A VFR C150 PLT ENCOUNTERS IMC AND COMPLETES AN UNSCHEDULED LNDG.

Narrative

I CALLED 1-800-WX-BRIEF AND RECEIVED A STANDARD BRIEFING AT ABOUT XA30. THE BRIEFER STATED THAT THE WX WOULD BE MVFR THROUGH MY INTENDED COURSE; WITH A BIT OF IFR NEAR ZZZ2 AND THEN MVFR AFTER THAT. THE WX AT ZZZ1 APPEARED BETTER THAN THE INFO THAT THE BRIEFER HAD; AND ZZZ2 IS LOCATED ON TOP OF A MOUNTAIN 3700+ FT MSL; SO I FIGURED THAT IMC AT ZZZ2 MEANT THAT THE CLOUD BASES WERE ABOUT THE SAME AS THEY WERE AT ZZZ1. THIS WAS A MISTAKE. I DEPARTED FROM ZZZ1 AND CLBED THROUGH THE BROKEN CLOUD LAYER. THE CLOUD BASES WERE AROUND 4000 FT AND THE TOPS WERE AROUND 6500 FT. I CLBED TO 6500 FT AND THEN UP TO 7500 FT. THE BROKEN CLOUD LAYER SOON TURNED TO AN UNDERCAST; BUT SINCE THE WX WAS SUPPOSED TO GET WORSE AND THEN GET BETTER; I CONTINUED TO FLY MY COURSE. AFTER I PASSED ZZZ2; THE UNDERCAST STARTED TO RISE. I CLBED TO 9500 FT MSL AS THE UNDERCAST WAS RISING; AND SOON I WAS IN THE CLOUDS. I SHOULD HAVE TURNED BACK; BUT I STARTED FLYING THE ACFT AS PER THE PVT PLT INST TRAINING AND THE IFR FLYING I'VE DONE AS A PLT RATED PAX. SINCE I EXPECTED THE WX TO GET BETTER; I PRESSED ON THINKING THAT THE UNDERCAST WOULD DSND BACK TO THE BROKEN UNDERCAST. I FLEW THIS WAY FOR 10 OR 15 MINS. THIS WAS ANOTHER MISTAKE. SOON; IT BECAME CLR THAT THIS WAS HERE TO STAY. I HAD BEEN MONITORING THE CTAF FREQS FOR NEARBY ARPTS; AND THERE WAS QUITE A BIT OF TFC AT ZZZ3. SO; I DSNDED FROM 9500 FT DOWN TO ABOUT 4800 FT; WHICH WAS AT THE HT OF THE HIGHEST OBSTACLE ON THE SECTION OF THE CHART THAT I WAS USING. NO GND CONTACT; SO I STARTED CLBING AND EXECUTED A 180 DEG TURN. A FEW HOLES ALLOWED ME TO SEE SOME WOODED MOUNTAINTOPS BELOW ME; BUT THE HOLES WERE TOO SMALL AND THE TERRAIN TOO RUGGED TO RISK A DSCNT INTO THE VFR CONDITIONS BELOW. THE MOUNTAINTOPS WERE CLOSER THAN I WOULD HAVE PREFERRED -- MAYBE 1000 FT BELOW. I STARTED CLBING BACK UP WITH 8500 FT MSL AS MY GOAL. DSNDING THAT LOW WAS YET ANOTHER MISTAKE. AS I FLEW BACK AND CLBED; THE WX GRADUALLY GOT BETTER UNTIL I WAS VFR ON TOP. LOOKING AHEAD; IT APPEARED THAT THE WX DIDN'T GET MUCH BETTER TOWARD ZZZ1; SO I ELECTED TO FLY TO ZZZ3 INSTEAD AND; IF WORSE CAME TO WORST; HAVE THEM TALK ME THROUGH ONE OF THE INST APCHS. ON THE WAY TO ZZZ3; I FOUND A HOLE IN THE CLOUDS; AND MADE A SPIRALING VFR DSCNT THROUGH THE HOLE. WHEN I POPPED OUT OF THE BOTTOM (ABOUT 3000 FT MSL); I PROCEEDED TO ZZZ3. I CALLED ZZZ3 AND THEY ALLOWED ME TO LAND VFR. THEY DIRECTED ME TO RWY 6; BUT AFTER I MENTIONED THAT I'D BEEN IN AN INADVERTENT IMC; THEY HAD ME FLY STRAIGHT-IN TO RWY 24. I THANKED THEM FOR THE PRIORITY. I SAT AT THE FBO AT ZZZ3 FOR ABOUT 3 HRS. I CALLED A FRIEND TO HAVE HER COME AND PICK ME UP; BUT CANCELED AFTER THE WX STARTED IMPROVING. ABOUT XF15; THE WX HAD IMPROVED AND THE ZZZ1 AWOS WAS RPTING VISIBILITY OF 7 MI AND WITH A BROKEN CLOUD LAYER OF 4000 FT AGL. I DEPARTED FOR ZZZ1 AFTER BUMBLING MY WAY THROUGH ZZZ3'S ATC. PART OF IT WAS DUE TO MY NOT HAVING THE ARPT INFO FOR ZZZ3; AND PART OF IT WAS THAT I HAD AN OUT-OF-DATE CHART. MY GPS WAS UP-TO-DATE (LEGAL FOR VFR); BUT IT'S EASIER TO GET RADIO FREQS BY LOOKING AT THE SECTIONAL -- AND I GOT THE OUT-OF-DATE ATIS FREQ. THE FLT TO ZZZ1 WAS UNEVENTFUL -- AT LEAST