By Llarisa Abreu

PHILADELPHIA (CBS) – High heat and excessive humidity return to the Delaware Valley on Tuesday. Highs are expected to soar into the mid 90’s and heat index values will hover between 103-104 degrees later in the day.

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A heat advisory is in effect for Philadelphia and surrounding counties and Berks from 11 a.m. Tuesday until 8 p.m. Wednesday.

The possibility for strong afternoon storms is on tap for today. Especially across northern communities. Strong thunderstorms look to develop over New England this afternoon and will drop into a portion of the Delaware Valley by this evening, mainly after 5 p.m. and before midnight.

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Dangerous heat and stifling humidity dominate again on Wednesday. Scattered afternoon and evening thunderstorms are possible on Wednesday with the highest coverage north and west of I-95.

The focus then turns to Tropical Storm Elsa and its influence on our weather Thursday, Thursday night and into Friday. The latest model guidance has brought the track of Elsa more westward with the storm center potentially passing over the region or just offshore. Much of the Delaware Valley is in the cone of uncertainty, as of the most recent update from the NHC. Thus, this increases our potential for more widespread heavy and even torrential rainfall. Elsa may impact us as a tropical depression or post-tropical system. The main threat will be flooding and flash flooding. The exact track and timing are TBD though moisture may start building in as early as Thursday morning. Additional threats may include gusty winds produced by embedded thunderstorms, gusty winds at the coast, and an isolated tornado.

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TROPICS: Sustained winds remain at 60 mph. Elsa will move near the lower FL keys overnight and is forecast to move north offshore of FL’s gulf coast before making landfall along the state’s northern big bend region on Wednesday. The storms will curve north and east by Wednesday night and make its closest approach to our area by Friday AM. Forecast continues to evolve.