From aswfc at bom.gov.au Wed Oct 1 10:47:36 2025 From: aswfc at bom.gov.au (Australian Space Weather Forecasting Centre) Date: Wed, 01 Oct 2025 10:47:36 +1000 Subject: [Ips-whfpr] ASWFC Weekly Prop. Report (01 October 25) issued 0047 UT on 01 Oct 2025 [SEC=OFFICIAL] Message-ID: <68dc7a28.a/YIw0ycHivlUx4E%aswfc@bom.gov.au> SUBJ: ASWFC WEEKLY HF PROPAGATION REPORT ISSUED ON 01 OCTOBER 2025 FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE AUSTRALIAN REGION SUMMARY AND FORECAST 1. SUMMARY (24 SEPTEMBER - 30 SEPTEMBER) Date T index Conditions 24 Sep 127 Normal MUFS: Cocos Island Region: Enhanced by 20% during local day. Enhanced by 100% during local night. Niue Island Region: Enhanced by 20-40%. Near predicted monthly values during local day. Enhanced by 20-30%. Southern Australian Region: Mostly near predicted monthly values. Antarctic Region (Casey/Davis/Mawson): Near predicted monthly values over the UT day. 25 Sep 129 Fair-normal MUFS: Cocos Island Region: Enhanced by 55% during local day. Enhanced by 85% during local night. Niue Island Region: Enhanced by 15-20% during local day. Northern Australian Region: Enhanced by 15%. Southern Australian Region: Near predicted monthly values during local day. Enhanced by 20% during local night. Antarctic Region (Casey/Davis/Mawson): Near predicted monthly values over the UT day. 26 Sep 119 Normal MUFS: Cocos Island Region: Enhanced by 20-25%. Niue Island Region: Enhanced by 45% during local day. Near predicted monthly values during local night. Northern Australian Region: Near predicted monthly values during local day. Enhanced by 25% during local night. Southern Australian Region: Enhanced by 15-30%. Antarctic Region (Casey/Davis/Mawson): Near predicted monthly values over the UT day. 27 Sep 130 Normal MUFS: Cocos Island Region: Enhanced by 30% during local day. Enhanced by 30% during local night. Niue Island Region: Near predicted monthly values during local day. Enhanced by 20% during local night. Northern Australian Region: Near predicted monthly values during local day. Enhanced by 50% during local night. Southern Australian Region: Enhanced by 20-35%. Antarctic Region (Casey/Davis/Mawson): Enhanced by 20% over the UT day. 28 Sep 136 Normal MUFS: Cocos Island Region: Enhanced by 45% during local day. Enhanced by 65% during local night. Niue Island Region: Near predicted monthly values. Northern Australian Region: Near predicted monthly values during local day. Enhanced by 50% during local night. Enhanced by 25% after local dawn. Southern Australian Region: Enhanced by 25% during local day. Enhanced by 30% during local night. Antarctic Region (Casey/Davis/Mawson): Near predicted monthly values over the UT day. 29 Sep 130 Normal-fair MUFS: Cocos Island Region: Near predicted monthly values during local day. Enhanced by 15% during local night. Niue Island Region: Enhanced by 20-30%. Northern Australian Region: Enhanced by 15-25%. Southern Australian Region: Near predicted monthly values during local day. Enhanced by 20% during local night. Depressed by 15-30% after local dawn. Antarctic Region (Casey/Davis/Mawson): Depressed by 15% over the UT day. 30 Sep 88 Poor-fair MUFS: Cocos Island Region: Enhanced by 30% during local day. Near predicted monthly values during local night. Enhanced by 45% after local dawn. Niue Island Region: Enhanced by 20-30%. Northern Australian Region: Enhanced by 15% during local day. Near predicted monthly values during local night. Southern Australian Region: Depressed by 20-30%. Antarctic Region (Casey/Davis/Mawson): Depressed by 30% over the UT day. Comment: G1 geomagnetic conditions were observed in the Australian region on UT day 30-Sep associated with southward orientated interplanetary magnetic field conditions. Planetary conditions reached G3 on 30-Sep. The cause of the recent enhanced southward IMF conditions is not definitive but appears to have preceded a coronal hole wind stream entry. This geomagnetic activity subsequently degraded middle to high latitude HF communications. Predicted Monthly T index for September: 109 2. FORECAST (01 OCTOBER - 07 OCTOBER) MUFS: Southern region MUFs depressed 20% on 01-Oct, with northern Australian MUFs expected to be near predicted monthly values to 15% enhanced. Southern region MUFs mildly depressed on 03-05 Oct in association with 27 day recurrent geomagnetic patterns. MUFs near predicted monthly values on other days. Propagation conditions: Poor to Fair on 1 Oct, fair on 03-05 Oct. Otherwise normal. Isolated SWFs probable during the week. T index: 50 for southern Australian region on 01-Oct. 120 for northern Australian region on 01-Oct. 100 for other days of the week. ASWFC SWF HF Communications Warning 86 was issued on 28 September and is current for 29 Sep to 1 Oct. ASWFC HF Communications Warning 88 was issued on 1 October and is current for 1 Oct only. 3. OUTLOOK (08 OCTOBER - 07 NOVEMBER) Degraded HF propagation conditions possible: 12-13 Oct, 30 Oct PLEASE NOTE: Space weather conditions can frequently be determined by short timescale events that cannot be forecast a week in advance, particularly at solar maximum. For an explanation of some of the terms in this report, go to https://www.sws.bom.gov.au, and follow links to Educational-> Glossary on Solar Terrestrial Terms. Australian Space Weather Forecasting Centre Bureau of Meteorology ASWFC at bom.gov.au www.bom.gov.au | www.sws.bom.gov.au