TURB ENCOUNTER WITH PAX AND CREW INJURY FOLLOWED BY DIVERT.

Narrative

ENCOUNTER WITH MODERATE TO SEVERE TURB. THE CAPT WAS FLYING THE ACFT AT FL370 AT .800 MACH USING THE AUTOPLT. THE CAPT HAD THE FASTEN SEATBELT SIGN ON AND MADE A PA. WE WERE FILED ALONG A766 FROM KLAMS TO KEHLI INTXNS; AND IN THE VICINITY OF KELPP INTXN WE HAD ASKED FOR AN EASTERLY (L) DEV FOR WX FROM HOUSTON OCEANIC; WHICH THEY ALLOWED US. WE CHOSE THAT DIRECTION TO STAY ON THE UPWIND SIDE OF THE WX. BOTH THE CAPT AND I HAD THE WX RADAR ON. MY RADAR PANEL WAS SELECTED TO THE 40 MI RANGE WITH WX/TURB MODE AND MAX GAIN SELECTED. PERIODICALLY; I WOULD VARY RANGE AND TILT TO GET THE BEST RETURNS FROM THE APCHING WX. IN THE AREA OF WHERE THE WX WAS; THE RADAR RETURNS WERE MOSTLY GREEN AND SOME AREAS OF YELLOW. OUR FLT PATH WAS PLANNED TO KEEP US CLR OF THESE AREAS. WHILE MAKING OUR DEV; WE ENTERED INTO A STRATUS LAYER; NOW RELYING SOLELY ON THE RADAR FOR WX AVOIDANCE. AS WE PASSED BY AN AREA OF WX; WE POPPED OUT OF THE STRATUS LAYER AND IN FRONT OF US WAS A RAPIDLY BUILDING CUMULUS CLOUD. THE CAPT TOOK CORRECTIVE ACTION TO AVOID THE BUILD-UP BY USING 25 DEGS R BANK SELECTED WITH THE AUTOPLT. HOWEVER; WE STILL ENTERED THE CLOUD FORMATION. THERE WAS AN ONSET OF MODERATE TURB AND THE ACFT BEGAN TO CLB BECAUSE OF THE STRONG UPDRAFT. AFTER THE ACFT BEGAN A CLB; THERE WAS A SHARP DROP; WHICH I WOULD CLASSIFY AS SEVERE TURB. LASTING ONLY MOMENTARILY. THIS DROP CAUSED THE AUTOPLT TO TRIP OFF. THE CAPT CONTINUED TO HAND FLY THE ACFT OUT OF THE AREA. ATC ADVISED US OF OUR ALTDEV AND WE THEN INFORMED THEM OF THE ENCOUNTER WITH SEVERE TURB. THEY ACKNOWLEDGED OUR RPT. THE FLT ATTENDANTS RPTED 1 INJURED FLT ATTENDANT AND ALSO INJURED PAX. THE CAPT IMMEDIATELY DECLARED A MEDICAL EMER AND DECIDED TO LAND AT THE NEAREST SUITABLE ARPT (IAH). WE NEXT INFORMED DISPATCH OF OUR SIT AND DIVERSION ARPT. THEN CALLED IAH; ASKED FOR MEDICAL ASSISTANCE AND GATE FOR OFF-LOADING INJURED FLT ATTENDANT AND INJURED PAX. WE WERE GIVEN PRIORITY FOR RWY 33R AT IAH; LANDED AND TAXIED TO GATE X WHERE WE WERE MET WITH MEDICAL ASSISTANCE.