S.B.
I'm wondering if it could be acid reflux.
My son started throwing up like that and I thought he had the flu. But, it went on for a week with no other symptoms and I took him to the doctor. It was reflux.
The doctor gave my son some medication, I didn't let him eat or drink anything after a certain time and elevated the head of his bed so he wasn't laying flat.
The vomitting stopped immediately.
If it continues, I'd run it past her pediatrician.
Best wishes.