Tracked live by the FAA, but its flight plan was first seen after takeoff, so we don't know the scheduled time and can't say whether it's late.

SOUTHWEST · FLIGHT WN 556 LANDED 5:31 PM CT, ~3 MIN LATE · SCHEDULED TIME UNKNOWN
Today

WN 556 · LAS → STL

took off 1:00 PM PT · landed 5:31 PM CT (scheduled time unknown)
Forecast issued Tue 9:00 PM ET · 5h after departure

Odds over time

Arrive at STL more than 15 minutes late?
51% chance · ±0 pts – · 24h
HOW SURE WE ARE Very high. The odds now come almost entirely from live conditions.
WEATHER FORECASTS LIVE IN THE AIR 0% 20% 40% 60% 80% 12h 6h Departs Lands