Wasatch Weather Weenies

As anticipated about a week ago, cool air pushed into northern Utah over the weekend, giving us a delightful Sunday with a high of 81 at the airport.  The 81 occurred around noon as temperatures actually decreased some in the afternoon as colder air moved in.  If my quick read of the observations over the past couple of months is correct, that's the lowest maximum temperature we've had since June 19th when the high was 80. Snow was observed on the higher peaks as the the trough moved across northern California.   Skiff of August snow at the top of @sugarbowlresort ! #CAwx pic.twitter.com/06yHKunZsx — Neil Lareau (@nplareau) August 24, 2024 In Utah, the pre-frontal southerlies fanned the Boulter Fire near 5 Mile Pass. I suspect this was the source of the smoke you could smell in the Salt Lake Valley on Saturday. #BoulterFire is estimated to be 1000+ acres, but with the erratic winds, it’s hard to get an accurate acreage. Bulldozers are being utilized to build the...

The weather over the past week has been wonderful by my standards. Four of the past six days have seen highs in the 80s, lows have been in the 60's, and we've had measurable rain at the airport on four days.  You might have done even better than that depending on where you live.   The GFS analysis for 0000 UTC 19 August (6 PM MDT Sunday) shows the situation as of yesterday afternoon.  An upper-level ridge predominates over west Texas and New Mexico with a deep upper level trough off the Pacific Northwest Coast.   This has put Utah in a so-called "monsoonal" flow around the upper-level ridge.   This general pattern will predominate over the next several days, with changes in the position and strength of the upper-level ridge and trough affecting our temperatures and likelihood of precipitation.  For example, the ECMWF forecast valid 0000 UTC 21 Aug (6 PM Tuesday) shows a slight westward shift in the ridge, weakening of the trough, and a bit mo...

It's been 25 years since the fateful day of August 11, 1999 when an F2 tornado moved through Salt Lake City, killing one worker at the Outdoor Retailer Convention and leaving a surgical knife of debris and damage in the Avenues.  It is still the only tornado that I have seen in person, and I hope it stays that way.  I prefer chasing powder.   The tornado missed our house at the time by about 2 blocks.  My parents were visiting and my father told me he was eating lunch, looked out the window, shouted "holy sh-t a tornado" and yelled for my mom to grab my one year old son and run into the basement.  There was debris on our roof, so that was a very smart move.   The best footage of the tornado was captured by the web cam operated by John Horel and the Department of Meteorology (now Atmospheric Sciences) on the roof of the Browning Building on the University of Utah Campus.   See my post from the 20th anniversary of the tornado [ The Meteoro...

Aqua/Modis Satelite Image of the Great Salt Lake on 4 Aug 2024 It is not uncommon to see reports of recent or long-term trends in the Great Salt Lake characteristics based on lake elevation.  This is a quantity that is measured at three locations, two with a fairly long record.  The first is Saltair in the south arm of the great Salt Lake.  The second is Saline in the north arm.   While convenient, they often differ by a decent amount.  This is because the lake is separated by a rock fill railroad causeway which limits the transfer of water between the two halves.  This results in differences in lake elevation (the south arm is typically higher), salinity (the north arm is saltier), and even color (see above; for an explanation see  https://wildlife.utah.gov/gslep/about.html .) However, with a little information about the lake bathymetry (i.e., the underwater terrain of the lake), one can take the elevations from Saltair and Saline, estimate the a...

July is over, thank goodness.  Despite a blissfully cool start to the month (the highs on the first four days of the month were in the 80s), KSLC ended up with 10 days reaching 100 or higher and an average temperature of 83.3°F, good for 8th highest since 1874.  Source: https://xmacis.rcc-acis.org/ Eighth might not seem too bad but it is higher than anything observed prior to 2000 (the 20th century record is 81.2°F in 1960).  The 21st century climate at KSLC is like Katie Ledecky.  She owns the 20 fastest times in the 1500-m freestyle swim, and the 21st century climate at the airport owns the 16 warmest Julys (based on mean temperature).   The airport also received only .08" of rainfall.  There have been four previous Julys with only a trace, so this isn't a record, but it made a typically dry July even drier.   Since I get a lot of flak about the local conditions at the airport measurement site, I'll add that this July was the 7th warme...