Daily Report

(last updated 18 Apr 2018 23:43 UT)

SUBJ: SWS DAILY SOLAR AND GEOPHYSICAL REPORT ISSUED AT 2330UT/18 APRIL 2018 BY Space Weather Services FROM THE AUSTRALIAN SPACE FORECAST CENTRE SUMMARY FOR 18 APRIL AND FORECAST FOR 19 APRIL - 21 APRIL STATUS INDICATORS SOL:GREEN MAG:GREEN ION: GREEN ----------------------------------------------------------- 1A. SOLAR SUMMARY Activity 18 Apr: Very low Flares: none. Observed 10.7 cm flux/Equivalent Sunspot Number for 18 Apr: 71/6 1B. SOLAR FORECAST 19 Apr 20 Apr 21 Apr Activity Very low Very low Very low Fadeouts None expected None expected None expected 10.7cm/SSN 75/13 75/13 75/13 COMMENT: Solar activity was at Very Low levels on UT day 18 April. Very Low levels of solar flare activity are expected for the next three UT days, 19-21 April, with a remote chance of C-class flares. No Earth-directed CMEs were observed in the available imagery during the last 24 hours. The weak CME from a filament eruption that was observed on UT day 17 April has been modeled and it is not expected to be geoeffective. On UT day 18 April the solar wind speed was mainly around 300 km/s. The IMF Bt ranged between 2 nT and 8 nT, and the Bz component of IMF was between -5 nT and 4 nT. Solar winds are expected to become enhanced either late on 19 April or early on 20 April due to the influence of a recurrent negative-polarity equatorial coronal hole. ----------------------------------------------------------- 2A. MAGNETIC SUMMARY Geomagnetic field for Australian Region 18 Apr: Quiet to Unsettled Estimated Indices 18 Apr : A K Australian Region 4 10023211 Cocos Island 2 11012110 Darwin 4 11012212 Townsville 5 11123111 Learmonth 4 10023211 Alice Springs 3 11012211 Culgoora 3 00023111 Gingin 4 10013221 Canberra 4 00023210 Launceston 5 10023221 Hobart 4 00023220 Estimated Antarctic Regional K Indices 18 Apr : Macquarie Island 7 00034310 Casey 5 22212210 Mawson 15 33222235 Observed Regional daily pc3 Indices 18 Apr : Darwin 0 (Quiet) Townsville 0 (Quiet) Learmonth 0 (Quiet) Alice Springs 0 (Quiet) Gingin 0 (Quiet) Canberra 0 (Quiet) Melbourne 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 18 Apr : A Fredericksburg 7 Planetary 8 Observed AFr/Ap Indices 17 Apr : A K Fredericksburg 3 Planetary 3 0110 1111 2B. MAGNETIC FORECAST Date Ap Conditions 19 Apr 12 Quiet to Active 20 Apr 12 Unsettled to Active 21 Apr 8 Quiet to Unsettled COMMENT: Magnetic conditions were mainly at Quiet levels across the Australian region during the UT day, 18 April, with an Unsettled period in the middle of the UT day. Conditions are expected to be at Quiet levels for the start of the next UT day, 19 April, then increase to Unsettled to Active levels either late on 19 April or early on 20 April due to the influence of a recurrent coronal hole. ----------------------------------------------------------- 3A. GLOBAL HF PROPAGATION SUMMARY Latitude Band Date Low Middle High 18 Apr Normal Normal Normal PCA Event : No event. 3B. GLOBAL HF PROPAGATION FORECAST Latitude Band Date Low Middle High 19 Apr Normal Normal Normal-fair 20 Apr Normal Normal Normal-fair 21 Apr Normal Normal Normal ----------------------------------------------------------- 4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY Date T index 18 Apr 8 Observed Australian Regional MUFs Cocos Island Region: No data available during local day. No data available during local night. Niue Island Region: Depressed by 20% during local day. Near predicted monthly values during local night. Northern Australian Region: Depressed by 15% during local day. Depressed by 15% during local night. Southern Australian Region: Near predicted monthly values during local day. Enhanced by 25% during local night. Antarctic Region (Casey/Scott Base/Davis/Mawson): Near predicted monthly values over the UT day. Monthly T index: Month T index Mar 2 Apr 2 May 1 4B. AUSTRALIAN REGION IONOSPHERIC FORECAST Date T index MUFs 19 Apr 7 Near predicted monthly values 20 Apr -5 15 to 25% below predicted monthly values 21 Apr -5 15 to 25% below predicted monthly values COMMENT: On UT day 18 April, MUFs were near predicted monthly values over most of the Aus/NZ region. There were minor depressions in the Northern Australian region during the local day and night, and minor depressions in the Niue Island Region during the local night. There were a few cases of Sporadic E blanketing. MUFs are expected to be mostly near predicted monthly levels on 19 April, with minor to moderate depressions possible on 20-21 April due to forecast geomagnetic activity. ----------------------------------------------------------- 5. SPACE ENVIRONMENT SUMMARY GOES satellite data for 17 Apr Daily Proton Fluence >1 MeV: 9.0E+05 Daily Proton Fluence >10 MeV: 1.7E+04 Daily Electron Fluence >2 MeV: 1.70E+08 (moderate fluence) Electron Fluence Daily Deep Dielectric Discharge Probability:14% Fluence (flux accumulation over 24hrs)/ cm2-ster-day. X-ray background: A1.6 DSCOVR Satellite Solar Wind Day Averaged Data for 17 Apr Speed: 301 km/sec Density: 4.2 p/cc Temp: 13100 K Bz: -1 nT (Courtesy Space Weather Prediction Center, Boulder USA) -----------------------------------------------------------