NOAA SEC Report of Solar-Geophysical Activity 23 Jul 2001

:Product: Report of Solar-Geophysical Activity

:Issued: 2001 Jul 23 2200 UT

# 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 204 Issued at 2200Z on 23 Jul 2001

IA.  Analysis of Solar Active Regions and Activity from  22/2100Z

to 23/2100Z:  Solar activity has been low. Region 9545 (N08W72)

produced today’s largest event, a C5/Sf at 0623 UTC. This region

continues to grow and exhibits bright plage as it approaches the

west limb. The group produced additional C-class events throughout

the day. Region 9543 (S25W31) continues to be the largest group on

the disk. The group shows the addition of several newly emerged

small spots, while the older large spots seem to be in decay. An

impressive CME was seen in the LASCO/C2 field of view just off the

northwest limb today at 1131 UTC.

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

mostly low, but there continues to be a slight chance for an

isolated M-class event.

IIA.  Geophysical Activity Summary 22/2100Z to 23/2100Z:

The geomagnetic field was mostly quiet to unsettled. There was a

brief active period from 0300-0600 UTC.

IIB.  Geophysical Activity Forecast:  The geomagnetic field is

expected to be mostly unsettled during the next three days, with a

fair chance for some active periods. The increase is anticipated

from possible coronal hole effects.

III.  Event Probabilities 24 Jul-26 Jul

Class M    25/25/25

Class X    01/01/01

Proton     01/01/01

PCAF       green

IV.  Penticton 10.7 cm Flux

Observed           23 Jul 143

Predicted   24 Jul-26 Jul  140/140/135

90 Day Mean        23 Jul 156

V.  Geomagnetic A Indices

Observed Afr/Ap 22 Jul  006/011

Estimated Afr/Ap 23 Jul  012/012

Predicted Afr/Ap 24 Jul-26 Jul  012/015-012/015-012/015

VI.  Geomagnetic Activity Probabilities 24 Jul-26 Jul

A.  Middle Latitudes

Active                35/35/35

Minor storm           15/15/15

Major-severe storm    10/10/10

B.  High Latitudes

Active                40/40/40

Minor storm           20/20/20

Major-severe storm    10/10/10