Monday, July 6, 2015

A Shift in the Pattern

The loop below shows the large-scale flow changes that have brought a pleasurable return of more seasonable temperatures to Utah and the Intermountain West.  Note in particular the westward shift of the upper-level ridge that was previously parked over northern Utah to the northeast Pacific.

Here's a closer look at the changes.  On June 29, the upper-level ridge and the highest temperatures at 700 mb (roughly 10,000 feet, color contours) were parked directly over Salt Lake City, resulting in a high temperature of 104ºF.  BTW, if you adjust that to sea level, you get a maximum of about 127ºF.

This morning, however, the upper-level ridge is thankfully over the north Pacific and our 700-mb temperatures are about 8ºC lower.

And, as a result, the National Weather Service forecast for the next few days is relatively pleasant.  


Sunday, July 5, 2015

It's Humid Out There!

By Salt Lake City standards, dew points don't get much higher than they are this morning.  At the Salt Lake City airport, the dew point maxed out at 67ºF at 9:50 AM and is currently sitting at a muggy 65ºF.

Nobody from the deep south will think much of this, but that's about as humid as it gets in Salt Lake City.  I don't know what the dew point records are for the Salt Lake City airport (pass them along if you know them), but I consider anything above 65ºF to be quite high and anything around 68ºF to be rare.

Although the humidity is good for the skin, it makes things far more uncomfortable and renders evaporative coolers completely ineffective.  It does, however, look like our run of >90ºF days, which sits at 20, will come to an end today.

Thursday, July 2, 2015

Heat Wave Tidbits

I feel quite disoriented this morning.  I awoke yesterday in Ketchikan, Alaska on a spectacular day.  Temperatures were comfortably in the 60s as we ferried across the Tongass Narrows to the airport.

I arrived yesterday evening at the Salt Lake City airport to an apocalyptic scene.  What the hell did you do to Utah while I was gone?  Where are the green Avenues foothills?  The patches of high mountain snow?  I haven't been gone all that long, but the transformation is dramatic.  

Much has gone on in the past week or two.  We've already spoken quite a bit about the June heat, but how about the air quality?  In Utah, we tend to think about wintertime inversions, but during the summer, our ozone can also become elevated.  Below is a time series of ozone levels on the University of Utah campus over the past 30 days.  Ozone is produced photochemically by the sun's ultraviolet radiation and shows a pronounced diurnal signal with a maximum in the late afternoon and a minimum overnight, as is clearly evident below.  However, you can also see how the peaks were highest during late June during the height of the heat wave.  

Things have been hot in the western United States and Canada, but also western Europe over the past couple of days as an upper level ridge built over the region.

The Weather Channel has a good summary of the weather records here.  98.1ºF at London's Heathrow Airport, which looks to be a July record for the UK (the all-time record is 101.3ºF set in Faversham (Kent) on 10 August 2003).  103.5ºF in Paris (2nd highest all time). 103.5ºF in Madrid (June record).  These are brutal temperatures, especially in northern France and the UK.

Wednesday, July 1, 2015

Salt Lake City Record Recap

No surprise here.  June 2015 spanked all previous Junes at the Salt Lake City Airport with a mean temperature of 77.5ºF.  That's 1.8ºF higher than the previous record holder, June 1988 (75.7ºF).

Source: NOAA Regional Climate Centers
And, in case you are wondering, Jan–June also came in as the hottest in the instrumented record with a mean temperature of 53.0ºF, topping 1934s 52.8ºF.

Source: NOAA Regional Climate Centers
And now onto July...

Tuesday, June 30, 2015

June Temperature Record Will Be Obliterated

With the intense warmth of the past few days, this June is now in uncharted territory for the highest mean temperature in Salt Lake City.

With one day remaining (today), the average temperature for June 2015 now sits at 77.1ºF, well ahead the record of 75.7ºF n June 1988.

Source: NOAA Regional Climate Centers
The overnight minimum was 77ºF and the high today is expected to once again eclipse 100, so the mean temperature for the month will increase further.  Although there's a slight chance of a thunderstorm today, which could lower the minimum temperature a bit below the 77ºF recorded this morning, it looks like we will obliterate the June temperature record.

Monday, June 29, 2015

The Hottest June Day Ever

In all likelihood, today will be the hottest June day on record in Salt Lake City.

The Salt Lake City International Airport recorded a minimum temperature of 78ºF overnight, tying the all-time high minimum for the month.

As of 10:30 am, it's already 92ºF and it looks like we are on pace for a max even higher than yesterday's 102ºF, which would put us at 103ºF or 104ºF.  If we hit 103ºF, our average temperature for the day, assuming we don't drop below 78 before midnight tonight, will be 90.5ºF.

On June 28 and 29, 2013, the Salt Lake City airport reported maximum temperatures of 105ºF, but the minima were 71ºF and 74ºF, yielding averages of 88ºF and 89.5ºF, respectively, lower than what I'm anticipating for today.

In addition, during that stretch of hot weather in late June 2013, the temperature sensor at the Salt Lake City airport was clearly reading high (see What's Up @ KSLC from August 20, 2013), so the books during that period are essentially cooked.

The bottom line is that you will experience the hottest June day ever in Salt Lake City today.

I say YOU because I have been happily ensconced in southeast Alaska since the Salt Lake heat wave began and haven't seen a temperature above 71ºF in over a week.  Note the rain jackets and smiling faces.

Heading home soon and not looking forward to it...