Launch Weather: A large surface high pressure system pushed east into the Atlantic on L-1 Day. Stratocumulus covered most of the Atlantic east of Florida on the morning of the launch. The stratocumulus clouds were expected to diminish during the day. The pressure gradient over Florida was increasing on launch day due to an eastward moving low-pressure system over the Midwest. Surface winds were expected to increase by late morning and remain gusty through the launch count. The launch-day forecast had scattered low clouds, with a slight chance of a ceiling, and gusty southeast winds, near headwind and crosswind limits. A 10-degree change in the wind direction would take the winds out of limits, for either headwinds or crosswinds. The coverage of the stratocumulus diminished as expected during the launch count but areas of clouds continued to move towards to coast. Surface winds remained gusty out of the southeast, occasionally going out of limits. During the last few hours of the launch count satellite imagery confirmed that an area of broken low clouds moving towards the Shuttle Landing Facility would not impact an RTLS landing and the slight chance of a ceiling was removed from the forecast. Wind speeds diminished slightly and the forecast was amended to reflect that change.

Landing Weather: The landing day's weather over Florida was dominated by a nearly stationary Bermuda high pressure system. The sea-breeze winds and scattered showers of the previous days were not expected on landing day due to a weakening gradient and mid-level drying. This drying had been consistently advertised in the models over the previous days. Early morning winds at KSC were expected to be light and variable, becoming east to southeast by around noon for the early afternoon landing. Areas of scattered to broken clouds were expected to dot the mostly clear skies over the Atlantic east of Florida through the day. SMG forecast that scattered clouds would develop over the land around late morning with daytime heating. The only concern was the slight possibility that one of the small areas of broken clouds would effect the Cape around landing time. As the landing count progressed scattered low clouds moved in over KSC and the easterly winds developed. Scattered clouds began developing over the land by late morning and very little vertical development was observed in the clouds. An area of broken clouds east of KSC moving towards the Cape was being tracked by satellite imagery but it was determined prior to the de-orbit decision that these clouds would remain off-shore at landing time.

SMG Lead Meteorologist was Karl Silverman working his 47th mission, 8th as Lead. Richard Lafosse was the Assistant Lead and Doris Rotzoll was the Lead Techniques Development Unit Meteorologist.

Submitted by:
Karl Silverman
STS-110 Lead Meteorologist