NSW - SHOWERS INCREASING ALONG THE COAST THURSDAY AND SHOWERS CLEARING THE NORTH. DRY ELSEWHERE.

OVERVIEW

Showers continue along the east coast with onshore winds bringing light to moderate falls across the areas that have been impacted heavily this Winter with further above average rainfall potential to continue for the coming days as the onshore flow via the block continues to hold firm.


A trough over interior QLD is bringing extensive shower and thunderstorm activity within the vicinity of the unstable air tonight. Some areas in the far northern areas of the Upper Western from Bourke north to the QLD border may see a month’s worth of rain again in the coming 24hrs.


Elsewhere, cold nights to continue nearer high pressure ridging through the southeast inland and sunny days to follow, but a trough approaching early next week may bring some cloud and patchy light rainfall back to areas on and west of the divide and clear the east coast of the easterly winds.


SHORT TERM

So, the blocking pattern once again is established, high pressure to the southeast of the state and an upper low over QLD, surface trough offshore QLD means we are in the pinch point between the two major weather systems, bringing onshore winds and showers to the coat with the chance of moderate falls.


The upper low will clear offshore the coast of QLD during the end of the week and the high will start to move towards the east southeast, this relaxing the unstable easterly flow over the weekend leading to a gradual decrease in the frequency of showers along the coast and drier air being pulled into the state.


Out west, a weakening trough will emerge through the state from Monday with areas of high and middle level cloud with periods of mainly light rainfall moving through southern areas of the state.


LONG TERM/ AREAS TO WATCH

I have been sharing on the social media pages that are available to you (join up!!) that the pattern may begin to flip towards] the end of the month and into early August with the chance of better frontal coverage over Southern Australia and a more mobile pressure pattern to boot, knocking out the block east of the country.


With the Indian Ocean Dipole developing further in the weeks ahead and the season starting to show signs of shifting towards warming up over parts of the northwest and north of the nation, this could help to see the jet stream become more unstable and rainfall to spread through the nation at a higher latitude rather than skirting south of the country as has been the case for a while.


Lots of moving pieces in the medium term and they are all wonderful, but once they move into the short-term forecast range, it is considered speculation, but worth watching for trends.


WEATHER VIDEO PM - WEDNESDAY 19TH JULY 2022

FORECAST

Rainfall Next 10 Days

Rainfall continues along the coast with moderate falls developing. The showery weather is forecast to continue over the course of the next few days with the heaviest of the rainfall over the northern coast down to about Newcastle. The rainfall may be heavier if we see a deepening low pressure system adopt a southerly track towards the QLD coast this weekend but at this time, showery weather for the coast with moderate falls is the call for now. Lighter falls down the NSW coast and drizzle near the VIC border where the high is sitting close to the region. Showers and thunderstorms over the northern interior with moderate falls and small hail will lift northwards during the coming 24hrs with the cloud decreasing into Friday. The weather is forecast to ease along the coast during the weekend and dry by next week for most areas. Light rainfall will develop along a trough in SA this weekend and that may spread into the southeast and eastern inland of the nation early next week with the trough weakening as it passes through.

The rainfall over QLD has been paired back a little with the heaviest focus of rainfall looking to be offshore, though some modelling does keep the heavier rainfall on the coast, but not convinced on that. The showers and storms over parts of the inland could produce moderate to heavy rainfall tonight and again Thursday over northern NSW with the risk of small hail and gusty winds into Thursday. Most of this should clear the inland by the weekend with the showers along the coast clearing by the end of the weekend into early next week as the flow begins to relax.

Frost Risk Forecast Thursday Morning

Similar to this morning, a general frost is expected over the far southern areas of the state bordering Victoria and to the west of the GDR in the southeast protected from the southeast to easterly flow. Mild weather to follow in the afternoon with sunshine and a mix of clouds.

MEDIUM TERM FORECAST

July 27th-August 4th, 2022

Moisture Watch

Moisture looks more aggressive in the modelling this afternoon and that is linked to the fast flow pattern developing over the west of the nation, which will be gradually spreading eastwards through to SA and VIC with that moisture likely to lead to more cloud cover and potentially widespread rainfall in Southern Australia as we move into early August. Most likely the east coast should dry out as the wind regime tends into the west and normal Winter conditions. The Indian Ocean is alive and kicking at the moment out west and is likely to impact areas further to the east.

Rainfall Anomalies

The rainfall anomalies are increasing above the average over the western parts of the nation where there is growing evidence of stronger frontal weather passing through and attaching into moisture leading to large cloud bands and more widespread moderate rainfall at frequent intervals. The moisture over the northeast of the nation could run through the waters north of Australia leading to higher coverage of showers than what is seasonally expected. The remainder of the nation is in white, even though above average rainfall is being forecast in areas of SA and VIC. But given the constant let downs, I am keeping the forecast confidence low and when you see green on this chart for these areas there will be further focus information on that in other areas on the website and on the Facebook page.

Temperature Anomalies

The temperatures are starting to increase over much of the interior, the heat engine showing the first rumblings of waking up. This is assisted by the persistent westerly winds developing throughout the end of July and into August, dragging in the warmer and moist air through the jet stream and clashing that with frontal weather. So ahead of fronts in the southeast, marginally warmer but cloud cover and rainfall approaching suppressing the full warm up that can be experienced in times of El Nino/+IOD. This is a signal that the climate drivers are underway as planned. The cooler weather continues about parts of eastern Australia in persistent southeasterly trades, but these should begin to weaken.

DATA - Refer to the video for further information and context.


00Z GFS - Surface Pressure Pattern and Rainfall Distribution - Next 2 Weeks

Refer to the video for further information and context in this low confidence forecast period as the models will struggle and the apps will be useless as will most automated guidance.

00Z GFS - Precipitable Water Values - Next 2 Weeks

The moisture load has not changed too much in the short term but it will be the placement of low pressure to the moisture that will dictate the rainfall spread across the nation as we move through the short term. But excellent signs continue to build for SA, VIC and western inland parts of NSW where rainfall may return to areas that need a little top up and quite frankly crop saving falls in SA. The moisture stream over WA is consistent and what you would expect to see at this time of year for the SWLD of the country. This will spread eastwards at some stage during the end of the month and the early part of July as you can see ahead looks interesting.

00Z ICON - Rainfall Accumulation - Next 8 Days

Refer to the video for more context and analysis

00Z GFS - Rainfall Accumulation - Next 10 Days

Refer to the video for more context and analysis

00Z CMC - Rainfall Accumulation - Next 10 Days

Refer to the video for more context and analysis

00Z GFS - Rainfall Accumulation - Next 2 Weeks

Refer to the video for more context and analysis

A closer look - and the rainfall numbers you see over much of the eastern inland of the nation and along the coast will be seen in the coming 5 days and then the focus of rainfall should begin to shift back over VIC and SA plus areas west of the divide through NSW. Now the rainfall over the weekend in the southeast inland, primarily through SA and VIC could be much higher than what is being shown here and that could be followed by further rainfall towards the end of next week and to end the month. So, there are some interesting signals to play with finally as the pattern shifts.

More coming up from 8pm EST with the rainfall developing for the end of the month and the broader data sets - the ensemble guidance very useful in these low confidence periods.


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