| Understanding Weather -not predictin- 01 August 2008 |
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| Written by John Olszewski | ||||
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Apart from sunrise and sunset visibly moving away from the stagnation of June and mid-July, the serenity of the past weeks kept its quiet placidity. The anomaly in the southern hemisphere’s synoptic patterns persists as the daily weather maps show. The patterns of the last few months are typical of summer, not winter.
On Thursday morning, there were two well-marked
anticyclones hugging the 40oS parallel. One lies east of Africa in the
southern Indian Ocean, the other lies 180o away off the coast of New
Zeeland. Other anticyclonic cells keep to their expected latitudes, further north, where the sub-tropical high pressure belt normally makes its roots: 300 South to 35o South. Between these higher barometric pressure cores, the various vortices and their fronts, instigated by their outflow of air, complete the synoptic display. The unusual ability for strong anticyclonic cells to squeeze to the south of some of these vortices continues (as noted earlier) where their southerly extensions are visible, so presenting ideal summertime patterns in mid-winter. Back home, the static upper-air anticyclone centred above the mid and eastern sub continent marks the upward extension of the equally-stagnant Mauritius core of the sub-tropical high pressure belt. We are on its western side, so we have clear skies, northerly-orientated breezes and pleasant daytime temperatures. With the consistent procession of temperate-zone vortices and fronts, it is unusual that, for weeks now, from Windhoek we have not seen a trace of the high level Cirrus cloud patterns created by these systems. One more question begging analysis. |
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