2012/2013 Denver Winter weather!

[Ntxw]

We need the days of the subtropical jet back. When those big lows swung up from NM to Colorado (trinidad storm tracks) that gives denver epic upslope . Unfortunately the cold PDO will dominate with La Ninas for the next 5+ years at least. Either it's a dry NW wind or warm chinook downslope, 1950s style

[Palmer divide shadow]

Ugh!!

[PTPatrick]

I here ya. He interesting thing about salt lake versus Denver is that while they average near the same snow in a given year(Denver a hair more), they get there differently. Salt lake is more consistent and its standard deviation from the mean(I would guess because I haven't actually done the math) is probably smaller than Denver's. our 55-60 inch average is made of many years of 20 inches and some well over 80 and up to 100. We are more feast or famine. Salt lake is however much more likely to have snow cover in the dead of winter as those are its snowiest months, while Denver's are spring and fall. And yeah SLC is generally hotter too and drier though summer. Denver has the benefit of wet gulf moisture driven storms forming along the front range. It's that summer moisture that allows us to have a much less "desert-like" feel...well that and crazy soil in Utah that barely support vegetation.

[PTPatrick]

I might add that Denver seems to have a very cyclic moisture and temp pattern. Looking at the historical record it just appears that we are in one of those dry cycles since around 98. There were some wet times in the early 70s to mid 90s. 50s and 30, and 1880s were drier and hotter for sure. I suspect enso and pna are somewhat to blame. And of course climate change in general but that's a whole nother debate. Suffice it to say I fear Denver might become the new Albuquerque if this really is the new normal and not just a warm/dry cycle.

[denversnowlover]

Hey palmer divide shadow! You are correct our snow accums in denver are almost the same to slc...we average just a bit more here. And like you said the benches get more sorta like here...you could consider the southern and western portion of Denver as the benches.

We are in the midst of a pattern change but we cannot seem to get a pattern shift that wants to stay over the area...if this la nina thing for 5+ years is true then we will have to rely on the summer storms to prevent us from drying up too much! The past couple years we have had nothing in the month of march and we need that in order to have a smooth transition into the summer months without too much fire activity.

La Nina's are tricky here in Colorado as well... La NIna phase can be a killer but can also bring smaller but more storms. We average a few inches less a year in la ninas (snowfall)

[Ntxw]

La Nina's are tricky here in Colorado as well... La NIna phase can be a killer but can also bring smaller but more storms. We average a few inches less a year in la ninas (snowfall)

There's not going to be 5+ years of La Nina just that we will likely see more of them vs Ninos . Individual Ninas aren't all bad for Denver, it's collectively the storms become less frequent and that adds up and you have a multi-year drought. Drought then begets more dryness and it's hard to break (began in the plains a couple of years ago) unless you get a string of good ninos or really wet patterns for years.

[Palmer divide shadow]

True.Plus Salt lake cheats with that lake effect lol.

[Scott Patterson]

Salt lake city is actually drier than Denver! WE to in Denver get the benefit from the mountains but we also benefit from the gulf of mexico and the canadian arctic air. SLC has a hard time getting the true cold air because of the rockies. When it comes to summer, Denver pummels SLC in the amount of moisture and is a couple degrees cooler than SLC.

====

You are correct our snow accums in denver are almost the same to slc...we average just a bit more here. And like you said the benches get more sorta like here...you could consider the southern and western portion of Denver as the benches.

I'd have to both agree with much of the above and disagree with some of the above. For several years, I used to live in Denver area in the winter and I grew up in Salt Lake (and obviously I am a weather nut).

Salt Lake City Airport and Denver Airport get about the same amount of snow. They are so close that which one gets more depends on which 30 year average (or other time period) you look at.

See here that 1948-2005, Salt Lake City averaged a bit more:

http://www.wrcc.dri.edu/cgi-bin/cliMAIN.pl?utsalt

http://www.wrcc.dri.edu/cgi-bin/cliMAIN.pl?codenv

In fact, the two cities are so close that if you keep a rolling average graph, they are close enough that one year’s snowfall is enough to toggle back and forth on the graph as to which one gets the most snow.

