Melbourne is enjoying its warmest July spell in seven years, but it will come to a chilly end this Wednesday, when a cold front arrives.
The city has just had its warmest July week since 2005, averaging a maximum of 16.4 degrees, almost three degrees above the long-term norm of 13.5. In July 2005, the average maximum was 17.1 degrees. The warmest July week on record was set in 1975, when maxima averaged 20.1.
Melbourne is also currently having its longest run of July days of 15 degrees-or-warmer since 2005. Today was the ninth day, three days short of the 2005 spell and four days short of the record, set in 1994.
Tomorrow is likely to be day number 10 with a forecast top of 16 degrees. This will again allow residents to shed the layers in the afternoon. Coats, scarves and gloves may be required in the morning with another nippy start likely. It won't get as cold as the four degrees experienced this morning but it should still feel chilly in the wind.
The lengthy run of mild days is due to the lack of powerful cold fronts.
We haven't had a powerful front in almost two weeks, which has allowed sunny breaks each afternoon to make the most of mild air over the region.
Come Wednesday, cloud will increase ahead of a cold front, the strongest front in a fortnight. The cloud will bring some cooling during the day but showers in the afternoon and evening will bring further cooling. Throw in the winds, and 14 degrees late in the afternoon will feel more like 10 degrees or less.
This will be the start of a run of five-or-six showery days with the temperature only reaching 13 or 14 degrees.
Coats, scarves, gloves and heaters will come in handy, even in the afternoons.
© Weatherzone 2012
16:06 EST The weather bureau has implemented a new system of forecasting the seasonal outlook called Predictive Ocean Atmosphere Model for Australia, or POAMA.