I will touch on this more this evening with the moisture spreading from north of the nation via the monsoonal flow redeveloping with increasing tropical weather. The moisture is expected to pool in from the easterly wind regime via the positive SAM with that increasing the chance of rainfall for inland and upping the chances of heavy rainfall for the east coast of NSW and QLD through the short and medium term.
There is evidence both the positive SAM phase and the MJO rotating through the north of the nation could both be long duration events of 2-3 weeks which could lead to prolonged wet weather for many areas, but on the other side of that coin is a few regions could be dry for a few weeks with increasing fire dangers.
It is clear to say that the wet areas, eastern and northern parts of the nation, the drier weather, the southern and western areas of the nation. The direr the weather, the further southwest you go through the nation, the wetter you will be the further north and east you go through the nation.
But a tropical system can change the spread of moisture and those wildcard systems need to be watched very closely.
18Z GFS - Surface Pressure Pattern and Rainfall Distribution - Next 2 Weeks
More details on this in the afternoon update but just refreshing the latest data sets showing the moisture increasing north and east and then spreading throughout during the medium term. Rainfall over the western and central parts of the nation will come down to where low pressure forms and whether we have tropical systems running south through WA or the NT.
18Z GFS - Precipitable Water Values - Next 2 Weeks
Very deep moisture establishing over northern Australia in the coming fortnight and that will be the engine room for inland rainfall developing over this period. The moisture is increasing via easterly winds with that moisture expected to pool over inland NSW and QLD with higher rainfall chances developing for large areas. Even in SA and WA, there is moisture available and spreading throughout so the heat that builds will not be dry, but without low pressure there will be a lack of rainfall in these areas so that low pressure element is something to look out for to get rainfall back onto the charts with higher confidence for these areas.
18Z GFS - Rainfall Accumulation Next 2 Weeks
More details on this forecast tonight
Rainfall Anomalies - Next 2 Weeks
This will move around but paints the wetter phase developing over the north and through the east with the climate drivers in place.
Tropical Depression Formation Risk
Keep an eye on the forecasts if you are living in northern Australia, you know the drill, it is that time of year with increasing chances of depression formation from northern WA and across the NT and Cape York with the risk of cyclone formation low at this time, but the risk is increasing as we get better data on which region is likely to fire most. The data supports that area to be north of Darwin and spreading southwest through to WA. That is a classic region for cyclone coverage in March. We saw that with TC Seroja last year in March which I covered extensively.
More coming up this afternoon.