5/10/97 England chase by Paul Knightley


From: Paul Knightley (spuknitl@reading.ac.uk):

Hi,
   I thought you might be interested in my account of a chase/bust here in
Central-Southern England, where chasing is in it's infancy.
   Saturday 10th May looked quite good for storms but they would be
embedded in a strong S-SWerly flow with numerous showers and lots of
intervening cumulus...not ideal but worth a look. 
   Mark Lowe, Andrew Hislop and myself set out from Reading at about 1pm
BST, encountering heavy rain, and lots of Saturday shopper traffic. We
headed out on the A4 towards Theale, then north on the A340 towards
Pangbourne. We crossed the river Thames and continued N towards Woodcote
on the B471, then left onto Catsbrain Hill (a good vantage point with
views from SW to NW.). We parked up here for a while noticeing several
large Cu and Cb. MW radio was quite active with sferics. We decided to
move SW as a large anvil was seen to our SW. We headed into Goring and
Streatly then out towards Aldworth on the B4009. We stopped again to take
our bearings and saw several large cells moving in. We decided to get NE
of them in an attempt to intercept them. We headed back to Streatly, and
onto the A4074 past Woodcote. We went N to Wallingford, then E on the
B4009. We got to the M40 motorway with the first cell already out of reach
(they were doing about 45mph!!). We got to High Wycombe, and decided it
wasn't going to work as the cells were dying, it was getting a bit late
for new cell development (about 5pm), and the old cells were just moving
too fast! 
    Chasing in Britain is alot more oppurtune than in the US partly
because storms are most numerous in Westerly type Polar Maritime air. This
makes them fast moving, short lived and they break out just about
anywhere! They are generally not severe, although sometimes roduce small
tornadoes. Our best storms come from the South from France or develop on a
slow moving CF coming in from the west, with a hot and humid SEerly. One I
saw last year from Catsbrain Hill had up to 115 flashes/min(mostly CC,
but quite alot of CGs), 1 inch hail and 60mph winds. It also had a wall
cloud, Beaver's tail and 2 tornadoes were reported from the system which
also had tennis ball sized hail in places. This occured on June 7, 1996. 
     There is a chance of warm-air storms here later in the week and I'll
kepp you posted to anything that might occur. 
  
    cheers,
     Paul.



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PAUL KNIGHTLEY                                                Dept. of Physics
spuknitl@rdg.ac.uk     http://www.rdg.ac.uk/~spuknitl    University of Reading.
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