Wasatch Weather Weenies

With the Fourth of July next Tuesday, we have a holiday weekend on tap.  My forecast for the weekend can be summarized in one word.  Combustible. The Brian Head fire gets everyone's attention, but both lightning- and human-sparked fires have been quick to flare up across the state.  Despite a good snow season, fire danger is rated as moderate to high across northern Utah and very high to extreme across southern Utah. Source: USFS Wild Fire Assessment System Precipitation has been scant across the state for several weeks, with 50% or less of average falling across much of the state over the past 60 days. Source: NOAA/NWS The past 60 days have also been unusually warm.  For example, the period from 29 April through 29 June is the 2nd warmest on record at the Salt Lake City International Airport (ignore the first year in the graph below as it contains several missing days). Source: NOAA Regional Climate Centers This has led to tinderbox condition...

GOES-16, previously called GOES-R, is a remarkable next-generation satellite that was launched in November.  Although not "official" yet, it has been providing remarkable imagery for several months. GOES is short for Geostationary Operational Environmental Satellite.  Geostationary means that the satellite is in an orbit in which it remains over the same point on the equator, allowing it to repeatedly sample roughly one half of the Earth at all times.  GOES-16 offers several major advances over previous US geostationary satellites including higher spatial resolution (0.5 km for the 0.64 um visible channel, 1 km for other visible channels, and 2 km for longer wavelength channels), which equates to approximately four times as many pixels, more frequent images (every 5 minutes over the continental US and as often as 30-60 seconds over selected regions), and 16 spectral "bands."  Previous GOES satellites sampled only 5 spectral bands.  The increased number of bands...

An addendum has been added to the end of this post concerning uncertainty about the source of the smoke or dust over the Salt Lake Valley this morning.   A smoky sunrise in the Avenues A weak trough passage last night has brought smoke into the Salt Lake Valley, along with a little lake stink. As far as troughs go, this one was about as weak as it gets and barely put a dent in the near-surface flow.  The trough is, however, more easily seen in upper air (700mb, about crest level) analyses, with the pronounced wind shift moving across the Salt Lake Valley early this morning. Thus, the smoke is not from the Brian Head fire, but more likely originates from one of the large incidents to our west and northwest over Nevada and Idaho. Source: https://fsapps.nwcg.gov/ Speaking of the Brian Head fire, lets take a few moments to talk a little bit about the meteorology leading up to the event, motivated in part by comments concerning yesterday's post. Sn...

As of yesterday, the Brian Head in southern Utah was the 8th largest fire in the state since 2003. Brian Head Fire has grown to over 42,000 acres. This makes it the 8th largest fire in UT since 2003. #utwx #BrianHeadFire #utfire https://t.co/9ID9QK6GiI — Randy Graham (@etherealwx) June 25, 2017 The National Interagency Fire Center reports that the fire started approximately 12:13 PM on Saturday June 17th and that the cause is still under investigation.  Their situation report issued at 5:30 MDT this morning reports a size of 42,800 acres, with 1,140 personnel working on the fire, plus 11 helicopters.  Twenty six structures have been lost. Images below are provided by the MODIS imager on NASA's TERRA satellite, which flies over the area in the early afternoon each day.  One can see a smoke plume, likely associated with the nascent fire, on 17 June.   Media reports suggest that increased wind from the southwest winds caused the fire to jump a line...

Greetings from Reykjavik.  I am on a 2-week trip to Iceland involving a week of vacation to drive and hike around the Ring Road, which encircles the island, and attend the International Conference on Alpine Meteorology.  I return to Salt Lake and the blistering heat of the American Southwest on Saturday.  Over the past 12 days, I haven't seen a temperature above 15ºC (59ºF).   Wonderful! Iceland is a spectacular country and a great place for a meteorologists (and geologists).  Think of it as a larger, lower version of Hawaii, with colder, windier weather, ice caps and glaciers, and bigger rivers and waterfalls.  The island is pretty much entirely volcanic.  There are few trees.  It lies near the Atlantic storm track, at the intersection of the Arctic and Atlantic Oceans, near the Arctic Ice Cap (for now) and east of Greenland Ice Sheet.  Volcanic eruptions, sometimes violent due to the presence of ice and water, are frequent, as are volcan...