The nearest official BoM weather station is located approximately 10 kilometres northeast of the Paraparap district at Geelong Airport (Mt Duneed). At 1530AEDST this station reported an air temperature of 31.9C and a wind direction of 70degrees at 10 knots and appears to be effected by a weak seabreeze extending from Port Phillip Bay. At 1600AEDST, the wind had shifted to 130degrees, which may indicate the arrival of a southeast sea breeze extending from Bass Strait (common in this district). By 1630 the southeast sea breeze had increased to 15knots, however the air temperature remained at 30.2 degrees. It would be feasible to estimate maximum temperature near the Paraparap district to be close to 32C or 33C just prior to the storm development and passage over the location.

Data extracted from the Melbourne Airport trace at 0Z(1100AEDST) shows a very steep temperature decline between 817hPa - 1850m (11.6C) and 707hPa - 3035m (0.6C). This represents a fall of 11.0C over a depth of just 1185m. This layer of rapid cooling probably did not alter greatly during the remaining 6 hours with surface temperatures approaching 32C at 1500AEDST and with the 0C (FZL) situated at about 3115m. A fall of 32C between surface and FZL places the lower 3000 metres within the potentially superadiabatic temperature profile. This is a significant aspect of conditions occurring during the development of this storm.

The FZL (freezing level) is recorded at 700hPa (3115 metres) at Tullamarine at 11am, and there is not a significant fall in temperature between 750 and 500hPa (see Figure 2) , and a weak inversion is present between 582hPa and 570hPa. The overall temperature decline between 700 and 500hPa (3115m and 5730m) is 15.1C (500hPa temp is -15.1), however above the weak inversion at 570hPa, the airmass dries out significantly with an air temperature of -8.9C and a dewpoint of -36.1C. Video and photo analysis shows that some cumulus were not penetrating above 500hPa, however, isolated stronger updrafts were able to move upward into the colder drier air above 500hPa when surface heating increased to create sufficient parcel buoyancy.