Storms and Convective Discussion - 20th April 2019 onwards

[Swansonson69]

Storms are looking good. North is taking one for the team. Good luck everyone. 

[Lu.]

Theres some stunning clouds down this end, moreso the skies at north Portsmouth are looking rather fierce!

[Atmogenic]

There is some lovely convection in the distance from my area which I presume are the cells near London from looking at the radar. Reminds me when I'm in Florida during the evening hours when the sun starts to set whilst still being able to see in the distance of bubbly cumulus and cumulus congestus clouds building up but eventually just fizzing out as the sun sets. 

Edited June 11, 2019 by Atmogenic

[Tom Quintavalle]

25 minutes ago, Atmogenic said:

There is some lovely convection in the distance from my area which I presume are the cells near London from looking at the radar. Reminds me when I'm in Florida during the evening hours when the sun starts to set whilst still being able to see in the distance of bubbly cumulus and cumulus congestus clouds building up but eventually just fizzing out as the sun sets. 

Yes, can report thunder from those cells you can see, here in Lee, S.E.London. That's the second evening running and looking like more thunder entirely possible, tomorrow.

Regards,

Tom.  

[Swansonson69]

Looks like theres back building again over the same area as yesterday. There must be some high rainfall totals around that area. 

[matt111]

Considering how dark it got earlier I only ended up with a few spots of rain and that was it. 

[TJS1998Tom]

12z looks promising for some heat in the next 10 days with risk of storms, hope the models pick up on this and that it doesn't downgrade again : P

[Swansonson69]

22 minutes ago, TJS1998Tom said:

12z looks promising for some heat in the next 10 days with risk of storms, hope the models pick up on this and that it doesn't downgrade again : P

Wednesday/Thursday have been looking interesting for a while now. Latest runs going for a plume type event. That's good amount of CAPE right there. 1,000J-2,000J

[Mapantz]

23 minutes ago, TJS1998Tom said:

12z looks promising for some heat in the next 10 days with risk of storms, hope the models pick up on this and that it doesn't downgrade again : P

I'd ignore that, i'm afraid. The 12Z GFS operational run is way out of kilter with the rest of the ensembles.

[Swansonson69]

1 minute ago, Mapantz said:

I'd ignore that, i'm afraid. The 12Z GFS operational run is way out of kilter with the rest of the ensembles.

I wouldn't ignore that, last couple days have being showing that kind of thing. 

[ChezWeather]

1 minute ago, Swansonson69 said:

I wouldn't ignore that, last couple days have being showing that kind of thing. 

Follow these charts at your own peril, 9 days out they are very unlikely to materialise, and as Mr Pantz has stated, this GFS run is on its own with these kind of scenarios tonight

A change of pattern may be coming but don't expect charts like this to verify 

[Zak M]

34 minutes ago, TJS1998Tom said:

12z looks promising for some heat in the next 10 days with risk of storms, hope the models pick up on this and that it doesn't downgrade again : P

I'm literally in the white zone

[Swansonson69]

4 minutes ago, zmstorm said:

I'm literally in the white zone

I'm just outside the dark red on the north side. 

[Swansonson69]

11 minutes ago, ChezWeather said:

Follow these charts at your own peril, 9 days out they are very unlikely to materialise, and as Mr Pantz has stated, this GFS run is on its own with these kind of scenarios tonight

A change of pattern may be coming but don't expect charts like this to verify 

I follow Gavs weather vids because very good at what he does. I wasn't expecting the flooding rains to come off at all because it looked way over the top but it came off. I don't rule anything when it comes to storms my friend. Neither should you or anyone. Just prey and hope it comes off lol.

[Summer Sun]

Day 2 Convective Outlook

VALID 06:00 UTC Wed 12 Jun 2019 - 05:59 UTC Thu 13 Jun 2019

ISSUED 20:49 UTC Tue 11 Jun 2019

ISSUED BY: Dan

Once again, broad upper trough will cover western Europe on Wednesday, with the main upper low centred over the Brest peninsula. The main trough will be somewhat negatively-tilted at first, become neutral then positively-tilted by the evening as the upper low begins to lift/extend northwards across England during Wednesday night.

The forecast evolution is rather messy due to various pulses of showery rain rotating eastwards along the northern flank of the dominating low, containing a mixture of dynamic and convective precipitation. Any of these pulses of rain could contain some embedded elevated convection, and hence carry a risk of a few isolated lightning strikes - especially across East Anglia / SE England during the morning hours, then NW England / N Wales late afternoon / early evening. Confidence on lightning coverage associated with these features is not particularly high, and so have refrained from introducing any specific SLGTs for now. 

... S / SE ENGLAND - AFTERNOON/EVENING ...

