Friday, March 31, 2017

High Wind Warning

Models have been trending toward an easterly downslope wind event tonight.  NWS has now issued a warning for the northern Wasatch Front.  Monitor forecasts, especially if you are in downslope wind prone areas.

Bizzaro World

With April Fools Day tomorrow and a crazy month of weather behind us, today brings a fitting "Bizzaro World" end to the month of March.

First, let's recap.  It has been simultaneously hotter than hell and anomalously wet this month.  We set five daily records for maximum temperature over a 7-day span from the 15th to the 21st, including a 79 on the 18th, dashing hopes of powder skiing over the U's Spring Break.  For all but today, the average temperature for the month is 50.2ºF, a full half degree warmer than the previous warmest March on record from 2015.  Although today will likely lower that 50.2ºF just a titch, a half degree gap is sufficient that this March will go down as the warmest on record.

But it's also been quite wet, at least at the Salt Lake City Airport.  Right now, 2017 rates as the 9th wettest march on record with 3.51 inches.  We may add a bit more to that today.  A record is out of reach, however, as 1891 saw a whopping 4.66 inches.

For the snow, March has proven to be a stinker.  At lower elevations, it's been a disaster.  For example, the Ben Lomond Trail SNOTEL (6000 feet) was well above average snowpack water equivalent at the beginning of the month, but has now lost nearly half of its snowpack and now sits at average.  In a typical year, they would peak in late March and lose snow in earnest in April.

Source: CBRFC
At mid elevations, the picture is mixed and dependent on aspect.  Some SNOTELs were able to survive without a net loss, but others saw snowpack reductions.  An example of the latter is Mill D North at 9000 feet in Big Cottonwood, which saw peak snowpack in early March and has had a net decline for the month, despite some gains in the past 10 days or so.  Presently they sit just above average.

Source: CBRFC
The sheltered, north-aspect Snowbird SNOTEL provides an example of a location that was able to whether the storm and exhibit a slight net gain for the period.  This doesn't mean that all of Snowbird saw a net gain.  Much depends on elevation and aspect.  Upper-elevation north can "weather the warmth" in March.  Other aspects less so.

Source: CBRFC
Which brings us to today.  I feel like I've been transported to a Bizzaro World where everything is backwards.  I awoke and went to get the paper and the visibility at my house was about 10 feet as the Avenues foothills were consumed, at least temporarily, by low clouds.  The scene is Cascadian on campus this morning, with abundant low clouds.

Surely there was a problem with the morning sounding from the airport.  Near saturated conditions from the surface to 500 mb is one thing, but the flow aloft is easterly!

Source: SPC
Those upper-level easterlies are expected to increase today and reach a peak this evening.  Napoleon knew all to well that bad things come from the east, and sometimes we get strong downslope winds with easterlies, but fortunately other aspects of the pattern are not favorable for such winds.  Nevertheless, I'd expect some oddball wind patterns in the mountains and some cloud and precipitation features that are a bit unusual for this part of the world.  In fact, I can see some low-level scud clouds moving from east to west across Sugarhouse from my office window right now.  You don't see that every day around here.

Finally, to wrap up the Bizzaroness, we got about 7 inches of snow at upper elevations in the Cottonwoods over the past 24 hours.  My take is that such a storm puts us precisely half way between mid-winter powder skiing and spring corn skiing.  Hopefully you can figure out what that means.


UTopia is a new local environmental TV series debuting on KJZZ (channel 14) at 8:30 PM this Sunday (April 2nd).  Their first topic: The Greatest Snow on Earth.  Here's a clip.

Thursday, March 30, 2017

What the Hell Is Going to Happen?

As we discussed yesterday, the pattern for today and tonight is one that poses a number of challenges for detailed forecasting in the Wasatch Range.  The basic problem is this.  We have a closed low developing over the Intermountain West and the position and intensity of the closed low development strongly influences the position and movement of the cold front that will push into northern Utah today, as well as the subsequent direction and intensity of the flow impinging on the Wasatch Mountains.  Mountain snowfall is strongly dependent on both of these factors, and thus there is a wide range of possible outcomes for storm totals through tomorrow.

