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shuggee

18 July 2011 - Storm/convective Forecast, Discussion And Reports

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Fresh thread for Monday. Several areas in the storm risk category...

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Fresh thread for Monday. Several areas in the storm risk category...

Can anyone post up which areas are most at risk? :unknw:

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Same sort of areas as today I'd wager. No chance for those of us in North West England, North Wales and parts of the Midlands i would imagine because we'll still be getting plagued by the wrap around occlusion that made today so vile.

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Probably the same areas that have be hogging the storms this year!Going to be saying goodbye to 2011 stormless just like 2010,2009,they say things come in 3's and this is proving to be one of them,I think if nothing happens this year im gonna give up the whole storm interest and start a new interest,Getting really boring now,Good luck all for tomorrow :)

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Just looked at the chart by Nick looks good for us in the southeast and surprise surprise scotlands in it aswell. haha

some quite good showers about today although I didn't hear any thunder but im sure my dog did.

Good luck everyone!

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Buxton has recorded 34mm over a 24hr period so far (confirmed by the NW radar which shows the topographic forcing occuring just overhead where I live all along the ridge axis South-North from the Cat & Fiddle inn up to New Mills. With localised spots outside of this around the White/Dark Peak also seeing high precip totals falling.

Many places are notorious for flooding but rarely get coverage in the press as the impact is minimal, but nearly always a given when faced with set-ups such as these. Castleton, the A6 between Matlock and Buxton in particular, low-lying areas along the banks of Dove Dale, Darley Dale etc. Unfortunately with the same amount of rainfall due to come in the next 48hr for us Pennine folk I can only see things getting exacerbated in river levels before things abate.

Only the one Flood Alert in the Northeast of the country as of yet.

http://www.environment-agency.gov.uk/homeandleisure/floods/default.aspx

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Here we go then, my round up of what all the other indicators point to:

post-6667-0-28448100-1310971689.png

Storm Forecast

Valid: Mon 18 Jul 2011 06:00 to Tue 19 Jul 2011 06:00 UTC

Issued: Sun 17 Jul 2011 17:43

Forecaster: TUSCHY

A level 1 was issued for N-Italy, S/E-Austria,Slovenia, parts of Croatia, Hungary, Slovakia, E-Poland, parts of Belarus, W-Ukraine and parts of Latvia and Lithuania mainly for a few large hail and strong to severe wind gust events.

A level 1 was issued for extreme W-Mediterranean mainly for strong to severe wind gusts and marginal hail.

SYNOPSIS

A large upper trough is still parked over far N/NW-Europe. Numerous short-wave troughs travel around this major trough with the most pronounced one crossing the Bay of Biscay during the night hours from the NW, re-intensifying the W-European trough. Scattered showers and thunderstorms also occur over E-Europe beneath lower geopotential heights with stable conditions over the far E-Mediterranean.

DISCUSSION

... NW/parts of W-CNTRL Europe ...

Beneath the large upper trough, cold mid-levels and a well mixed maritime air mass assist in numerous areas with somewhat enhanced thunderstorm probabilities. Not much severe is expected as shear will be weak, but a few marginal hail events are expected. Thunderstorm coverage decreases after sunset.

post-6667-0-46080900-1310971827.jpg

Forecaster: Chris

Last Updated: 20:15 Sunday, 17th July 2011

Valid: 00:00 Monday, 18th July 2011 - 23:59 Monday, 18th July 2011

Areas Affected:

All of Britain in Watch. Thunderstorm for S Scotland and N England and SE England.

Synopsis:

Britain will yet again be dominated by a large, slow moving vertically stacked area of low pressure (Surface low around 985mpb) centred in the North Sea. Various occlusions will continue to drift around this area of low pressure bringing cloud and rain or showers.

