Narrative:

I intended to stay in the pattern to regain my night currency; I was the only occupant in the aircraft. Prior to leaving for the airport; I checked aviationweather.gov and found the current metars for the closest reporting sites were showing VFR conditions (as I recall; ceilings around 25;000 feet and visibility of 6 miles). The taf was forecasting fog to develop; but not for another 2 hours or so. I thought I could perform a quick 30 minute flight to do 3 takeoffs and landings; all the while staying in the pattern.after arriving at the field; I checked the ground visibility and had no problem seeing the runway lights at the far end of the runway; city lights far off in the distance; and aircraft flying overhead. There was a slight haze in the air; but it did not seem to be enough to restrict in-flight visibility. However; almost immediately after taking off (approximately 200 feet AGL); I lost all reference to the ground. I made a downwind turn; on a parallel heading to the runway; but could not see the runway lights at pattern altitude.at that point; I realized I would need to go elsewhere; so I proceeded to head away from the field; and in the opposite direction from the class B area. I climbed to 1;600 feet; and at some altitude I broke out of the fog.I decided to contact approach and request an ILS approach into the closest field with an ILS approach. I confessed to the controller my predicament; and let him know that I did not have any approach plates with me; although I did have an approach-certified GPS on board.the controller was extremely helpful in getting me set up for the approach; and vectored me in such a fashion as to give me plenty of time to prepare. I landed; parked at one of the local fbos; and called my wife to pick me up.I learned three main things from this experience: 1) fog can develop very quickly; 2) always have my electronic flight bag with me; even when flying in the pattern; and 3) it's important to stay proficient so as I can be at the top of my game when flying approaches. Also; I should have immediately climbed to get above the fog when I encountered it; rather than attempting to stay at pattern altitude and return to the field. I had the mistaken impression that the fog might have been localized to the departure end of the runway since conditions looked so favorable on my takeoff roll.

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Original NASA ASRS Text

Title: A low time instrument rated pilot departed a CTAF airport for night landings in his PA-28 and it became IMC. He contacted the TRACON; was honest about his situation and was vectored without charts for an ILS to a nearby airport.

Narrative: I intended to stay in the pattern to regain my night currency; I was the only occupant in the aircraft. Prior to leaving for the airport; I checked aviationweather.gov and found the current METARs for the closest reporting sites were showing VFR conditions (as I recall; ceilings around 25;000 feet and visibility of 6 miles). The TAF was forecasting fog to develop; but not for another 2 hours or so. I thought I could perform a quick 30 minute flight to do 3 takeoffs and landings; all the while staying in the pattern.After arriving at the field; I checked the ground visibility and had no problem seeing the runway lights at the far end of the runway; city lights far off in the distance; and aircraft flying overhead. There was a slight haze in the air; but it did not seem to be enough to restrict in-flight visibility. However; almost immediately after taking off (approximately 200 feet AGL); I lost all reference to the ground. I made a downwind turn; on a parallel heading to the runway; but could not see the runway lights at pattern altitude.At that point; I realized I would need to go elsewhere; so I proceeded to head away from the field; and in the opposite direction from the Class B area. I climbed to 1;600 feet; and at some altitude I broke out of the fog.I decided to contact Approach and request an ILS approach into the closest field with an ILS approach. I confessed to the Controller my predicament; and let him know that I did not have any approach plates with me; although I did have an approach-certified GPS on board.The controller was extremely helpful in getting me set up for the approach; and vectored me in such a fashion as to give me plenty of time to prepare. I landed; parked at one of the local FBOs; and called my wife to pick me up.I learned three main things from this experience: 1) fog can develop very quickly; 2) always have my Electronic Flight Bag with me; even when flying in the pattern; and 3) it's important to stay proficient so as I can be at the top of my game when flying approaches. Also; I should have immediately climbed to get above the fog when I encountered it; rather than attempting to stay at pattern altitude and return to the field. I had the mistaken impression that the fog might have been localized to the departure end of the runway since conditions looked so favorable on my takeoff roll.

Data retrieved from NASA's ASRS site 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.