GFS, NMM and UKV all showing interest for Thursday onwards especially as an area of low pressure parks itself close by and generates lots of showers, some of which are likely to be thundery with hail. We are not talking intense summer heat and plumes of course, but some nice springlike thunderstorms with good convective skies and rainbows.

Admittedly I am more about chasing than forecasting, I sometimes try to forecast but I am best leaving that to the experts. I can though, see the opportunity. If I capture a thunderstorm within the next week, it will be the first time I have ever captured a thunderstorm in March and 2023 will be my 20th year of storm chasing.

MUCAPE charts from Thursday to Sunday from the NMM

  

  

I was actually going to start a new Thread on the 13/3/23 but I wasn't sure if I was allowed to so I left it to someone with more experience such as yourself, I seen ESTOFEX gave a forecast for this date and so to did Dan from Convective Weather who has a forecast for today. Apparently there was a Tornado in Great Hucklow Derbyshire
13 Mar 2023 as reported on TORRO also Derbyshirelive.

It's an early start this year, lets hope that's a good sign for the year ahead :).

Edited March 21, 2023 by Raindrops

[Thunders]

4 hours ago, Raindrops said:

I was actually going to start a new Thread on the 13/3/23 but I wasn't sure if I was allowed to so I left it to someone with more experience such as yourself, I seen ESTOFEX gave a forecast for this date and so to did Dan from Convective Weather who has a forecast for today. Apparently there was a Tornado in Great Hucklow Derbyshire
13 Mar 2023 as reported on TORRO also Derbyshirelive.

It's an early start this year, lets hope that's a good sign for the year ahead :).

Let’s hope it’s a good year for storms

 

[Raindrops]

11 minutes ago, Thunders said:

Let’s hope it’s a good year for storms

 

I had a few good late storms last year I was surprised to see so much activty late in the season.

Yes I hope we all have a story to tell this year let's all remember to stay safe and respect the power of mother nature.

Happy hunting.

[Eagle Eye]

Me and Jayy's forecast for tomorrow (I did the text part, he did the timings and map)

Convective outlook

Wednesday 07:00 - 20:00

A mixed mode setup over Ireland is likely on Wednesday with a trough passing through in the morning with unstable air behind it before stalling and weakening. This occurring after a diffuse warm front and then a diffuse cold front. Also followed by an occluded front. That ends up with fairly cold air over Ireland but it should still be warm enough given latent heat release forecasts for surface heating around mid day to spark hefty showers. Initially these may not be that strong with an isolated strike or two but in the afternoon an occluded front pushes through and lifts up cold upper air and much better lifting into the atmosphere. Moisture continues to advect NE'wards and so MUCAPE increase up to 700 J/KG perhaps up to about 750 K/KG max. Also, some daytime convection over Scotland is noted on a few models such as the UKV with 200 J/KG of CAPE and a small amount of potential convergence.

Both deep-layer shear and low-level shear are likely to be quite high (low-level shear could be as high as 50 knots)  with the hodographs potentially supporting an isolated Supercell and/or a small tornado. SRH values at the low-levels in excess of 300 m² s² also supports this as do the current modelling for some rotating updrafts. Which also supports small hail given the lapse-rates as well but high shearing at the low-levels looks likely to protect that to just small-hail given that the lapse-rates are becoming increasingly hotter and towards -6.0⁰C where the hail heat becomes marginal.

This convection looks to converge and strengthen also in conjunction with a lobe of high potential vorticity. Convection is likely to grow into a few clusters and also isolated thunderstorm possibly enough for Supercells across Ireland in the daytime depending on the amount of saturation in the atmosphere. E.G higher saturation and its likely to form into clusters more and also the lightning potential decreases making it difficult to forecasting the amount of lightning ad the timing of saturation advection and the angle depends on both of the axis of the initial trough and the occluded front.

Also a PV lobe across the south/southeast coast in daytime and a small amount of CAPE could allow for a few showers capable of the odd lightning strike. Ahead of the cold front in central England and there's some skinny CAPE that may allow for a few pre-frontal showers under daytime heating capable of an isolated lightning strike.

Beyond that and the clusters are looking likely to form into a squall line 'connecting up' with a lifting cold front with perhaps a few remaining thunderstorms behind that though its primarily a wind threat from the squall line as it approaches Wales, SW England and NW England potentially up to NW Scotland. We will update beyond that tomorrow.

Also edited a few pictures from last year.

The hodographs are looking fairly supportive for perhaps a Supercell and isolated funnels/tornado's and that's when here. I've added the white arrows to show what the low-level shear (first curving arrow) and the deep-layer shear (second straight arrow) and as you can see it's quite close to what it should be. This looks more multicellular than Supercellular given what the yellow shows but I could see the potential for a Supercell here and maybe a tornado but that relies on a lot more than just the low-level shearing.

 

[Metwatch]

Small surprise storm just rattled through here, set off a car alarm with a few loud rumbles. 

Looks like it had some hail just south east of here judging by the Coventry Airport webcam.

Edited March 22, 2023 by Metwatch

[CoventryWeather]

Can confirm in Coventry we had a storm. I'm a little further west, but still saw lightning and loud, crackley thunder. 

It's a stunning cloud though, will try and post a few from my canon in a bit, but heres a cheap phone one.

[Jamie M]

Line convection might play a role tonight, being sure to maintain my 16-day consecutive streak of rain every day! 

 

[alexisj9]

16 minutes ago, Jamie M said:

Line convection might play a role tonight, being sure to maintain my 16-day consecutive streak of rain every day! 

