Abstract
We report on an extreme ionospheric plasma density enhancement and
Global Positioning System (GPS) scintillation at dawn, observed within
the expanding equatorial ionization anomaly (EIA). The total electron
content (TEC) in central America reached 50~TECu at
sunrise, the value almost twice as high as the normal afternoon peak.
The enhanced EIA expanded poleward and westward from just below
20$^\circ$ magnetic latitude (MLAT) to beyond
30$^\circ$ MLAT at sunrise. The chief ramification
of the enhanced EIA was strong GPS scintillation which was observed
poleward of 30$^\circ$ northern MLAT and lasted
until 8:00 local time. In total, the scintillation lasted for
$\sim$5~hours at latitudes north of
20$^\circ$MLAT in central America.