The same goes for precipitation.

Denver is slightly cooler in summer, but average temperatures are very close the rest of the year.

Some might look at the data and assume they have similar climates, but at mentioned there are big differences.

Although both airports have almost identical snowfall averages, but the average snowfall gradient from location to location is actually much greater in the Salt Lake City area. It is true that in Denver, which each storm that passes through the Denver area, some places can get pounded with a foot or two while some get only an inch or two, but over time and over years and decades this tends to balance out more. It is true that the west and south sides of Denver get more snow, but it isn’t as sharp as a gradient as it is in Salt Lake. Some of the benches of Salt Lake (such as Olympus Cove) actually average well over 100” of snow a year (Olympus Cove actually averages 120”; probably the highest amount on the benches).

In the Salt Lake area, average snowfall actually increases 100” annually for every 1000 feet of elevation gained. The Salt Lake Airport is actually at one of the driest locations in the Salt Lake Valley. Overall, I’d have to say that the Salt Lake Valley probably averages a bit more snow.

While it is true that the south and west sides of Denver get more snow than other places, there are reasons the gradient isn’t as pronounced as it is in the Salt Lake City area.

The two biggest reasons for the steeper snowfall gradients for long term averages in the Salt Lake area is because of the position of the Wasatch Mountains and the Great Salt Lake.

It’s amazing how different the snowfall is on opposite sides of the Great Salt Lake. Because almost all the storms hitting Salt Lake move west to east, check out the snowfall and precipitation values for the locations on the west side of the Great Salt Lake:

http://www.wrcc.dri.edu/cgi-bin/cliMAIN.pl?utlaks

Lakeside, right on the west shore of the lake receives an average of only 6.24 inches of precip a year and only 19.8 inches of snow a year. The Salt Lake City Airport, on the east side of the lake and at the same elevation receives about 60 inches of snow and about 16 inches of precipitation (depending on what time period you look at). A few miles away and on the bench, Olympus Cove receives 120”. Alta, only 9 miles from the Salt Lake Valley floor receives 55 inches of precip a year and 524” of snow.

The Wasatch Mountains and Great Salt Lake have a huge effect on snowfall totals. It is true that upslope winds also create more snowfall from certain storms in the Denver area, but the effect isn’t as pronounced.

Besides the lake, one of the main reasons for this is that the Wasatch Mountains actually rise much more abruptly above the Salt Lake Valley than does the Front Range above Denver.

The highest mountains visible from Denver are actually significantly higher than the highest mountains visible from the Salt Lake area. However, the Wasatch rise much more steeply and abruptly and the Front Range rise is much more gradual. Parts of the Wasatch rise 7000 feet in 3-3.5 miles. This is due to geology; the Wasatch Mountains are a fault block range while Front Range is mostly a folded range.

There are other interesting differences in snowfall between the two cities as well. Salt Lake actually has more frequent big winter dumps, but the really big snowstorms in Denver are bigger than anything that hits Salt Lake. The big storms that hit Salt Lake usually bring a lot of snow, but seldom are the winds and nasty blizzard conditions present.

Snowfall aside, precipitation wise, both annual averages are almost identical, but Denver is wetter in summer and Salt Lake is wetter in winter.

Although average temperatures are about the same in winter in both cities, there are some very interesting differences as have been pointed out.

Because of the mountains east and north of Salt Lake City and because of the moderating effect of the Great Salt Lake, Denver has more of the arctic blast where the temperatures plunge below zero (although interestingly the all time extreme lows in SLC are just as low). Although usually initially not as cold, when the arctic blast do reach Salt Lake City, the cold air usually sticks around a lot longer due to temperature inversions.

