FRIDAY MORNING WEATHER - SEVERE WEATHER INCREASING FOR THE EAST, RAIN DEVELOPING WEST, DRY SOUTHEAST

The weather not budging a whole lot from yesterday where we have a stagnant pressure pattern thanks to a slow moving high pressure ridge that is controlling weather for southern and southeast areas, leading to settled conditions with seasonal temperatures for the most part. But once you head through SA and into the southern NT, we see temperatures well above average through this week with not much rainfall forecast.


On the periphery of the high pressure system at the upper and lower levels is where you find the rainfall and inclement weather.


In the west, the remains of Charlotte expected to bring up the chance of rainfall in the days ahead with a deep trough over parts of the inland leading to widespread rainfall emerging across the outlook period, especially for the western third. A secondary burst of moisture spreading through the Indian Ocean may increase the rainfall chances throughout the coming weeks. Also we need to watch the tropical system that may emerge over the NT in the coming week.


Speaking of that feature, the system is forecast to emerge north or northeast of Arnhem Land and then move into somewhat favourable conditions for further development of the system. There is a moderate chance of this feature becoming a cyclone north of the NT next week, moving west bound. The name, Darian will be assigned to this system.


Over eastern areas of the nation, the positive SAM is now being observed with the rainfall increasing for the eastern inland as forecast, those falls moving some areas well and truly back above average for the month, some areas beyond the record March rainfall observed in their history. It has been a wet month for the southeast of QLD and much of eastern NSW. These areas under severe weather threats over the coming days.


Elsewhere things are fairly quiet and unlikely to change that much though weather over the east will ease for a while next week ahead of further rainfall chances later next week into the first weekend of April. And will have to keep an eye on the system wafting off the NW of Australia which is Darian, that may be able to spread moisture south and east through the nation.


Lets take a look

FORECAST

Rainfall Next 10 Days

We are still operating on the low confidence side of forecasting for the west and north, but confidence is increasing for the east coast and drier areas of the southeast carry a much higher confidence. It is very tricky to pin down the overall impacts of Charlotte in the west still but that should start to become clearer today as we see how far east she comes and what is left of her. In the east, the wettest weather to be found over the eastern third of QLD and NSW , now looking to stay mostly east of the ACT still. Much of the southeast and southern inland of the nation is expected to remain drier with the ridge close by and ridging in force for the coming week. The pattern over the north also very interesting, the models split on the idea of the impact of developing tropical low pressure northeast of the NT. This would have significant impact on the rainfall spread over northern Australia. It is looking more likely that if a tropical low or cyclone forms, it will run west bound through the nation's northwest but the modelling is still quite poor. The ridge to the south of the nation the is the ultimate driving force behind where that system and moisture will go, steering it most likely to the west. In the medium term, the forecast is still looking very active, with moisture from the northwest Indian Ocean, the positive SAM and the dregs of the MJO still having some influence on the rainfall and thunderstorm activity for western, northern and eastern parts of the nation with the drier spots remaining as they are, much of SA, Central Australia and the western ports of NSW and QLD at this time time. But as we know, this can easily change with so much weather around.

SHORT TERM CLIMATE DRIVERS

SOUTHERN ANNULAR MODE - SOUTHERN OCEAN - ON THE JOUNREY TO NEUTRAL IN THE COMING WEEK.

The SAM is still positive and will take until the end of the month to get back to neutral values. This sets up what could be a very wet spell for the east coast with that energy to be played out across the nation's east in the coming week or two. The SAM remains at neutral values through towards mid April but once again, there is a bias to yet another positive phase to unfold. This would continue the wet bias for the east of the nation and suppress cold fronts coming through southern Australia.

MJO - TROPICS - MOVING TOWARDS THE EQUATOR THEN COULD MAKE ANOTHER RUN AT THE NORTH OF THE NATION MID TO LATE MONTH.

This will still result in an active week of tropical weather, we have seen Billy and Charlotte form in the past week. There looks to be another tropical low form off the NT and if a cyclone will be named Darian. The system looks to adopt a westerly track through the outlook and may move into the Indian Ocean and at this rate could rapidly move back into play for mid to late April north of Australia.

THUNDERSTORM FORECAST THIS WEEK

Thunderstorm Forecast Friday

Thunderstorms will continue to evolve over the east from Thursday with another batch of severe storms possible as a slow moving trough moves through the eastern inland. There may be a low pressure system that deepens offshore the Central or Southern Coast of NSW. This could see a batch of storms roll up the NSW coast as well. Over the north, the storm coverage is increasing with severe storms possible, via damaging winds. The storm risk will roll down a trough over inland QLD into northern inland NSW with a slight chance of flash flooding at this time. There could be increasing thundery weather over northwest Australia with the threat of TC Charlotte or a tropical low approaching sending in moisture across the region which will feed a trough over inland areas.

Thunderstorm Forecast Saturday

Thunderstorms are forecast to continue about the eastern inland and may be more widespread than what is being indicated here so be watching the upcoming forecasts. The thunderstorm coverage over the north may become more widespread about the Top End with heavy rainfall possible leading to flash flooding in the northeast. Thunderstorms may develop along the west coast of WA with some of the storms possibly severe about parts of the Central West and Gascoyne with gusty winds and heavy rainfall.

