Astronomy, Photography and Weather

General Category => Weather & Atmospherics => Topic started by: martinastro on June 23, 2011, 01:52:28 pm



Title: Spanish Plume/Severe Storms? - England/UK - Mon & Tues June 27th & 28th
Post by: martinastro on June 23, 2011, 01:52:28 pm
Looks like the best GFS charts in years for England this Monday with nearly 3000 CAPE and LIs of -7 for that region covering a large area in the form of a Spanish Plume-type set up. This is a early heads up to great storm potential, and possibly the finest storms in years. I won't be here over the weekend so could someone please post a convective outlook on Sun night when it's available, thanks. Here's that chart from Netweather GFS, it will get downgraded a bit however it still looks insane!

(http://i56.tinypic.com/10py3xx.png)

I've never seen charts like this before since I got into this subject  :)


Title: Re: Spanish Plume/Severe Storms? - England - Mon June 27th
Post by: Anton on June 23, 2011, 02:34:24 pm
Incredible looking charts could this be the big of the year lets hope so. Martin I will post CFS chart Monday, looks as if Ipswich & Norwich are currently seeing very frequent sferics.


Title: Re: Spanish Plume/Severe Storms? - England - Mon June 27th
Post by: markt on June 23, 2011, 06:11:37 pm
Looks like fun!   :o 8)


Title: Re: Spanish Plume/Severe Storms? - England - Mon June 27th
Post by: martinastro on June 23, 2011, 06:56:56 pm
Thanks Anton! - check out Tue's charts, -11 LIs....OMG, never seen anything like it before in this country, severe storms and easy supercell/MCS potential..that's rite I wrote -11 LIs, that's not a typo  :)

(http://i55.tinypic.com/2lldil2.png)

I have changed the threat title to taken in Tue's potential, there's also a risk of storms on Sunday too but keep that for another thread.


Title: Re: Spanish Plume/Severe Storms? - England/UK - Mon & Tues June 27th & 28th
Post by: Anton on June 23, 2011, 07:26:51 pm
It only gets better, seriously thinking on travelling east on Monday to capture any action even though it is some way from home but less miles than Cornwall so thatís a bonus. Travailing North tomorrow around Yorkshire / Humberside. Martin I will post any developments over the weekend if things change and if you want to PM your mobile number I can also text you if things start to develop sooner, I have access to Netweather charts and 5min radar.


Title: Re: Spanish Plume/Severe Storms? - England/UK - Mon & Tues June 27th & 28th
Post by: paulster78 on June 23, 2011, 11:46:55 pm
Absolutely mouthwatering charts!!  Crazy crazy figures those with explosive convective potential, yes they will be downgraded (downgraded on the 18z run) but nice to see this showing up, if nothing else but to get a bit of banter going-i will definitely be watching developments over the weekend.


Title: Re: Spanish Plume/Severe Storms? - England/UK - Mon & Tues June 27th & 28th
Post by: markt on June 24, 2011, 12:26:26 am
Oooo!  Very nice!!!  :o 8)

I'm watching developments closely  ;D


Title: Re: Spanish Plume/Severe Storms? - England/UK - Mon & Tues June 27th & 28th
Post by: JohnC on June 24, 2011, 10:05:17 pm
I'll get the car tanked up and photo gear  etc. ready Sunday night-  will keep a very close eye on this so keep the info. going chaps. Tuesday looks like it will move westwards too ,much nearer to the Midland and Gloucestershire.


Title: Re: Spanish Plume/Severe Storms? - England/UK - Mon & Tues June 27th & 28th
Post by: JohnC on June 25, 2011, 08:29:13 am
Mmmm. well, high hopes for the UK, but, as ever  we may miss it apart from the extreme SE

http://www.wetterzentrale.de/pics/Rtavn8411.png


Title: Re: Spanish Plume/Severe Storms? - England/UK - Mon & Tues June 27th & 28th
Post by: paulster78 on June 25, 2011, 09:07:22 pm
Still on course for Monday!!

