Issued 27th November 2018. The balance between the Central Coast and South East Coast of QLD including far North East NSW getting severe and potentially dangerous storms on Wednesday is balancing on a knife edge! Above image showing EXTREME CAPE (very severe storm energy levels) along the coast via BSCH.
Initially on Sunday and Monday global forecast data was suggesting a very dangerous storm set up from Rockhampton south to Coffs Harbour however this has changed somewhat but still remains highly uncertain…
A 995hpa deep low is expected to track South East across Northern and Central NSW during Wednesday while extending a very strong surface trough up into Southern, South East and Central QLD districts. This trough will mark a sharp boundary between moist strong Northerlies ahead which turn very strong dry and gusty Westerlies behind it.
Ahead of the trough strong instability is forecast however the EXACT timing and position is absolutey critical to severe thunderstorm forecasts and development. No matter which global model we refer to now they all differ ever so slightly, however, MOST suggest that severe storm activity will start right on the coastal edge and move offshore during the morning to lunch time on Wednesday.
The extreme forecast difference can come down to either 100km onshore or offshore with people being impacted… Initially we issued a worst case scenario forecast however we now believe the confidence in this has dropped to around 25%. We are damned either way we forecast so we have chosen the conservative approach and will leave the rest down to very close live observations on Wednesday with warnings being quickly issued if required.
Central and Southern inland QLD and Northern inland NSW should expect some showers or isolated storms during the morning which could contain damaging winds while moving quickly East. Then very dry gusty Westerly winds develop with areas of dust. This dust may also reach the coast on Wednesday afternoon.
Along the Central and Southern QLD coast including the North East NSW coast we do expect a band of showers and isolated storms early Wednesday morning which MAY or MAY NOT rapidly develop as they cross the coast at around lunch time.
The best that we can suggest is to keep a very close eye on the weather situation during Wednesday.
HSC premium members maps and forecast have been updated to reflect the above scenario. Subscription is available HERE! Below image showing the strong gusty Westerly winds behind the trough on Wednesday via Windy.com