MONDAY MORNING WEATHER - SIGNIFICANT STORM SYSTEM OUT WEST. AREAS OF RAIN EASTERN INLAND.

OVERVIEW

Widespread rainfall is expected to continue about the eastern inland this morning and afternoon with a weakening upper trough that should lift north and clear tonight through QLD. A stronger system out west is the feature to watch today with the risk of damaging winds and heavy rainfall as the first of a series of strong cold fronts move through.


Fine weather returns for much of SA with a much moister atmosphere with cloud developing but not too many showers about the region.


A period of severe weather is expected to sweep in from the west during the coming week and the risk of damaging winds and heavy rainfall will become a feature with this large wave and series of low pressure and cold fronts.


Clearance from the west is forecast to move east throughout the latter part of the week with the coming weekend looking much more settled with decreasing rainfall chances over the southeast and eastern inland.


SHORT TERM

A series of strong cold fronts headlines the forecast with moderate to heavy rainfall along the features as they move through. Heavy orographic rainfall is expected to be seen over NE VIC and SE NSW nearby the ACT with the risk of flooding with this feature wave moving through. The moisture levels are somewhat off the charts so this could lead to rainfall being elevated above what models are showing.


For the south of the nation, widespread showers, with local thunder and hail and a few areas picking up moderate falls are possible through the middle to latter part of the week. Heavy falls may develop about the Adelaide Hills and SE areas of SA with the risk of flash flooding.


Showers with damaging to locally destructive winds are possible over the SWLD during this week with the showery weather easing by Thursday but not totally clearing.


Showers over the southeast will begin to clear from the weekend with a much more relaxed pressure and if you are living up north through the NT and QLD remaining dry for most areas as the dry rolls on.


LONG TERM/AREAS TO WATCH

Once we get this system off the board, does the moisture linger over the southeast and eastern inland or is it transported offshore? That is the question that remains unanswered today and for most of this week, will remain unanswered. Understand that there will be rainfall events coming and going for northern and eastern Australia reflecting the moisture content that is present.


There is uncertainty on the scale of the frontal weather that is passes from west to east and whether the negative SAM remains in place. If we see the negative SAM in place, this will lead to further strong fronts to pass through and the vision of this is not quite clear so expect further changes to the weather pattern and forecast in the coming week as we deal with the active weather in the short term. How the pattern evolves this week will impact the weather that develops in the medium term.


WEATHER VIDEO AM - MONDAY 1ST AUGUST 2022

FORECAST

Rainfall Next 10 Days

Rainfall is extensive over the west of the nation today with moderate to locally heavy falls with the frontal passage passing through. The showery weather will continue over the eastern inland with mainly light to moderate falls on and west of the divide through NSW and the ACT before conditions clear tonight. A few showers ease over the south of the nation with high pressure digging in. Showers will begin to redevelop over the west of SA from Tuesday with a strong cold front approaching and light rainfall extending throughout the remainder of the state during Tuesday as the front slides southeast. Out west, another strong cold front moves through leading to widespread showers and gales with moderate falls. Fine in the east. Though that doesn’t last that long with a strong upper-level wind field supporting the development of very deep cloud cover in response to moisture spreading throughout NSW and NE VIC. Heavy rainfall peaks during Thursday with falls over 100mm possible for some areas in the elevated terrain. This may result in flooding for some areas. Heavy rainfall extends northwards up the NSW ranges on Friday mainly west of the divide through NSW and extending into southern QLD, but it appears the rainfall winds down during Saturday. A low passing through SA and VIC during Thursday through Saturday, the system is expected to weaken, and this will see the rainfall coming down in intensity, but the weather does not clear to the end of the weekend. There are further signals that rainfall may persist over the interior of QLD during the weekend, but guidance is poor.

THUNDERSTORM FORECAST

Thunderstorm Forecast Monday

An inland trough over the eastern inland may see a few middle level showers and thunderstorms developing with no severe weather risks at this time. A strong cold front approaching the west of the nation may bring the risk of severe thunderstorms, with destructive wind gusts possible with thunderstorms given the very strong wind fields in place.

Thunderstorm Forecast Tuesday

The strong cold front from WA during Monday whips into the Bight on Tuesday with the risk of strong to gale force winds. Moderate rainfall from any thunderstorms are possible and strong and squally winds.

