This is a flight level measurement from a hurricane hunter plane at 5:30. Surface sustained winds are somewhat less due to friction. This is a serious increase from earlier readings, and in fact the strongest winds recorded since the storm formed. This is also surprising since Keith's satellite presentation appears to have weakened and the same plane extrapolated the storm's lowest surface pressure at 957 millibars, up 14 from this morning (the higher the pressure the weaker the storm). It will be interesting to see how the NHC's next update handles these conflicting indicators.
Keith's eyewall, though shrouded by cirrus and thus not visible to satellite imagery, appears to still be intact. The eye itself has stalled midway between Belize City and San Pedro.
If the above wind measurements are correct, and if the eye resumes its westward crawl, folks in Belize City need to prepare for an extended period of very high winds. Reinforced concrete structures offer the best protection. If in a wood-frame building, stay away from windows and exterior doors, remain on the lowest floor in a windowless interior room such as a bathroom (unless in a flood-prone area, in which case you should have already evacuated to higher ground), and place heavy furniture against the windward wall (the wall on the west side of the building if the eye passes to your north).