Narrative:

Event happened when flying a VFR flight plan from boulder, co, to las vegas, nv. I received my final WX briefing two hours prior to flight. Per flight service, no updates were expected within that time. WX predicted was VFR conditions with no flight precautions given. The flight began as a routine VFR cross country flight. Approximately 45 mins into the flight, after starting over the mountains, WX conditions deteriorated. I followed what appeared to be a safe corridor continuing west. After flying in VFR conditions another 20 to 30 mins, the cloud top began to rise at an accelerated rate. When making small turns both to the left and right to examine the situation, it was discovered that the clouds had closed in behind me. It appeared the only alternatives I had were to enter IFR conditions or fly above the clouds. To avoid flying in IFR conditions, I continued to fly above the clouds. At first this was accomplished at an acceptable altitude. However, as the cloud top rose, it was apparent that I was going to have to fly into positive controled airspace (above 18000'). To maintain safe cloud clearance, for a brief amount of time I climbed to 19400', immediately descending when possible to an altitude just above 18000'. This was only maintained until the cloud top lowered. At that time, I immediately descended below 18000' and continued the flight.

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Original NASA ASRS Text

Title: GA SMA INFLT ENCOUNTER WITH WX. PLT FLEW INTO PCA TO STAY ON TOP OUT OF IMC.

Narrative: EVENT HAPPENED WHEN FLYING A VFR FLT PLAN FROM BOULDER, CO, TO LAS VEGAS, NV. I RECEIVED MY FINAL WX BRIEFING TWO HRS PRIOR TO FLT. PER FLT SVC, NO UPDATES WERE EXPECTED WITHIN THAT TIME. WX PREDICTED WAS VFR CONDITIONS WITH NO FLT PRECAUTIONS GIVEN. THE FLT BEGAN AS A ROUTINE VFR CROSS COUNTRY FLT. APPROX 45 MINS INTO THE FLT, AFTER STARTING OVER THE MOUNTAINS, WX CONDITIONS DETERIORATED. I FOLLOWED WHAT APPEARED TO BE A SAFE CORRIDOR CONTINUING W. AFTER FLYING IN VFR CONDITIONS ANOTHER 20 TO 30 MINS, THE CLOUD TOP BEGAN TO RISE AT AN ACCELERATED RATE. WHEN MAKING SMALL TURNS BOTH TO THE L AND R TO EXAMINE THE SITUATION, IT WAS DISCOVERED THAT THE CLOUDS HAD CLOSED IN BEHIND ME. IT APPEARED THE ONLY ALTERNATIVES I HAD WERE TO ENTER IFR CONDITIONS OR FLY ABOVE THE CLOUDS. TO AVOID FLYING IN IFR CONDITIONS, I CONTINUED TO FLY ABOVE THE CLOUDS. AT FIRST THIS WAS ACCOMPLISHED AT AN ACCEPTABLE ALT. HOWEVER, AS THE CLOUD TOP ROSE, IT WAS APPARENT THAT I WAS GOING TO HAVE TO FLY INTO POSITIVE CTLED AIRSPACE (ABOVE 18000'). TO MAINTAIN SAFE CLOUD CLRNC, FOR A BRIEF AMOUNT OF TIME I CLBED TO 19400', IMMEDIATELY DSNDING WHEN POSSIBLE TO AN ALT JUST ABOVE 18000'. THIS WAS ONLY MAINTAINED UNTIL THE CLOUD TOP LOWERED. AT THAT TIME, I IMMEDIATELY DSNDED BELOW 18000' AND CONTINUED THE FLT.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.