Hail in winter? Unusual weather hits Lismore
LISMORE was surprised with a late storm last night, which brought heavy rain, strong wind gusts, thunder, lightening and unexpectedly, hailstones.
North Coast Storm Chasers 2.0 said 23mm of rain was recorded in the 10 minutes to 7.30pm at Lismore Airport.
While hail is unusual for the Northern Rivers at this time of year, the Bureau of Meteorology said hail can occur at any time of year, but large hail is most common in Australia during spring and early summer.
"This is when temperatures are warm enough to promote the development of strong thunderstorms and the upper atmosphere is still cool enough to support growth of stronger storms.
"In winter, showers and thunderstorms don't have the same strong updrafts as spring and early summer storms, so the hail tends to be smaller in size."
BoM meteorologist Helen Kirkup the larger hail was "more a summer phenomenon but it does happen in winter, more with smaller hailstones".
"Sometimes you get a piece of hail formed nicely and other times it's a lot of little pieces stuck together that have been sucked up in an updraft a number of times.
"In terms of winter its about how cold the column of air is and you need minus degree temperatures.
"With this low pressure system we had a really strong updraft and low temperatures, so we had hail forming.
"If hail starts to form and circulates in the storm for a while it grows.
"The low's created the situation for a storm to form...if the winds align vertically you get a really strong circulation.
"It gives the potential for a lot of spin to develop in the thunderstorm."
Rain this year has been very welcome, as averages are still well below average.
For Lismore, the average rainfall to June it 780.7mm (over 94.7 days) according to Weather Zone.
But 2019 has only brought 478.4mm this year (92 days).
From 9am yesterday at 7am this morning Lismore airport received the highest recorded in the region with 27mm, and 25mm for Casino.
This was further to rain over the weekend with the following measurements for 24 hours to 9am yesterday (Sunday June 16):
Ballina AP - 31mm
Lismore AP - 18mm
Byron Bay - 7mm
Tuckomobil - 24mm
The Channon - 11mm
Alstonville - 7.4mm
Casino - 7mm
For the rest of the week BoM predicts mostly sunny conditions and a slight (20 per cent) chance of a shower along the coastal fringe tomorrow and Wednesday, but near zero chance elsewhere.
There is also a Strong Wind Warning in place for Byron Coast.