A flood watch has been issued by the National Weather Service ahead of what is expected to be a rainy Christmas Eve morning in the Coachella Valley. 
The flood watch, which will take effect at midnight Thursday and last through noon Friday, was issued because an atmospheric river is expected to deliver heavy rainfall to the region. The National Weather Service website states that a flood watch means that flooding is possible and people should be prepared to take action.
The National Oceanic and Atmospheric Administration defines atmospheric rivers as  “relatively long, narrow region in the atmosphere — like rivers in the sky — that transport most of the water vapor outside of the tropics.”
“It looks like it will start raining in the Coachella Valley early Friday morning and it looks like it will rain pretty consistently into Friday afternoon,” said NWS meteorologist Casey Oswant.
Between 0.5 and 1 inch of rain are expected in the Coachella Valley, Oswant said, with higher rainfall totals expected closer to the San Gorgonio Pass and less rain expected moving east. 
Holiday travelers will need to exercise caution, particularly those traveling through or near the San Gorgonio Pass, she said. 
“People definitely should watch out for flooding,” said Oswant. “The washes might start flowing and cross over the road. ‘Turn around, don’t drown’ is what we like to say.” 
The flood watch also covers a large swath of southwest Southern California extending west of the Coachella Valley and south of Anaheim and Long Beach. 
The storm comes as the Coachella Valley enters a winter period where rainfall is more common, said Oswant. However, this storm is expected to bring as much or more rain than the valley typically sees in the whole month of December, which is about 0.68 inches.
Oswant added that it could also get pretty windy in the valley, especially along the San Gorgonio Pass and on the mountain slopes. 
According to the NWS forecast, the Coachella Valley is also expected to see rain again on Christmas Day. There is also a slight chance of rain on Sunday and Monday. 
Paul Albani-Burgio covers breaking news and the City of Palm Springs. Follow him on Twitter at @albaniburgiop and via email at paul.albani-burgio@desertsun.com.