Daily Report

(last updated 11 May 2024 23:40 UT)

SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT ISSUED AT 2330UT/11 MAY 2024 FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE SUMMARY FOR 11 MAY AND FORECAST FOR 12 MAY - 14 MAY STATUS INDICATORS SOL:** RED ** MAG:** RED ** ION: ** RED ** ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx ----------------------------------------------------------- 1A. SOLAR SUMMARY Activity 11 May: R3 Flares Max Fadeout Freq. Sectors M1.0 0105UT possible lower West Pacific X5.8 0123UT probable all West Pacific M1.2 0743UT possible lower Mid East/Indian M1.7 0915UT possible lower Mid East/Indian M3.1 1018UT possible lower European X1.5 1144UT probable all European M1.2 2041UT possible lower East Pacific/ North American Observed 10.7 cm flux/Equivalent Sunspot Number for 11 May: 214/165 1B. SOLAR FORECAST 12 May 13 May 14 May Activity R2-R3 R2-R3 R2-R3 Fadeouts Probable Probable Probable 10.7cm/SSN 220/170 220/170 215/165 COMMENT: Solar activity on UT day 11-May was at the R3 level due an X5.8 flare from AR3664(S18W58, beta-gamma-delta). This region also produced the X1.5 and M8.8 flares. Several lower class R1 flares were also observed. This large and complex region has shown some growth and redistribution in its intermediate spots and some decay in its trailer spots. The regions solar longitude is now quite west, with subsequent CME events likely to be more component arrivals or increasingly Earth misses. Very small regions AR3670(N19E08, beta) and AR3671(N24E05, beta) are showing growth. New unnumbered very small spots have appeared at S25E25. There are currently seven numbered regions and one unnumbered region on the solar disk. All other sunspot regions are either stable or in decay. Solar activity is expected to be at R2-R3 levels over 12-14 May. The GOES solar proton flux reached S2 at the 10MeV energy level with a peak flux of 116PFU at 11/0910UT and is currently at S1. A 100MeV energy solar proton event was also observed with a peak flux of 7.8PFU at 11/0720UT. The X5.8 flare was associated with a CME with a component impact expected to arrive 13/1300UT. The M8.8 flare was associated with a narrow westward CME and is modelled as an Earth miss. The X1.5 flare was not associated with a CME. Following the strong shock observed in the solar wind at 10/1637UT, the solar wind environment on 11-May was extremely enhanced. The solar ranged from 592 to 993 km/s and is currently near 850 km/s. The peak total interplanetary field strength (IMF, Bt) was 56 nT and the north-south IMF component (Bz) range was +22 to -50 nT, with Bz strongly orientated southwards during the interval 11/0000-1430UT. The solar winds IMF Bt has now greatly reduced, however the solar wind speed is still fast and is currently at 850km/sec. A partial shock signature is evident in the solar wind at 11/1756UT. Further CMEs are arrivals are expected over 12-May and 13-May which are expected to induce less severe activity. These CMEs are associated with an X1 flare at 09/144UT, an X3.9 at 10/0654UT and an X5.8 at 11/0123UT. The last event has been modelled more as a component arrival due to AR3664 increasingly westward solar longitude at the time of the event. Two small isolated coronal holes are visible on the solar disk at N25W35 and S35W35. ----------------------------------------------------------- 2A. MAGNETIC SUMMARY Geomagnetic field for Australian Region 11 May: G4 Estimated Indices 11 May : A K Australian Region 127 76788655 Cocos Island 64 55667554 Darwin 76 65677545 Townsville 110 76787555 Learmonth 131 76788665 Alice Springs 98 76777555 Gingin 123 76688665 Canberra 129 66888654 Kennaook Cape Grim 207 76999755 Hobart 227 87999755 Estimated Antarctic Regional K Indices 11 May : Macquarie Island 211 76999765 Casey 61 65666545 Mawson 191 76765899 Observed Regional daily pc3 Indices 11 May : Darwin 92 (Minor storm) Townsville 160 (Severe storm) Learmonth NA Alice Springs 180 (Severe storm) Gingin NA Canberra NA Pc3 pulsations are high frequency (10-45 second period) variations of the Earths magnetic field. Daily pc3-indices are the daily sum of 20 minute pc3-indices for that station and have been shown to be well correlated with rejection of high resolution aeromagnetic survey flight-line data. NOTE: Indices may have been generated from data obtained