IMC IN VFR FLT BY ROTARY WINGED TFC DURING TRAINING FLT.

Narrative

WHILE ENRTE FROM MOD TO OAK I ENCOUNTERED A LOW CLOUD CEILING. I WAS ABLE TO CONTINUE THE FLT FLYING VIA HWY 580 WBOUND. AS I TRIED TO CROSS ALTAMONT PASS I WAS NOT ABLE TO STAY IN VMC. WHILE ATTEMPTING A 180 DEG TURN I ENTERED THE LOW CLOUDS. THE ONLY VISIBILITY I HAD WAS STRAIGHT DOWN. DURING THE L PEDAL TURN I DRUG THE ROTOR RPM DOWN TO THE POINT OF ACTIVATING THE LOW RPM WARNING SYS. I WAS ABLE TO FIND AND LAND AT TRACY ARPT UNTIL CONDITIONS IMPROVED. I DID OBTAIN A WX BRIEFING VIA THE FSS TAPES (THE FLT ORIGINATED IN OAKLAND WITH STOPS IN SAC AND MOD). BOTH SAC AND MOD WERE RPTING SCATTERED TO OVCST AND 5 MI VISIBILITY IN HAZE. DURING THE BRIEFING I COULD NOT FIND OUT INFO ABOUT OVCST LAYERS. ON THE PREVIOUS LEGS OF THE FLTS BOTH DESTS WERE CLR; WITH LOW OVCST LAYERS FROM 5-10 MI IN BTWN. PART OF WHAT LED TO THIS INCIDENT WAS MY DESIRE TO COMPLETE THE FLT. I AM A COMMERCIAL HELI STUDENT; THIS WAS MY LAST XCOUNTRY REQUIREMENT BEFORE MY CHKRIDE. I HAD BEEN TRYING TO MAKE THIS FLT FOR 6 WKS BUT HAD BEEN UNABLE TO DUE TO WX. THIS ALSO SHOWED ME THAT JUST LISTENING TO FORECAST SURFACE OBSERVATIONS CAN LEAD A PLT TO DRAW FALSE PICTURES OF THE WX PICTURE.