(http://i613.photobucket.com/albums/tt215/paulster78/Weather%202011/GFS27611.jpg)


Title: Re: Spanish Plume/Severe Storms? - England/UK - Mon & Tues June 27th & 28th
Post by: JohnC on June 26, 2011, 10:48:44 pm
Checked  the above chart at 2245 Sunday and that high CAPE area has moved west to my doorstep-the high values  being just east of me. We're due TS's  from 7.00pm onwards into late evening. I'll be close to Southampton from 10.30am to 1.30 pm and then drive home so hopefully will see some storm initiation en-rout travelling through the  south central region to south west  Midlands.


Title: Re: Spanish Plume/Severe Storms? - England/UK - Mon & Tues June 27th & 28th
Post by: markt on June 26, 2011, 11:07:45 pm
Looking forward to this one! :)


Title: Re: Spanish Plume/Severe Storms? - England/UK - Mon & Tues June 27th & 28th
Post by: Anton on June 27, 2011, 12:55:43 am

(http://redditchweather.com/estofex monday.png)

Storm Forecast
Valid: Mon 27 Jun 2011 06:00 to Tue 28 Jun 2011 06:00 UTC
Issued: Sun 26 Jun 2011 22:34
Forecaster: DAHL

A level one threat has been issued across the SE UK mainly for large hail, damaging wind gusts, and tornadoes.

SYNOPSIS

A high-amplitude upper flow pattern exists over Europe, with a longwave trough setting up over the eastern Atlantic. Another long-wave trough is present over eastern Europe and will close off into a cut-off cyclone on Monday. At low levels ... the eastern Atlantic trough supports advection of warm/moist air into western and central parts of Europe, as well as the northward expansion of an EML plume atop this warm/moist air mass.
The SE European trough is accompanied by a rather intense SFC low, but elsewhere rather quiescent synoptic-scale surface conditions prevail.

DISCUSSION

... SE United Kingdom ... N France ... Benelux ...

It seems that some instability will develop in the pre-frontal air mass across the southern British Isles and western continental Europe as the mid-level lapse rates increase in response to the northward spreading EML. The GFS CAPE values are not to be trusted given suspected problems in the surface-flux scheme that overestimates the diurnal latent-heat flux cycle. ECMWF shows that some 500 - 1000 J/kg of CAPE will develop over the SE British Isles and up to 2000 J/kg over France and the Benelux countries, which seems to be more reasonable than what GFS is advertising.

First storms should develop over the SE British Isles amidst the 850 hPa thermal gradient, probably in the afternoon hours, gradually increasing in coverage as the day/evening progresses. The activity should migrate across the Channel region and expand southwards during the night, when the convection will likely become slightly elevated. It seems that upscale growth into one or more elevated MCSs may occur, affecting extreme N France and the Benelux countries early Tuesday morning.

The severe threat with the convection over the British Isles in the afternoon and evening hours should be dominated by well-organized multicells and supercells given DLS of about 20 m/s (increasing from about 15 m/s over the extreme SE parts of the UK to over 25 m/s over the central portions of the UK) and rather strong LLS (exceeding 10 m/s over the extreme SE UK). However ... CAPE should be weakest where shear is strongest, and vice versa. Also, the LLS maximum is expected where DLS is weakest. Despite these somewhat negative factors, it seems that isolated large hail and damaging winds will occur, and perhaps also a brief tornado or two. At this time, a LVL1 threat seems to be sufficient, though an upgrade to LVL2 may be required if the CAPE and shear fields become aligned more favorably, or if CAPE proves to be higher than currently anticipated.



Title: Re: Spanish Plume/Severe Storms? - England/UK - Mon & Tues June 27th & 28th
Post by: paulster78 on June 27, 2011, 01:39:20 am
11pm Sun

Moderate Risk of Thunderstorms N.Wales & Northern UK 15Z-21Z

Prime Risk Large Hail & CG's

Slight Risk of Tornado Development 15Z-18Z as per red box

Currently some broad variation within the models ATM. Though for me based on the GFS I see a prime region for strong convection as per map below. In fact based on the overlay of strong CAPE values to vertical shear we will have the basis for supercell development. I am further encouraged by a very dry incursion within the mid levels which is likely to increase lapse rates quite dramatically. As Chris mentioned, vertical shear should sustain an isolated storm long enough for large hail to build within the updraft. Some strong convective gusts are possible though likely to be non severe!