Let's focus initially on the 0600 UTC initialized NAM forecast for 0000 UTC (1800 MDT) this afternoon.  At that time, the NAM calls for the closed low to be centered over southern Nevada.  There are two bands of precipitation over Utah, one over the central part of the state, the other over western Utah.  The latter is associated with the approaching cold front.

This model run then stalls the front right on the east bench.  The series of images below show the winds and three-hour accumulated precipitation that results overnight.  Note how the wind shift remains very near the Wasatch range (the northwesterlies stop penetrating eastward) and the bulk of the precipitation falls to the west of the Central Wasatch.

Ultimately, this solution lays down only 0.13" of water and 1.1" of snow at Alta by 6 AM tomorrow and only .18" of water and 1.6" of snow by tomorrow night.  Basically, a near skunking.

Depressed?  Well, I can tilt your emotions anyway I want if I cherry pick a different model.  The reason for this is that there is a great deal of sensitivity in the storm totals at any given location to the precise position, movement, and intensity of the closed low.  The diagram below is a "spaghetti diagram" and it shows the 5460 m 500-mb contour from all 21 members of the Short Range Ensemble Forecast System at 0000 UTC (1800 MDT) this afternoon.  There is good agreement on the low position, but disagreement on position, scale, and intensity, and there lies the rub.

So when we look at the downscaled SREF forecasts for Alta, we see a wide range of possible outcomes from about 0.35 inches of water to about 1.8 inches.  Most of the members, however, cluster between about 0.5 and 1 inch of water, which would likely translate to 5-10 inches of snow given the anticipated 10% water content.

The NCAR ensemble is a bit more optimistic.  Most members are between 1 and 1.5 inches, but a few go bigger than that.

My view of these forecasts is that things haven't changed all that much from yesterday.  Something in the 6-12 inch range lies in the "most likely" category, but the pattern and large spread produced by the ensembles means that the range of possible outcomes is fatter than that and fatter than the "average" Wasatch storm.  Of greatest concern is the possibility that the frontal band stalls and never quite makes it into the central Wasatch.  We saw an event like this only several days ago and it remains a possibility for later today and tonight.  Let's hope that doesn't happen.

Wednesday, March 29, 2017

An "Interesting" Forecast

The forecast for tomorrow and Friday is one that falls into my "interesting" category.

It's interesting primarily because it is one in which the large-scales are evolving rapidly.  Linear extrapolation from the west coast won't cut it in a storm like this.  It is only through the magic of numerical weather prediction that we can anticipate the rapid development of a closed low over the Intermountain west.

To highlight the remarkable change, let's first take a look at the situation at 1800 UTC (Noon MDT) today.  Utah is under the influence of a short-wave ridge (hence the beautiful blue skies), but further upstream, an upper-level trough lies over the eastern Pacific, with precipitation downstream over the Pacific Northwest.  

Presently, as evinced in the plot above, the trough is what we call open wave, because the height lines (and flow streamlines) do not close in a circle.  

The models, however, forecast for the trough to undergo rapid development and close off over the Intermountain West, as illustrated by the GFS forecast below for 0600 UTC (0000 MDT) Friday.  

Currently, in advance of the trough, it appears we will see some periods of mountain snow developing tomorrow in moist south-southwesterly flow and then heavier snow with the cold frontal passage later in the day.  

Numbers being put out right now by the 12-km NAM for Alta call for a couple of tenths of an inch of water equivalent in the moist southwesterly flow tomorrow, then very intense snowfall with a few tenths of an inch of water with the front around 6 PM, and then some additional precipitation in the wake of the front in the post-frontal and eventually "wrap around" phase as the trough moves downstream.  Total water is a bit over an inch.  

