The humidity is knocking on the door of the state with the central and northern areas of the nation under a signfiicant plume of moisture. We have seen the offshoot of that in the form of high and middle level cloud today, the high pressure over the region stifling rainfall chances.

But that high is on the way out, the ridge is expected to weaken and this will open the door for rain and thunderstorms to return to the forecasts as we track through mid week and into the weekend.

The potential for severe weather is present but perhaps not as high as what was being advertised last week.

Precipitable water values are elevated and this will likely lead to a lot of cloud cover which may offset the severe weather risks, keeping the surface based instability low and temperatures lower as well. Will have to watch trends moving through tomorrow.

Otherwise tomorrow is your last dry day to do the outdoor chores, rainfall spreads back in from the west from Wednesday.

Lets take a look


Rainfall Next 10 days

Rainfall is expected to move into the far west and northwest tomorrow in the form of scattered showers and thunderstorms developing as moisture increases. This band of showers and thunderstorms will move slowly eastwards reaching the GDR during Wednesday night and then over the divide towards the coast by Thursday. Areas of rain will be present with the thunderstorms from Wednesday to Friday and may persist over the state through the north over the weekend before returning state wide from next week. The weather is expected to humid and unsettled for a while and with thunderstorms, the rainfall accumulation will be very tricky to forecast ahead of time, so use the range as a guide at this stage, knowing your number will vary. I will be drawing a separate chart for the rainfall event coming through on Wednesday night through Thursday from tomorrow.

Thunderstorm Forecast Tuesday

Non severe thunderstorms are expected over the far northwest and west during the late afternoon and evening with a few moderate falls about under thunderstorms.

Flood Risk Next 6 Weeks

This is a heads up risk evaluation based off the data sets below, that the return of riverine flooding is a high chance along pockets of the divide and a broad low to moderate risk for the eastern and southeast inland of the nation.

Now to all the data sets.


Euro 00z - Surface Pressure Pattern and Rainfall Distribution - Next 10 Days

Not much change from this morning. The Euro is quite aggressive in the thunderstorm development with the chance of heavy rainfall over outback areas of WA, NT and SA. That is supported by the other modelling but they differ on rainfall placement so be aware that colours will chop and change but the atmosphere, from run to run, is largely unchanged. That is the parameter to focus on. The troughs of low pressure moving out of WA will run into the moist airmass, which I will add is well above normal, near record values in some spots. So simple math means, that equals the chance of record rainfall totals for some during this period. The Euro has a strong trough passing through the southern states this week, before it stalls out over the eastern inland this weekend in a soupy and unstable northeast flow around a big high in the Tasman. The next storm system develops out of the heat trough over in WA and that may wrap into a low pressure system while moving through SA this weekend with another round of strong to severe storms before that deepens over VIC and NSW with further rain and thunderstorms. Another system may emerge from WA once again continuing the conveyor belt of wet and humid unsettled weather. This should not come as a surprise as I have given you a 2-3 week lead in time. To the west of all the unsettled humid weather, cooler than normal and dry for SWLD of WA through much of this period. Over QLD, the NT and northern WA, severe thunderstorms are possible off and on through this period with flash flooding the biggest concern (that applies nationwide with a saturated atmosphere). The shower and rainfall coverage with thick cloud eventually bringing down the heat values nationwide.

Euro 00z - Precipitable Water Anomalies - Next 10 Days

This paints the picture and shows you the highest moisture values of the spring so far. You marry the above average anomalies with low pressure, your result is high levels of thunderstorm activity, and widespread rainfall with above average rainfall expected for many parts of the nation. Maybe some drier air being drawn into the southern states at the end of the run, but other solutions do not support this so will watch trends. Weather over in SWLD cooler and drier with onshore winds and stable air.

Euro 00z - Precipitable Water Values - Next 10 Days

Values in the yellow are 2 inch PW values, meaning that the air is tropical, saturated right up the trace of the atmosphere and this means lots of cloud, rain, thunderstorms and cooler humid weather for many areas. The drier weather will eventually spill into the southern coastal areas but may not sweep out the humidity over much of the northern two thirds of the nation. So this could exacerbate attempts to harvest, efficiently and the higher humidity may cause damage to crops via severe weather and that high moisture content for a long duration.

Euro 00z - Rainfall Accumulation - Next 10 Days

Refer to video for more and the post after 9pm EDT for more details.

Uneven blotchy rainfall data represents the thundery nature of the outlook period.

GFS 00z - Rainfall Accumulation - Next 10 Days

Refer to video for more and the post after 9pm EDT for more details.

CMC 00z - Rainfall Accumulation - Next 10 Days

Refer to video for more and the post after 9pm EDT for more details.

CFS 00z - Rainfall Accumulation - Next 6 Weeks

Refer to video for more and the post after 9pm EDT for more details.

More details coming up on all things rainfall and there are some wild solutions floating around out there. I will break down the details for you all.

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