The Mountainwatch Detailed Forecast is provided by our resident meteorology sensei "The Grasshopper". The South Island analysis is issued around 7am every morning (maybe later on weekends) and is intended to provide an additional human element to the automated forecast data provided above. Sometimes we won't agree exactly with the model data - but if we ever call something significantly different we'll do our best to explain why.
7:00am Thursday 30 July 2015
Sunny and cold this morning. Plenty of frost about in the valleys.
A powerful low out to the south-west has been dominating the South Island weather for some time. For today the Island takes a breather as high pressure builds in giving us a mostly fine day - it seems almost strange to say that for the South Island doesn't it? The fine weather won't last long however, as the low sends in a cold front from the south-west tomorrow bringing cloud and rain onto the divide in the afternoon. Early Saturday the front sweeps the South Island -there will be a rain-snow mix for most with the freezing level staying high. Skies will clear in the afternoon as high pressure builds in the fronts' wake. A more powerful cold front slams into the South Island from the same direction on Sunday giving another shot of snow near to the divide - the problem is that most resorts are on the wrong side of the divide and will only see a couple of light rain or snow showers.
Image of the day: Wow! I can actually see the South Island today, what a rare sight. Source:: BOM (vandalised by the Grasshopper)
Thursday 30 July:
Friday 31 July:
Fine in Canterbury. Increasingly cloudy close to the divide out west with light snow developing above 1400m in the evening. Wind hold an issue for resorts exposed to the north.
Saturday 1 August:
Snow falling very early morning in resorts especially exposed to those northerlies e.g. Treble Cone where 8-15 cm of wet snow could fall above 1600m. Other resorts will get a rain-snow mix. Those sheltered from the divide will stay mostly dry. Watch out for wind hold on a stiff northerly.
Sunday 2 August:
A similar story to Saturday with rain-snow mix crossing the South Island accompanied by strong to gale force north-westerlies. Snow amounts will be highest close to the divide above 1200m where another 4-10 cm of wet snow could fall. Partly cloudy skies in the Southern Lakes and parts of Canterbury in the rain shadow.
On Monday and Tuesday a low approaches from the south-west. A cold front associated with this low drags in some moist and mild air from the north-west late Monday and on Tuesday. There is the potential for some heavy rain along this frontal boundary. It is still too early to put details on this yet as the models are not in agreement. Things are more favorable for snow from next Wednesday onwards as the region of low pressure moves to the south of South Island adding a bit more variety into the mix.
That's all from the Grasshopper. Wanna keep your finger on the pulse of all things snow? Join my weekly email list by filling in the box above. If you have a question or feedback for me join in the discussion below, or hit me up on facebook or twitter.