Many people in the Central West district of WA just tried to sleep through overnight temperatures 8-10 degrees above the norm for February.

A low pressure trough, positioned just off the Central West coast, is the main reason the district is currently so hot. A regular synoptic pattern this time of year, the trough draws in hot air from inland. However, when sitting offshore, sea breezes are restricted and winds off the land persist. A high pressure ridge to the east helped to cause a steeper pressure gradient last night, causing winds to stay gusty and not letting cooler air aloft sink towards the surface. As a result, some places had their hottest night in years.

After heating up to over 40 degrees on Friday and remaining above 33 degrees at midnight, Geraldton Airport only dipped down to 29.2 degrees around 6am Saturday. This is exactly ten degrees above the February average minimum, and the hottest minimum for that site which dates back to 2011. A comparison station at the airport recorded a minimum of 30.3 degrees in February 2010. The hottest ever minimum recorded in Geraldton was 31.1 degrees at the Geraldton Town weather station in January 1926.

Mullewa stayed warm at 28 degrees, a balmy eight degrees above average. This site has a much longer history, and this morning's minimum is well shy of the record of 33.3 degrees set in 1947. Jurien Bay dipped to 25 degrees, a warm seven above average. Most other centres in the Central West were around 3-6 degrees warmer overnight than what is normal for February.

Fortunately, cooler nights are on the way as the trough begins to move east overland. Geraldton should cool to the low twenties overnight, but will still be around 2-4 degrees warmer than normal.