The tricky thing about these sorts of events is that where and how the low closes off affects the timing of the frontal passage and the position of the wrap around precipitation.  I have seen cold fronts stall out when the low closes off early, resulting in a skunking for the central Wasatch.  On the other hand, I've also seen situations where the low closes and tracks optimally, and we get both a pummeling from the cold front, but then also the wrap round precipitation.

As things stand now, I'm cautiously optimistic.  If current model forecasts hold, then a 6-12" dump with perhaps more if we're lucky seems likely by Friday morning.  I wouldn't call in sick yet though.  This is a dynamic situation, so let's see how the forecasts look tomorrow.

Tuesday, March 28, 2017

A Remarkable Alta Snow Burst

Yesterday afternoon from noon to 1 PM MDT,  Alta was pounded with intense snowfall.  The automated Alta-Collins stations recorded 0.25 inches of water equivalent in that hour, and the interval snow-depth sensor reported an increase in snow depth of 7 inches.

Due to round off errors and other issues, perhaps the 1-hour snowfall wasn't 7 inches, but something closer to six, which is what I've heard reports of from friends in the vicinity.

In any event, it sounds like a very intense snowfall period.  The question is why.

And the answer is that I don't know!

Nothing jumps out from the radar loop for the period (Alta identified roughly with a red box near the center of the frame).  There is a brief period with relatively high radar reflectivities (yellow color fill indicates >35 dBZ) that would be consistent with strong, localized snowfall, afterwhich the echoes are actually non-existent.

Often, there is a very poor correlation between snowfall rates and radar reflectivity in Little Cottonwood Canyon for a variety of reasons.  One is that the radar beam is partially blocked.  Another is that the snow growth can sometimes occur at low levels below the unblocked portion of the beam.  Thus, we get little insight into the intensity of yesterday's snow from the radar loop.

A curious aspect of the burst is that temperatures at the time were relatively high.  At Alta-Collins (9670 ft) it was about -2 to -3ºC.  The snow that fell, however, appears to be of low density (6 inches of snow with 0.25" of water equates to a water content of about 4%).  Thus, the snow was likely comprised primarily of dendrites and dendritic aggregates (dendrites that have stuck together).  In layman's terms, "goose feathers." Dendrites typically form at temperatures of -12 to -18ºC, which means the flakes formed at about 4000-5000 meters above sea level based on yesterday afternoon's sounding.  When I think back to lower density events at Alta, I think of shallower storms, but that does not appear to be the case yesterday.

So, it was an interesting burst of snow the causes of which are unknown to me.  I wish I was there! Feel free to share your ideas and observations.

Saturday, March 25, 2017

Major Upgrades to the NAM

After a long delay, the National Centers for Environmental Prediction (NCEP) finally implemented their long awaited and likely final upgrade to the North American Mesoscale Forecast System (NAM) on March 15th.

The changes are extensive.  The grid spacing of the NAM nest over the continental US decreases from 4 to 3 km.  Calls to major model physics packages are more frequent, updates to cloud microphysics parameterizations (critical for the simulation of precipitation), a new data assimilation system (to create model initial conditions), assimilation of new observational datasets, and more.  A complete rundown is available here.

NCEP is also providing NAM output now at higher frequency.  I've updated so that it is now possible to access the NAM 3-km nest at hourly temporal resolution.  The loops are great and should aid in anticipating the onset and ending of precipitation.  Below is last night's NAM forecast of 1-h accumulated precipitation and winds for 2100 UTC (3 PM MDT) this afternoon showing the effects of the slow moving cold-frontal precipitation band that is spreading into the Salt Lake Valley this morning.

The older 4-km NAM nest had a major overprediction problem in the mountains.  NCEP has told me that they think this new version will be better in that regard, but the proof is in the pudding.  We'll have to watch it for a few events and see how it does.

