Owwww, do they mean us?
Storm Forecast
Valid: Fri 24 Aug 2012 06:00 to Sat 25 Aug 2012 06:00 UTC
Issued: Thu 23 Aug 2012 23:04
Forecaster: TUSCHY
A level 1 was issued for SE Ireland mainly for heavy rain.
A level 1 was issued for parts of W/SW UK and NW France mainly for a few tornado events, marginal hail and strong wind gusts.
SYNOPSIS
Brisk SW-erly flow pattern continues over most of W/C-Europe. This assists in the set-up of an active baroclinic boundary, which runs from S/C France to Poland. Numerous disturbances graze that boundary and cause scattered to widespread thunderstorm initiation. Hot and dry conditions prevail over the Mediterranean. A strong depression enters the forecast area from the west with unsettled conditions affecting Ireland and UK.
... W/SW-UK, parts of Ireland and parts of NW France ...
A strong 995 hPa depression moves from Ireland to W-UK. Attendant well structured cold front enters the forecast area from the west during the day with a slow eastward motion forecast. A pronounced dry slot overtakes the cold front and assists in an active thunderstorm period mainly within the highlighted 50% lightning area. Those storms evolve within an environment with strong directional shear (e.g. 15 m/s LL shear and 200 J/kg SRH-1) and LCLs well below 1000 m. A few tornado events are possible next to strong wind gusts and marginal hail. The severe risk decreases after sunset although some surface based convection may persist over N-France. Strong shear still supports an isolated better organized thunderstorm event with strong wind gusts and an isolated tornado event. Hence the level 1 was expanded all the way to NE France.
An occlusion wraps around the depression's center with an augmented probability for training thunderstorm activity mainly over S-Ireland. Heavy rain will be the main hazard as modified subtropical air wraps around the center of the depression.
Well that backs Nick F's view and UKASF also going with:
Moderate
Forecaster: Dan
Last Updated: 2012-08-23 21:34:00
Valid: 2012-08-24 00:00:00 - 2012-08-24 23:59:00
Synopsis:
Upper trough approaches from the Atlantic, with a deep surface low at the surface. A plume of high ThetaE is advected around the centre of the low in associated with a cold front/occlusion complex. Some convection is expected embedded along and behind the front.
Discussion:
Cold front/occlusion migrates northwards and eastwards across England, Wales and Ireland with embedded convective elements likely. Favourable lapse rates and a few hundred J/kg MLCAPE may allow some sporadic sferic activity to occur, more likely over SW England, S Wales and S Ireland.
20kts DLS and >25kts LLS may allow some line convection to occur along the front, and with backed surface winds a funnel or weak tornado is possible, especially along the south coast where backed winds are heightened due to the onshore component. Hail up to 1.5cm in diameter is possible from stronger cores embedded within the line.
Scattered convective showers/storms are also expected behind the main front.
... S IRELAND ...
Behind the front, under the centre of the low with light and variable winds (and thus low-level convergence), >900J/kg CAPE is possible as cool mid-levels (-17/-18C at 500mb) overspreads the area. Sferic activity could be quite widespread here for a time during the afternoon and evening hours, provided there is enough insolation to generate surface-based convection. It is worth noting that the MDT is purely dependent on sufficient cloud breaks.
Hmmmm, some agreement then?! Nothing yet from SkyWarn or TORRO, here's a few charts to ponder:
There's that CAPE in the SW:
Just getting into the South and South East reaches by dark:
Note the hotspot over Portsmouth/IOW?
Not so much surface base CAPE:
Lapse rates are still up at 21Z
Plenty of rain!
Extensive tornado threat area!
Helicity right over the South coast:
Isolated thunderstorms in The Channel and over SW England (Come on Jane Louise!!!)
Still going up through the Midlands and heading NE into the night!
Time to update your radar subscriptions if you haven't already!!
Latest SatRep:
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