Skyhawk 172/Cutlass 172
Flight Crew Commercial; Flight Crew Flight Instructor; Flight Crew Instrument
Flight Crew Last 90 Days 150; Flight Crew Total 1300; Flight Crew Type 800
Situational Awareness; Training / Qualification
Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter VFR In IMC; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Provided Assistance; Flight Crew Diverted; Flight Crew Requested ATC Assistance / Clarification
Human Factors; Procedure; Weather
I was planning on going on a short 30 minute local flight.  We had been experiencing low ceilings throughout the prior week; but it usually lifted significantly once the sun rose.  Upon checking the METAR for [destination]; I found the visibility to be 9 miles and the ceiling to be 1;400 feet.  I decided to wait until the ceiling became higher. After about 30 minutes; it appeared that the ceiling had lifted more and I was seeing much more blue sky than I was previously; although it appeared somewhat hazy.  I rechecked the METAR again and found that they were now reporting 7 miles and a 300 foot ceiling.  Seeing that the ceiling didn't appear that low near the airport I was departing from and thinking that there were probably some localized low clouds at [destination] that were skewing the METAR reading; I elected to takeoff since I thought I could always stay in the pattern and land quickly if I found the ceilings to be lower than they appeared. Once I took off; I started to enter the haze at approximately 200 feet and quickly found myself in IMC. I am instrument rated so I transitioned to instruments and continued climbing since I knew that it wasn't thick. I cleared the low ceiling at approximately 500 feet and was in bright blue skies; but I couldn't see the airport to land. So; I listened to the ATIS and found that they were now reporting 1/2 mile visibility and a 300 foot ceiling with another close airport reporting the same. Upon hearing that; I immediately called the FSS and asked them what the nearest VFR airport was. They said that every airport within about 50 miles was either IFR or Low IFR due to fog that had rolled in quickly. From there; I called the Tower and told them about my situation and that I had about 1.25 hours of fuel on board and asked if they had any suggestions.  Since my plane wasn't IFR certified/equipped for shooting an instrument approach; they suggested waiting for the fog to burn off since visibility appeared to be getting better from their vantage point.  I aggressively leaned the mixture and throttled back to conserve fuel and flew a large racetrack pattern while the Tower gave me occasional weather reports.  I flew like that for about 50 minutes; but once I realized I couldn't wait any longer due to my fuel; I switched to Approach and advised them of the situation.  While we were formulating a plan; the Controller told me that [another airport] just became VFR and he gave me vectors to the airport. Once I got within about 2 miles; the ceiling broke up and I was able to make a normal descent and landing.I learned a great deal from this flight.  When I saw the ceiling drop so quickly; I should have pulled up the METAR for several other airports in the area to see if they were reporting similar weather.  And even better; I should have gotten a weather briefing from a FSS before I took off.  Although the fuel I took would have normally been sufficient for the short flight I was doing; I should have taken more fuel if the weather looked marginal so I would have more options in case the weather took a turn for the worse or if another issue came up.  And; most importantly; I should have realized that the weather originally reported before I took off (the 1;400 foot ceiling) was below my personal minimums and I should have made a no-go decision.
C172 pilot flew VFR in IMC until VFR On Top and then; with ATC assistance; landed at an alternate field that was VFR after fuel became an issue.