Also, high-resolution model guidance like this has tremendous physical realism.  It's quite alluring.  However, that doesn't necessarily mean that it is skillful.  You can have a very realistic precipitation pattern, but if it is in the wrong place, you have a bad forecast.  This can be especially problematic at longer lead times and is a reason why one needs to be cautious using a single high-resolution model rather than an ensemble.

Nevertheless, even with those predictability limitations, I'm hoping that we will find that this upgrade is a significant step forward.

Friday, March 24, 2017

Looking Back at Yesterday's Epic Deluge

Yesterday we were in clear outlier mode in Salt Lake City as we broke the all-time record for precipitation on a calendar day in March and experienced one of the wettest days ever.  I mangled some of the numbers in the previous post, so we'll take a little bit of time today to look back on the event and set the record straight.

The primary large-scale feature driving the event was a mid-level trough that moved very slowly across Salt Lake City and stalled very near the Wasatch Crest for most of the day.  This trough was a large-scale feature extending northeastward to the Canadian border, and served as the locus for precipitation development along much of its lengths.  The image below shows the scene at 2000 UTC (2 PM MDT).  Wind barbs are at 700 mb (10,000 ft).  Gaps in the radar echo coverage in portions of Wyoming reflect both poor radar coverage and some orographic effects.

Cloud and precipitation bands of this type are sometimes called "wrap-around" because the wrap around the backside of the surface or low-level trough.  Indeed that was the case yesterday, as shown below with the sea level pressure analysis, although I'm not entirely satisfied with that classification of this system for a variety of reasons I won't get into here for lack of time.

The National Weather Service reports that the daily precipitation was 1.97".  Note that this is for the midnight to midnight calendar day based on Mountain Standard Time.  We are currently on Mountain Daylight Time.  If the calendar day was defined based on daylight time, the daily total would have been an even larger 2.07 inches, based on surface airways observations provided by the airport.  This highlights an important aspect of meteorological records.  Calendar day records are not the same as 24-hour records, since the latter can use arbitrary start and end times.  Often, major precipitation events straddle calendar days and are broken into two smaller pieces.  If you are using statistics of 24-hour precipitation based on calendar day records to design your storm-runoff system, this is an issue to consider!  Nevertheless, many meteorological records are based on calendar days, I suppose for historical and practical reasons.  For example, many of our meteorological records are collected by volunteers who provide daily observations of maximum temperature, minimum temperature and precipitation amount.

Below is a summary of the 50 largest calendar day precipitation events at the Salt Lake City airport and, prior to the creation of the airport, downtown.  1.97" makes yesterday the 6th wettest calendar day on record and the wettest March day on record.

Source: NOAA Regional climate Centers
The precipitation, however, was not evenly distributed during the calendar day.  It was heaviest prior to about 6 AM MDT, when over an inch fell in the prior 6-hour period, and ceased at 5:40 PM MDT (at the airport, showers lingered on the east bench).  Radar imagery at about 4 AM MDT (0957 UTC) shows that the area around the Airport and portions of the I-15 corridor to the north experience very heavy precipitation with areas of radar reflectivity greater than 35 dBZ (yellow) and localized pockets above 40 dBZ.  Although I'm not showing a loop, these areas of heavy precipitation were quasistationary for much of the night and very important in pushing the precipitation amounts at Salt Lake City to record levels.  

Source: NCAR/RAL
As wet as it was at the airport, there were locations that were wetter.  Tooele recorded 2.49 inches of precipitation and the Rocky Basin Settlement SNOTEL in the Oquirrh Mountains recorded 2 inches of precipitation water equivalent and 22 inches of snow from midnight to midnight MST.  

