JACK FROST HITS
By BELINDA SCOTT
ICE crystals hanging around until smoko ? that's cold.
The Coffs Coast has been shivering and shaking this week with the lowest temperatures so far this year and frosts that linger in shady spots until as late as 11am.
The sparkling frosts turning the Bellinger and Orara valleys into silver and white wonderlands have crept as close to the coast as Toormina, which experienced a light frost yesterday. Weather observer with the Department of Meteorology at Coffs Harbour, Greg Crow, said the icy nights and silvery mornings were caused by an unmoving high pressure ridge extending along the Coffs Coast, which had arrived last week, and also caused the inversion layer which is trapping smoke from wood fires in the hollows around Emerald Beach and other suburbs.
Mr Crow said the high pressure was trapping still air against the cold ground, pushing ground temperatures below zero and forming ice crystals on the grass. Frost will only form when the ground temerature falls below -0.9C.
Ground temperature plunged as low as -4.5C at Coffs Harbour on Monday night ? well below the night's minimum air temperature of 1.2C.
Even though it has been the coldest for 2006, this week's chill hasn't broken any records, being well above Coffs Harbour's record July ground temperature of -6.2 and minium air temperature of -3.2.
"There's always a week or two each winter of cool, dry air. There's a low pressure system with an associated front moving towards us that should get here about late Thursday or Friday, and should give us a couple of warm nights and a bit of rain, but another high is approaching next week," he said.
By contrast top daytime temperatures this week at Coffs Harbour have been around 19.8-20.5C and at Nana Glen up to 22.
And at Port Macquarie, Monday night saw the city a rare -2, while Taree, at -3, equalled the minimum temperature recorded by Charlie Scrimshaw at Nana Glen.
Mr Scrimshaw said so far this month Nana Glen has had eight days of white frosts out of 11.
Ironically, Dorrigo has avoided some of the worst of the chill factor because it is perched high on the Plateau, above the coldest air.