Here’s what is making the weather headlines today.

HEAVY RAIN IN THE WEST

A front pushing into the West Coast of the South Island this morning brings some heavy rain, easing to showers this afternoon.

As the front moves northwards it may bring some heavy rain to the far north later today and into eastern Bay Of Plenty. Metservice have a few watches out, check them out here.

WARM IN THE EAST

Eastern regions of both Islands have a warm day today, the eastern South Island (eastern Canterbury more specifically) should score the warmest temperatures getting into the early twenties.

THUNDERSTORMS ON WEDNESDAY

Cold upper air should lead to a few thunderstorms on Wednesday in both Islands.

For the South Island this is most likely to occur in the ranges of Buller / Tasman and Nelson. In the North Island Auckland has a possibility in the morning then Waikato through to Manawatu during the afternoon.

In the first map below (Lifted Index) we can see instability in the areas mentioned above, below 0 means the atmosphere is becoming unstable. The second map shows temperatures at about 500hPa which is roughly 5560m high up, temperatures are as low as -26 degrees celsius at this level, this aids in making the atmosphere unstable.

There are other factors involved in thunderstorm generation but the above basic conditions are a good starting point. Surface moisture levels are higher over the North Island so heavier rainfall could be expected there should storms form.

• 

•