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From: oler@rho.uleth.ca (Cary Oler)
Newsgroups: rec.radio.info
Subject: (PKT): ALERT: MINOR (TO MAJOR) GEOMAGNETIC STORM ALERT
Message-ID: <$gmsa4052a.1994@ampr.org>
Date: Mon, 21 Feb 1994 11:59:31 MST
Followup-To: rec.radio.amateur.misc,rec.radio.shortwave
Lines: 72
Approved: rec-radio-info@ve6mgs.ampr.ab.ca

bid: $GMSA4052A
MAJOR STORM ALRT - 21FEB94
PACKET RADIO REPORT
SOLAR TERRESTRIAL DISPATCH
(PACKET: VE6MGS@VE6MC.#EDM.AB.CAN.NOAM)
(INTERNET: COLER@SOLAR.STANFORD.EDU)

ATTENTION:

        An energetic flare shock arrived much earlier than anticipated,
        at 09:00 UTC on 21 February.  The shock produced a sudden storm
        commencement at ground levels that measured a very respectable 93 nT
        at Boulder.  Simultaneously, protons at greater than 10 MeV increased
        rapidly to a peak of near 10,000 pfu at 09:10 UTC.  They have been
        falling ever since and should fall below event levels of 10 pfu by
        the end of the UTC day or early on 22 February.  Geosynchronous
        satellites are observing magnetopause crossings.  Both GOES-6 and
        GOES-7 have crossed the magnetopause boundary for relatively brief
        periods over the last 6 hours.  Additional crossings are expected
        throughout this UTC day.  Polar Cap Absorption soared to levels in
        excess of 10 to 12 dB, resulting in complete radio blackout
        conditions on HF transpolar and transauroral circuits.  Blackout or
        near-blackout conditions will continue despite falling PCA values,
        due to the energetic geomagnetic and auroral storm which is presently
        in progress.

    HIGH RISK PERIOD:  21 - 22 February (UT days)
MODERATE RISK PERIOD:  21 - 23 February

POTENTIAL LOW-MIDDLE LAT
      POT

      POT

POTENTIAL PEAK LOW-MIDDLE LAT
      POT

  EXPECTED DOMINATING LOW-MIDDLE LAT
        EXPECTED DOMINATING HIGH LAT

   POT
        POT
          EXPECTED HF PROPAGATION CONDITIONS:  FAIR

POTENTIAL FOR MIDDLE LAT
        POT
          EXPECTED HF PROPAGATION CONDITIONS:  FAIR TO OCCASIONALLY USELESS

  POT
        POT
          EXPECTED HF PROPAGATION CONDITIONS:  FREQUENT RADIO BLACKOUTS

POTENTIAL RISK FOR GEOSYNCHRONOUS MAGNETOPAUSE CROSSINGS:  * OBSERVED *

SUSPECTED SOURCE OF OBSERVED/EXPECTED ACT
        A well-placed, energetic proton flare.


---------------------------------       ---------------------------------
EST. POT
---------------------------------       ---------------------------------
       SEVERE STORM : 40 %                 LOW LAT
        MAJOR STORM : 40 %              MIDDLE LAT
        MINOR STORM : 20 %                HIGH LAT
     ACT
---------------------------------       ---------------------------------
 PROBABLE SI ASSOCIATION : OBSERVED      EST

ESTIMATED FORECAST PEAK PLANETARY 24-HOUR A-INDEX DURING STORM: 65 - 80


**  END OF PACKET ALERT (1/1)  **