Narrative:

On our flight to ZZZ the WX packet indicated that there might be WX issues in ZZZ from a line of thunderstorms moving towards ZZZ. I had our departure city add an extra 1000 pounds of fuel over what the release called for. The flight proceeded uneventfully until directed to hold as published at intersection on 10 mi legs. Radar was indicating a small red cell just on the western edge of this holding pattern (on the outbound turn). I elected to fly the holding pattern anyway for 3 erroneous reasons. First; upon checking in on frequency I heard part of a conversation between ATC and another aircraft. ATC said something to the effect that it was just heavy rain showers and not convective activity (I don't know if this was exactly what was said but that was how I interpreted it). Second; I didn't think ATC would define a holding pattern that flew you into a storm cell (reinforcing the above conversation). Third; I selected the turbulence mode of the radar and saw no turbulence displays. 2 weeks earlier I had gone through an area of heavy rain displaying red on the radar that also had no turbulence displays without any problems; so I thought I was in the same situation here. During this whole time we were IMC. Because of the WX in the area I had the seat belt sign on and had the flight attendants clean the cabin early and take their seats. They were down when we started entered holding. We entered holding (15000 ft MSL; 220 KTS I think) and started our turn outbound. After about 90 degrees of turn; we entered the cell and experienced severe turbulence. I disconnected the autoplt (I was the PF) and increase bank to 60 degrees to hurry our exit. The aircraft pitched and rolled violently. Although the altitude and pitch varied I never really felt I had lost control. The first officer informed ATC we were unable to hold altitude due to turbulence. This lasted for 1-2 mins before we exited eastbound. We were then cleared to hold further east. By the time we were to start our inbound leg ATC cleared us for the arrival direct intersection. This was going to send us back through the WX. I asked if other aircraft were getting through and he said they were by deviating north and paralleling the approach. We asked for deviation clearance and started inbound. I stated that it looked like we could get to intersection but would have trouble avoiding WX after that. ATC suggested traffic might be getting in under the WX. We were cleared to descend but things were not looking good. We were now VMC/IMC. As we got closer we started to hit turbulence again. Not wanting to go through severe turbulence again and not seeing a clear course through; I elected to abort the arrival. We started a right turn back towards the east (initial turn north) and informed ATC. They told us we could not turn right because of a traffic conflict. We then started a left turn. The only traffic that I saw was left of us and high. The left turn was also going to put us back into the WX that we were offsetting north for. I declared an emergency and turned right. By this time I had experienced severe turbulence; had to help my new first officer with FMC programming (at one point xferring aircraft control to input FMC information); declare an emergency to avoid WX entry again and still didn't see a safe way into ZZZ. From the time we entered holding ZZZ had changed landing runways and had a new ATIS requiring more FMC work. A dispatch divert plan was also waiting for us. I was quickly reaching the point where I was reacting more than anticipating so I decided discretion was the better part of valor and called for a divert. The divert went uneventfully but it took me until ZZZ1 approach to get the message across that the only reason I declared an emergency was so I could turn in a certain direction. Having reviewed this event in my mind I obviously realized that I created most of the problem with my decision to fly a holding pattern that entered an area of severe WX. There was no reason why I couldn't have requested to hold further east. With a new first officer I also could have elected to stay in holding until we got everything set up and we could have inquired more thoroughly how others were getting into ZZZ. We could have descended in holding to see if we really could have flown under the WX. I had added extra gas before we took off specifically to give myself more time; which I then did not use. However; once things got going; the best decision I made was to divert and sort it all out on the ground. With regards to ATC; I'm still wondering why turning in the direction I was initially clear to deviate in was a problem. I was not left with any other option. No one was injured during the flight. Better radar interpretation. Be proactive and change ATC holding if the ATC plan is going to cause a problem. Slow down and don't rush events when there is gas and time to do so. If things are going downhill change the plan.

