Status Report

Joint USAF/NOAA Report of Solar and Geophysical Activity 17 Jun 2005

By SpaceRef Editor

June 17, 2005

Filed under Space Weather Prediction Center (NOAA), Space Weather Solar-Geophysical Activity, US

Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Environment Center and the U.S. Air Force.

Updated 2005 Jun 17 2210 UTC

Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 168 Issued at 2200Z on 17 Jun 2005

IA. Analysis of Solar Active Regions and Activity from 16/2100Z
to 17/2100Z: Solar activity is expected to be low. Newly numbered
Region 780 (S07E66) produced the only C-class activity of the
period, a C1 flare at 17/1904Z. Active Regions 775 (N10, L=055) and
776 (S05, L=046) have both rotated around the west limb. A post CME
loop system on the west limb persisted through the early part of
this period following yesterday’s M4 proton flare from Region 775.
Region 779 (S18W19) continues to slowly grow and is now an E-type
beta-gamma spot group; however, no activity of note occurred.

IB. Solar Activity Forecast: Solar activity is expected to be low.
C-class flares are possible from Regions 779 and 780.

IIA. Geophysical Activity Summary 16/2100Z to 17/2100Z:
The geomagnetic field was quiet to active. The most disturbed
conditions occurred early in the period during intervals of
sustained southward Bz. Solar wind speed decreased from over 650
km/s to under 550 km/s by the end of the period. The elevated solar
wind conditions are due to the combined effects of CME transient
flow and a high speed coronal hole stream. A greater than 100 MeV
proton event began at 16/2125Z following yesterday’s M4 flare. The
event ended at 17/0730Z with a peak flux of 2.9 pfu at 16/2315Z. A
greater than 10 MeV proton event began at 16/2200Z, peaked at
17/0500Z at 44 pfu, and ended at 17/1805Z. The greater than 2 MeV
electron flux at geosynchronous orbit was at high levels again
today.

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to range from quiet to minor storm levels. Elevated solar
wind speed is expected to produce occasional active conditions on 18
June. It is unlikely that much of the ejecta associated with
yesterday’s M4 flare and CME is Earth directed; however, a glancing
blow may create active to minor storm periods on 19 June. Quiet to
unsettled levels are expected on 20 June. The greater than 10 and
greater than 100 MeV protons are expected to return to background
levels over the next day.

III. Event Probabilities 18 Jun-20 Jun