Joint USAF/NOAA Report of Solar and Geophysical Activity 18 Jul 2002

:Product: Report of Solar-Geophysical Activity

:Issued: 2002 Jul 18 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 199 Issued at 2200Z on 18 Jul 2002

IA.  Analysis of Solar Active Regions and Activity from  17/2100Z

to 18/2100Z:  Solar activity was at high levels.  Region 30 (N18W38)

produced an X1/2b flare at 18/0744 UTC with an associated Type II,

Type IV, and discrete frequency radio bursts.  SOHO/LASCO imagery

indicates a faint full halo CME.  Region 30 continues its gradual

decay but retains a beta-gamma-delta magnetic classification.

Region 36 (S07E37) has grown to 860 millionths and 26 spots.  This

large compact region did not produce any significant activity during

the last 24 hours.

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

moderate.  M-Class activity is expected from Region 30 and Region

36.  There is also the possibility of isolated X-class activity from

these regions.

IIA.  Geophysical Activity Summary 17/2100Z to 18/2100Z:

The geomagnetic field was at quiet to unsettled levels.  The PCA

event that began on 16/2215 UTC ended at 18/0300 UTC with a peak

absorption observed on the Thule 30 MHz riometer of 6 Db at 17/1600

UTC.  The greater than 10 MeV proton event that began on 16/1750 UTC

ended at 18/1550 UTC, peak value reached 234 pfu at 17/1600 UTC.

IIB.  Geophysical Activity Forecast:  The geomagnetic field is

expected to be quiet to active.  A CME shock from the X1 event on

18/0744 UTC is expected to arrive early on day two of the forecast

period.

III.  Event Probabilities 19 Jul-21 Jul

Class M    75/75/75

Class X    20/20/20

Proton     50/15/15

PCAF       Yellow

IV.  Penticton 10.7 cm Flux

Observed           18 Jul 181

Predicted   19 Jul-21 Jul  185/185/190

90 Day Mean        18 Jul 161

V.  Geomagnetic A Indices

Observed Afr/Ap 17 Jul  015/018

Estimated Afr/Ap 18 Jul  008/010

Predicted Afr/Ap 19 Jul-21 Jul  015/020-015/015-012/020

VI.  Geomagnetic Activity Probabilities 19 Jul-21 Jul

A.  Middle Latitudes

Active                25/35/25

Minor storm           10/15/10

Major-severe storm    01/05/01

B.  High Latitudes

Active                30/40/30

Minor storm           15/20/15

Major-severe storm    05/05/05