Narrative:

At about XA00 local, FSS WX briefing indicated a ceiling could be expected at 1000 ft AGL through XF00 local then becoming 2000 ft AGL at XF00. By XF00 local, ceilings were forecast to be 2500 ft AGL. After XF00, visibility was expected to be no less than 5 mi. By the time my student and I were ready to preflight at XF00, ATIS was reporting a ceiling of 1300 ft broken and 2900 ft overcast with visibility at least 5 mi. Cloud coverage at the lower level appeared to be breaking up into about 3 1/10 mi scattered, especially upwind to the northeast. Before takeoff, I asked another instructor just taxiing in about the cloud coverage and he reported an end of the lower layer to the northeast. I thought this to be the forecasted clearing of the lower layer and decided to depart VFR with my student to the northeast. Just to be prepared, however, I chose to fly an IFR equipped C152 with current inspections, verified my own currency, and took current charts along just in case. Approximately 5 mi north of day at 2500 ft MSL, we encountered very light rain which reduced visibility from an estimated 7 mi to approximately 4 mi. A few scattered clouds, what I believed to be the remainder of the lower deck, appeared ahead, so we climbed to 3500 ft MSL. At that point, the lower layer became broken and it was very difficult to pick out the upper deck clouds because they blended in so well with the overall light gray sky color. At that point, we were still VFR, but the conditions were deteriorating rapidly. I called day departure and requested a turn south back to day. The controller requested a left turn to 180 degrees and a descent to 2500 ft MSL. During the maneuver, a cloud appeared from the murk and I was able to avoid it. We lost VMC for approximately 20 seconds but then resumed VFR navigation. Eventually we requested a local IFR and returned to day without further incident. Next time I'll be more conservative regarding the WX and turn back or pick up an IFR clearance sooner.

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Original NASA ASRS Text

Title: INSTRUCTOR AND STUDENT FLEW IN IMC WITHOUT IFR CLRNC IN CLASS E AIRSPACE.

Narrative: AT ABOUT XA00 LCL, FSS WX BRIEFING INDICATED A CEILING COULD BE EXPECTED AT 1000 FT AGL THROUGH XF00 LCL THEN BECOMING 2000 FT AGL AT XF00. BY XF00 LCL, CEILINGS WERE FORECAST TO BE 2500 FT AGL. AFTER XF00, VISIBILITY WAS EXPECTED TO BE NO LESS THAN 5 MI. BY THE TIME MY STUDENT AND I WERE READY TO PREFLT AT XF00, ATIS WAS RPTING A CEILING OF 1300 FT BROKEN AND 2900 FT OVCST WITH VISIBILITY AT LEAST 5 MI. CLOUD COVERAGE AT THE LOWER LEVEL APPEARED TO BE BREAKING UP INTO ABOUT 3 1/10 MI SCATTERED, ESPECIALLY UPWIND TO THE NE. BEFORE TKOF, I ASKED ANOTHER INSTRUCTOR JUST TAXIING IN ABOUT THE CLOUD COVERAGE AND HE RPTED AN END OF THE LOWER LAYER TO THE NE. I THOUGHT THIS TO BE THE FORECASTED CLRING OF THE LOWER LAYER AND DECIDED TO DEPART VFR WITH MY STUDENT TO THE NE. JUST TO BE PREPARED, HOWEVER, I CHOSE TO FLY AN IFR EQUIPPED C152 WITH CURRENT INSPECTIONS, VERIFIED MY OWN CURRENCY, AND TOOK CURRENT CHARTS ALONG JUST IN CASE. APPROX 5 MI N OF DAY AT 2500 FT MSL, WE ENCOUNTERED VERY LIGHT RAIN WHICH REDUCED VISIBILITY FROM AN ESTIMATED 7 MI TO APPROX 4 MI. A FEW SCATTERED CLOUDS, WHAT I BELIEVED TO BE THE REMAINDER OF THE LOWER DECK, APPEARED AHEAD, SO WE CLBED TO 3500 FT MSL. AT THAT POINT, THE LOWER LAYER BECAME BROKEN AND IT WAS VERY DIFFICULT TO PICK OUT THE UPPER DECK CLOUDS BECAUSE THEY BLENDED IN SO WELL WITH THE OVERALL LIGHT GRAY SKY COLOR. AT THAT POINT, WE WERE STILL VFR, BUT THE CONDITIONS WERE DETERIORATING RAPIDLY. I CALLED DAY DEP AND REQUESTED A TURN S BACK TO DAY. THE CTLR REQUESTED A L TURN TO 180 DEGS AND A DSCNT TO 2500 FT MSL. DURING THE MANEUVER, A CLOUD APPEARED FROM THE MURK AND I WAS ABLE TO AVOID IT. WE LOST VMC FOR APPROX 20 SECONDS BUT THEN RESUMED VFR NAV. EVENTUALLY WE REQUESTED A LCL IFR AND RETURNED TO DAY WITHOUT FURTHER INCIDENT. NEXT TIME I'LL BE MORE CONSERVATIVE REGARDING THE WX AND TURN BACK OR PICK UP AN IFR CLRNC SOONER.

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.