Hi,

 

Yesterday, APR13 during sunset at Denver-CO KDEN, approx 23:30 ZULU, the ATIS at KDEN under ASN active read winds 350/17 A3011 while all other services I use announced winds 170/17 A3011. Temperature and other components were the same, but If the winds difference was not by 180 degrees, I may not have noticed.

 

This is the first time ASN brought me so strange numbers for a single location. My destination was KPHX and there the ATIS was OK.

 

Any ideas?

 

Best

 

Just looked at the 3-day weather history for KDEN on a NOAA web site. Yesterday, April 13th, between 21:30Z and 23:30Z, there was a major wind shift at the airport, in which the winds went from northerly to southerly within that two-hour window - there was probably a frontal passage during that time.

 

If the real-time report for KDEN was delayed by even one hour on the AS server feed right at the time you were flying, it would account for the discrepancy. I've found the ASN server is usually quite up-to-date, but occasionally a particular airport METAR may miss an update - which was more evident in this case because the R/W winds did change substantially in a short period of time.

Hi Jim,

 

Thanks, this should explain such radical inversion and very rare ASN lapse.

 

Best

For the record, Monday afternoon 4/13 from 14:30 to 16:30 MDT there was a pretty good shift in the Winds as a Cold Front rolled through the Front Range. 

 

It was the precursor for the Wx we're currently experiencing; a Low in the Four Corners area that is bringing an Upslope condition to the Front Range, bringing considerable Winds and Precipitation to the Denver Metro area in the form of both rain and snow.

 

I'm not complaining, of course... we need the Moisture!

 

:smile:

I can't be so specific, but the same type of occurance happened to me a few days ago (April 29th?, early evening). I have my A/C "parked" at Slatington Field in PA (69N). The reporting airport was entered as KABE. I opened ASN, started FSX, and opened up my A2A C-172 for a short 'round the patch' flight. Funny, but I heard thunder, and the skies were overcast. I had walked the dog about 10 minutes previously (in the same neighborhood, of course), and it was clear as a bell CAVU, cool and starry.  So I went and looked at the ASN map and picked the "clouds" view, which also showed a fairly solid overcast. KABE is about 15 miles to the east, but it didn't seem like there would be that big of a difference, and the cloud cover was extensive. I've never seen ASN do this before (I do have the latest update). I'm running FSX SE, and at the time that's all that was running - ASN and FSX.

 

Just wondering...