University of Utah Curie Club

This is almost a day late and a dollar short, but I want to give a shout out to the University of Utah Curie Club, which seeks to inspire women to pursue careers in science and reach the top of their field, and help women scientists balance family, scientific discovery, and the battle for research funding.

I say a day late and a dollar short because I only learned of the Curie Club last night and the first gathering was yesterday.  However, they meet monthly and have an impressive lineup of discussion leaders for the 2016/17 academic year.

Monthly gatherings are open to all undergraduate and graduate women in STEM (Science, Technology, Engineering, and Math) fields.

Newton Brings Steady Rain to Southeast Arizona

Former Hurricane Newton continues it's northward movement and is moving through Sonora this morning on its way to southern Arizona.  A predecessor rain event lies across Arizona and New Mexico.

As of 6 am MDT this morning, Newton had wakened to tropical storm strength with maximum sustained winds of 60 mph.  Still, he has held together rather well over the Gulf of California and State of Sonora.  Data coverage in Sonora is very limited, but one inland site near Hermosillo reported maximum sustained winds of 45 mph with a peak gust of 64 mph.

Source: Mesowest

The major impacts of Newton now will be rain and related flooding.  The National Weather Service has issued flash flood watches for southeast Arizona and southwest New Mexico.  As I write this, they have a flash flood warning out for the Nogalas Wash with nearby rainfall reaching as high as 1.25 inches in the past 24 hours.

Source: NWS

 As precipitation shields go, this one is about as broad and continuous as they get in that part of the world.  Most of the gaps you see in the radar image below are areas where the beam is blocked by topography.  On the other hand, intense cells have been limited so far.

Source: NCAR/RAL

The sounding from Tucson this morning was juicy, with a surface dewpoint of 66ºF and a precipitable water of 4.7 cm.  Southeasterly and easterly flow in advance of Newton extends to about 700 mb (10,000 ft).

Source: NCAR/RAL

Given the high humidity, the good news is that temperatures are mild (71ºF) and I suspect the locals will enjoy the rain, which has fallen continuously since about 1 am MDT at the Tucson airport.  The view of the Santa Catalina Mountains from the University of Arizona campus this morning makes me so jealous.  They will get more rain today than we've had in Salt Lake in 3 months!

Source: University of Arizona

More on this event at the Madweather blog by Bob Maddox, former director of the National Severe Storms Lab.  

Hurricane Newton Aims for Tucson

Hurricane Newton passed Cabo San Lucas early this morning, producing sustained winds at the CSLB7 observing site (735 feet above sea level) reaching 79 mph with a peak gust of 116 mph, both around 2 am MDT.

Source: MesoWest

Model forecasts call for Newton to weaken, but bring a strong slug of moisture into southern Arizona tonight and tomorrow.  The high-resolution NAM loop below shows the sea-level circulation center weakening but tracking across northwest Mexico, eventually reaching Tucson.  Southeast Arizona and New Mexico bear the brunt of the precipitation, especially tomorrow.

There are multiple sources of uncertainty in precipitation forecasts related to landfalling tropical storms, but include (1) track and (2) the chaotic nature of convective storms.  The latter can lead to large spatial and temporal variations in precipitation, even over short distances (see also the Madweather blog).  Last night's NCAR ensemble, for example, produced anywhere from 1 to 4 inches of precipitation at Davis-Monthan AFB near Tucson.

Source: NCAR

The NWS has issued a flash flood watch for most of southeast Arizona and southwest New Mexico and it looks like some impressive gully washers are likely.

Unfortunately, the moisture will not be coming to northern Utah.  Did you know it's been since June 13 since we had more than 0.08" at the Salt Lake City Airport!  If only Newton's apple fell a bit further from the tree.  

Hints of Fall

I don't want to overstate it as yesterday's high temperature was only 5ºF below average for the day, but it's nice to feel a hint of fall in the air.  Yesterday and last night were cool enough that we actually had to partially close the windows to keep the house from getting too cold.  That's such a nice change from the nuclear summer we've been experiencing.

In the mood for further chilling, I decided to do a quick hike up Snowbird yesterday afternoon.  When time is limited, I've always found that to be a great workout with the added advantage of limiting wear and tear on my increasingly creaky knees.

I had completely forgotten about Oktoberfest, so, in addition to the cooler air giving me a taste for the coming winter, I also got a full-blown taste of Little Cottonwood gridlock.