in cooperation with the following organisations: Geoscience Australia, University of Newcastle Space Physics Group, Australian Government Antarctic Division and International Center for Space Weather Science and Education, Japan. Estimated AFr/Ap Indices 11 May : A Fredericksburg 268 Planetary 317 Observed AFr/Ap Indices 10 May : A K Fredericksburg 80 Planetary 157 3322 3999 2B. MAGNETIC FORECAST Date Ap Conditions 12 May 75 G3 13 May 45 G1-G2 14 May 18 G0 COMMENT: ASWFC Geomagnetic Warning 24 was issued on 11 May and is current for 11-12 May. G4 geomagnetic conditions were observed in the Australian region on UT day 11-May, with G5 geomagnetic conditions observed in the Antarctic region. The geomagnetic storm activity was induced by several CMEs. Further CME arrivals are anticipated on 12 and 13-May, which are expected to induce G3 conditions. Geomagnetic activity is then expected to decline by 14-May. ----------------------------------------------------------- 3A. GLOBAL HF PROPAGATION SUMMARY Latitude Band Date Low Middle High 11 May Fair Poor-fair Poor(PCA) PCA Event : 10MeV Proton/PCA Event Began at 1350UT 10/05, Ended at 0050UT 11/05 and, 10MeV Proton/PCA Event Began 11 05 2024 0210UT and is in progress and, 100MeV Proton/PCA Event Began 11 05 2024 0155UT and is in progress 3B. GLOBAL HF PROPAGATION FORECAST Latitude Band Date Low Middle High 12 May Fair-normal Poor-fair Poor(PCA) 13 May Fair-normal Poor-fair Poor 14 May Normal Normal-fair Fair COMMENT: HF radio communication conditions on UT day 11-May were strongly degraded due to severe geomagnetic storm activity. Degraded HF conditions are again expected for middle to high latitudes for 12-May. Strong equatorial scintillation was observed in the Australian region. High latitude/polar cap HF communications have also been impact by increased absorption on 11-May. ----------------------------------------------------------- 4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY Date T index 11 May 113 Observed Australian Regional MUFs Cocos Island Region: Near predicted monthly values during local day. Enhanced by 30% during local night. Niue Island Region: Near predicted monthly values during local day. Enhanced by 70% during local night. Northern Australian Region: Depressed by 20% during local day. Enhanced by 40% during local night. Enhanced by 30% after local dawn. Southern Australian Region: Depressed by 55% during local day. Enhanced by 25% during local night. Antarctic Region (Casey/Davis/Mawson): Proton event in progress, increased absorption observed. Monthly T index: Month T index Apr 125 May 114 Jun 116 4B. AUSTRALIAN REGION IONOSPHERIC FORECAST Date T index MUFs 12 May 100 Near predicted monthly values 13 May 70 15 to 30% below predicted monthly values 14 May 90 Near predicted monthly values COMMENT: ASWFC Preliminary HF Communications Warning 49 was issued on 9 May and is current for 10-12 May. ASWFC SWF HF Communications Warning 50 was issued on 9 May and is current for 10-12 May. Maximum usable frequencies (MUFs) on UT day 11-May were strongly depressed by 20-50% during the local day and strongly enhanced during local night hours in association with geomagnetic storm activity. Strong spread F was observed during local night hours for southern Australian region sites. A shortwave fadeout was observed 11/0101-0405UT in association with the X5 flare. An extended interval of equatorial ionospheric scintillation was observed at Darwin, Niue and Weipa 11/1139-2040UT. MUFs are expected to be initially near predicted monthly values on 12-May, becoming degraded overnight with further ionospheric depressions, though not as severe, are likely on 13-May. Frequent shortwave fadeouts are expected. ----------------------------------------------------------- 5. SPACE ENVIRONMENT SUMMARY GOES satellite data for 10 May Daily Proton Fluence >1 MeV: 4.9E+08 Daily Proton Fluence >10 MeV: 1.2E+06 Daily Electron Fluence >2 MeV: 2.10E+06 (normal fluence) Electron Fluence Daily Deep Dielectric Discharge Probability: 1% Fluence (flux accumulation over 24hrs)/ cm2-ster-day. X-ray background: C5.2 DSCOVR Satellite Solar Wind Day Averaged Data for 10 May Speed: 425 km/sec Density: 6.7 p/cc Temp: 68700 K Bz: -2 nT (Courtesy Space Weather Prediction Center, Boulder USA) -----------------------------------------------------------