Sunday, June 9, 2013

The Timing Is Wrong

Forecasts that I've seen on the news and in the media the past couple of days have been hinting that we would hit the big 100 on Monday.  It's going to be hot today and tomorrow, but it looks to me like the timing might be wrong to get to the triple digits.

The problem is this.  There is a tongue of very warm air forecast to move across Utah late today and tonight in advance of a closed low that is approaching Utah from the southwest.  The warm tongue is forecast to extend across southern and central Utah by 6 PM MST this afternoon.

As a result, Salt Lake is not in the heart of the warm air this afternoon and our 700-mb temperatures only make it to about +15 or +16ºC.  That's unseasonably warm and good enough for temperatures in the low to mid 90s, but not enough for the big 100.

The warm tongue then moves over us late this evening and tonight.  By mid-day tomorrow, cooler air (cooler being relative here!) associated with the closed low is already starting to move in and 700-mb temperatures are dropping.  By noon tomorrow, they are already back to +15ºC again.  

Timing is everything.  In this case, it appears we'll just miss out on the phasing of the warmest airmass and afternoon heating needed to get to 100.  Of course there's always "hope" that the models are wrong.  Hope here being purely for the psyche factor of 100.  The mid and high 80s are far more desirable.


  1. Can only find a couple stations on Mesowest that actually hit 100, but KSLC was one of them.

    1. Yeah, it must have gotten momentarily to 99.5. The 5-min data we get, which is based on temperatures to the nearest whole degree C, shows only one observation above 37F and that was at 14:15 MDT:

      14:20 36C/96.8F
      14:15 38C/100.4F
      14:10 36C/96.8F

      Given that the data is in whole degree C, that likely means a 5-min spike from perhaps 36.4C, which would round down to 36, to 37.5C, which rounds up to 38. The NWS has a record event statement out stating that it hit 100. The airport is typically the hottest place in the valley, so it makes sense that they would be one of the few to hit 100. A site on the edge of the airport that reports 1-min data only got to 95.4. Land surface characteristics and exposure can make a difference, and that must have been the case today. C'est la vie.

      This is an example of the Steenburgh effect. The more strongly you question a forecast, the more likely that forecast will verify ;-).


    2. Looks like we just recovered back to 100 at KSLC again (1650 MDT). Oh the humanity...