Discussion:

Similar to yesterday, the main convection will be driven by moderate CAPE values and bands of PVA that will circulate the broad area of low pressure with 500mb temperatures around -19C which is nothing too significant. The PVA will be most pronounced across S England while the best of the CAPE will be across S Scotland and N England, hence two separate areas of Thunderstorms are forecast. Highest CAPE across S Scotland will be in the region of 600-700 j/kg (similar CAPE values were gave widespread thundery activity on Sunday afternoon). DLS is almost non-existant and LLS is also very weak across Britain, (higher values in Ireland of LLS, but CAPE values will remain very low there). Therefore any heavier showers should again have short lived updraft/downdraft regions, but may form lines due to PVA bands, especially in S England. A little speed shear is possible between the surface and 850mb and along with terrain there could be a few funnels reported near the strongest updrafts in those regions.

Main threats: Heavy rain/localised flooding, small hail (less than 1cm generally) and a some CGs.

SKYWARN UK SEVERE WEATHER WATCH #038

ISSUED: 1200UTC SATURDAY 16TH JULY 2011 (SM/GJ)

UPDATED: 2300UTC SUNDAY 17TH JULY 2011 (GJ)

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

ALL AREAS SCOTLAND

NORTHERN IRELAND

NORTHERN ENGLAND

NORTH WALES

EAST MIDLANDS

COASTAL AREAS OF WEST SCOTLAND, WALES AND ENGLAND.

IN EFFECT FROM 1200UTC SAT 16TH UNTIL 1200UTC MONDAY 18TH JULY 2011

STALLED LOW PRESSURE SYSTEM INTENSIFYING OVER SCOTLAND WITH ASSOC OCCLUDED FRONTS

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

HEAVY RAIN...GALES...STRONG GUSTS...FLOODING...THUNDERSTORMS

DISCUSSION:

DUE TO THE COMPLEXITY OF THE CURRENT LOW SYSTEM OVER THE UK, A BROAD WATCH IS ISSUED AS THERE IS GOOD CONFIDENCE OF POTENTIAL THREATS WITHIN SPECIFIC AREAS OF THE UK. AS THE INITIAL OCCLUSION MOVES EAST TODAY, HEAVY AND THUNDERY SHOWERS WILL MOVE SLOWLY THROUGH NORTHERN IRELAND, SCOTLAND, NORTHEAST ENGLAND AND THE EAST MIDLANDS. THESE SHOWERS ARE EXPECTED TO PERSIST THROUGH THE NIGHT OVER SCOTLAND, ADDING TO SATURATING PRECIPITATION AMOUNTS AND GENERATING A SUSTAINED FLOOD RISK. SIMILARLY, STORMS MAY COVER SCOTLAND AND NORTHEAST ENGLAND AGAIN THROUGH SUNDAY WITH AN ATTENDANT HEAVY RAIN RISK. ALSO THROUGH SUNDAY, THE WRAP AROUND OCCLUSION BRINGS POTENTIALLY GALE FORCE WINDS WITH DRIVEN HEAVY RAIN INTO NORTHERN IRELAND AND NORTH WALES, WITH DRIER BUT VERY GUSTY CONDITIONS FOR COASTAL AND EXPOSED AREAS OF WESTERN, SOUTHERN AND SOUTHEASTERN UK.

UPDATE: OCCLUDED FRONTS WRAPPED AROUND THE LOW WILL CONTINUE TO BRING MODERATE TO HEAVY RAIN FOR AREAS OF NORTHERN IRELAND, WALES AND PARTS OF WESTERN ENGLAND. THERE REMAINS A RISK OF GALE FORCE WINDS FOR WESTERN COASTS, AND HIGH GROUND AND EXPOSED AREAS OF NORTHERN ENGLAND, POSSIBLY EAST MIDLANDS LATER IN THE PERIOD AND A SHORT TIME AFTER.

