NOTWITHSTANDING POSITIVE WX REPORTS; INEXPERIENCED C172 PLT ON VFR FLT PLAN ENCOUNTERS REDUCED VISIBILITY DUE TO SMOKE FROM WILDFIRES. RECEIVES ASSISTANCE FROM ATC TO DIVERT TO A NEARBY ARPT WHERE VISIBILITY WAS ONLY 3/4 MILE.

Narrative

I WAS FLYING BACK FROM ZZZ AT AROUND XA00. I HAD CALLED FOR A WX BRIEFING AND THE BRIEFER ADVISED A CONVECTIVE SIGMET HAD ENDED 1 HR EARLIER; AND ENRTE STATIONS WERE RPTING VFR CONDITIONS -- 7-10 MI VISIBILITY AND SKY CLR BELOW 12000 FT. I CHKED THE WX COMPUTER AT THE ARPT AND CONFIRMED WHAT THE BRIEFER TOLD ME. I TOOK OFF FROM ZZZ AT XA15 ENRTE TO ZZZ2 WHEN I ENCOUNTERED SMOKE FROM WILD FIRES BURNING TO THE SW OF MY RTE. VISIBILITY GRADUALLY DROPPED BELOW VFR MINIMUMS. I TRIED TO FOLLOW ROAD THAT I USUALLY FOLLOW TO GET BACK; BUT REALIZED I WAS DSNDING TOO LOW FOR SAFETY. I STARTED A CLB TO 2500 FT; ON A HDG OF ROUGHLY 330 DEGS. AT THIS POINT; I LOST VISUAL CONTACT WITH THE GND AND WAS SOLELY ON INSTS. I CONTACTED NORFOLK APCH FOR HELP AND THEY STARTED OFFERING VECTORS IMMEDIATELY. THEY TOLD ME I WAS 5 MI S OF ZZZ2; TOLD ME TO DSND AND MAINTAIN 1500 FT; AND ASKED ME IF I WOULD LIKE TO GO TO ZZZ2 OR ZZZ1. THEY ADVISED ME ZZZ1 WAS RPTING VFR CONDITIONS-- 7 MI VISIBILITY; VISUAL APCH RWY XX IN USE. I DSNDED ONLY ABOUT 100 FT BEFORE DECIDING ZZZ1 WAS THE MUCH BETTER DECISION. THEY VECTORED ME TOWARDS ZZZ1 ON A HDG OF 320 DEGS; THEN TOLD ME TO SPOT THE DEHAVILLAND AT MY 10 O'CLOCK POS AND FOLLOW HIM IN. AFTER 2 MINS; I ADVISED APCH THAT I COULD NOT SPOT THE PLANE; AND SO THEY VECTORED ME ONTO FINAL APCH. I COULD ONLY SPOT THE RWY WHEN I WAS ABOUT 3/4 MI FROM IT. MY BIGGEST MISTAKE WAS NOT TO TURN AROUND IMMEDIATELY WHEN VISIBILITY STARTED DETERIORATING. MY SECOND MISTAKE WAS A PREPARATION MISTAKE -- I SHOULD'VE HAD MY APCH PLATES WITH ME AND MY LOW ALT ENRTE CHARTS; BUT NOTHING IN THE FORECAST LED ME TO BELIEVE THAT CONDITIONS WOULD BE LESS THAN VFR. I THINK THE ONLY THING THAT COULDN'T BEEN DONE WAS A WARNING OFFERED TO PLTS DURING WX BRIEFING THAT THERE IS THICK SMOKE IN THE AREA BEING PUSHED BY THE WINDS ALOFT. THE WINDS ALOFT WERE REALLY MY ONLY HINT THAT SMOKE WAS DRIFTING OVER MY DEST AND I DID NOT PAY IT ENOUGH HEED.