The weather service said the best chance for severe storms to develop will be late Friday afternoon into Friday evening.
The warning is for Northumberland, Juniata, Snyder and Perry County as well as southeastern Union County until 5:30 p.m. The storms are expected to be heaviest between 7 and 10 p.m.
"Damaging winds are probably the main threat" from Thursday's storms, Davis said.
A moderate rip current risk was in effect through Wednesday night, according to the weather service in Newport-Morehead City. This will bring a chance of showers and thunderstorms on Friday afternoon into Friday evening. With the big increase in temperatures Saturday, there will also be a chance of more scattered thunderstorms. Scattered damaging wind gusts to 70 miles per hour are likely.
Wednesday's storm toll rises to 16 in west UP
In Uttar Pradesh, dust storm, lightning and heavy rain claimed 16 lives in Mathura, Etawaha, Aligarh, Hathras and Agra districts. Most of the deaths were caused by falling walls or trees in Etawah and Mathura districts, an official at the authority told AFP.
Sunday's Mother's Day forecast isn't looking to spectacular at the moment, with highs in the mid-60s and showers possible through the day.
An unseasonably strong high will dominate the upper-level weather pattern through the weekend.
It should be dry Monday for the start of the workweek, the weather service said.