C150 PLT AND SAFETY PLT ENCOUNTER TURB; DOWNDRAFTS; WINDSHEAR AND TSTMS AT NIGHT AND ENTER DEN CLASS B AIRSPACE WITHOUT CLRNC.

Narrative

I WAS ON A TRAINING FLT WITH A FRIEND (INST; COMMERCIAL; AND CFI RATINGS) IN ORDER TO DO SOME NIGHT FLYING AND INST APCH PRACTICE. WE DEPARTED BOULDER; CO; NEAR DUSK. SOLID VFR WX; THEN FLEW A COUPLE OF APCHS AT FNL; THEN AFTER A VOR APCH AT GXY; LANDED AT GXY FOR A BREAK AND FUEL STOP. WHILE FUELING AT GXY; WE NOTICED THAT CALM WINDS WERE CHANGING TO BLUSTERY WINDS OUT OF THE W. LIGHTNING WAS VISIBLE TO THE NW; BUT STARS AND MOON COULD STILL BE SEEN IN ALL OTHER QUADRANTS. ON INITIAL TAXI; AWOS INDICATED A MODERATE W WIND (APPROX 15 KT); BUT THIS CHANGED TO CALM AS WE ARRIVED AT THE RUN-UP AREA FOR RWY 27. LIGHTNING APPEARED CLOSER; BUT HARD TO JUDGE DISTANCE. WINDS STILL CALM AFTER RUN-UP COMPLETED; WE TOOK OFF ON RWY 27; ANTICIPATING A QUICK RETREAT TO 1V5. INITIALLY; WE HAD A GOOD RATE OF CLB (400-500 FPM) UNTIL I TURNED S AND AWAY FROM THE LIGHTNING; STILL TO OUR NW AT APPROX 500-600 FT AGL. AT THIS POINT; WE PROBABLY WENT THROUGH A SHEAR LAYER; AS THE CALM WIND HAD OBVIOUSLY CHANGED - GND TRACK INDICATED A STRONG WIND FROM THE NW; AND THE CLB RATE DIMINISHED TO ZERO; EVEN WITH THE PLANE PITCHED FOR VY. CONCERNED ABOUT POSSIBLE STRONG DOWNDRAFTS (AT LOW ALT); I TURNED TO THE W; WHICH PROVIDED SOME MINIMAL CLB; ON AND OFF; BUT WAS PROBLEMATIC AS THE LIGHTNING WAS NOW APPEARING QUITE CLOSE. I THEN TURNED S; TOWARDS CLR SKIES; STILL SHOWING POOR CLB RATE -- EFFECTIVELY TRYING TO 'OUTRUN' THE APCHING TSTM. THIS COURSE TOOK US DIRECTLY TOWARDS THE DENVER CLASS B AIRSPACE. MODERATE TURB; NEARBY LIGHTNING; AND THE DIFFICULTIES WITH CLB RATE; ALL CONSPIRED TO MAKE US VERY CONCERNED WITH OBTAINING SUFFICIENT ALT. AS SOON AS WE ENCOUNTERED UPDRAFTS; I PUSHED US UP TO NEARLY 9000 FT MSL. RECOGNIZING THAT THIS WOULD BRING US ABOVE THE FLOOR OF CLASS B AIRSPACE; I ASKED MY FRIEND TO GET ME THE DENVER APCH FREQ ASAP. AFTER SOME MAP-FUMBLING; WE GOT THE FREQ AND CALLED APCH -- NOW JUST WITHIN THE BOUNDARIES OF CLASS B(2-3 NM INSIDE?). WE WERE GIVEN A SQUAWK CODE; AND AFTER RADAR CONTACT WE WERE ALSO GIVEN AN ADMONISHMENT FOR HAVING ENTERED CLASS B AIRSPACE WITHOUT A CLRNC. I EXPLAINED THAT WE WERE INTENT ON AVOIDING THE UNCOMFORTABLY CLOSE TSTM ACTIVITY AND WE WERE GIVEN A CLRNC AND ROUTING; DIRECT TO BJC; AT 10500 FT MSL. AFTER LISTENING TO THE 1V5 AWOS FOR THE BULK OF OUR RTE; NOTING STRONG BUT STEADY W WINDS AT APPROX 20 KTS; AND PRIOR TO ENTERING CLASS D AIRSPACE; WE REQUESTED A CHANGE IN OUR ROUTING; TO 1V5; AND ARRIVED UNEVENTFULLY. ANALYSIS: WITH LIMITED NIGHT FLYING EXPERIENCE (MY FRIEND'S TOTAL HRS ARE APPROX 370 HRS); AND WITH NO INSTRUMENTATION FOR DETERMINING LIGHTNING DISTANCE; WE MISTAKENLY TOOK OFF INTO AN APCHING TSTM. CONCERNS WITH STORM PROX; TURB; AND GAINING SUFFICIENT ALT CAUSED US TO ENTER CLASS B AIRSPACE WITHOUT A CLRNC.