Joint USAF/NOAA Report of Solar and Geophysical Activity 07 April 2012

Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Weather Prediction Center and the U.S. Air Force.
Updated 2012 Apr 07 2200 UTC

Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 098 Issued at 2200Z on 07 Apr 2012

IA. Analysis of Solar Active Regions and Activity from 06/2100Z
to 07/2100Z: Solar activity was low. Region 1452 (N17W23) produced a
C2 x-ray flare and occasional B-class flares. It gradually decayed
to a small B-type group during the period. Region 1450 (N15W59)
gradually decayed to a C-type group during the period and produced
an isolated B-class flare. However, it retained a beta-gamma
magnetic configuration. No new regions were numbered.

IB. Solar Activity Forecast: Solar activity is expected to be very
low to low during days 1 – 3 (08 – 10 April) with isolated C-class
flares likely from Region 1452.

IIA. Geophysical Activity Summary 06/2100Z to 07/2100Z:
The geomagnetic field was quiet to active with minor to major storm
periods at high latitudes during 07/0900 – 1500Z. This activity was
associated with a period of sustained southward IMF Bz, enhanced IMF
Bt, and increased solar wind speeds.

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at mostly quiet levels until late on day 1 (08
April). A CME passage is expected to commence late on day 1 (from
the partial-halo CME observed on 05 April). Consequently, activity
is expected to increase to unsettled levels beginning late on day 1
and continue until early on day 3 (10 April). There will also be a
chance for active levels on day 2 (09 April) along with a chance for
minor storm levels at high latitudes. Activity is expected to
decrease to quiet to unsettled levels on day 3 as CME effects
subside.

III. Event Probabilities 08 Apr-10 Apr
Class M 05/05/05
Class X 01/01/01
Proton 01/01/01
PCAF Green

IV. Penticton 10.7 cm Flux
Observed 07 Apr 099
Predicted 08 Apr-10 Apr 100/100/100
90 Day Mean 07 Apr 116

V. Geomagnetic A Indices
Observed Afr/Ap 06 Apr 003/004
Estimated Afr/Ap 07 Apr 010/010
Predicted Afr/Ap 08 Apr-10 Apr 008/010-013/015-006/008

VI. Geomagnetic Activity Probabilities 08 Apr-10 Apr
A. Middle Latitudes
Active 10/25/10
Minor storm 01/15/01
Major-severe storm 01/01/01
B. High Latitudes
Active 15/30/15
Minor storm 10/25/10
Major-severe storm 05/10/05