Joint USAF/NOAA Report of Solar and Geophysical Activity 20 March 2011

:Product: Report of Solar-Geophysical Activity
:Issued: 2011 Mar 20 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 079 Issued at 2200Z on 20 Mar 2011
IA. Analysis of Solar Active Regions and Activity from 19/2100Z
to 20/2100Z: Solar activity was at very low levels. Region 1175
(N14W36) continued to grow in areal coverage and produced the
largest event of the period, a B7 X-ray event at 20/0733Z. Surging
and low-level B-class X-ray emissions from the vicinity of the SE
limb signal the return of old Region 1165 (S20, L=198).
IB. Solar Activity Forecast: Solar activity is expected to be at
predominately very low levels with a chance for C-class events for
the next three days (21 – 23 March). A slight chance for isolated
M-class activity exists all three days due to the return of old
Regions 1165 late on 21 March and 1164 (N24, L=179) late on 22
March.
IIA. Geophysical Activity Summary 19/2100Z to 20/2100Z:
The geomagnetic field was quiet. Solar wind velocities at the ACE
satellite remained low, averaging about 350 km/s. The Bz component
of the interplanetary magnetic field was southward the entire
period, not varying much beyond 0 to -5 nT.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at predominately quiet levels for days one and two
(21 – 22 March). By midday on day three (23 March), a small coronal
hole high speed stream is expected to rotate into a geoeffective
position.
III. Event Probabilities 21 Mar-23 Mar
Class M 10/20/20
Class X 01/01/01
Proton 01/01/01
PCAF green
IV. Penticton 10.7 cm Flux
Observed 20 Mar 092
Predicted 21 Mar-23 Mar 095/100/105
90 Day Mean 20 Mar 094
V. Geomagnetic A Indices
Observed Afr/Ap 19 Mar 002/004
Estimated Afr/Ap 20 Mar 003/005
Predicted Afr/Ap 21 Mar-23 Mar 005/005-005/005-008/008
VI. Geomagnetic Activity Probabilities 21 Mar-23 Mar
A. Middle Latitudes
Active 10/10/15
Minor storm 01/01/05
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/20
Minor storm 01/01/10
Major-severe storm 01/01/01