SEPTA will suspend most of its operations for 24 hours beginning Saturday morning due to a looming snowstorm that threatens to drop roughly a foot of snow on Philadelphia.

SEPTA General Manager Jeffrey Knueppel said all service except the Broad Street Line and Market-Frankford Line will be suspended beginning at 4 a.m. Saturday, NBC Philadelphia reported.

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“The Broad Street and Market-Frankford lines are important to carry emergency personnel, hospital employees and other essential workers during the storm,” Knueppel said at a news conference Friday.

Knueppel said the system will likely be fully up and running by Sunday morning, depending on conditions. 

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“Customers who use CCT connect service are encouraged to move up critical medical appointments to today. Service on Saturday and Sunday will be limited to dialysis patient only," Knueppel said.

Snow is expected to start falling late Friday night and will last until early Sunday morning.