Convective / Storm Chat And Discussion

[Hughsey]

Not sure if already mentioned but temperatures forecast for around 30 degrees on monday which has triggered a yellow warning for thunderstorms in EA and SE monday night

Valid from - 27 Jun 2011, 21:00

Valid to - 28 Jun 2011, 12:00

"Heavy showers and thunderstorms from Monday evening through into Tuesday could merge into longer spells of thundery rain giving the potential for 25-50 mm in a few hours. There is a risk of flash flooding and large hail. "

Looking good for my first storm of the year.

Edited June 25, 2011 by hughsey

[paul m]

Looking good for 7pm onwards tomorrow and Monday

[Staffordshire]

Lol i hope so.

South Leeds

Yeah your in a good spot

[Guest Kent-Weather]

Is anyone else beginning to fear the Eward shift of instability may inevitably push everything so far E that the UK completely misses out from Monday onwards

[Coast]

With all the excitement about tomorrow and Tuesday, I missed this ESTOFEX level 1 for the North East!

Storm Forecast

Valid: Sun 26 Jun 2011 06:00 to Mon 27 Jun 2011 06:00 UTC

Issued: Sat 25 Jun 2011 16:46

Forecaster: TUSCHY

A level 1 was issued for parts of UK mainly for strong to severe wind gusts, isolated large hail and an isolated tornado risk.

SYNOPSIS

The structure of a large-scale trough at roughly 20° W remains a bit difficult to analyze with numerous short-waves exiting/entering that feature during the forecast. Overall, a slow movement to the east is forecast and the trough axis will cross the 20th degree of longitude during the end of the day. Further amplification and an overall neutral tilt allow low-end impact to the European thunderstorm forecast (despite UK). However, ahead of this trough, a disturbance, centered over the Canary Islands, is expected to become absorbed by the approaching trough. This disturbance lifts to the north just west of Portugal although models diagree in the final placement of this feature.

Large-scale ridge downstream affects W/CNTRL Europe with hot and dry conditions. A deep cyclonic vortex becomes quasi-stationary over the Black Sea and results in unsettled conditions over far SE-Europe.

DISCUSSION

... Parts of central UK ...

Model discrepancies remain significant regarding QPF with EZ the drier outlier and GFS/WRF the more bullish ones regarding initiation. Persistent moisture advection from the south and the tip of the northeastward spreading EML create an environment with modest MLCAPE (500 - 800 J/kg) and a weak cap. Also mid-level forcing will cross the highlighted area from the southwest during the evening hours onwards, so at least isolated thunderstorms may evolve. Thunderstorms would be within a favorably sheared environment (20 m/s DLS, 15-20 m/s 0-3 km shear, modest LL speed/directional shear), so isolated large hail, strong to severe wind gusts and an isolated tornado event may occur with strongest thunderstorms. In fact, would not be surprised to see an enhanced tornado risk with locally more than 50 J/kg 0-3 km SBCAPE and large-scale veering of the 850-500 hPa wind field next to very low LCLs. Isolated thunderstorms move rapidly off to the E/NE with dry conditions thereafter.

EZ breaks out some weak precipitation signals over far SW-UK during the morning hours of the 27th, but this remains an outlier for now, so do not highlight that in this outlook.

... Further areas of interest ...

The gradually intensifying depression over the Black Sea may push thunderstorm clusters from E-Ukraine to the west during the end of the forecast with heavy rainfall. However, there are not yet any indications for a concentrated excessive rainfall event, matching our level criteria.

Also, GFS has some weak convective precipitation signals over south-central France during the past few runs. However, to break the cap with 850hPa temperature at or above 20°C, we indeed need those GFS magical surface dewpoint numbers of 20 °C and above (roughly 10K bias compared to ECWMF during peak time heating). We will leave this area without a lightning area for now.

[Coast]

SkyWarn following on from NW and ESTOFEX for today:

SKYWARN UK SEVERE THUNDERSTORM WATCH #031

ISSUED: 2130UTC SATURDAY 25TH JUNE 2011 (GJ)

SKYWARN UK HAS ISSUED A SEVERE THUNDERSTORM WATCH FOR THE FOLLOWING REGIONS:

NORTHERN ENGLAND

NORTHEAST WALES

WEST MIDLANDS

EAST MIDLANDS

EAST ANGLIA

IN EFFECT FROM 1100UTC UNTIL 2100UTC SUNDAY 26TH JUNE 2011

WARM MOISTURE PLUME DESTABILISED UNDER JETSTREAM FORCING

THERE IS A POSSIBILITY OF SEVERE THUNDERSTORMS AFFECTING THE INDICATED REGIONS IN THE TIME PERIOD SPECIFIED. THREATS WITHIN THIS WATCH INCLUDE, BUT ARE NOT LIMITED TO:

HEAVY RAIN...STRONG GUSTS...HAIL...LIGHTNING...FLASH FLOODING...FUNNELS/TORNADOES

DISCUSSION:

