[South West and Central Southern England Discussion - Dec 2023 onwards]

When does a convective discussion become a ‘tornado warning’?

Answer - when an ill-informed journalist on a local rag completely misinterprets the information.

 

Tornado warning issued for Dorset

WWW.BOURNEMOUTHECHO.CO.UK

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A TORNADO warning has been issued for Dorset today.

 

[Storms and Convective discussion- October 2023]

The trough and associated squall modelled to move across the SW and into the SE and EA later tomorrow (Sat 28th Oct) needs watching. Potential for bow elements and embedded structure given the parameters. GFS high res returning up to 500 0-3km SRH across the south at 15Z.

[2023 Tornado Events, Outbreaks and Chat]

Mesoscale trends look favorable for a couple of discrete supercells in far NE MO, initiating at around 22Z and tracking NE in an environment supporting top end SRH. The last two HRRR runs on simulated has a tornadic cell initiating around Edina, MO and moving towards Burlington, IL by 00Z. DPs already approaching 66F into central MO now. The current activity should be monitored for an OFB further enhancing the vectors.

The nocturnal risk into AR later is also looking serious and might well end up as the headline maker.

[South West and Central Southern England Regional Weather Discussion]

15 minutes ago, *Stormforce~beka* said:

Oh snoooore the lying pizza wedge is back! Says it's raining over me ... It's not!! Someone tell me WHY It does this!!!?

Hi - I can help you with this and indeed it is frustrating.
The data in the Wiltshire/W Hampshire area is augmented by the radar site near West Dean, a few miles SW of Salisbury. This station has had a problem for quite a while where a quadrant of the scan in a wedge pointing east is corrupted, resulting in 'lines' and wedges of false enhancements and diminished returns.
It doesn't happen all the time but it can be annoying when tracking fine detail and intensities.

[2021 Tornado events, chat & reports]

This location is in far SW TN for 21Z tomorrow from the latest NAM. A classic supercell signature with long-looped hodograph. The HRRR analysis will prove interesting when this comes into range.

[Model output discussion - is the beast awakening?]

1 minute ago, nick sussex said:

The ECM is sensational with some stunning snow accumulations likely however I’d really urge some caution before complete pandemonium breaks out in here l

I know it’s hard but we need to see the first big hurdle modelled we’ll within T96 hrs .

Very wise words

[Model output discussion - Into 2021]

4 minutes ago, Penicuikblizzard said:

A met office forecaster in one of the papers has said there is a El Niño building in the Pacific which could contradict the current situation and end up giving us milder wetter conditions, any views on this comment??

Can you reference that as it’s clearly incorrect. ENSO still in La Niña phase (waning) and not forecast to go neutral until March at the earliest.

https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf

 

 

[Model output discussion - The run up to Christmas]

44 minutes ago, Jason M said:

Don't over rely on the accuracy of those charts. Back then the best selling home computer was the ZX81 which had a 1K (yes, 1K) memory !!! And yes, I had one   There is more computing power in your TV remote than there was in the mainframes back then and these charts are nothing more than a broad guess. Trust me, 850s were lower than -5c. 

They weren’t that much lower than -5. After the initial Pm/Am incursion, uppers were generally between -4 and -6. The 11th and 12th had slack winds under a col which produced some very cold nights and very low surface temperatures. This contributed to the brief heavy snowfall on the 13th despite the ‘marginal’ uppers.

Reanalysis charts are available here:

Reanalysis archives

WETTERZENTRALE.DE

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Reanalysis archives of the past decades covering Europe.

 

[Tornado threat 18th March onward]

4 minutes ago, Paul Sherman said:

Lol would not call it a Sleeper Day - Probably the best day of May In my Opinion

Pretty much these are the 3 days that could save May coming up

After that its goodnight Vienna for a couple of weeks

I called it a sleeper day as I’ve been pretty much asleep for most of the season so far

‘Some’ similarities with the Dodge City day 24th May 2016.

[Tornado threat 18th March onward]

Thurs 21st May 
Could be a ‘sleeper’ day in SW KS with a very sharp trough/DL forming in the TX panhandle - 65F dps generate >3000 cape in ESE surface flow. 
I’d be lunching in Dodge City KS.

[Tornado threat 18th March onward]

Talking about this evening - ‘backdoor’ risk ramping up for far SW MO and far SE KS. 
 

