Weather situation more like Autumn than Spring

By Peter Nelson on November 14, 2017

Since the 4th of November there has been warm sunny days after cool crisp mornings. Daily maximum temperatures have been a couple of degrees above the month's normal whilst the overnight minimums to 13th November have been about two degrees below normal.

This type of weather conditions are more likely during the autumn months rather than any spring months. So far this month apart from a weak cold front clipping our region at the beginning of this month, there has not one frontal passage affecting our region.

This is unusual for November when our regions experience normally six frontal passages. The last 10 days has seen very little wind as well; also very like autumn. A large high pressure system has taken 10 days to advance eastwards from south of the Bight to it's present position just east of Tasmania.

A low pressure trough has more or less remained stationary extending from northern WA and northern part of the NT to just west of the Bight and this is a typical blocking situation commonly occurs during autumn. There has been little or no rain so far this month.

Most places in our region has received only a few mms. However, few places in inland parts of WA and the NT have received moderate falls from thunderstorms such as 27 mms at Alice Springs last Saturday 11th November under the influence of this low pressure trough over the interior.

Pressure systems are continuing to move very slowly eastwards. Whether we receive significant rain from this inland low pressure trough will depend on it's strength when it reaches our region and whether it parks itself over our regions for a few days and not move away quickly.

There was a classical blocking situation in our region 17 years ago in November 2000 when a low pressure trough remained stationary for a fortnight in our region. I was living in Coonabarabran when 259 mms fell in 10 days and there was nine successive days of no sunshine and very little wind despite thunderstorm activity.

There were major floods everywhere. There wont be anything that dramatic this month. In addition the year 2000 was very wet generally, not so this year.

By Peter Nelson on November 14, 2017

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