Status Report

Joint USAF/NOAA Report of Solar and Geophysical Activity 16 May 2005

By SpaceRef Editor
May 17, 2005
Filed under , ,

Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Environment Center and the U.S. Air Force.
Updated 2005 May 16 2200 UTC

Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 136 Issued at 2200Z on 16 May 2005

IA. Analysis of Solar Active Regions and Activity from 15/2100Z
to 16/2100Z: Solar activity was moderate. Region 763 (S16E04)
produced three low level M-class flares. The largest of these
flares was a M3.5 at 15/2236 UTC. This region has increased in size
and complexity and now exhibits a beta-gamma magnetic
classification. Beginning at 16/1350 UTC, LASCO imagery showed what
appeared to be a partial halo CME. This event was actually two
events. The first was a DSF near Region 759 (N11W35) at
approximately 16/1243 UTC and the second was a backside event at
approximately 16/1358 UTC. Most of the front side ejection was
directed northward; therefore, the event is not likely to be

IB. Solar Activity Forecast: Solar activity is expected to be low
to moderate.

IIA. Geophysical Activity Summary 15/2100Z to 16/2100Z:
The geomagnetic field was at quiet to minor storm levels with a
period of major storm conditions between 16/0300 UTC and 0600 UTC.
Solar wind speed at ACE has been steadily decreasing from
approximately 800 km/s to 550 km/s by the end of the period. The Bz
component of the IMF has remained south between -1 nT and -10 nT
during this reporting period. The greater than 2 MeV electron flux
at geosynchronous orbit was high today.

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be unsettled to active with an isolated minor storm
period possible on 17 May due to a recurrent coronal hole high speed
stream becoming geoeffective. Quiet to unsettled conditions are
expected on 18 and 19 May.

III. Event Probabilities 17 May-19 May

  • Class M 50/50/50
  • Class X 10/10/10
  • Proton 10/10/10
  • PCAF yellow

IV. Penticton 10.7 cm Flux

  • Observed 16 May 099
  • Predicted 17 May-19 May 100/100/095
  • 90 Day Mean 16 May 092

V. Geomagnetic A Indices

  • Observed Afr/Ap 15 May 044/105
  • Estimated Afr/Ap 16 May 020/030
  • Predicted Afr/Ap 17 May-19 May 012/020-008/012-005/010

VI. Geomagnetic Activity Probabilities 17 May-19 May

A. Middle Latitudes

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

B. High Latitudes

  • Active 30/25/20
  • Minor storm 25/10/10
  • Major-severe storm 15/01/01

SpaceRef staff editor.