COMPARED TO THE DEPARTING FLT. I FLEW LOWER THAN I WOULD HAVE NORMALLY; AND BELOW THE MOUNTAINTOPS. THE CTLR WANTED ME TO FLY NW TO MAKE HIS JOB EASIER; BUT I WAS LOW ENOUGH THAT FLYING NW WOULD HAVE PUT ME INTO CONFLICT WITH THE MOUNTAIN. I FLEW ALONG THE MOUNTAIN AS BEST I COULD; AND FOLLOWED THE RAILROAD TRACKS HOME. I DID A NICE SHORT-FIELD LNDG AT ZZZ1; TOO. LESSONS LEARNED/CORRECTIVE ACTIONS TAKEN: 1) THE WX IS UNPREDICTABLE AND I'VE REALLY LEARNED MY LIMITS ON THIS ONE. CORRECTIVE ACTION: DON'T DO THIS AGAIN! 2) THE WX SIT CHANGED SLOWLY ENOUGH THAT I COULD GET USED TO EACH CHANGE; ONE AT A TIME. BEFORE TODAY; WHEN I THOUGHT ABOUT VFR INTO IMC; I ALWAYS THOUGHT ABOUT FLYING INTO A VERTICAL WALL OF CLOUD; AND I FIGURED I WAS SMART ENOUGH THAT SUCH A THING WOULDN'T HAPPEN TO ME. BUT; THAT WASN'T HOW IT HAPPENED -- THE TRANSITION HAPPENED OVER A SPAN OF SEVERAL MINS AND HAPPENED GRADUALLY ENOUGH THAT THERE WASN'T ANY SURPRISES BIG ENOUGH TO STARTLE ME INTO TURNING BACK; AND SO I DELAYED MY 180 DEG TURN MUCH LONGER THAN I SHOULD HAVE. 3) GPS -- I HAD A GARMIN 295 HANDHELD GPS. IT WAS A LIFESAVER; PROVIDED GREAT SITUATIONAL AWARENESS; AND A GREAT CHK FOR THE GYRO INSTS IN THE ACFT. HOWEVER; I WOULD HAVE TURNED BACK MUCH EARLIER IF I HADN'T HAD IT. 4) I DIDN'T CALL CTR BECAUSE I DIDN'T HAVE THEIR FREQ HANDY. I SHOULD HAVE. IN THE FUTURE; I WILL LOOK THIS UP BEFORE I DEPART. 5) I'VE BEEN A LITTLE OVERCONFIDENT LATELY -- I'M CLOSE TO TAKING MY IFR WRITTEN AND I'VE FLOWN ACFT IN IMC; BUT NOT AS PIC. I'VE ALSO SUCCESSFULLY PUSHED THE WX ENVELOPE IN VFR CONDITIONS LATELY; AND IT WAS EASIER THAN EXPECTED. TODAY; I PUSHED TOO FAR. 6) THROW AWAY OUT-OF-DATE CHARTS. JUST BECAUSE THE DATABASE IN THE GPS IS UP-TO-DATE DOESN'T MEAN THAT THE OLD CHART WILL BE CORRECT. THE MAIN DIFFERENCE THAT I NOTICED WAS THE ATIS FREQ AT ZZZ3. THE OUT-OF-DATE CHART THAT I HAD WITH ME IS NOW IN A TRASH CAN AT ZZZ1. 7) AN INST RATING IS NECESSARY FOR THE ENVIRONMENT IN WHICH I FLY. I'VE CONTACTED MY FAVORITE CFI TO SEE IF HE'S READY TO START INSTRUCTING ME ON THE ART OF INST FLYING; AND I WILL BE VERY EAGER TO ATTEND THE INST GND SCHOOL THAT I HAD SCHEDULED TO ATTEND. 8) I WOULDN'T HAVE ATTEMPTED THIS FLT IF I'D HAD A PAX. THAT SHOULD HAVE GIVEN ME PAUSE. MAYBE I SHOULD CONSIDER MYSELF AS A PAX IN ADDITION TO CONSIDERING MYSELF TO BE PIC? 9) THE MODE C IN THE ACFT I WAS FLYING HAS BEEN AN INTERMITTENT PROB FOR OTHER MEMBERS OF THE CLUB. IT WAS OFF BY 600 FT WHEN I APCHED ZZZ3 (WHEN I ADVISED THEM OF A POTENTIAL PROB) AND WASN'T RPTING DURING MY DEP. JUST BECAUSE THE FLT I PLANNED DIDN'T REQUIRE A MODE C DOESN'T MEAN THAT THE ACTUAL CONDITIONS DIDN'T REQUIRE IT. ALL IN ALL; I'M HAPPY TO BE BACK ON THE GND TODAY. I'M GOING TO GO TO A PICNIC THIS EVENING AND ENJOY THE COMPANY OF MY FRIENDS AND NEIGHBORS. I'VE READ THIS CHAIN OF EVENTS IN MANY ACCIDENT RPTS; AND ALWAYS THOUGHT THAT I WAS TOO SMART FOR IT TO HAPPEN TO ME -- BUT I WASN'T PREPARED FOR THE GRADUAL NATURE OF THE DEVELOPING EMER. WHEN I DSNDED TO THE LEVEL OF THE HIGHEST OBSTACLE ON THE CHART (BELOW THE MEA FOR THE AREA); I WAS PROBABLY ONE MISTAKE AWAY FROM BEING A STATISTIC. THIS IS QUITE SOBERING; AND I PLAN TO BE MORE CAUTIOUS AND BETTER PREPARED (INST RATED) IN THE FUTURE.