Thunderstorm Forecast Sunday

An upper trough may linger over the eastern inland triggering showers and thunderstorms, some of these could be severe inland of the coast and west of the divide through southeast QLD and northeast NSW. Heavy rainfall would be the main issue for now. Gusty storms possible over the north will continue with some of these producing damaging wind gusts. Thunderstorms also possible over the west of the nation with moisture from the remains of Charlotte leading to unsettled conditions. Marginal chance of severe weather at this time.

Thunderstorm Forecast Monday

Thunderstorms look to become more widespread about the western interior of WA with severe thunderstorms possible. Heavy rainfall leading to flash flooding and damaging winds are the main issues out west as the remains of Charlotte approach. Over the north, showers and thunderstorms should also continue with the potential for damaging winds across the Top End and western Cape York with a tropical low nearby. There may be some scattered storms over the southeast of QLD and northeast of NSW. Some chance of severe weather here too with heavy rainfall leading to flash flooding the main issues but the risk has diminished since yesterday. Dry and stable elsewhere with ridging.

Thunderstorm Forecast Tuesday

Deep moisture still stuck over parts of the southwest and west of the nation will be lifted by a trough in northeast winds leading to widespread showers and thunderstorms. Some of the thunderstorms will lead to heavy rainfall and a flash flood risk in some areas of the Lower West, Central West, Gascoyne and back through to the Pilbara and back to the tropics and NT. Developing tropical low offshore the NT may form into a cyclone with damaging winds in the rotating bands around the system. Storms decreasing in coverage over the northeast tropics and stable over the east.

SEVERE WEATHER RISKS THIS WEEK

Severe Weather Risks - Saturday through Monday

The proximity of Charlotte to the coast over the coming days will dictate how much moisture is drawn into the state, how much of the moisture gets fed into a trough leading to scattered showers and storms and whether we see severe weather develop as a result. Given the low confidence forecast, the risk areas are broad and will be moved around until there is better consistency. But the bottom line is, the closer you are to the coast from about Carnarvon southwards to the Capes and inland to the Wheatbelt, thunderstorms could develop with heavy rainfall and damaging winds occurring this weekend. There may be a separate issue for damaging winds and heavy rainfall developing if the remains of Charlotte are swept into the Lower West Coast and Southwest this weekend along a front. So a few moving pieces that carry low confidence in the short term, means that forecasts will likely change rapidly placing many of you either under active warnings.

Severe Weather Watch - Friday through Tuesday

Watching very closely the emergence of the upper level low moving into western NSW during Friday and how that interacts with the moisture and the existing trough sitting over the northeast of NSW and southeast QLD. Could see a rather expressive period of convection and given the dynamics, the chance of severe weather with storms is elevated over inland areas. Along the east coast, in east to northeast winds feeding the system, we could see heavy showers and flash flooding initially, and deepening on the rainfall coverage and the performance of the troughs together, there may be intense rainfall returning to parts of the coast. The most likely areas would be the extreme coastal fringe between Sydney and Yamba at the moment. The severe weather contracts into the northeast and east of the ranges by next week. The most active severe weather will be over areas south of about Chinchilla in QLD.

TROPICS

Tropical Depression Watch

A depression is likely to form within the coming 2-3 days off the Arnhem Coast with a good chance of this system becoming more organised later in the weekend into next week. Significant convection has already been observed overnight with some moderate to heavy falls of rainfall with storms clipping the coastal areas of the northeast in recent days. The weather is expected to remain of routine values for most of the Top End while this system develops further in the Arafura Sea during the weekend and next week. Pay attention to forecasts and warnings this weekend and into next week as this evolves.

Tropical Cyclone Risk

The risk of a cyclone forming in this region is not overly high but it is appearing on some of the models now. But the Euro is clearly the most aggressive when it comes to dealing with this system and does verify it north of the Top End as a cyclone during the early to middle part of next week before spreading westwards.

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 pressure pattern is largely unchanged and as explained in the video in detail, the smaller (mesoscale features) will dictate the distribution of rainfall through the coming week. The wettest parts of the nation will be found over the western interior through the Ag Areas of WA, the east coast and extending into Ag Areas of Northern NSW where flooding has already occurred this month and obviously over the north, very damp weather to continue with the development of the tropical feature sitting offshore. Where that system goes is still up in the air but I am tipping a west bound track at this time. Dry weather for the next week elsewhere.

12z Euro Precipitable Water Anomalies - Next 10 Days

Moisture once again largely unchanged from last nights update though the only area of change is with the tropical system that in this particular run makes a run to the east and southeast towards QLD next week. I am still tipping that system to move west however. West coast and East coast looks fairly humid and wet with below average temperatures for the east and above average temperatures out west. The dry air, still stuck over parts of central and southeast Australia.

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 Euro Rainfall Accumulation - Next 15 days

Refer to video for more information

12z GFS Rainfall Accumulation - Next 16 days

Refer to video for more information

More coming up throughout the day with your Climate Outlook refresher due this morning as well.