Understanding Weather – not predicting – 25 January 2013

What happened? What do we believe: our eyes or our charts? For long years, centuries in fact, mankind’s navigators only had eyes, then came instruments to offer values, now most recently we have technology. With only eyes, sailors set out and, most importantly, usually returned. The eyes had it! Today, our reliance on our most up to date presentations has become overbearing: rightly or wrongly? A week ago eyes and charts focussed on a worthy weather pattern so close to our skies. The probability of some rain provided a combination of desire and need. The response was confusing. By the new week, the well-developed equatorial low pressure core had progressed, taking away its rainy potential, leaving the entire country beneath an upper air anticyclonic core extending far to the west and identifiable at all levels throughout the Troposphere. To burden matters further the high pressure core was, throughout, identifiable along the 30oS latitude (the climatological norm) while ensuring a zonal flow (west to east) more in keeping with an ENSO synoptic pattern. The one respite was that an east wind flow persisted above our northern skies. But more optimistic patterns were at best remote and this in mid-January! Both eyes and charts remained unrewarded. Then came Wednesday. Both charts and eyes saw little to enthuse: Search, though, revealed-a satellite image featuring lower cloud levels and surprisingly a distinct vortex circulation off-shore our central coast. This is a cold water area, so this had to be an upper air circulation, despite the limiting chart patterns.