This can easily be demonstrated by looking at this month’s temperatures so far. Notice that Salt Lake City just went through a 14 day period where the temperature never rose to freezing:

http://www.wunderground.com/history/air ... story.html

This is common during inversions in Salt Lake City, but is very rare in Denver. Salt Lake City almost never gets Chinooks in winter either (both of which help make the snow stick along longer at times). In the SLC area, there are Chinooks in the springtime at some of the canyon mouths, but only at the canyon mouths. Because of inversions and lack of Chinooks, Salt Lake City has never (dating back at least 139 years), seen a 70 degree temperature in any of the winter months (December, January, and February). Denver actually sees 70 degree temperatures in winter somewhat frequently, or at least they aren’t extremely rare. In Salt Lake, the record high in January is 63F and January temperatures have only hit 60 or above on five occasions in the last 100 years.

Other differences:

Someone mentioned that the climate in Salt Lake City is ideal, but the worst part is the inversions. They are really nasty because of the pollution. Denver gets the brown cloud, but Salt Lake’s inversions are even worse and it’s nasty to breath the air. Luckily you can go up to the benches (sometimes the inversion is strong enough to reach the benches) and mountains and get out of it.

Despite the fact that they can get big snowstorms, severe weather in Salt Lake is very rare. They have had a few tornadoes, but these are very rare. Thunderstorms do occur, but are mild in comparison to many places in Colorado. Hail can occur, but anything above pea sized is rare. I did see it hail golf ball sized hail once, but only once. The worst part is the inversions, or at least the air pollution that is in the inversions.

[Palmer divide shadow]

Good read ..I lived on the tooele bench.We got hammered due to our location from the great salt lake.The inversions were the worst.The worst one was the one in 04 after the snowstorms during xmas.We were below freezing 35 str8 days. I miss winter there.It was more consistent.

[denversnowlover]

There is one difference I didnt see mentioned and its also very common...people look at the snowfall for DIA. DIA does not receive nearly as much as "Denver" does due to the fact that it is quite a bit farther east..that was one of the worst things they could do is make DIA the official reporting station of Denver...its amazing what the few miles west will do. Stapleton was a much more accurate measurement of moisture compared to DIA and is much more applicable to the city itself.
Plus when it comes to upslope yes Denver's mountains are more gradual than SLC we still receive greater upslope in Denver due to the larger elevations and the extent of the range as well as the palmer divide.

[zephyr99]

It's going to be in the 50's and low 60's for at least a week in Denver after this little cool down. Weather wise, I am bored out of my mind. Really scared about the 2013 fire season. I'm hoping to leave Denver sooner than later.

[Scott Patterson]

Really scared about the 2013 fire season.

Yes; and so far this year statewide snowpack this year is even worse than last year. Plus last year still had much moisture left over from 2011.

Snowpack graph:

ftp://ftp-fc.sc.egov.usda.gov/CO/Snow/s ... tate13.gif

[Palmer divide shadow]

Bump in this weeks storm.Are we going to get good snows from this storm finally east of the mountains?

[Dencolo]

Yes, east of the mountains may get hammered, but well east. Basically, if you were to continue the border of Wyoming/Nebraska down through Colorado, anything east of there may get up to a foot of snow according to the GFS. The Denver area? Not so much.

[Dencolo]

You know when you have that gut feeling that the forecast form the NWS is either overplaying or underplaying snow potential? I really think the current forecast of 60% chance of snow with 1 to 3 inch accumulations is on the very low end. GFS and NAM not only continue to come in wetter, but come more west with the precipitation as well. Personal forecast - 4 to 8 for metro area. Now to sit back and watch!

[Dencolo]

Okay, WSW posted. Didn't see if earlier because while it included my town (Littleton), it does not include my county (JeffCo).

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
903 PM MST TUE FEB 19 2013

...WINTER STORM POSSIBLE FOR EASTERN COLORADO...

