Wasatch Weather Weenies

 " The rain fell on the Earth four days and four nights " -Genesis 7:12 (paraphrased) I suppose its blasphemous to paraphrase the bible, but by the time the current storm is over tomorrow, it will be about a four-day event, so it seems appropriate.   Below are gauge-measured precipitation totals for the first 3 days of this storm (i.e., from 1500 UTC/0900 MDT Saturday to 1500 UTC/0900 MDT Tuesday). Many stations, even in valley locations, are over an inch.  2+ inches at many locations along the east bench of the Wasatch Range from Orem to Ogden.  Some statiions over 6" in the Wasatch Range.  This data hasn't been quality controlled and a few big amounts might need to be adjusted, but the normally somewhat reliable Timpanogos Divide and Snowbird SNOTEL stations are at 7.00 and 7.30 inches, respectively.   Source: Mesowest The Collins snowstake has about 8" of dense snow on it this morning.   Snowbird has 10" on theirs, giving them early b...

It's been an active 48 hours over northern Utah thanks to the Saturday showers and thunderstorms, remnants of Rachel, and several other precipitation drivers. The plot below shows the estimated precipitation over northern Utah for the 48-hour period ending at 1400 UTC (0800 MDT) today (Monday, October 12.  Everyoen got some, but the biggest amounts are on the Alpine Ridge above Little Cottonwood Canyon and over the south slope of the Uintas where there are local accumulations of more than 3.5 inches.  Most of the central and northern Wasatch has seen at least an inch.  The lightest accumulations are in the northwest Salt Lake Valley (<0.5").   Source: MRMS Big Cottonwood Canyon was closed for a while yesterday due to flooding on the road. 🚧 Uphill Restriction Alert 🚧 SR-190: @SLCO_OOTS @UtahDOT are restricting uphill traffic due to flooding and debris on road. 📍: traffic will be turned around at mouth. ‼️ETO to uphill traffic: UNKNOWN https://t.co/tAZHyS...

Tropical Storm Rachel is currently well off the coast of Baja California, but it and its remnants are expected to affect the southwest United States this weekend and Monday.  The latest track and intensity forecast shows Rachel moving on a northeastward path, ultimately making landfall somewhere on the northwest coast of Baja or the California Coast near San Diego as a Tropical Storm.  By 5 PM Sunday, Rachel is forecast to be a post-tropical cyclone as it moves into Utah.   Source: NHC A post-tropical cyclone has lost its tropical characteristics, including its warm core and symmetrical storm structure, but maintains a low-level circulation and in some cases evolves into a mid-latitude frontal cyclone through a process known as extratropical transition .  In this case, Rachel is forecast to maintain a low-level circulation all the way to Utah because it is gaining the assistance of a strong upper-level trough that is digging down the Pacific Coast, as evident i...

Yesterday (Tuesday) morning, the Salt Lake City International Airport observing site, which is located at the south boundary of the airport just north of I-80, observed as rogue of a rogue shower as you will ever see.  The storm produced rain at the observing site from about 0725–0755 MDT, generating 0.16" according to the rain gauge.   KSLC Time Series 0725–0755 MDT 6 Oct 2026. Source: NWS. The radar at 1317 UTC (0717 MDT) showed the rogue cell moving over the airport as it intensified.  The cell was perhaps 5 km across and developed pretty much over or just upstream of the southeast corner of the airport.     The weather cam image at the top of this post, taken looking west from the University of Utah, shows just the narrow area of falling precipitation associated with the cell.  What conspired to make such an isolated precipitation shaft is known only to Mother Nature.   Radar-estimated precipitation from the National Severe Storms La...

There are three provocative public lectures coming up this month at the University of Utah.   Two are this week, are hosted by The Wilkes Center for Climate Science and Policy, and will be given by Myles Allen, who is visiting from the University of Oxford.  The first explores the role of climate change in extreme weather events.   The second explores what it would take to stop global warming.   Each of these is being given in the L.S. Skaggs Applies Science Building, which is a new building (and my home) just off of University Street.  I don't think it shows up on Google Maps yet, but it is immediately west (and connected to) the Stewart Building (see  https://map.utah.edu/?buildingnumber=18 ). Do not confuse it with the Skaggs Biology Building which is a bit farther to the east.   The third talk is an evening Frontiers of Science lecture being given by Nobel Laureate Martin Chalfie on October 22.  Parking and RSVP information...

Two very powerful cyclones, one from the tropics and one from the mid to high latitudes, are going to conspire over the next several days to break the jet stream.  The tropical cyclone is Typhoon Choi-Wan, currently southeast of Japan with maximum sustained winds of 110 knots.  Source: Joint Typhoon Warning Center The mid to high latitude cyclone hasn't formed yet, but is expected to develop over the Sea of Okhotsk on Wednesday.  The ECMWF HRES forecast below from Tropical Tidbits is valid 1800 UTC Wed Oct 7 and includes sea level pressure contours (black lines) and 500-mb height (color fill).  The big circle identifies the mid to high latitude system, the little circle Choi-Wan, which at this point is transitioning into an extratropical system, and the black line the upper level ridge downstream of these two systems.   Source: Tropical Tidbits By 1800 UTC Saturday 10 October, those two cyclones have merged into a massive 976 mb low over the Bering Sea....