Status Report

Joint USAF/NOAA Report of Solar and Geophysical Activity 30 October 2011

By SpaceRef Editor
October 30, 2011
Filed under , , ,

:Product: Report of Solar-Geophysical Activity
:Issued: 2011 Oct 30 2200 UTC
# Prepared jointly by the U.S. Dept. of Commerce, NOAA,
# Space Weather Prediction Center and the U.S. Air Force.
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 303 Issued at 2200Z on 30 Oct 2011
IA. Analysis of Solar Active Regions and Activity from 29/2100Z
to 30/2100Z: Solar activity was low. There were several C-class
flares during the past 24 hours. Most of these were from newly
emerging Region 1334 (N13E24) which is currently a C-type group with
area of about 70 millionths. Region 1330 (N08W35) continues to be
the largest group on the disk and managed to produce two C-class
flares. However, Region 1330 appears to be decreasing in sunspot
area. There continues to be indicators of a new region rotating
around the east limb with latitude around 15 degrees North. A CME
was observed in the LASCO C2 coronagraph beginning at about 0812Z
but was confirmed to be from the backside using STEREO imagery.

IB. Solar Activity Forecast: Solar activity is expected to be
generally low. There continues to be, however, a slight chance for
an isolated M-class flare.

IIA. Geophysical Activity Summary 29/2100Z to 30/2100Z:
The geomagnetic field was initially quiet. An increase to unsettled
to active levels with some minor storm periods at high latitudes
occurred after 1003Z after a disturbance in the solar wind impacted
the magnetosphere. The disturbance was also seen at the ACE
spacecraft at about 0855Z: solar wind increased from around 280 km/s
to about 320 km/s, Bt from 3 nT up to about 6 nT, and density from
less than 1 p/cc up to about 6 p/cc. The solar wind parameters
continued to show somewhat elevated signatures for the remainder of
the period. There was also a solar sector boundary crossing on 29
October at about 2111Z from negative to positive polarity and the
presence of a positive sector was clearly indicated throughout the
interval. In addition, solar wind speed and temperature were showing
an increasing trend near the end of the interval. It appears that
the initial phase of the disturbance was related to the DSF/CME that
occurred on 26 October. However, it also appears that the expected
high speed stream is beginning to be evident in the solar wind

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be unsettled for the next 24 hours (31 October) with a
chance for active periods as the high speed stream is expected to be
more clearly evident. Quiet to unsettled levels are expected for the
second day (01 November) and quiet levels are expected to
predominate on the third day (02 November).

III. Event Probabilities 31 Oct-02 Nov
Class M 10/10/10
Class X 01/01/01
Proton 01/01/01
PCAF Green

IV. Penticton 10.7 cm Flux
Observed 30 Oct 127
Predicted 31 Oct-02 Nov 130/130/125
90 Day Mean 30 Oct 124

V. Geomagnetic A Indices
Observed Afr/Ap 29 Oct 002/002
Estimated Afr/Ap 30 Oct 007/008
Predicted Afr/Ap 31 Oct-02 Nov 010/010-005/008-005/005

VI. Geomagnetic Activity Probabilities 31 Oct-02 Nov
A. Middle Latitudes
Active 35/10/10
Minor storm 10/05/05
Major-severe storm 05/01/01
B. High Latitudes
Active 40/20/10
Minor storm 25/15/05
Major-severe storm 15/05/01

SpaceRef staff editor.