Provided there is sufficient insolation across southern England, then cool air aloft coupled with surface heating of a moist low-level airmass (11-13C dewpoints) should yield 300-700 J/kg MLCAPE. Low-level wind convergence, derived from a combination of sea breeze, trough axis and even differential heating boundary (quasi dryline) will likely provide the trigger for a few scattered showers and thunderstorms to develop over southern counties of England during the afternoon and evening hours. Thunderstorms are also likely over the Cherbourg peninsula, drifting close to the Channel Islands.

Close to the upper low, shear will be rather weak with fairly unidirectional winds with height - that said, reasonable flow at the EL should act favourably for venting. Hail will be possible from the most intense cells, with a risk of surface water flooding given slow storm motion and existing saturated ground.

During the evening hours the risk of a few showers/thunderstorms may expand across the northern Home Counties before a general weakening trend occurs by late evening.

... EAST ANGLIA / SE ENGLAND - OVERNIGHT ...

As the upper trough extends / lifts northwards on Wednesday night, the associated cool mid-levels overspreading the in-situ warm, moist low-level airmass will serve to increase instability, particularly over the eastern English Channel and southern North Sea. Consequently an increase in coverage of a few scattered showers / thunderstorms seems plausible, particularly during the early hours, hence the inclusion of a SLGT for coastal parts of East Anglia - although this may need extending farther inland depending on trends.

http://www.convectiveweather.co.uk/forecast.php?date=2019-06-12

[Another Kent clipper]

Does anyone know why the GFS does this?  

[Swansonson69]

8 minutes ago, Another Kent clipper said:

Does anyone know why the GFS does this?  

They like trolling us storm fanatics? Something like that will come off eventually. Just about being patient. 

Edited June 11, 2019 by Swansonson69

[LightningLover]

Ooooh, tomorrow looks fairly interesting for East Sussex!!

[Mapantz]

36 minutes ago, Another Kent clipper said:

Does anyone know why the GFS does this?  

Mainly, because it's the lower resolution part of the GFS op run. It usually lowers CAPE values when it gets to the higher resolution part of the run, but it can still be on the high side. Higher resolution models will give a better idea, but of course, they don't go out as far as the GFS. They can still be a bit on the high side themselves, but are usually more trusting. You could also look at extended skew-t diagram, they may be better. The best information will come from soundings on the day from RASP etc

[NO LONGER POSTING]

So the EURO4 once again trumps all other high res models (maybe not Arome as it also did good yesterday) when it comes to convective weather... 

Not really too sure how today is going to pan out...There is a lot of clag associated with the front moving North over the south coast currently... 

 

 

[Hodgheg]

The first thing I do to check our convective potential is to compare the BBC graphics with the Met office forecast precip and see if they agree on anything. The are both way off each other today for the south east. BBC has rain to the north and showers breaking out this aft and evening whereas the Met office shows the more general area of rain further south with few convective showers. 

[BrickFielder]

  An upper level trough extends down across the UK and parts of western Europe with a surface low over Northern France. Circling around this trough are a number of jetstreaks with associated left exit regions where winds diverge aloft. As the JetStreak over the continent moves north the main exit region moves north with a surface low developing over north west Europe and the north sea. A smaller jetstreak appears across the central part of the UK for a short time this afternoon with its associated left exit.
  Similar to yesterday low level convergence zones will develop across the south east moving north westwards slightly during the afternoon. Along these areas weak thunderstorms are likely to develop which are likely to be slow moving and lead to localized flooding. Winds are fairly lite so pulse storms are likely. Forecast SkewT's show a moderate cloud top heights and a moist profile making heavy rainfall likely.
  Not quite sure of the impact of the short lived left exit region for the jetstreak across the UK this afternoon. My thinking is that the divergence aloft could give some isolated over shooting tops. Even moister air profiles across central England could then give rise to some very heavy rainfall with some weak embedded thunderstorms.

[tomp456]

12 hours ago, Another Kent clipper said:

Does anyone know why the GFS does this?  

The map is accurate. For France only. 

[Matty88]

So my phone just buzzed with a meto warning for thunderstorms - but the charts aren't making me particularly excited today only for the prospect of some potentially heavy bursts of rain with some weak tstorms possible. All in all - seems a bit overkill to call it a thunderstorm warning in my books. Estofex don't even have a slight on us today  a heavy rain warning warranted - possibly yes, but thunderstorm? Nahh 

Edited June 12, 2019 by Matty88

[Summer Sun]

Amber rain warning issued for East Lothian, Midlothian Council & Scottish Borders on Thursday

https://www.metoffice.gov.uk/weather/warnings-and-advice/uk-warnings#?date=2019-06-13&id=04d59864-da28-437b-8b86-caf2b831bcfa&details 

Edited June 12, 2019 by Summer Sun