Joint USAF/NOAA Report of Solar and Geophysical Activity 17 October 2010

:Product: Report of Solar-Geophysical Activity
:Issued: 2010 Oct 17 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 290 Issued at 2200Z on 17 Oct 2010
IA. Analysis of Solar Active Regions and Activity from 16/2100Z
to 17/2100Z: Solar activity was at low levels due to a few C-class
events from Region 1112 (S20W44), the largest a C1.7 x-ray event
observed at 17/0859Z. The region continued to evolve over the past
24 hours, increasing in both area and extent, while maintaining
Beta-Gamma magnetic characteristics. New Region 1116 (N22W14) was
numbered as a simple bi-polar spot group.
IB. Solar Activity Forecast: Solar activity is expected to be at
very low to low levels all three days of the forecast period (18 –
20 October), with a chance for M-class events from evolving Region
1112.
IIA. Geophysical Activity Summary 16/2100Z to 17/2100Z:
The geomagnetic field ranged from quiet to minor storm levels during
the period. Activity was at quiet to unsettled levels until about
17/0700Z when the field became disturbed. Geomagnetic activity
increased to active to minor storm levels through 17/0900Z,
returning to mostly quiet levels through the remainder of the
period. At about 17/0400Z, signatures at the ACE satellite indicated
gradual increases in temperature, density and wind velocity. The Bz
component of the interplanetary magnetic field (IMF) turned
southward, and remained south for about 7 hours, reaching a maximum
deflection of -7nT at 17/0737Z. The Bt component of the IMF reached
a maximum of 10nT at 17/0520Z. This short-lived disturbance is
thought to have been a result of a glancing blow from the
slow-moving CME observed on 10 October.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at quiet to active levels all three days of the
forecast period (18 – 20 October). Isolated minor storm periods are
possible on 19 October. A coronal hole high speed stream (CH HSS) is
expected to rotate into a geoeffective position late on 18 October,
followed by a second geoeffective CH HSS likely to arrive early on
20 October. These features, coupled with possible effects from the
CME observed on 14 October, expected to arrive on 19 October, are
the reasons for the forecasted increase in geomagnetic activity.
III. Event Probabilities 18 Oct-20 Oct
Class M 25/25/25
Class X 01/01/01
Proton 01/01/01
PCAF Green
IV. Penticton 10.7 cm Flux
Observed 17 Oct 084
Predicted 18 Oct-20 Oct 086/086/086
90 Day Mean 17 Oct 081
V. Geomagnetic A Indices
Observed Afr/Ap 16 Oct 003/006
Estimated Afr/Ap 17 Oct 009/013
Predicted Afr/Ap 18 Oct-20 Oct 008/010-012/012-008/010
VI. Geomagnetic Activity Probabilities 18 Oct-20 Oct
A. Middle Latitudes
Active 20/30/20
Minor storm 05/15/05
Major-severe storm 01/01/01
B. High Latitudes
Active 25/35/25
Minor storm 15/20/15
Major-severe storm 01/01/01