The central Wasatch didn't do as well because the strongest precipitation along the band was just to the west, along with the northwesterly flow behind the mid-level trough.  As a result, the large-scale precipitation dynamics in the central Wasatch yesterday were weaker.  If one looks at the wind time series on top of Alta's Mt. Baldy, one can see the slow trough passage from 0000 MDT on the 23rd to 1800 MDT on the 23rd with the wind shifting very gradually from south to north-northwest.  Note, however, how weak the winds were for much of the period, especially from 0000-1200 MDT.  It wasn't until the trough had passed late in the day that the northwesterly flow intensified, but by then, the larger-scale precipitation dynamics were dying.  

Source: MesoWest
It wasn't a total disaster for the central Wasatch.  For the midnight to midnight MST period, Alta-Collins picked up about 9 inches of snow and 0.82" of water.  However, this is less than observed in the northern Wasatch and far less than observed in the Oquirrh Mountains.  

The spring pattern continues tonight and tomorrow with a cold front moving in and bringing mountain snow to the central Wasatch starting early tomorrow morning.  The NAM meteogram below tells the story pretty well.  This looks to be a quick hitting event, dumping several inches of snow in the morning, tapering off quickly to snow showers afternoon.  

Last night's NCAR ensemble produced anywhere from 0.6 to 1.6 inches of water for Alta-Collins.  Most members are between 0.6 and 1.1 inches of water.  

Probably 4-8 inch totals lie in the most likely range, but lets keep our fingers crossed we can do a little better.  

Thursday, March 23, 2017

One of the Wettest Calendar Days Ever in Salt Lake City

Editors note: Post has been updated to note that the records are for Salt Lake City, specifically the airport and prior to that downtown.

Editors note 2: ARGH!  I can't do math either, and daily records are probably based on MST rather than MDT.  NWS is reporting 1.59" so far, so scratch the 1.70" noted in the post below (we may get there eventually) and use 1.59", putting us at #13.  Yes, still very wet!  Please forgive me...

If my math is correct, we have now had 1.70" of precipitation (water equivalent) at the Salt Lake City airport from Midnight to Noon.

That would rank as the wettest calendar day ever in March and the 11th wettest calendar day ever in the Salt Lake City area based on online records at the NOAA Regional Climate Centers.  Prior to today, here's the rankings.

Source: NOAA Regional Climate Centers
I think it is pretty likely that we will move into the top 10, but suspect that top 5 is out of reach.  Still, this has been an extremely wet calendar day.

Much Needed Precipitation

After a stretch of remarkably dry and unseasonably warm weather, precipitation and cooler weather has finally returned to northern Utah.  Radar imagery this morning shows widespread precipitation over much of the Wasatch Front.

Source: NCAR/RAL
Take a close look, however, and you might notice that the echoes over the central Wasatch are weaker than those upstream and indeed that has been the case for most of the night.  In addition, total precipitation from midnight to 8 AM MDT at the Salt Lake City International Airport is a whopping 1.35 inches, but only 0.29" at Alta Collins.

Mother Nature slaps powder skiers across the face yet again!

And if you want to see why, check out the radar loop below.  Note how the slow moving trough has been camped right over the central Wasatch for the past couple of hours.  No flow.

At least it is snowing and not raining now in the mountains, and snow will continue today.  Although it's a slow start, with only 3 inches since midnight at Alta-Collins, I expect another 4-8 inches through 6 PM this evening as the trough swings through.  Let's hope for better.

Wednesday, March 22, 2017

A Juicy Late March Airmass

Well, it's a juicy one out there this morning.  The meteogram from the Salt Lake City airport shows and abrupt 5ºF drop in temperature and 9ºF rise in dewpoint just before midnight MDT as the flow shifted to NW-N with the passage of a modest cold front.

Source: MesoWest
Source: MesoWest
Dewpoints increased further to the high 40s by about 6 AM and as I write this are lingering around 45ºF.  For the most part, a dewpoint in the high 40s doesn't get much attention, but for us, they are the highest observed in the past 30 days (see blue line below) and possibly much longer than that (MesoWest only provides point-and-click access to the past 30 days).

