Narrative:

We left ord as usual with scattered thunderstorms to the northwest and east. Our clearance was westerly vectors with a climb to FL300. The radar showed no known hazards on our route; but at FL260 ZAU cleared us for a right turn to about 300 degrees. We started to experience an increasingly rough ride to a point that we were in occasional moderate chop. At this point our radar picture showed turbulence at all forward quadrants and what appeared to be patchy outlines of a large precipitation area that looked to be the remnants of a large cell that had recently dissipated. The ride continued to deteriorate as ATC directed a further turn to the north that would send us deeper into the displayed precipitation. By this point we were experiencing continuous moderate turbulence with extensive st elmo's fire on the windscreen. I had every expectation at this point to expect severe turbulence ahead. We asked for vectors south to exit the precipitation area and ATC denied the clearance. At this point I declared an emergency with ATC and told them that we were turning to a heading of 240 degrees to exit the precipitation area to avoid passenger injury and possible structural damage to the aircraft. They directed us to stop our climb at FL260 and we complied. Once on the 240 degree heading; it was obvious that this new heading was still not enough to exit the area promptly so I told ATC that we were coming further south to a 220 degree heading. They acknowledged the call and kept us a FL260 for another 30-40 mi to avoid traffic overhead. Once we exited the precipitation; we were able to look back at a very defined line of clouds that had been the cause of the turbulence. Our radar did display other WX in the area that we could confirm with lightning so we knew the radar was actually performing properly. The remainder of the flight was uneventful.

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Original NASA ASRS Text

Title: MD80 FLT CREW ENCOUNTERS MODERATE TURB AND PRECIP DURING CLB FROM ORD; DECLARES EMER AND TURNS TO EXIT WX.

Narrative: WE LEFT ORD AS USUAL WITH SCATTERED TSTMS TO THE NW AND E. OUR CLRNC WAS WESTERLY VECTORS WITH A CLB TO FL300. THE RADAR SHOWED NO KNOWN HAZARDS ON OUR RTE; BUT AT FL260 ZAU CLRED US FOR A R TURN TO ABOUT 300 DEGS. WE STARTED TO EXPERIENCE AN INCREASINGLY ROUGH RIDE TO A POINT THAT WE WERE IN OCCASIONAL MODERATE CHOP. AT THIS POINT OUR RADAR PICTURE SHOWED TURB AT ALL FORWARD QUADRANTS AND WHAT APPEARED TO BE PATCHY OUTLINES OF A LARGE PRECIP AREA THAT LOOKED TO BE THE REMNANTS OF A LARGE CELL THAT HAD RECENTLY DISSIPATED. THE RIDE CONTINUED TO DETERIORATE AS ATC DIRECTED A FURTHER TURN TO THE N THAT WOULD SEND US DEEPER INTO THE DISPLAYED PRECIP. BY THIS POINT WE WERE EXPERIENCING CONTINUOUS MODERATE TURB WITH EXTENSIVE ST ELMO'S FIRE ON THE WINDSCREEN. I HAD EVERY EXPECTATION AT THIS POINT TO EXPECT SEVERE TURB AHEAD. WE ASKED FOR VECTORS S TO EXIT THE PRECIP AREA AND ATC DENIED THE CLRNC. AT THIS POINT I DECLARED AN EMER WITH ATC AND TOLD THEM THAT WE WERE TURNING TO A HDG OF 240 DEGS TO EXIT THE PRECIP AREA TO AVOID PAX INJURY AND POSSIBLE STRUCTURAL DAMAGE TO THE ACFT. THEY DIRECTED US TO STOP OUR CLB AT FL260 AND WE COMPLIED. ONCE ON THE 240 DEG HDG; IT WAS OBVIOUS THAT THIS NEW HDG WAS STILL NOT ENOUGH TO EXIT THE AREA PROMPTLY SO I TOLD ATC THAT WE WERE COMING FURTHER S TO A 220 DEG HDG. THEY ACKNOWLEDGED THE CALL AND KEPT US A FL260 FOR ANOTHER 30-40 MI TO AVOID TFC OVERHEAD. ONCE WE EXITED THE PRECIP; WE WERE ABLE TO LOOK BACK AT A VERY DEFINED LINE OF CLOUDS THAT HAD BEEN THE CAUSE OF THE TURB. OUR RADAR DID DISPLAY OTHER WX IN THE AREA THAT WE COULD CONFIRM WITH LIGHTNING SO WE KNEW THE RADAR WAS ACTUALLY PERFORMING PROPERLY. THE REMAINDER OF THE FLT WAS UNEVENTFUL.

Data retrieved from NASA's ASRS site as of January 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.