[Tornado threat 18th March onward]

Mon 4th May aside some meagre offerings for the next 6 days minimum as a high pressure rules - and GFS has a strong cold plunge Friday scouring out what gulf moisture there is for a further few days. 
I would be flying tomorrow. Actually quite pleased I’m not to be honest. 

[Tornado threat 18th March onward]

18Z meso returned 4500+ of surface CAPE near and east of OKC. 
Big loaded gun situation this evening.

[Tornado threat 18th March onward]

SPC have introduced a 10% tor risk for E OK and far W AR this evening in response to revised soundings just to the E of the frontal boundary.

Storm Prediction Center Apr 28, 2020 1300 UTC Day 1 Convective Outlook

WWW.SPC.NOAA.GOV

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Severe weather, tornado, thunderstorm, fire weather, storm report, tornado watch, severe thunderstorm watch, mesoscale discussion, convective outlook products...

 

 

[Tornado threat 18th March onward]

I wouldn't discount a couple monster supercells now in C OK this evening going on recent trends and HRRR in particular ticking the kinematics up a notch or two.

With 4000+ of SCAPE available to any parcels that break the strong looking cap these storms will explode. Although shear isn't screaming tornado to me there's always the chance of subtle boundary interaction, a bit of backing of surface flow and bingo.

Virtual target Bartlesville, OK for 21Z initiation (potentially)

 

[Tornado threat 18th March onward]

There could be some monster hailers in C OK down the line if the cap breaks tomorrow evening.
I do see a tornado threat up into far NE MS and into IL on the south flank of the low but this is conditional.

[Tornado threat 18th March onward]

8 hours ago, Allseasons-si said:

WOW

look at that beast.

Lowish dp and highish kinematics often produce the best visible structure. 

[2020 Tornado Season]

Despite being denied my annual fix of Plains panoramas and Applebees, I’m intending to look at risks from afar as they occur and contribute to target forecasting and real-time analysis. No harm in keeping the skills honed.

It’s looking reasonably active in the next three weeks with a repeating ridge/trough pattern seeing several surges of gulf moisture into the Plains. Next Mon and Fri look quite potent at the moment (GFS).

I was Austrian Airlines out on May 5th. No luck so far with refund but I might look at rebooking using the credit voucher for next year - no harm in forward planning

[Tornado threat 18th March onward]

On 09/04/2020 at 10:03, Paul Sherman said:

Hmmm Not so sure about the quiet pattern

Sunday looks like a borderline High Risk to me.

 

Yep agreed. Spoke too soon! Got the feel of the 2011 Super-outbreak with that negative tilt and off the scale kinematics.

[Tornado threat 18th March onward]

After a quiet pattern now for a week or so GFS especially brings a favourable pattern back from 17th Apr with a strong southerly displaced jet and robust moisture return into the southern plains.

The period 17th-22nd Apr could be very active.

[2020 Tornado Season]

I guess it was always going to be so Paul.

I’m not embarrassed to admit the loss of my annual pilgrimage to the Plains has been quite difficult to accept but we will get through this and be hunting down those supercells again next year.

[Tornado threat 18th March onward]

Thanks to Kirkaldy Weather for creating this thread and keeping the season virtually alive for those of us who have had our trips cancelled.

This Saturday 28th March sees some of high=end kinematics for strong tornadoes in Illinois:

 

[Advanced planning mapping tool.]

Good luck with the trip but I’ve not used advance route planning - as you know chasing is an ‘on spec’ job with route revisions often every 10 minutes. If I had to plan routes based on features rather than the weather it might not work too well!

[24/8/19 ENC risk CO/KS]

The impressive summer season continues with another 5% tor for SW KS (especially) this afternoon. This stood out for me with some very late May wind dynamics delivering some nice looking looped curves - I’d be lunching in Sublette, KS (dodgy gas station) or probably the big Love’s on the way out of Liberal (much nicer )

[1/6/19 update from KS]

Slim pickings at the moment if anyone is wondering why the info has been a tad sparse these last few days.

I chased over 600 miles on Thursday searching for storms in SE NM and got a high ppn cell near Clovis. Yesterday was blank but today we got on a decent storm near Sublette KS that turned for a while - enough to get a decent piece of time lapse.

With only subtle shortwaves turning around the base of a rather weak upper trough across the west it’s more of the same until midweek then the tours may have to look North - way North perhaps.