The Lachlan River is expected to reach the major flood level of 10.55m at the Iron Bridge in Forbes on Monday.

The State Emergency Service's updated flood bulletin, as of 6.10am Saturday, says we should now prepare for major flooding.

Heavy rainfall recorded in the upper parts of the Lachlan River catchment on Thursday night has resulted in significant river level rises in the upstream tributaries.

This flood water combined with increased spills from Wyangala Dam has caused moderate flooding at Cowra.

The flood peak currently at Cowra is expected to reach Nanami on Saturday night, with major flooding.

Major flooding is likely at Forbes, Cottons Weir and Jemalong from early next week - with predictions to be made once the peak is observed at Nanami.

The Lachlan SES branch asks that we consider delaying non-urgent travel, and where river heights continue to rise residents need to consider the impact of potential isolation.

Peak flood predictions will be made for locations downstream of Nanami once upstream peaks have been observed.

A flood warning is current for the Belubula River and Mandagery Creek.

If you need sandbags: They are available at the SES depot on the corner of Farnell Street and School Road. You can phone 132500 to ask for delivery, and our volunteers are hard at work this morning.

Roc Walshaw from the local SES advises those who are new to town or haven't experienced a flood speak to their neighbours about flood impacts on your property.

The SES will doorknock areas where people are advised to evacuate as required.

As of 6.10am Saturday

At Nanami: The Lachlan River at Nanami is expected to reach the moderate flood level - 9.7m - on Saturday afternoon. The river level is likely to reach 11.3m early Sunday morning, with major flooding.

At the Iron Bridge: The Lachlan River at Forbes Iron Bridge is expected to exceed the minor flood level (8.80 metres) Saturday afternoon. The river level is expected to exceed the moderate flood level (9.50 metres) Sunday morning and is likely to reach the major flood level (10.55 m) during Monday.

In 2016, the river reached 10.67m at the Iron Bridge.

Cottons Weir: The Lachlan River at Cottons Weir is likely to exceed the moderate flood level (5.30 metres) Sunday evening. The river level is likely to reach the major flood level (6.60 metres) during Monday.

Jemalong Weir: The Lachlan River at Jemalong Weir Downstream is likely to reach the major flood level (7.70 metres) during Wednesday.

Road closure notices Forbes Shire Council road closures and Live Traffic.

Nanami - Exceed Moderate Saturday afternoon. Low lying areas adjacent to the river can flood. The Kangarooby Creek could encroach upon the Gooloogong - Cowra Road. The approach road to the Paytens Bridge on the Bandon-Eugowra Road may flood on the Eugowra side of the bridge.

The Gooloogong-Cowra Road (Lachlan Valley Way) floods, Detours are available via Grenfell or Eugowra. The water can become deep and fast in major floods.

The Gooloogong Eugowra Road can be flooded. Alternate access to Eugowra may still be available via Canowindra. Access to Forbes is still available via Grenfell.

Forbes Iron Bridge - Minor Saturday to Moderate Sunday morning to Major during Monday: The Park on Lake Forbes floods including footpaths, low lying areas adjacent to the river can flood.

Multiple roads are likely to be flooded including Gooloogong Road at Dukes Crossing, Wirrinya Road at the Dog and Duck Crossing on Bundaburrah Creek, Grenfell Road (Henry Lawson Way) at Muddy Lagoon, lower Wambat Street, Rifle Range Road, Bathurst Street.

Caravans and campers need to move away from low lying areas.

Water may break out of Lake Forbes.

Cottons Weir - Moderate on Sunday, Major on Monday: A number of roads are flooded including the Forbes-Gooloogong Road (Lachlan Valley Way) at Dukes Crossing and the Forbes-Old Grenfell Road (Henry Lawson Way) at Muddy Lagoon/Bundaburrah Creek, New Grenfell Road at Bundaburrah Creek and the Escort Way - preventing access south and east between Forbes, Grenfell, Gooloogong and Eugowra. Alternative access available via the Newell Highway.

Predictions for Jemalong Weir to come, Rural residents in the Jemalong and Bedgerabong areas will be impacted. Water may be across North Condobolin Road at "Little Plains".