Source: MesoWest
Thus, my skin and lungs greatly appreciated the pulse of moisture I felt when I went out for the paper at 6 AM.

Although we've cooled off some, temperatures remain above average for a morning in March in both the valleys and the mountains.  In the case of the latter, at 7 AM it was 36ºF at the base of Alta and 33ºF at Alta-Collins (9700 feet).  Alta-Collins picked up 4" of snow last night with 0.81" of water.  It may have started out as rain at that elevation, but I suspect most of the 0.81" fell as snow, so we're talking thick, creamy stuff.  It's tough to say from the web cams, but it appears most of the precipitation below about 9000 feet fell in the form of rain overnight.  What a waste of water!

On my way to the bus at about 7 AM, I saw a number of flashes of lightning over the Wasatch.  Indeed, flashes were detected this morning around the Bear River Migratory Bird Refuge, the south Salt Lake Valley, the Cottonwoods, and Parley's Canyon (see filled circles below).

What you see is what you get and for the rest of the day today, scattered showers and thunderstorms are on tap.  Snow levels will remain high and probably around 8000-9000 feet, but may temporarily drop in heavier precipitation.  

Right now it looks like a pretty good deluge tonight and tomorrow as the main trough comes through, with snow levels mercifully lowering tonight and reaching near bench level by about 8 am tomorrow morning.  This sounds crazy, but the skiing might actually be good tomorrow at upper elevations.  The average water content of the snow will be high, but that will help bury the spring snow, and it should be right-side up.  

Tuesday, March 21, 2017

Let's Get Back to April

The weather over the past week in northern Utah has been pretty outrageous.  Over the past 7 days, maximum temperatures at the Salt Lake City airport have been in the 70s and we will add an 8th today.  The overnight minimum last night was 61ºF, 6ºF warmer than the average high on this day.  We set daily records on four days and have a shot at another today (the current record is 74ºF).

The maximum temperatures during the past week are consistent with the average maximums from mid May to early June.  The lowest maximum temperature observed over the past 7 days is 70ºF, consistent with the average high on May 10.  The highest, 79ºF, is consistent with the average high on June 5th.

Spring is a period of great weather variability so swings from one extreme to another are not unusual.  However, the past week blows everything previously observed completely out of the water.  For the March 14-20 period, we have averaged 60.9ºF, a full 4ºF warmer than the next highest March 14-20 period in 1910.

Source: NOAA Regional Climate Centers
The records at mountain sites are less complete and do not extend back as far, but if we look at Alta, we see a similar story, although the gap relative to #2 (2007) is only 2ºF. 

Source: NOAA Regional Climate Centers
So, the past week has not only been warm, but it has been warmer than any comparable period in the instrumented record.

The impact of this warmth on the snowpack is staggering.  Significant losses in snowpack water equivalent have been observed at many SNOTELs.  Provided below are examples from Ben Lomond Trail (down 7 inches), Farmington Canyon (down 9 inches), and Mill-D North (Big Cottonwood Canyon, down 5 inches).  

Source: Colorado Basin River Forecast Center
That drops each of these SNOTEL stations to near average for the date.  

If you want a better story, you need to find a SNOTEL that is high and protected from the sun.  One example is Snowbird, where snowpack water equivalent has remained steady, illustrating the value of high-altitude north-facing terrain. 

Source: Colorado Basin River Forecast Center
There's been a lot of talk about a "pattern change" and yes, it is going to cool off a bit after today with conditions more like early April through the weekend.  That means unsettled conditions, valley rain and mountain snow.  The hit and miss nature of precipitation during the period makes for a wide range of possible accumulations in the mountains.  For example, the spread in our downscaled Short-Range Ensemble Forecast (SREF) product is pretty ginormous through Friday afternoon (00Z/25) with the driest member generating under 0.1" and the wettest more than 1.6" of water equivalent at Alta.  

