By Ron Smiley

PITTSBURGH (KDKA) — While most were sleeping, the Flash Flood Watch was extended through Thursday evening.

Now, a Flash Flood Warning has been issued for Allegheny, Washington and Westmoreland counties through 5:30 p.m. and 5:45 p.m. The National Weather Service says radar shows heavy rain set to move across the area, particularly from Peters Township to Elizabeth.

The watches and warnings are not a surprise with same dynamics in play that we have seen over the past couple of days.

(Photo Credit: KDKA)

Active weather will be caused by an environment that is conducive to big rain totals. We are stuck between high pressure situated over Tennessee with ample moisture in place. The merged jet stream is also causing lift along a persistent surface boundary. Everything is enhanced each and every day by surface heating that adds to instability.

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This pattern finally breaks down on Thursday as the high moves off the East Coast, allowing the boundary to lift and weaken.

We are expecting at least two dry days in a row on Friday and Saturday with a good chance Sunday will also be completely dry.

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