Another cold-front and sharp upper trough is likely to reach the SW-Cape
on Sun 5th, before moving along the Cape coast, and reaching the
Drakensberg by Mon 6th. More than usual amounts of snow, at lower than
usual elevations are shown by current model runs (GFS and NOGAPS up to
00Z on Thurs 2nd). Earlier model runs indicated the possible formation
of a strong cutoff-low along the KZN coast on Tues 7th, though this now
seems less likely.
As usual with this kind of system, there is still considerable
uncertainty at longer durations (4-5 days), particularly in the position
of the South Atlantic High pressure cell. The models also show another
frontal system making landfall on Thurs 9th (7 days ahead), and the
close spacing of the two systems can reduce certainty in developments
over KZN on Tues 7th (5-6 days ahead).
The NCEP custom GFS charts are broken this morning (Thurs 2nd), and the
NCEP ensemble might also not update today, so I can't post many images
yet. The site snow-forecast has updated, and gives an excellent
animation of the likely outcome: www.snow-forecast.com/maps/dynamic/southafrica
P.S. It's hard to come up with names for the never ending series of
cold-fronts arriving this winter, since they all have some things in
common, but each is slightly different (depending on your location
relative to the position of the storm).
Compiled by Gordon Richardson (StormchasingSA)
No comments:
Post a Comment