THERE IS NOW STRONG SHORT-RANGE CONFIDENCE IN A POSSIBLY SEVERE CONVECTIVE RISK AFFECTING MOST OF THE NORTHEN HALF OF ENGLAND DURING SUNDAY AFTERNOON AND EVENING. A WARM AND MOIST AIRMASS IS IN PLACE ACROSS THE UK, WITH A STRONG FLOW OF WIND THROUGH THE UPPER LAYERS ALONG THE RIGHT EDGE OF THE JETSTREAM. CAPE VALUES OF OVER 1000J/KG MAY BE ACHIEVED IN STRONG EARLY AFTERNOON SUNSHINE, WITH INCREASING DEEP LAYER SHEAR PROVIDING ORGANISATION FOR STRONG STORMS. THE RISK COVERS ALL AREAS, BUT STRONGEST STORMS ARE EXPECTED AROUND THE EAST MIDLANDS PRIMARILY, WITH POSSIBILITIES OF MODERATE HAIL SIZES EXTENDED TO THE NORTHEAST OF ENGLAND AND THE PENNINES. SUCCESSIVE STORMS MAY LEAD TO INSTANCES OF FLASH FLOODING. PLEASE MONITOR TRAVEL INFORMATION AS NECESSARY. THIS WATCH MAY BE UPGRADED.

[Neilsouth]

I see very little potential for tomorrow(sunday). There is too much upper ridging, and the GFS tends to overdo mid level moisture. The ECMWF, UKMO GM and NAE break out next to nothing, and i prefer their solutions at this time vs the GFS. But i could be proven wrong !

PJB from yesterday for today, he doesn't think there will be much going on

Edited June 26, 2011 by Victor Meldrew

[Guest]

He makes a good point, and there are a few over on UKWW who think the ridging could be too strong. The warnings are there though because there is the likelihood that a few isolated storms could develop, and if they do, they are doing so in an environment conducive to severe weather.

[seabreeze86]

All the ingrediants are there for later today 1000 plus cape -4 lift and a very moist atmosphere, never seen so much potential for my area although the experts are saying they will be fairly isolated thunderstoms if they occur, if the are within 50 miles or so i will be chasing good luck all

[Rob]

GFS currently showing -1700 CAPE and -5 LI here for tomorrow, lovely jubbly, yes please!!

[Thundery wintry showers]

Some showers starting to sprout up around Cleadon in Tyne and Wear. Oddly, it's stemming from pretty ordinary-looking sheets of cumulus and stratocumulus that often arise from warm, moist south-westerly types, and one of them spread up into a large TCu just east of here. It certainly seems that I'm in a decent position to see some significant convective activity later today.

[karyo]

All the showery activity is to the northwest of me and the flow is taking it further away! So frustrating! :-(

Karyo

[P-M]

Has that blob electrified as it moves North? Sorry haven't got access to see. I know the ones off the Northeast coast have (as reported on theweatheroutlook) but just wondered about the one that started near Preston....

[Static Prevails]

Looks like convection is really starting to fire up in the North West, with showers forming around Liverpool and heading north east into North Yorkshire and other north eastern areas. Whether any of these showers become thundery remains to be seen.

[Chris.R]

just heard a sferic that was quite close. First one I've heard all day.

[Chris.R]

And a nother one. Ooooooooo, a nother one and a clap of thunder! Yeahhhh. I get the first storm of the day.

[Static Prevails]

And a nother one. Ooooooooo, a nother one and a clap of thunder! Yeahhhh. I get the first storm of the day.

I've been watching that develop. Congratulations!

I wonder if anything will start firing up further south or if Liverpool will be as southern as things get.

[Chris.R]

now heavy rain and more thunder.

[karyo]

If only the thunderstorm from Liverpool can shift towards Manchester! Still sunny here but I can see the clouds to the west.

Karyo

[Chris.R]

another burst of rain just now but now all stopped.

[MikeUpjohn]

Hoping for something big this evening. Beginning to look more promising again dare I say it, now I've said that I'll probably kill it all! Lol.

[weatherobsuk]

METAR for Liverpool. I think even that caught them out by surprise, given it was made only 5 min's ago.

http://en.allmetsat.com/metar-taf/united-kingdom-ireland.php?icao=EGGP

[P-M]

Yes, the best line for storms looks like starting at Crosby, through Preston, lancs; over the pennines, Darlington Co Durham and out over to Middlesborough...... signing out but certainly back later

Think it's a tad further north from Boro TBH. I am watching a storm here thats currently in the Houghton area and very impressive cloud burst just watched it get heavier and heavier and now the odd flicker of lightning. I am on a top floor flat btw thats how I can see! Very impressive although wouldn't like to be out in that downpour. I am about 7 miles away from the CB and it's still muggy and sticky here.

[PersianPaladin]

A few rumbles of thunder here with moderate rain.

[paul m]

I seriously doubt that Leeds is going to get anything now as the storms seem to be breaking out further north