Status Report

NOAA SEC Report of Solar-Geophysical Activity 29 Sep 2001

By SpaceRef Editor
September 29, 2001
Filed under , ,
:Product: Report of Solar-Geophysical Activity
:Issued: 2001 Sep 29 2210 UT
# Prepared jointly by the U.S. Dept. of Commerce, NOAA,
#Space Environment Center and the U.S. Air Force.
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 272 Issued at 2200Z on 29 Sep 2001
IA.  Analysis of Solar Active Regions and Activity from  28/2100Z
to 29/2100Z:  Solar activity has been moderate.  Two M1/1f flares
were observed -- the first at 28/2125 UTC from Region 9634 (N12W15),
and the second a long duration event at 29/1106 UTC from Region 9636
(N13W02).  For the latter event, SOHO/LASCO imagery suggests an
associated faint halo with an earthward-directed component possible.
Region 9628 (S17W62), the largest on the visible disk, also
produced several optical flares with strong C-level enhancements
throughout the first half of the period.  New Region 9642 (N03E70)
was numbered today.
IB.  Solar Activity Forecast:  Solar activity is expected to be
predominantly moderate over the next three days.  Isolated major
flares are possible, particularly from Region 9628 and nearby Region
9632 (S18W48).
IIA.  Geophysical Activity Summary 28/2100Z to 29/2100Z:
Geomagnetic field activity has been quiet to active.  A 17 nT sudden
impulse was observed on the Boulder magnetometer at 29/0940 UTC,
preceded by an earlier shock passage observed on the ACE satellite. 
Several active periods occurred through the remainder of the day. 
Solar wind speed remains elevated and IMF signatures suggest the
predominant influence of a coronal hole high speed stream.  The
proton event which began on 25 September remains in progress but
continues to wane, with current 10MeV flux levels at about 25 pfu.
IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to be predominantly active for the next two days, under the
combined influence of high speed stream effects and possible
transient shock passages from the CME activity of 28 September. 
Isolated minor storm conditions may occur at higher latitudes during
this period.  Today's CME activity may further result in additional
shock passage effects on day three.  The proton event in progress is
expected to end within the next 24 to 36 hours, barring further
enhancement from any major flares.
III.  Event Probabilities 30 Sep-02 Oct
Class M    80/80/80
Class X    25/25/25
Proton     99/50/20
PCAF       yellow
IV.  Penticton 10.7 cm Flux
Observed           29 Sep 240
Predicted   30 Sep-02 Oct  240/240/235
90 Day Mean        29 Sep 175
V.  Geomagnetic A Indices
Observed Afr/Ap 28 Sep  010/013
Estimated Afr/Ap 29 Sep  015/020
Predicted Afr/Ap 30 Sep-02 Oct  020/030-020/020-018/018
VI.  Geomagnetic Activity Probabilities 30 Sep-02 Oct
A.  Middle Latitudes
Active                30/30/25
Minor storm           15/15/10
Major-severe storm    10/10/10
B.  High Latitudes
Active                35/35/30
Minor storm           20/20/15
Major-severe storm    15/10/10

SpaceRef staff editor.