21OWS_ATLANTIC-EUROPE_FITL_THUNDERSTORM-STANDARD_30.gif

21OWS_EUROPE_MODEL-DATA_UKMO-GLOBAL_TS-THREAT_SFC_18_00Z.png

PGNE14_CL_small.gif

cape.curr.1700lst.d2.png

33_19.gif

30_24.gif

gfs_icape_eur15.png

gfs_layer_eur15.png

Another messy day of rain

gfs_kili_eur15.png

gfs_lfc_eur15.png

gfs_spout_eur15.png

gfs_stp_eur15.png

Pretty much anywhere could see something today, but yet again Ireland and Scotland seem to do better from the brief look around I've had, but I'm fingers crossed down here for later today.

post-6667-0-28448100-1310971689_thumb.pn

post-6667-0-46080900-1310971827_thumb.jp

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Thanks coast, Saves me ages browsing page after page :)

Looks like a slightly better chance for round here today but still not great.

Gonna be another fun day for the North and East.

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Thanks coast, Saves me ages browsing page after page :)

Sorry it's so big! Another interesting day already with quite a bit of convective cloud over the South Downs earlier. The brief thunder I heard yesterday afternoon was a nice surprise.

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Dewpoints are looking good for this end of the day:

Reurmetd.gif

Rdtlmetd.gif

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Well 9pm on the 18th of July 2010 was the last time I saw a storm (quite a memorable one too) so I have 12 hours before my season is over for 2011 lol and unfortunately im not hopeful for anything either today....roll on 2012 :) and good luck to everyone else

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Well 9pm on the 18th of July 2010 was the last time I saw a storm (quite a memorable one too) so I have 12 hours before my season is over for 2011 lol and unfortunately im not hopeful for anything either today....roll on 2012 :) and good luck to everyone else

I've had a pretty good season, so you must have been incredibly unlucky. I traveled to Bridlington two weeks ago where I was fortunate enough to be treated to a fantastic lightning display. I think if the storms won't come to you, it's best to go out and find them :D

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personally I think it'll be a day of heavy showers for me and the rest of the south east.

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I've had a pretty good season, so you must have been incredibly unlucky. I traveled to Bridlington two weeks ago where I was fortunate enough to be treated to a fantastic lightning display. I think if the storms won't come to you, it's best to go out and find them :D

Any storms in my area always die as they head North towards Doncaster area and come alive once North of York (really do have a circle I can draw on a map as my storm shied lol) and unfortunately chasing them isnt an option this year :(

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Any storms in my area always die as they head North towards Doncaster area and come alive once North of York (really do have a circle I can draw on a map as my storm shied lol) and unfortunately chasing them isnt an option this year :(

That storm shield of yours seems to include this area. Can you remove it please

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That storm shield of yours seems to include this area. Can you remove it please

Ive lost count with the amount of storms thats missed my area by 5 mile in the last few months.Looks like another cloudy and dry day up here :nonono:

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The skies look promising for convection at Cleadon this morning but the radar doesn't- an area of persistent frontal type rain seems to be advancing south through Northumberland.

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Heavy downpour here, didn't see this on the radar!

EDIT: stopped already, I think its just developing.

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What sort of dewpoints do we need to look for for stormy weather?

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What sort of dewpoints do we need to look for for stormy weather?

Ahh, it's only one of the ingredients! Here are a couple of overviews (in US, imperial measurements) that may help:

http://www.theweatherprediction.com/severe/cookbook/

http://www.accuweather.com/blogs/news/story/30586/tornadoes-severe-thunderstorms.asp

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What sort of dewpoints do we need to look for for stormy weather?

I'm no expert but I believe if the DP is relatively close to the actual temperature, where possible, this would be favourable! For example, I'm currently 16.2c with a DP of 12.9c which isn't that great to be honest. Dewpoints of 15c or above would be much more condusive for storms, alongside all the other necessary atmospheric factors.

A peek at the latest radar suggests bands of frontal band (as mentioned by TWS) crossing the UK which are currently non-electrically active.

One band is sinking southeastwards from Blackpool to almost Nottingham, another heading due east from western wales into the midlands, a mass over eastern parts of scotland and another soaking heading for the southwest later on from southern ireland.

From what I can see, not a great day for convection I'm afraid. :wallbash:

Cheers

gottolovethisweather

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