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Original NASA ASRS Text

Title: B737-700 FLT CREW REPORTS ENCOUNTERING SEVERE TURBULENCE DURING HOLDING AND DIVERSION TO ALTERNATE TO AVOID FURTHER ENCOUNTERS.

Narrative: ON OUR FLT TO ZZZ THE WX PACKET INDICATED THAT THERE MIGHT BE WX ISSUES IN ZZZ FROM A LINE OF TSTMS MOVING TOWARDS ZZZ. I HAD OUR DEP CITY ADD AN EXTRA 1000 LBS OF FUEL OVER WHAT THE RELEASE CALLED FOR. THE FLT PROCEEDED UNEVENTFULLY UNTIL DIRECTED TO HOLD AS PUBLISHED AT INTXN ON 10 MI LEGS. RADAR WAS INDICATING A SMALL RED CELL JUST ON THE WESTERN EDGE OF THIS HOLDING PATTERN (ON THE OUTBOUND TURN). I ELECTED TO FLY THE HOLDING PATTERN ANYWAY FOR 3 ERRONEOUS REASONS. FIRST; UPON CHKING IN ON FREQ I HEARD PART OF A CONVERSATION BTWN ATC AND ANOTHER ACFT. ATC SAID SOMETHING TO THE EFFECT THAT IT WAS JUST HVY RAIN SHOWERS AND NOT CONVECTIVE ACTIVITY (I DON'T KNOW IF THIS WAS EXACTLY WHAT WAS SAID BUT THAT WAS HOW I INTERPED IT). SECOND; I DIDN'T THINK ATC WOULD DEFINE A HOLDING PATTERN THAT FLEW YOU INTO A STORM CELL (REINFORCING THE ABOVE CONVERSATION). THIRD; I SELECTED THE TURB MODE OF THE RADAR AND SAW NO TURB DISPLAYS. 2 WKS EARLIER I HAD GONE THROUGH AN AREA OF HVY RAIN DISPLAYING RED ON THE RADAR THAT ALSO HAD NO TURB DISPLAYS WITHOUT ANY PROBS; SO I THOUGHT I WAS IN THE SAME SITUATION HERE. DURING THIS WHOLE TIME WE WERE IMC. BECAUSE OF THE WX IN THE AREA I HAD THE SEAT BELT SIGN ON AND HAD THE FLT ATTENDANTS CLEAN THE CABIN EARLY AND TAKE THEIR SEATS. THEY WERE DOWN WHEN WE STARTED ENTERED HOLDING. WE ENTERED HOLDING (15000 FT MSL; 220 KTS I THINK) AND STARTED OUR TURN OUTBOUND. AFTER ABOUT 90 DEGS OF TURN; WE ENTERED THE CELL AND EXPERIENCED SEVERE TURB. I DISCONNECTED THE AUTOPLT (I WAS THE PF) AND INCREASE BANK TO 60 DEGS TO HURRY OUR EXIT. THE ACFT PITCHED AND ROLLED VIOLENTLY. ALTHOUGH THE ALT AND PITCH VARIED I NEVER REALLY FELT I HAD LOST CTL. THE FO INFORMED ATC WE WERE UNABLE TO HOLD ALT DUE TO TURB. THIS LASTED FOR 1-2 MINS BEFORE WE EXITED EBOUND. WE WERE THEN CLRED TO HOLD FURTHER E. BY THE TIME WE WERE TO START OUR INBOUND LEG ATC CLRED US FOR THE ARR DIRECT INTXN. THIS WAS GOING TO SEND US BACK THROUGH THE WX. I ASKED IF OTHER ACFT WERE GETTING THROUGH AND HE SAID THEY WERE BY DEVIATING N AND PARALLELING THE APCH. WE ASKED FOR DEV CLRNC AND STARTED INBOUND. I STATED THAT IT LOOKED LIKE WE COULD GET TO INTXN BUT WOULD HAVE TROUBLE AVOIDING WX AFTER THAT. ATC SUGGESTED