FRIDAY MORNING WEATHER - A COOL START FOR SOME IN THE EAST, HOT IN THE WEST - TROPICS TURNING ACTIVE

Updated: Mar 11

The weather has certainly shifted away from the wet phase of the past month with a drier picture for large sections of the nation thanks to ridging and large amounts of dry air in place this morning.


But conditions once again will start to shift through the eastern inland as onshore winds feed a weak trough heading west bound through QLD and into NSW bringing showers and storms and the west coast and adjacent inland, along a cooler change, likely to see showers and thunderstorms develop for the very dry SWLD.


The tropics also likely to see an uptick in the amount of showers and thunderstorms as the MJO approaches the northwest of the nation leading to an increase in instability. This perhaps is the last of the wet season rainfall opportunity for the inland areas of the tropics through the NT and WA.


If we see a tropical system emerge out of this tropical weather, then it is likely to run west through the tropics and land in the Indian Ocean and in this situation moisture usually spreads across the nation and runs into frontal/trough weather over the southern states. This is a common way for long dry spells to break for the south at this time of year.


Anyway more on that in the 6 week outlook later today too.


For now we keep an eye on the shower coverage over the east coast, the coverage of storms in the inland of NSW and QLD and whether these can make it into northern VIC and the ACT this weekend, the development of that extra tropical weather over the north in the medium term and whether we can see some more widespread falls coming to southern and western Australia.


Lets take a look

FORECAST

Rainfall Next 10 Days

Rainfall remains a very complex entity to forecast for southern and eastern areas of the nation. We have a few troughs on the board with the chance of showers and thunderstorms and that uneven distribution of rainfall that I have spoken about for the past few days. We also have the development of the upper low mid to late next week which is lighting up rainfall projections like a Christmas tree for SA, VIC, NSW and the ACT at times. But for now we have to wait through the weekend to assess the data sets to see where the systems are tracking next week. There will be unsettled weather in the southeast and east but who gets what, remains to be seen. In the mean time, widespread showers for coastal NSW and QLD with moderate accumulation and heavy accumulation over the FNQ tropics. The northern tropics also seeing routine showers and thunderstorms but these could increase as the MJO approaches the eastern Indian Ocean. For WA, a west coast trough deepens today and there is likely to be light scattered falls with lightning active thunderstorms. Thunderstorms may bring heavier rainfall totals Saturday and Sunday before the system moves into SA early next week. This is one part of the complex system next week which could bring an increased risk of widespread falls for SA and then the southeast.

Thunderstorm Forecast Friday

Thunderstorms are likely to redevelop near a stalled trough over Central QLD with one or two of those storms turning severe with heavy rainfall and damaging winds the main concern. Thunderstorms continue over the northern tropics but no severe weather is expected at this time. Thunderstorms may develop over the western interior through Perth and into the southwest coast with gusty winds and moderate rainfall.

Thunderstorm Forecast Saturday

Thunderstorms are forecast to spread through western parts of QLD and into northwest NSW with the chance of thunderstorms turning gusty through Central and Northern NSW and into Southern and Central QLD. Thunderstorms continuing to be gusty over the NT and parts of the Kimberly. Storms also developing in the SWLD of WA or continuing from Friday over the region with the chance of gusty winds, but most storms should be below severe thresholds in this area.

Thunderstorm Forecast Sunday

Thunderstorms will continue to move westwards through the eastern inland with a trough. Thunderstorms may become severe through southwest QLD and northwest NSW with heavy rainfall and damaging winds. Damaging winds also possible with thunderstorms over the NT. Thunderstorms increasing in coverage over the eastern inland as the trough broadens through the day.

DRIVERS TO WATCH


SOUTHERN ANNULAR MODE - SOUTHERN OCEAN

The SAM is set to move back to neutral values from today through the weekend and we could see a negative phase develop next week for a period but once again, with La Nina waning, may not be a large period of neutral or negative values. We have seen in recent days that the negative signal next week is softening which is what you expect in the broader climate situation and that looks to shorten the life of the negative movement next week, so if you are living over the eastern parts of the nation, we could see more wet weather events into the medium term and the easterly winds to return, meaning drier warmer weather over the west and south. When the SAM in this place, it opens the door for further ECL development.

MJO - TROPICS

No change to the guide from the last week, though the speed of the MJO rotating through the nation's north is slower it appears, but the impact will be the same with increasing showers and thunderstorms for the north of the country. And we could see the late season cyclone activity across the northern waters as well which act as wildcards and they are also the key to many Autumn Breaks across the nation, not always, but certainly play a part of fanning moisture throughout the nation, especially WA and SA through the southeast inland.

DATA - Refer to video for more information and the model comparison and context about all the forecast products you see from me.


12Z Euro Surface Pressure Pattern and Rainfall Distribution - Next 10 Days

The weather is generally settled for many areas this weekend. We have a trough in QLD and NSW through the coming weekend which is likely to trigger strong to severe storms in a narrow band so many areas as mentioned will remain warm and dry. The east coast, showers are running up and down the coast of QLD into NSW with onshore winds which is seasonal for this time of year but no severe weather event in the short term. Over the north the coverage of the tropical showers and thunderstorms will increase over the next week or so with the MJO on the approach which will play a part in increasing rainfall chances for WA into the medium term and for now, we may see the last of the high 30s in the region with some luck once we get the weekend trough through to the east and get into that cooler airmass for the weekend and next week. The heat is on for parts of the south this weekend and into the southeast inland this week ahead of another strong trough emerging from SA which could see a large scale rain and storm event unfold in a zone from eastern SA through southern QLD, NSW and VIC. The ingredients are there for another ECL to form in the coming 10-15 days but the confidence remains low to moderate. As mentioned in the video, the rainfall and temperature guide beyond about 5 days is quite poor at the moment.

12z Euro Precipitable Water Anomalies - Next 10 Days

Certainly seeing the drier airmass becoming overrun once again by the moisture spreading out of the easterly wind regime over NSW and QLD into VIC and then SA through the weekend and next week. Also seeing the moisture increasing for northern Australia via the trade winds in the east, spreading throughout the tropics and the moisture also being pulled south from the equator as the upper flow turns northeast to northerly. This is in advance of the MJO passing through the Indian Ocean over the coming 10 days. Over in the west, high level moisture is continuing to feature and will likely emerge next week from the north and west via the jet stream so we could see more patchy rainfall opportunities later on in the period, this may feed into waves of low pressure south of the nation, so watching that closely. That is usually a signal of a seasonal shift on the way as well, which can take the best part of 3-4 weeks to take place.

12z Euro Rainfall Accumulation - Next 10 days

Refer to video for more information

12z GFS Rainfall Accumulation - Next 10 days

Refer to video for more information

12z CMC Rainfall Accumulation - Next 10 days

Refer to video for more information

12z GFS Rainfall Accumulation - Next 16 days

Refer to video for more information

The latest 6 week outlook coming up later this morning which will now look clearly into a period where more rainfall is ahead of us once again so that will be interesting reading and viewing for those looking for an Autumn Break.