NOAA SEC Report of Solar-Geophysical Activity 20 Mar 2002

:Product: Report of Solar-Geophysical Activity

:Issued: 2002 Mar 20 2210 UTC

# 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 079 Issued at 2200Z on 20 Mar 2002

IA.  Analysis of Solar Active Regions and Activity from  19/2100Z

to 20/2100Z:  Solar activity was low. A long-duration C4 flare began

at 1544 UTC and lasted until 1919 UTC. The corresponding source on

the disk was not entirely certain but it seemed most likely to be

correlated to activity observed in Region 9866 (S08W73). Additional

C-class subflares occurred during the day, with many of these coming

from Region 9875. Region 9875 showed steady growth during the past

24 hours. Three new region were assigned today: 9876 (S16E65), 9877

(N18W29), and 9878 (N08E75).

IB.  Solar Activity Forecast:  Solar activity is expected to be low

to moderate during the next three days.

IIA.  Geophysical Activity Summary 19/2100Z to 20/2100Z:

The geomagnetic field was quiet until 1329 UTC when a sudden impulse

(SI) occurred. Since then the geomagnetic field has ranged from

quiet to active levels. The SI was caused by an interplanetary shock

which was seen at the ACE spacecraft at 1307 UTC. The disturbance is

most likely the result of the halo CME was observed in LASCO C2 at

18/0254 UTC. The shock also pushed the greater than 10 MeV proton

fluxes up to about 19 PFU at 1525 UTC. The proton event fluxes

dropped below event level at 1820 UTC.

IIB.  Geophysical Activity Forecast:  The geomagnetic field is

expected to be mostly unsettled for the next three days. There is a

chance for some isolated active levels on the second day as a

possible response to yesterday’s partial halo CME.

III.  Event Probabilities 21 Mar-23 Mar

Class M    50/50/50

Class X    05/05/05

Proton     10/10/05

PCAF       yellow

IV.  Penticton 10.7 cm Flux

Observed           20 Mar 188

Predicted   21 Mar-23 Mar  175/170/165

90 Day Mean        20 Mar 213

V.  Geomagnetic A Indices

Observed Afr/Ap 19 Mar  015/017

Estimated Afr/Ap 20 Mar  010/010

Predicted Afr/Ap 21 Mar-23 Mar  010/010-015/015-010/008

VI.  Geomagnetic Activity Probabilities 21 Mar-23 Mar

A.  Middle Latitudes

Active                25/35/25

Minor storm           20/25/20

Major-severe storm    10/15/10

B.  High Latitudes

Active                25/35/25

Minor storm           20/25/20

Major-severe storm    10/15/10