TFC MIGHT BE GETTING IN UNDER THE WX. WE WERE CLRED TO DSND BUT THINGS WERE NOT LOOKING GOOD. WE WERE NOW VMC/IMC. AS WE GOT CLOSER WE STARTED TO HIT TURB AGAIN. NOT WANTING TO GO THROUGH SEVERE TURB AGAIN AND NOT SEEING A CLR COURSE THROUGH; I ELECTED TO ABORT THE ARR. WE STARTED A R TURN BACK TOWARDS THE E (INITIAL TURN N) AND INFORMED ATC. THEY TOLD US WE COULD NOT TURN R BECAUSE OF A TFC CONFLICT. WE THEN STARTED A L TURN. THE ONLY TFC THAT I SAW WAS L OF US AND HIGH. THE L TURN WAS ALSO GOING TO PUT US BACK INTO THE WX THAT WE WERE OFFSETTING N FOR. I DECLARED AN EMER AND TURNED R. BY THIS TIME I HAD EXPERIENCED SEVERE TURB; HAD TO HELP MY NEW FO WITH FMC PROGRAMMING (AT ONE POINT XFERRING ACFT CTL TO INPUT FMC INFO); DECLARE AN EMER TO AVOID WX ENTRY AGAIN AND STILL DIDN'T SEE A SAFE WAY INTO ZZZ. FROM THE TIME WE ENTERED HOLDING ZZZ HAD CHANGED LNDG RWYS AND HAD A NEW ATIS REQUIRING MORE FMC WORK. A DISPATCH DIVERT PLAN WAS ALSO WAITING FOR US. I WAS QUICKLY REACHING THE POINT WHERE I WAS REACTING MORE THAN ANTICIPATING SO I DECIDED DISCRETION WAS THE BETTER PART OF VALOR AND CALLED FOR A DIVERT. THE DIVERT WENT UNEVENTFULLY BUT IT TOOK ME UNTIL ZZZ1 APCH TO GET THE MESSAGE ACROSS THAT THE ONLY REASON I DECLARED AN EMER WAS SO I COULD TURN IN A CERTAIN DIRECTION. HAVING REVIEWED THIS EVENT IN MY MIND I OBVIOUSLY REALIZED THAT I CREATED MOST OF THE PROB WITH MY DECISION TO FLY A HOLDING PATTERN THAT ENTERED AN AREA OF SEVERE WX. THERE WAS NO REASON WHY I COULDN'T HAVE REQUESTED TO HOLD FURTHER E. WITH A NEW FO I ALSO COULD HAVE ELECTED TO STAY IN HOLDING UNTIL WE GOT EVERYTHING SET UP AND WE COULD HAVE INQUIRED MORE THOROUGHLY HOW OTHERS WERE GETTING INTO ZZZ. WE COULD HAVE DSNDED IN HOLDING TO SEE IF WE REALLY COULD HAVE FLOWN UNDER THE WX. I HAD ADDED EXTRA GAS BEFORE WE TOOK OFF SPECIFICALLY TO GIVE MYSELF MORE TIME; WHICH I THEN DID NOT USE. HOWEVER; ONCE THINGS GOT GOING; THE BEST DECISION I MADE WAS TO DIVERT AND SORT IT ALL OUT ON THE GND. WITH REGARDS TO ATC; I'M STILL WONDERING WHY TURNING IN THE DIRECTION I WAS INITIALLY CLR TO DEVIATE IN WAS A PROB. I WAS NOT LEFT WITH ANY OTHER OPTION. NO ONE WAS INJURED DURING THE FLT. BETTER RADAR INTERP. BE PROACTIVE AND CHANGE ATC HOLDING IF THE ATC PLAN IS GOING TO CAUSE A PROB. SLOW DOWN AND DON'T RUSH EVENTS WHEN THERE IS GAS AND TIME TO DO SO. IF THINGS ARE GOING DOWNHILL CHANGE THE PLAN.

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.