Notes on Developing Cold Fronts
Percentage Forecasting:
This percentage system below will now be used for snow shower forecasting. Settled snow is generally too hard to predict for the upper mountains.
5% to 10% chance = unlikely to see much snow.
10% to 20% chance = very slight chance of snow.
20% to 30% chance = slight chance of snow.
30% to 40% chance = slight to moderate chance of snow.
40% to 50% chance = moderate chance of snow.
50% to 60% chance = moderate to good chance of snow.
60% to 70% chance = get out the skis.
70% to 80% chance = get out the snow plow.
80% to 100% chance = I'm lying and drinking too much green cordial.
Winter 2010 notes:
24-2-10: Fingers crossed Winter 2010 is a good one. Updates will begin here in late May.
NB: The forecasts and outlooks above are informal considerations presented by blackheathweather.com. Please refer to the main page for official BoM forecasts.
Debunk The Myth
I often hear it said in Blackheath that we didn't get snow because it was too windy. There is no scientific basis to this at all. Its just that most cold fronts come from a SW direction and are usually windy and bring more snow to the Oberon Plateau than they do to the Blue Mountains. Its not because its too windy that we don't get snow its because we are downwind of the Oberon Plateau and during most cold fronts they 'steal' most of our snow. Without wind, the cold air from down south wouldn't get here in the first place. So snow lovers, tell your mates that its not the wind that prevents the Blue Mountains from getting snow at all, its the Oberon Plateau in most situations.
NB: We still can get nice snowfalls from the SW but you need cold upper levels (at least minus 27C at 500hPa) and good mid level moisture at 700hPa to create a nice moist and unstable mix. Don't forget it was very windy from the SW during the 19-6-07 fall and cold upper level air and good moisture in the lower levels was the reason we got such good snow.
