Issued at 3:30pm July 19th 2017. Tasmania is expected to see a winter blast being driven up from Antarctica to impact the entire State tonight resulting in low to medium level snowfall and some good falls. Above image via BSCH showing the cold pool South of Tasmania moving towards the State.
The combination of an elongated low pressure region over New Zealand and the Tasman Sea, and an elongated high pressure system over the Great Australian Bight and Central Australia is expected to help channel frigid air up from Antarctica to engulf Tasmania and parts of South-Eastern Australia (Snowy Mountains) this evening and into Thursday. The cold air is already being felt over Tasmania with Hobart hovering around 10ºc for most of the day but feeling as cold as 2ºc at times, Mt Wellington has only briefly nudged 1ºc earlier and feeling more like -10 to -15ºc at times.
Forecast temperatures at 1500m ASL early Thursday morning via WindyTV (blue is below 0ºc, aqua is -5ºc or less and pink is -10ºc or less)
Despite cold conditions impacting the State already, its not until this evening and especially overnight tonight into Thursday when the snow potential rapidly increases. A very cold pool of air with temperatures of -4 to -7ºc at 1500m ASL is expected to begin impacting the South-West of the State this evening, and then the rest of the State by Midnight. This cold air will be associated by an increase in moisture levels which will allow for snow to begin falling to around 500m. The cold air is expected to linger through Thursday where snowfall is likely down to 400m across the State and possible to as low as 300m in the South during the morning before gradually rising by late morning and then even more into the afternoon. This will mean places like the Lenah Valley could awake to flurries and towns in the upper parts of the Hobart Hills (just 20 minutes from Hobart) could get some ground coverage by sunrise. Falls of 20cm+ are possible over Cradle Mountain and the Cradle Valley, with lighter falls elsewhere.