NOAA SEC Report of Solar-Geophysical Activity 20 Feb 2002

:Product: Report of Solar-Geophysical Activity

:Issued: 2002 Feb 20 2210 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 051 Issued at 2200Z on 20 Feb 2002

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

to 20/2100Z:  Solar activity increased to high levels. Region 9825

(N16W81) produced an impulsive M5/1n flare at 20/0612 UT associated

with Type II and IV radio sweeps and an Earth-directed halo coronal

mass ejection (CME). Region 9825 also produced an impulsive M4 flare

at 20/0251 UT associated with Type II and IV radio sweeps and an

impulsive M4 at 20/0959 UT. This activity appeared to coincide with

the rapid emergence of opposite-polarity flux northwest of the

leader spots, but detailed analysis was hampered by its proximity to

the west limb. Region 9830 (S16W06) remained the largest and most

magnetically complex sunspot group on the disk as multiple magnetic

delta configurations persisted within its leader spots. It produced

an impulsive C9/1n flare at 20/1626 UT associated with minor

discrete radio emission. New Region 9835 (S08W61) produced an

impulsive M3/Sf flare at 20/1711 UT. New Regions 9836 (S02W26) and

9837 (N07E70) were also numbered.

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

moderate to high levels. M-class flares are expected. There is a

chance for isolated major flare activity from Region 9825 (which

will cross the west limb oné‰juFebruary) and Region 9830.

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

Geomagnetic field activity was at quiet to unsettled levels. A brief

greater than 10 MeV proton event at geosynchronous orbit began at

20/0730 UT, reached a maximum of 13.5 PFU at 20/0755 UT, and ended

at 20/0800 UT. This proton event was likely associated with the

M5/1n flare at 20/0612 UT from Region 9825.

IIB.  Geophysical Activity Forecast:  Geomagnetic field activity is

expected to be at quiet to unsettled levels during 21- 22 February.

Field activity is expected to increase to unsettled to minor storm

levels on 23 February due to an expected CME passage associated with

today’s M5/1n flare. There will be a slight chance for a proton

flare during the period.

III.  Event Probabilities 21 Feb-23 Feb

Class M    75/70/70

Class X    10/10/10

Proton     10/10/10

PCAF       yellow

IV.  Penticton 10.7 cm Flux

Observed           20 Feb 193

Predicted   21 Feb-23 Feb  200/205/205

90 Day Mean        20 Feb 222

V.  Geomagnetic A Indices

Observed Afr/Ap 19 Feb  004/004

Estimated Afr/Ap 20 Feb  010/008

Predicted Afr/Ap 21 Feb-23 Feb  007/008-012/015-016/020

VI.  Geomagnetic Activity Probabilities 21 Feb-23 Feb

A.  Middle Latitudes

Active                15/30/40

Minor storm           05/10/15

Major-severe storm    01/01/05

B.  High Latitudes

Active                20/35/40

Minor storm           10/15/20

Major-severe storm    01/05/10