My attention is primarily drawn to a small zone where low level direction shear turns a full 90 deg (red box). The convergence closer to the coast could well trigger a tornado or two. Winds above 850 mb look fairly straight lined so not sure if any mesocyclone development will extend upwards into the mid level efficiently.

The larger picture may well see some minor convective storms develop across other parts of the UK though dynamic lift looks rather weak for anything substantial. Hence my focus within the convective box below!


(http://i613.photobucket.com/albums/tt215/paulster78/Weather%202011/risk1.jpg)

CREDIT: Tony Gilbert


Title: Re: Spanish Plume/Severe Storms? - England/UK - Mon & Tues June 27th & 28th
Post by: paulster78 on June 27, 2011, 01:45:32 am
(http://i613.photobucket.com/albums/tt215/paulster78/Weather%202011/UKASFStorm--ViewForecast_1309135184168.jpg)


Areas Affected:
Most of England and Wales (only focusing on UK areas)

Discussion:
Very tricky situation for Monday afternoon into Tuesday morning...

Overall set-up...Large upper trough located to the west of the British Isles over the Atlantic will dig in through the day, spreading areas of PVA across much of the country. Very warm to hot and humid surface air will be in place, particularly across southern/eastern Britain where temperatures could near or exceed 30C in places and dew-points could exceed 20C will provide some of the ingredients necessary for strong to potentially severe thunderstorms in the Severe & Thunderstorm warned area. A breakdown of the areas can be found below:

Severe area: (a portion of E England)...I will stress before I begin, the risk of afternoon thunderstorm development is particularly low, however if any do develop they could become severe...Some of the warmest surface temperatures will be located in this area upper 20s to near 30C possible. Along with dew-points in the low 20s this could produce CAPE values in the region of 2000j/kg. Deep layer shear values will be near 35-40kts in this region, enough to separate updraft/downdraft regions and potentially produce a few mesocylones/supercell thunderstorm IF afternoon, surface based convection can develop. Cap strength will likely be fairly strong as upper ridge is slow to clear the east of England. This will produce a dry/warm layer separating the hot humid surface air from the cooling upper level air above it. At the moment, both NAE and GFS are reluctant to break the cap and produce this surface based convection, so chances of it occurring are in the 20% realm, however if they do develop they would do so quickly and produce severe weather with the potential of large hail (up to 2.5cm), strong gusty winds, particularly given the drier mid-layers, frequent CGs and potentially a few isolated tornadoes. - Low level shear is in the range of 15-20kts and SSE to SSW surface convergence is possible in this region, indicated by the 12z NAE.

Thunderstorm Area: (S and E England) This area will be monitored for mid-level instability thunderstorms which are likely to develop across France during the afternoon and move northward across the area during the evening and overnight. Lightning (mostly in cloud), gusty winds and some hail could be associated with these elevated storm even into Tuesday morning in East Anglia and Eastern England.


Title: Re: Spanish Plume/Severe Storms? - England/UK - Mon & Tues June 27th & 28th
Post by: markt on June 27, 2011, 07:07:52 am
Excellent updates guys, thanks!  I'm on the periphery of all this so who knows what will come of it for me.  Needless to say I will be taking a raincoat to work with me this morning...  ::)


Title: Re: Spanish Plume/Severe Storms? - England/UK - Mon & Tues June 27th & 28th
Post by: Anton on June 27, 2011, 10:56:06 am
Updated Monday 10:51 AM

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.

Current data from my Davis Pro Weather Station 27 June 2011 10:53:00

Temperature Temps 28.8įC
Heat Index       30.8
Dew Point        20.5
Rel Humidity     61%

Pressure (hPa):
Current          1012.36
Trend (per hour) -0.23




Title: Re: Spanish Plume/Severe Storms? - England/UK - Mon & Tues June 27th & 28th
Post by: markt on June 27, 2011, 11:28:56 am
Some BIG clouds and sharp showers starting to develop in SW England...  At the speed they're coming in we'll be seeing their effects in the midlands in the next couple of 3 or 4 hours...


