MARCH 2004 PART 2:
FIRST CONVECTIVE EPISODE OF SPRING - 21st-23rd

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Yet another Northerly outbreak occurred over the weekend of March 20th-21st and lasted well into the following week - and with the charts indicating instability the time was eagerly awaited, so that it was a disapointment on Sunday 21st to awake to a canopy of grey stratus and hazy skies!

The cloud-deck only started to fragment in the afternoon by which time it was a bit late for the remaining solar heating to initiate any poweful convection over the area - so it seemed. Areas of the UK that had not fared so badly with cloud cover were by now experiencing violent thunderstorms in places, including a probable supercell storm with large hail and a damaging tornado near the Oxfordshire-Gloucestershire border at about 1730z that afternoon....

.....down at Borth meanwhile a few smaller Cbs had fired up but the light was dreadful for photography - too much low-level moisture about...
...here, looking inland from Borth Head, a Cb has fired up over Plynlimon. You can also see the edge of the low cloud that had plagued us all day; out to sea in the opposite direction clearer skies were present plus further heavy showers drifting shorewards from the NW. These appeared to be decaying but a highly turbulent-looking cloudbase came overhead complete with the following feature...
...I watched this for a while through binoculars as it passed over. The clouds were definately swirling and the central protruberance does look a bit like a funnel cloud. However, while rotation was visible in the cloud above, the protruberance could not be seen to be spinning. My guess is some weird kind of wind-eddy, perhaps set up by the parent cloud passing in off the sea and up over Borth Head. That was it for the 21st....
...on the afternoon of the 22nd I drove to Newtown then back up past Trefeglwys towards the Machynlleth-Llanidloes mountain road. Big cumulonimbus cells had fired like this one, looking back east...
...while straight ahead (and into the sun), towering altocumulus were shooting upwards at a rate of knots....
...a good vantage point this, approaching the Machynlleth-Llanidloes mountain road...
...as a cumulonimbus fired up (with the sun shining through the anvil) I headed down to Llanidloes where it caught up with me giving 20 minutes of heavy sleet and snow...
..here's its rear end as it heads south in the direction of Rhayader - quite a powerful cell but it didn't give any thunder. My last view of it showed distant mamatus forming on the underside of the anvil, but by then it was getting too dark to continue: so on to the next (and best) day...
...conditions only looked marginally unstable on the 23rd but once the temperature had risen enough convection kicked off with gusto after about 1300z and the sky rapidly filled with the anvil-tops of cumulonimbus clouds... this is just outside Machynlleth looking south....
...and a bit further up the road looking north...
...looking south again, but the view north was by now far more interesting (next few pics)....
Here, a rapidly developing clump of hail showers is affecting the Arans and nearby hills. Sunlight started to illuminate the falling shafts of hailstones...
...as the showers developed further the precipitation intensified...
...making fascinating subject material. The whole lot came over in due course and small hailstones bounced off the car and road alike. Meanwhile another hefty Cb was intensifying over Plynlimon and further new ones were being generated so I headed down to Llanidloes, then on to Llangurig and west through the core towards Aberystwyth....
....by the time I reached Eisteddfa Gurig, having driven through some much heavier hail with a bit of snow too, Cbs filled the sky with hardly any gaps in between, as this pic shows. By the time I had reached Devil's Bridge 8/8 cloud was the order of the day: I continued towards Aber and came out into sunshine only 4 miles from the coast. The convective weather was now decaying away as it was getting late into the afternoon but the higher ground was still white with hailstones. A good afternoon out getting in amongst the weather though.....
...and heading back up towards Machynlleth signs of the coming Spring were everywhere in the hedgerows, always a cheering sight!
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