Forecast for Thursday, December 7

Issued: Wednesday, December 6 Launch Weather Officer: Kathy Winters, 45th Weather Squadron Synoptic Discussion: "A cold front will move through Central Florida Thursday causing isolated showers and significant cloud cover through the launch window. The probability of KSC weather prohibiting launch increased to 60 percent due to the significant low-level moisture expected with the front. High pressure behind the front will migrate over the Eastern US, increasing the pressure gradient over Central Florida causing launch wind and Shuttle Landing Facility (SLF) crosswind concerns. "Our primary concern for launch day is a low cloud ceiling." Clouds: Stratus few at 1,500 feet with tops at 2,500 feet and 1/8ths sky coverage; Stratus broken at 3,000 feet with tops at 4,000 feet and 5/8ths sky coverage; Altostratus broken at 6,000 feet with tops at 8,000 feet and 5/8ths sky coverage; and Cirrus broken at 20,000 feet with tops at 22,000 feet and 5/8ths sky coverage Visibility: 7 miles Launch Pad Winds: North-northwesterly from 340 degrees at 15 gusting to 22 knots Temperature: 58 degrees F Relative Humidity: 77 percent Weather: None Probability of Violating Weather Constraints: 60 percent Concerns: Low cloud ceiling

Times of note

Thursday's launch window: 9:31-9:41 p.m. EST Thursday's target liftoff time: 9:35:45 p.m. EST Friday's launch window: 9:08-9:18 p.m. EST Friday's target liftoff time: 9:13:13 p.m. EST Saturday's launch window: 8:42-8:52 p.m. EST Saturday's target liftoff time: 8:47:31 p.m. EST

Forecast for 24-hour delay

Friday's Probability of Violating Constraints: 70 percent Concerns: Low cloud ceiling, isolated showers, winds at launch pad 39B and crosswinds at Shuttle Landing Facility

Forecast for 48-hour delay

Saturday's Probability of Violating Constraints: 60 percent Concerns: Low cloud ceiling, isolated showers, winds at launch pad 39B and crosswinds at Shuttle Landing Facility