Status Report

Joint USAF/NOAA Report of Solar and Geophysical Activity 17 Dec 2004

By SpaceRef Editor
December 17, 2004
Filed under ,

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

Updated 2004 Dec 17 2210 UTC

Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 352 Issued at 2200Z on 17 Dec 2004

IA. Analysis of Solar Active Regions and Activity from 16/2100Z
to 17/2100Z: Solar activity was very low. Region 710 (S07W72) has
shown a slight increase in area and spot number, but remains quiet.
New regions 712 (S10E50) and 713 (S10E70) were numbered today.

IB. Solar Activity Forecast: Solar activity is expected to be very
low to low. There is a chance for a C-class flare from the new
regions near the southeast limb.

IIA. Geophysical Activity Summary 16/2100Z to 17/2100Z:
The geomagnetic field was at quiet to active levels with a period of
minor storming between 17/0300Z and 17/0600Z. The active to minor
storm levels were due to the continued influence of a geoeffective
coronal hole high speed stream. There was an increase in the solar
wind speed at ACE from approximately 550 km/s to 650 km/s during the
reporting period.

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be quiet to active with minor storm periods possible at
high latitudes on 18 December. Expect quiet to unsettled with
isolated active conditions on 19 December as the high speed coronal
hole stream subsides. Expect quiet to unsettled levels on 20

III. Event Probabilities 18 Dec-20 Dec

  • Class M 05/05/05
  • Class X 01/01/01
  • Proton 01/01/01
  • PCAF Green

IV. Penticton 10.7 cm Flux

  • Observed 17 Dec 090
  • Predicted 18 Dec-20 Dec 090/090/095
  • 90 Day Mean 17 Dec 104

V. Geomagnetic A Indices

  • Observed Afr/Ap 16 Dec 008/010
  • Estimated Afr/Ap 17 Dec 014/020
  • Predicted Afr/Ap 18 Dec-20 Dec 008/015-006/008-004/005

VI. Geomagnetic Activity Probabilities 18 Dec-20 Dec

A. Middle Latitudes

  • Active 20/15/10
  • Minor storm 10/10/05
  • Major-severe storm 01/01/01

B. High Latitudes

  • Active 25/20/15
  • Minor storm 15/10/10
  • Major-severe storm 05/05/01

SpaceRef staff editor.