.AN UPPER LEVEL STORM SYSTEM WILL MOVE ACROSS NORTHERN NEW MEXICO
WEDNESDAY NIGHT THEN NORTH-NORTHEAST ACROSS KANSAS ON THURSDAY. A
LARGE AREA OF SNOW IS EXPECTED TO FORM ACROSS MOST OF EASTERN
COLORADO...NORTHERN KANSAS AND MOST OF NEBRASKA WEDNESDAY NIGHT
AND THURSDAY. THE LATEST DATA INDICATES AREAS ALONG THE FRONT
RANGE COULD RECEIVE SOME LOCALLY HEAVY SNOW AS WELL MAINLY WEDNESDAY
NIGHT ALONG AND EAST OF I-25 FROM DENVER SOUTH TO THE PALMER
DIVIDE. ROADS WILL BECOME SNOW COVERED AND ICY WHICH WILL MAY
TRAVEL HAZARDOUS.

COZ040-041-201215-
/O.EXB.KBOU.WS.A.0002.130221T0000Z-130221T1200Z/
NORTH DOUGLAS COUNTY BELOW 6000 FEET/DENVER/WEST ADAMS AND
ARAPAHOE COUNTIES/EAST BROOMFIELD COUNTY-
ELBERT/CENTRAL AND EAST DOUGLAS COUNTIES ABOVE 6000 FEET-
INCLUDING THE CITIES OF...AURORA...BRIGHTON...CITY OF DENVER...
DENVER INTERNATIONAL AIRPORT...HIGHLANDS RANCH...LITTLETON...
PARKER...CASTLE ROCK...ELBERT...FONDIS...KIOWA...LARKSPUR
903 PM MST TUE FEB 19 2013

...WINTER STORM WATCH IN EFFECT FROM WEDNESDAY AFTERNOON THROUGH
LATE WEDNESDAY NIGHT...

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A WINTER STORM
WATCH...WHICH IS IN EFFECT FROM WEDNESDAY AFTERNOON THROUGH LATE
WEDNESDAY NIGHT.

* TIMING...SNOW WILL DEVELOP LATE WEDNESDAY AFTERNOON INTO
WEDNESDAY EVENING. SNOW WILL CONTINUE WEDNESDAY NIGHT AND COME
TO AN END EARLY ON THURSDAY.

* SNOW ACCUMULATIONS...6 TO 8 INCHES WILL BE POSSIBLE WITH THE
HEAVIEST SNOW EXPECTED ALONG AND EAST OF I-25 FROM DENVER SOUTH
TO THE PALMER DIVIDE.

* WIND/VISIBILITY...EAST WINDS OF 10 TO 20 MPH WILL BECOME MORE
NORTHERLY WEDNESDAY NIGHT INTO THURSDAY. VISIBILITY MAY BE REDUCED
TO A QUARTER MILE AT TIMES DUE TO SNOW AND BLOWING SNOW.

* IMPACTS...ROADS ARE EXPECTED TO BECOME ICY AND SNOWPACKED. IN
ADDITION TO SLICK ROADS...POOR VISIBILITIES DUE TO SNOW AND
BLOWING SNOW WILL MAKE TRAVEL HAZARDOUS

[Palmer divide shadow]

Im just glad we finally have something to talk about.5-8 inches forecast here.And I agree,this system comes in wetter and more to the south .

[PTPatrick]

Yeah but interestingly there is still some model spread. Nam would have ou believe a bullseye of .5 inches over the metro tapering toward the east then back up toward Kansas. Gfs has a trowel setting up over the east metro coring DIA to castle rock, and has inch bullseye but its way out east of DIA roughly. But even it gives the metro (minus westminster to boulder) close to .5 inches. If the gfs backs that up, I'd say watch out. Hard to say snow amounts. It's close to spring. But fortunately is still bee old and nit super Warm past few days. 10:1 snow ratio with temp looking mid 20s overnight is probably on the low end. I could see 15:1 which gets Denver in 8 inch territory. Hopefully the models are our friend as the day wears on!

[Dencolo]

Wow, 12z NAM drops the precip bomb on Denver. About a foot of snow. BTW, anyone remember the last time we had new snow on top of old snow? Seams like forever. And now, maybe snow on snow on snow come later in the week.

[Stephanie]

I hope you do get snow on top of snow. I know that this is your water and I'm heartened to see decent sized storms affecting the middle of the country. Colorado is so interesting because it's split into two - flat Plains and mountains.