Thus, this is indeed like April.  Good skiing will require a good dumpage and we're just going to have to wait and see if that happens and how quickly things add up.  The snow we do get is likely to be higher density, which is probably what we want at this stage. 

Sunday, March 19, 2017

Going Solar

Last July, we closed on a new home and moved to another location in the Avenues.  Our first order of business was to replace the roof, which was nearing end-of-life, and install solar.

We worked through the University of Utah's Community Solar program, which provides a discount on solar installations.  The install was done by Creative Energies, who did a great job.  Due to the popularity of the program, we had to wait a couple of months for install, which finally happened in early December.

Solar install in early December.
We are fortunate to have great exposure for solar, with a roof that faces south-southwest and has no major shadowing from local buildings or trees.  We lose just a little solar late in the day due to coniferous trees on the west side of the home, but the impact is small and the cooling we receive from those trees in the summer probably reduces our electrical usage more than what we would gain if we removed them.

There was some anxiety in terms of the grid-tie capabilities being connected by Rocky Mountain Power.  They take a few weeks to do this and we were hoping to be able to take the tax rebates during the 2016 tax year.  Incredibly, they connected the system on December 31st, just sneaking in under the wire.

Production in January and February was pretty limited due to snow cover, cloud cover, and low sun angle, but this month we've been killing it.  Our biggest production day was last Wednesday, when we reached a total production of 34.4 kilowatt hours.  Production totals every 15 minutes for that day show an optimal situation with no cloud cover.  We lose just a bit of production late in the day due to tree shading.

Of course, solar production is at the whims of the weather and a more typical day with occasional clouds yields a production curve with more gaps.

How large of a system to purchase was based on our desire to produced as much power as we use, but given that this is a new home for us, we had to do some guesswork.  We suspect that we are going to end up producing more power than we are consuming over the full year and that this gap will grow some as we perform upgrades to the home to reduce electrical consumption.   We figure when we buy an electric vehicle, we can put the surplus to good use.  We also have room on the roof for expansion of the solar array if we desire to do so in the future.

Saturday, March 18, 2017

Poof Goes the Snowpack

It's no surprise that this week's record setting warmth has destroyed the the low-elevation snowpack.  We have precious few low-elevation SNOTEL locations, but the one at Ben Lomond Trail has lost about 4 inches of water equivalent through yesterday and I suspect it will see another couple of inches go away today.  On the plus side, it still sits well above average for this time of year, although it is located in an area that is somewhat shaded from the afternoon sun.

Curiously, some of the upper-elevation SNOTEL sites have shown declines the past couple of days including Brighton and Mill-D.

I haven't been out in the central Wasatch during this warm spell and don't have a good feel for what is happening at those sites.  Although it has been warm, I suspect the snowpack is not ripe yet and that those declines are not necessarily due to melt.  It's possible they are due to sublimation given how hot and dry it has been.  The graphs above don't include today, which is a worst-case scenario for sublimational losses given the extreme warmth and wind.  It may be worth a look tomorrow.

A quick look at the latest observations through 3:55 PM MDT shows we've been flirting with 79ºF at the Salt Lake Airport, but I haven't seen anything pushing 80 in the 5 minute data yet.  We'll see if we can hit the psyche point.

Friday, March 17, 2017

Freaky Friday Forecast

OK, this is getting ridiculous.

If that forecast verifies, it will be the earliest 79ºF recorded at KSLC.  The record high for March is 80ºF, recorded on March 31, 2012.

Thursday, March 16, 2017

First Half of March Doesn't Make Top 10

Shockingly, given the blistering heat of late, the first half of March (through the 15th), only rates as the 11th warmest all time in the Salt Lake area.

Source: NOAA Regional Climate Centers
Granted, we are still running well above average, and we're not too far behind the warmer "half Marches", but still not in record territory.

A big reason we're behind is the two cold surges that occurred around the first of the month and then on the 6th.  

The one on the 6th really knocked the temperatures down.  Ah, the good old days!