Title: Re: Spanish Plume/Severe Storms? - England/UK - Mon & Tues June 27th & 28th
Post by: paulster78 on June 27, 2011, 03:34:05 pm
Outlook from Torro...

TORRO CONVECTIVE DISCUSSION 2011/011

A TORRO CONVECTIVE DISCUSSION has been issued at 13:40GMT on Monday 27th June 2011

Valid from/until: 13:40GMT - 09:00GMT on Monday 27th/Tuesday 28th June 2011 for the following regions

Parts of (see map)

Much of England

Central and eastern Wales

Extreme SE Scotland

THREATS

Wind gusts to 60mph; heavy rain; cloud-ground lightning; isolated tornadoes; hail to 3cm

DISCUSSION

Reasonably steep lapse rates/EML atop moist boundary layer, approaching upper trough, and local surface convergence/diurnal heating has allowed thunderstorms to form across N England. These are within a regime of 35-40 knots of 0-6km shear, and so may have time to organise before moving offshore. Instability and shear are suffificent for hail to around 3cm diameter, 60 mph winds, and perhaps a tornado, but overall coverage appears too low to warrant a watch.

Further south, an area of mid-level showers is spreading NE across parts of Wales and the Midlands, with further showers/thunderstorms to the west of NW France. The activity over the mainland may root into the boundary layer as it continue to move NE, with an attendant risk of hail/wind/tornado, but at this stage, uncertainty about development precludes a watch.

The activity west of NW France should continue towards SW England this afternoon and then spread NE this evening and overnight. Further activity is expected to develop/move in from the SW across portions of Cent S and SE England and E Anglia overnight and into tomorrow morning. Much of this should be elevated, but cloud layer shear of 20-25 knots may be enough for mid-level rotation to develop, with an attendant risk of hail, perhaps to 3cm. Again, uncertainty over development and overall severe coverage precludes the issuance of a watch at this stage.

Forecaster: RPK.

(http://i613.photobucket.com/albums/tt215/paulster78/Weather%202011/TORROMAP1.jpg)


Title: Re: Spanish Plume/Severe Storms? - England/UK - Mon & Tues June 27th & 28th
Post by: paulster78 on June 27, 2011, 03:38:07 pm
Storms have now exploded up in a very short space of time around the Newcastle area..


Title: Re: Spanish Plume/Severe Storms? - England/UK - Mon & Tues June 27th & 28th
Post by: markt on June 27, 2011, 10:41:03 pm
It's all missing me so far - just a few big spots of rain...  :(


Title: Re: Spanish Plume/Severe Storms? - England/UK - Mon & Tues June 27th & 28th
Post by: paulster78 on June 28, 2011, 02:09:23 am
I think it missed almost everybody Mark!  Big let-down today on the storm front with all the good forecasts out, but all is not lost. Checkout the huge MCS in Northern France which could give folk in the SE a nice show if it can hold together and survive the channel crossing, decent amount of sferic plots showing up on it too

Also couple of home-grown storms have have popped up tonight.

(http://i613.photobucket.com/albums/tt215/paulster78/Weather%202011/MCS1.jpg)

Sat image courtesy: SAT24.com


Title: Re: Spanish Plume/Severe Storms? - England/UK - Mon & Tues June 27th & 28th
Post by: rjgjr on June 29, 2011, 03:17:06 am
Beuatiful and dramatic shot of the mammatus clouds Dennis!


Title: Re: Spanish Plume/Severe Storms? - England/UK - Mon & Tues June 27th & 28th
Post by: markt on June 29, 2011, 07:35:54 am
Great mammatus indeed Dennis!  8)


Title: Re: Spanish Plume/Severe Storms? - England/UK - Mon & Tues June 27th & 28th
Post by: JohnC on June 29, 2011, 10:31:23 am
Nice mammatus,Dennis. I've only ever seen it in the US.

I see the SE got a pasting yesterday. Would you believe it,my wife went to London yesterday on the train and when I picked her up at the station at 7.00pm she said she saw some 'wonderful' lightning Aaaaaagh.   ;D