Geraldton is bracing for a scorcher tomorrow, with the temperature expected to reach the high 30s.

The Bureau of Meteorology has forecast a top temperature of 38 degrees.

The forecast is for progressively cooler weather after that, with an expected top of 29 degrees on Sunday and mid to low 20s early next week.

The bureau says there is a 20 to 30 per cent chance of rain on Sunday and Monday.

The forecast top temperatures elsewhere in the Mid West and Gascoyne tomorrow are: Morawa 40; Kalbarri and Moora 38; Jurien Bay 37; Carnarvon 32.

A catastrophic fire danger warning is in place for Carnarvon today.