I start writing this post based on an email from a friend, VC. I started to wonder about how much it really did rain at the airport last month. But The National Weather Service(NWS) in Flagstaff has rewritten the history books. Just last week, they claimed we had tied the record (See Arizona Daily Sun: Flagstaff ties record set in 1919 for wettest July. In yesterday’s NWS Month in Review post, they state, “Flagstaff in particular was hit with several strong thunderstorms, even during the early portions of the month, resulting in the 2nd wettest July of all time.” Their report also shows a drop in the previously reported amount by 1/100th of an inch to 7.57. Set aside that the record was bogus since measured in downtown Flagstaff and current measurements are at the airport, the shift in the data just looks fishy.
Here is the email that got me to thinking.
I was tracking the rain during July , and can NOT believe that the
airport only got 1/100 of an inch on July 31. I was right outside the
gates while it was raining hard!
I think there was something weird with the recording because there was at
least a 12 hour delay in reporting rainfall after 6 pm on July 31.
I thought I would look at stations in the nearby area on wunderground.com. Two airport stations shown on WunderMap at Wunderground.com.
Two airport stations shown on WunderMap at Wunderground.com
These two stations are less than 1000 feet apart. The one near the runway labeled as KFLG and corresponds to the National Weather Service Station. The other station labeled as MQFLA3 and is a Remote Automated Weather Station (RAWS) operated by the US Forest Service. Looking at the data they reported for July 31, they are very close 0.01 and 0.02 inches. I don’t doubt that it poured heavily at VC’s spot and managed to miss both weather stations. I drove through two downpours on my two-wheeler this last week. Both were no more that a few hundred feet across. It just wasn’t measured.
But, when I compared both stations’ daily rainfall reports for all of July, I saw sizable differences on several days. The monthly amounts were off, too. Keep in mind these aren’t the official records.
Tale of two stations. July precipitation for MQFLA3 and KFLG as reported to wunderground.com
I think it is remarkable that two stations so close together could have so many days with such different amounts of precipitation. Overall, the MQFLA3 site shows 8.8 inches on wunderground. The KFLA site showed the record tying 7.58 inches. This is a large 1.22 inch difference.
Personally, I think the National Weather Service should compare apples to apples. We set a record dating back to 1950. This is the only consistent data set to base a record on. Also, I think they should tell us why the cut the precipitation total for the month of July to below the 1919 record.
postscript: There is more strangeness to report here. Stay tuned.