Narrative:

Cedar city flight service did not know of 'ol center WX advisory for severe turbulence in mountains in nv, and ut,' yet it was broadcast over the mormon mesa VOR tweb. At fuel stop slc, same FSS asked me when I got my last briefing, about 1 hour ago, well, there's been no change since then. I asked them to look at their WX radar for possible thunderstorm's from slc to pocatello. They said none, no precipitation none forecast. Climbing out of slc at 10500' over ogden I told them I saw lighting cloud to cloud. They said there was none. I said 'this is a PIREP! I see it.' they said 'stand by', then they said 'oh yes, there are some cells in malad city and pocatello area with precipitation.' I am in a single engine aircraft, at night, with a passenger, over the rocky mtns (northern wasatch range) with strong level 3 and 4 thunderstorms. Nocturnal, increasing, with lightening cloud to ground, moderate to severe turbulence and a FSS that told me none existed and none forecast, and barely believed my PIREP. I diverted to the east northeast (030 degree) to avoid and attempt to circumnav the small scattered nocturnal thunderstorms. Salt lake city center on 127.7 handed me off to another sector 134.5 and I was too low to reach them. I stayed above the mountain peaks but as low as I could safely fly in order to see the lightening and the clouds. I was unable to get around the thunderstorms and, in fact, they were increasing in number and intensity. I flew northeast to 70 NM DME of jackson hole and then turned back and circled montebello, identification. In case a precautionary landing was necessary. After about 1 hour it was obvious these thunderstorm's were not going to dissipate. This was a rather large group of level 3 and 4 nocturnal thunderstorm's, prefrontal in nature, and probably created by a upper level trough. We gave up and returned to salt lake city, climbed to 12500' and recontacted salt lake city center on 127.7. We were headed 180 degrees, my dead reckoning estimate to salt lake. Center gave us a vector of 190 degree 10 degree different. Though unable to maintain altitude due turbulence with strong up and down drafts, we landed uneventfully at salt lake city. With this kind of help from flight service it's only a matter of time before they cause an accident. I think the safest WX reports are PIREPS and FSS is not to be trusted. I believe FSS inactions and sloppy forecasting are due to 4 things. Night time fatigue. Low morale. Automated FSS. Less service stations.

Related reports:

Google
 

Original NASA ASRS Text

Title: SMA IN CRUISE ENCOUNTERS SEVERE TURB AND TSTM ACTIVITY NOT FORECAST OR NOTED BY FSS AND FSS SEEMS UNRESPONSIVE TO PIREP ON THE CONDITIONS MADE BY REPORTER.

Narrative: CEDAR CITY FLT SVC DID NOT KNOW OF 'OL CTR WX ADVISORY FOR SEVERE TURB IN MOUNTAINS IN NV, AND UT,' YET IT WAS BROADCAST OVER THE MORMON MESA VOR TWEB. AT FUEL STOP SLC, SAME FSS ASKED ME WHEN I GOT MY LAST BRIEFING, ABOUT 1 HR AGO, WELL, THERE'S BEEN NO CHANGE SINCE THEN. I ASKED THEM TO LOOK AT THEIR WX RADAR FOR POSSIBLE TSTM'S FROM SLC TO POCATELLO. THEY SAID NONE, NO PRECIP NONE FORECAST. CLBING OUT OF SLC AT 10500' OVER OGDEN I TOLD THEM I SAW LIGHTING CLOUD TO CLOUD. THEY SAID THERE WAS NONE. I SAID 'THIS IS A PIREP! I SEE IT.' THEY SAID 'STAND BY', THEN THEY SAID 'OH YES, THERE ARE SOME CELLS IN MALAD CITY AND POCATELLO AREA WITH PRECIP.' I AM IN A SINGLE ENG ACFT, AT NIGHT, WITH A PAX, OVER THE ROCKY MTNS (NORTHERN WASATCH RANGE) WITH STRONG LEVEL 3 AND 4 TSTMS. NOCTURNAL, INCREASING, WITH LIGHTENING CLOUD TO GND, MODERATE TO SEVERE TURB AND A FSS THAT TOLD ME NONE EXISTED AND NONE FORECAST, AND BARELY BELIEVED MY PIREP. I DIVERTED TO THE E NE (030 DEG) TO AVOID AND ATTEMPT TO CIRCUMNAV THE SMALL SCATTERED NOCTURNAL TSTMS. SALT LAKE CITY CTR ON 127.7 HANDED ME OFF TO ANOTHER SECTOR 134.5 AND I WAS TOO LOW TO REACH THEM. I STAYED ABOVE THE MOUNTAIN PEAKS BUT AS LOW AS I COULD SAFELY FLY IN ORDER TO SEE THE LIGHTENING AND THE CLOUDS. I WAS UNABLE TO GET AROUND THE TSTMS AND, IN FACT, THEY WERE INCREASING IN NUMBER AND INTENSITY. I FLEW NE TO 70 NM DME OF JACKSON HOLE AND THEN TURNED BACK AND CIRCLED MONTEBELLO, ID. IN CASE A PRECAUTIONARY LNDG WAS NECESSARY. AFTER ABOUT 1 HR IT WAS OBVIOUS THESE TSTM'S WERE NOT GOING TO DISSIPATE. THIS WAS A RATHER LARGE GROUP OF LEVEL 3 AND 4 NOCTURNAL TSTM'S, PREFRONTAL IN NATURE, AND PROBABLY CREATED BY A UPPER LEVEL TROUGH. WE GAVE UP AND RETURNED TO SALT LAKE CITY, CLBED TO 12500' AND RECONTACTED SALT LAKE CITY CTR ON 127.7. WE WERE HEADED 180 DEGS, MY DEAD RECKONING ESTIMATE TO SALT LAKE. CTR GAVE US A VECTOR OF 190 DEG 10 DEG DIFFERENT. THOUGH UNABLE TO MAINTAIN ALT DUE TURB WITH STRONG UP AND DOWN DRAFTS, WE LANDED UNEVENTFULLY AT SALT LAKE CITY. WITH THIS KIND OF HELP FROM FLT SVC IT'S ONLY A MATTER OF TIME BEFORE THEY CAUSE AN ACCIDENT. I THINK THE SAFEST WX RPTS ARE PIREPS AND FSS IS NOT TO BE TRUSTED. I BELIEVE FSS INACTIONS AND SLOPPY FORECASTING ARE DUE TO 4 THINGS. NIGHT TIME FATIGUE. LOW MORALE. AUTOMATED FSS. LESS SVC STATIONS.

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.