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 2144 LANDED 5:11 PM ET, ~16 MIN LATE · SCHEDULED TIME UNKNOWN
Today

WN 2144 · STL → BOS

took off 1:50 PM CT · landed 5:11 PM ET (scheduled time unknown)
Forecast issued Tue 4:00 PM ET · 1h after departure

Odds over time

Arrive at BOS more than 15 minutes late?
46% 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% 11h 6h Departs Now Lands