Red Snake in September!

The growth of Oktoberfest the past few years is quite astounding.  In fact, I don't know if I've ever seen more cars parked at Snowbird than I did yesterday, even in the winter.

Full House

How about a full tram, on the way down.  

Further evidence of the need for improved full-season (or at least two-season) mass transit in the canyons.  Alternatively, a number of carpool apps are now available.  Perhaps one will go viral for the Cottonwoods this winter.  

Frontal Flirtations

Weak fronts can be extremely difficult to pin down at night and in the morning when the nocturnal inversion that forms overnight tends to obscure larger-scale wind and temperature contrasts.

Nevertheless, evidence of a weak front moving over the Salt Lake Valley can be seen in the meteograms at the Salt Lake City airport overnight.  Note how winds shift from southeasterly to northwesterly from about 2300 to 0100 MDT.  Without larger-scale forcing, the preferred flow direction at the airport overnight is southeasterly, so northwest flow is a dead give away that something is up.

Source: MesoWest

This morning, the MesoWest surface analysis at 0836 MDT shows northerly or northwesterly flow across much of the western Salt lake Valley, easterly flow near the University of Utah (consistent with overnight drainage and canyon flows).  Temperatures are generally in the low to mid 60s in that area.  In contrast, a number of stations in Utah Valley show southerly flow and temperatures in the 70s, suggesting that the weak front has pushed to near Point of the Mountain.

Source: MesoWest

I'm no expert in this area, but I'm guessing that the front took one look into Utah County, saw the Y on the hill, and decided it was better off hanging around the U than to spending time today at BYU.  

Forecasts for today show a somewhat disorganized pattern with the front weakening and another push of colder air moving into the state later in the day.  The HRRR forecast for 0000 UTC (1800 MDT), for example, shows strong southerly flow pushing into southern Salt Lake County, where it meets an apparent lake breeze or perhaps remnants of last night's front.  A stronger windshift lies over the northwest corner of Utah.  

The net impact of this pattern will be a gradual cooling trend with temperatures today in the high 80s along the valley floor and mid 80s tomorrow.   With a weak frontal boundary, there's a chance of a shower or thunderstorm, but really, given what we've been through the past few weeks, the day should be quite pleasant.  Mountain biking this morning was simply splendid.

Just How Dry Was This Summer?

Last night I awoke with a start to drops hitting the roof and leaves rustling on the windows.  My heart raced in anticipation of rainfall.  Alas, it wasn't to be.  A few sprinkles, some gusty winds, and it was over.

Similarly, this morning teased us with an ominous sky, virga, and even some mammatus clouds.

As I walked to the bus, I briefly felt raindrops on my face and arms.  So exciting!  However, hopes were once again dashed as the system moved off to the northeast.

Just how dry has it been this summer?  Well, August 31 is in the books and we can now take a look back at all of meteorological summer (June, July, and August).  Total rainfall at the Salt Lake City airport was 0.67", making it the 11th driest all time.

To put that into perspective, the histogram below shows the amount of precipitation falling in Salt Lake City by year back to 1874 ordered from high to low (I've left the years off since there are so many).  2016 is highlighted in red.  Yes, there have been drier summers, but the amount of water in the rain bucket this year is quite low and in the 10% driest summers.

For temperature, we fell just shy of the hottest of all time (behind 2013), but ended up 2nd and a full degree warmer than the next highest summer, 2007.

Source: NOAA Regional Climate Centers

You put that combination of little precipitation and exceptional warmth together and you probably have the "driest" summer on record in Salt Lake, or at least something that is close to that, if you think about it from the perspective of precipitation minus evaporation.

In the foothills, most of the grasses turn brown during the summer, but this year one sees gamble oak and other species highly stressed with browning leaves.  Near the mouth of Dry Creek just northeast of campus, where most plants survive for the summer, everything appears to be dead.

Although we may get lucky with a shower or thunderstorm today (or unlucky if it happens during the football game), we need things to turn around quickly or we are going to be entering the cool season with a huge deficit in soil moisture.   If we have a big snow season (wouldn't that be grand), that won't be a problem, but if we have another meager year, it will cut into the runoff as the first "reservoir" to be filled when the snow starts to melt is the soil.

At least cooler weather is on the way.  Looking forward to it.

Addendum:

Plot of summer precipitation @KSLC chronologically by year added below at request of commenter.