 

Still dull and misty, with low cloud occasional very light rain still falling here, this line looks much more interesting, I expect it'll weaken before getting here though.

Edited March 22, 2023 by alexisj9

[Argyle10]

Radar keeps cutting out down here

[Eagle Eye]

Forecast for this evening and tomorrow 

Convective Outlook ️

Wed 22nd 20:30 - Thu 23rd 20:00

 

Through the evening a squall line is expected to push across the Irish Sea towards Western parts of the main island perhaps strongest around Wales before weakening as it pushes inland. There may be a few storms behind it in band's of convergence but only a strike or two at best.

 

Behind the occluded front and there's a few vorticity lobes with one stretched across the south with a subtle trough in the SW/S in the morning advancing east and one around parts of north Wales. Some thunderstorms are possible in the morning hours in those areas.

 

Then as the afternoon approaches and the showers across the south become more of a mess. MUCAPE is likely to increase to around 500 J/KG in the Midlands upwards and across Ireland. With daytime heating and latent heat release around the surface then subtle convergence areas given moderate shearing allowing for decent storm formation and clustering.

 

The saturation and storm heights profiles don't look that supportive for strong thunderstorms with frequent lightning hence its only a low-end slight in the area of highest confidence.

 

Though there is a small chance for Supercells with a cold front to the south advecting shearing parallel to its advance to the southern most Storms in the midlands/North and strong low-level shearing with 200 m²s² of SRH may allow for an isolated tornado with the strongest Storms.

 

Small hail, sporadic lightning and an isolated Supercell and/or tornado is possible with the strongest storms. Along with the wind gusts from the squall line overnight.

[Buzzard]

Bit lively here in LB. Trying to get to sleep! No electric activity but very squally and heavy rain. 

[Rush2019]

Some sferics early this am, Anglesey NW Wales.  Intense echoes feeding in to the NW currently, 6am.

[Dangerous55019]

12 minutes ago, Rush2112 said:

Some sferics early this am, Anglesey NW Wales.  Intense echoes feeding in to the NW currently, 6am.

Morning @Rush2112… (and everyone else) … Just to back up what you’ve posted… 

After a wild and windy night last night, I’ve just heard on the wireless about the risk of thunderstorms today, and decided to have a look.

It looks like Holyhead has had a storm today, and also something off the coast of Blackpool as well!

Let’s hope that 2023 is a much more active one than last year was for us all.

[Dangerous55019]

There looks to be another line of convection kicking off around the Aberdyfi area, and stretching in land!

[Eagle Eye]

These showery/thundery breakdowns don't look like stopping soon .

 

Edited March 23, 2023 by Eagle Eye

[Atmogenic]

3 minutes ago, Eagle Eye said:

These showery/thundery breakdowns don't look like stopping soon.

 

much more interesting though then the constant dull and cold weather we've been having

[A Face like Thunder]

Dark and heavy shower here in S Cheshire, and I suspect that we shall be getting more of the same during the day.

[Weather-history]

Showery day

 

[Eagle Eye]

Convective Outlook ️

 

Thu 23rd 20:30 - Fri 24th 20:00

 

An occluded front moving east/southeast will be followed by a subtle trough in the morning which may spark showers and a thunderstorm or two along the south coast. Followed  by surface heating and bands of PV allowing for storms across the British Isles throughout the daytime.

 

MUCAPE in excess of 500 J/KG and supportive soundings given moderate deep-layer shear may allow for fairly tall storms which you would expect increases lightning potential especially along the corridor of strongest PV.

 

Deep lapse-rates and fairly low low-level shear may allow for hail up to 1 or 2 cm's in size. Also supported by forecasted deep updrafts though unlikely to be rotating given the buoyancy and SRH forecasted.

 

Saturation is likely to be high and ao clustering is likely given the MUCAPE forecasted and so heavy rain could fall in convergence areas for quite a few hours on and off.

 

Lightning is likely to be fairly sparodic given the saturation forecasts and similar events but lightning could organise itself into quite frequent with the strongest Storms. Buoyancy at the boundary-layer is also likely to be fairly weak and that's certainly a 'bust' mode for lightning and Storms but convergence should allow vertical forcing to increase in some areas.

 

Upscaling into a squall line is possible in two bands of PV in the southeast area and the midlands-south west in the evening/overnight according to the AROME though lightning risk in those is likely to be fairly limited and it'd mainly a wind risk.

 

Some hail, winds nearing 100 km/h by the coasts of Wales and the SW with 70 km/h by the coasts of the S and the SE with 55 km/h wind gusts with the squall lines inland and possibly up to 80 km/h in southern to central Ireland throughout the day and overnight. Along with heavy rain is all possible. A Supercell cannot be ruled out as well but not too much supportive evidence widespread. Some hodographs do support a Supercell but only a small chance.

[mike5900]

Just had a few fumbles of thunder. Also a few bits of large hail. 

[ChezWeather]

Some nice skies up in the Peaks today

[Windblade]

Huge cg and a rumble from a very heavy shower at Shooters Hill about 12.05pm. Couldn't take any pics as was driving but it was extremely localised as I could see the edges of it above me and blue sky a couple of miles each side of it. I'm in Welling now and can see the cell in it's entirety as it has drifted northeast. Textbook anvil on it. I'm off the 2023 starting blocks. 

 

 

Edited March 24, 2023 by Windblade

[Arnie Pie]

Convection just kicking of in the Midlands, hopefully something more sparky this afternoon

just in case

https://www.youtube.com/watch?v=Cp6CL_nJlsg

[Metwatch]

Some decent convection around with a short heavy shower passing momentarily.