Status Report

Joint USAF/NOAA Report of Solar and Geophysical Activity 20 Jul 2004

By SpaceRef Editor
July 20, 2004
Filed under , ,

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

Updated 2004 Jul 20 2210 UTC

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 202 Issued at 2200Z on 20 Jul 2004

IA. Analysis of Solar Active Regions and Activity from 19/2100Z
to 20/2100Z: Solar activity increased to high levels today. Region
652 (N10E32) produced an M8/3b major flare at 20/1232Z with an
associated Tenflare of 3000 sfu’s. A Type II radio sweep with an
estimated shock velocity of 485 km/s and a Type IV also accompanied
the flare. The C6/Sf flare that occurred at 20/1126Z in conjunction
with the flare mentioned above produced what appears as a full halo
CME signature on LASCO C3 imagery. The delta structure seen as the
dominate intermediate spot remains intact and the magnetic
classification continues to exhibit beta-gamma-delta properties.
Region 652 continues to show growth in spot area which now exceeds
1600 millionths in white light. Region 649 (S10W27) continues to
show decay and was limited to C-class flare activity today. Delta
structures are evident in the leading polarity spot cluster while
yesterday’s trailing polarity delta spot is no longer discernible.
A significant and continued loss of spot area was again seen over
the past 24 hours. No new regions were numbered today.

IB. Solar Activity Forecast: Solar activity is expected to be at
moderate to high levels. Region 652 is capable of producing further
major flare activity.

IIA. Geophysical Activity Summary 19/2100Z to 20/2100Z:
The geomagnetic field was at quiet to unsettled levels.

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at predominantly unsettled levels on 21 and 22 July.
A shock passage from the combination of the C6 and M8 x-ray flares
today is expected to pass the ACE spacecraft early on 23 July.

III. Event Probabilities 21 Jul-23 Jul

  • Class M 75/75/75
  • Class X 30/30/30
  • Proton 15/20/25
  • PCAF green

IV. Penticton 10.7 cm Flux

  • Observed 20 Jul 175
  • Predicted 21 Jul-23 Jul 180/175/170
  • 90 Day Mean 20 Jul 098

V. Geomagnetic A Indices

  • Observed Afr/Ap 19 Jul 011/009
  • Estimated Afr/Ap 20 Jul 008/008
  • Predicted Afr/Ap 21 Jul-23 Jul 008/008-010/012-025/025

VI. Geomagnetic Activity Probabilities 21 Jul-23 Jul

A. Middle Latitudes

  • Active 15/15/40
  • Minor storm 05/10/25
  • Major-severe storm 01/05/15

B. High Latitudes

  • Active 15/20/45
  • Minor storm 05/15/25
  • Major-severe storm 01/05/15

SpaceRef staff editor.