Status Report

Joint USAF/NOAA Report of Solar and Geophysical Activity 27 Apr 2005

By SpaceRef Editor
April 27, 2005
Filed under , ,

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

Updated 2005 Apr 27 2210 UTC

Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 117 Issued at 2200Z on 27 Apr 2005

IA. Analysis of Solar Active Regions and Activity from 26/2100Z
to 27/2100Z: Solar activity decreased to very low levels. Region
756 (S06E42) was limited to the production of low level B-class
flares during the period. Sunspot area underwent a rapid increase
today with most the of growth being attributed to the southern delta
structure. Further magnetic analysis indicates that there may be a
delta structure just north of center in the trailing portion of the
large spot. Plage fluctuations and surging have been reported
throughout the period. Region 755 (S13W54) had several umbra
re-emerge today and remains simply structured. No new regions were
numbered today.

IB. Solar Activity Forecast: Solar activity is expected to be at
low levels. Region 756 has the capability of producing an isolated
M-class flare.

IIA. Geophysical Activity Summary 26/2100Z to 27/2100Z:
The geomagnetic field was at quiet levels again today.

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at quiet to unsettled levels. There is a slight
chance that the partial halo CME observed on 25-26 April might
produce isolated active conditions on 29 April.

III. Event Probabilities 28 Apr-30 Apr

  • Class M 30/30/30
  • Class X 01/01/01
  • Proton 01/01/01
  • PCAF green

IV. Penticton 10.7 cm Flux

  • Observed 27 Apr 095
  • Predicted 28 Apr-30 Apr 100/100/100
  • 90 Day Mean 27 Apr 090

V. Geomagnetic A Indices

  • Observed Afr/Ap 26 Apr 002/005
  • Estimated Afr/Ap 27 Apr 001/005
  • Predicted Afr/Ap 28 Apr-30 Apr 003/008-010/010-008/010

VI. Geomagnetic Activity Probabilities 28 Apr-30 Apr

A. Middle Latitudes

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

B. High Latitudes

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

SpaceRef staff editor.