Ionospheric Summary and Forecast

Ionospheric Summary

(last updated 28 Nov 2025 23:30 UT)

Date T index 28 Nov 94 Observed Australian Regional MUFs Cocos Island Region: Mostly near predicted monthly values. Niue Island Region: Enhanced by 20-25%. Northern Australian Region: Near predicted monthly values during local day. Enhanced by 15% during local night. Depressed 15-20% after local dawn. Southern Australian Region: Mostly near predicted monthly values. Depressed 20-30% after local dawn. Antarctic Region (Casey/Davis/Mawson): Near predicted monthly values over the UT day. Monthly T index: Month T index Oct 104 Nov 89 Dec 90

Ionospheric Forecast

(last updated 28 Nov 2025 23:30 UT)

Date T index MUFs 29 Nov 65 Depressed 15 to 20%/near predicted monthly values 30 Nov 90 Near predicted monthly values 01 Dec 90 Near predicted monthly values COMMENT: ASWFC HF Communications Warning 112 was issued on 28 November and is current for 29 Nov only. ASWFC SWF HF Communications Warning 113 was issued on 28 November and is current for 29 Nov to 1 Dec. Maximum usable frequencies (MUFs) in the Australian region on UT day 28-Nov were mostly near predicted monthly values to 15% enhanced, becoming depressed by 15-30% after local dawn this morning, possibly in association with mild overnight geomagnetic activity. Spread F was observed during local night hours at Hobart. Sporadic E was observed at times at Hobart and Niue. Australian region MUFs are expected to be initially depressed 15-20% on 29-Nov, recovering as the day progresses. MUFs are expected to be near predicted monthly values during 30-Nov to 01-Dec. Isolated HF fadeouts are possible.