Thunderstorm Forecast Wednesday

A new rain band forming over the eastern inland with strong wind fields aloft across QLD and NSW may see thunderstorms developing. Storms may be gusty and possibly severe but will check that out early in the week. Another strong cold front approaching the west will bring showers and storms, with damaging wind gusts possible and small hail. A few thunderstorms skirting the SA coast remains in place as a weakening cold front slide southeast.

WEATHER ISSUES

DAMAGING WINDS

Strong to gale force winds are forecast to develop ahead of a strong cold front on Monday with isolated severe wind gusts over 120km/h possible as the front moves through. The winds will spread inland with the system but ease later into Monday night with strong to gale force winds continuing about coastal areas through Tuesday.

A secondary strong front will move through during Wednesday with gale force winds, locally storm force about coastal areas south of Perth to the Eucla. Winds in this region may once again exceed 120km/h at times and be shifting from the west into the southwest. The winds ease later Wednesday night over inland areas and coastal areas from Thursday afternoon.

DAMAGING WINDS WEDNESDAY TO FRIDAY

A strong cold front and tight pressure gradient will give rise to gale force northwesterly winds with wind gusts up to 110km/h possible about coastal areas and at elevation. Winds up to 90km/h possible over the inland areas as the strong winds aloft are mixed to the surface with light areas of rainfall under the jet stream. Winds are forecast to ease from Thursday afternoon and tend southwesterly.

DAMAGING WINDS -WEDNESDAY TO FRIDAY

Strong gradient northwesterly winds are forecast to develop during Wednesday afternoon for Victoria and overnight for NSW and peak during Thursday, especially over elevated terrain where winds could exceed 130km/h in Alpine areas. Heavy rainfall with strong land gale will cause significant disruption throughout the southeast of NSW and northeast of VIC. Prepare now for power outages throughout the end of the week if you are living in elevated parts of the southeast.

RIVERINE FLOOD RISK - THURSDAY TO FRIDAY

Severe weather related to rainfall rates over 30mm/hr for a 6-12hr period could lead to high impact flash flooding throughout the region, in combination with snow melt coming off the mountains, there may be some higher chances of riverine flooding in areas exposed to these high run off rates. Flooding is a high to very high chance for the end of the week and into the weekend and this risk may be expanded further to the north in NSW.

FORECAST

AUGUST 7TH-14TH 2022

Moisture Watch Next Week

The moisture content across the nation is expected to remain in place but there is a high degree of uncertainty surrounding impacts and thus, leaving the whole nation under risk is the right call and then we can work back from there throughout the week as the data becomes clearer rather than moving the yellow shading around drastically responding from run to run.

Rainfall Anomalies

Some areas may see lingering rainfall with the southwest of the nation and running along the northern tropics the most likely to see any above average rainfall chances. Some moisture lingering throughout the interior may spit out some patchy rainfall and a few showers in onshore winds for the east coast with a departing long wave is also possible. Seasonal rainfall will continue with frontal weather for the south and southeast.

Temperature Anomalies

The big shift in guidance has been the victory for the cooler air to shove the jet stream further north and dam that warmer air back over the heat engine, but that will break and come south through mid-month. The question will be with the warmer air, does it shift southwards into moisture and then interact with strong cold fronts or troughs again?

CLIMATE DRIVERS - SOUTHERN ANNULAR MODE - STATUS - NEGATIVE

The SAM is currently negative and should stay so this week before we see the members diverge towards the second week of August, though a few more members have shifted to positive next week.

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

Refer to the video for more information and the model comparison and context with the fast flow pattern and energetic and powerful weather patterns.

12z Euro Precipitable Water Anomalies - Next 10 Days

We know that the moisture values coming through the atmosphere for this time of year is quite excessive and the impacts have been felt with the first lot in recent days with overnight rainfall in many locations with thunderstorms in the east. Next surge coming into the west today already bringing widespread cloud and rainfall. That will be surge of moisture that brings the severe weather to many locations this week with heavy rainfall leading to flash flooding likely to feature. The deeper moisture moves north and east by the end of the weekend, but it could be lingering over the interior with a chance of inland rainfall return at the end of the period and spreading southwards into frontal weather.

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 today on the severe weather coverage and potential moving throughout the nation - heavy rainfall threats and damaging winds issues.