Meteorologist Jim Woodmencey

Seasons are definitely changing this week, with word of a “big storm” heading our way, which began its hype on Monday. Sometimes the mere mention of the word “snow” in the forecast will set off a 4-alarm warning, among skiers especially, even in September!

This will actually be the second storm this September to bring snow to the Tetons. The first one was on September 18th, and most of that snow has melted off except for a skiff on north faces above 10,000-ft.

This incoming storm will bring even colder air with it and snow levels will get down near the valley floor, probably by Thursday the way it looks right now. It will be selective about where it deposits the bulk of the snow, as the whole weather system divides as it crosses the Rockies.

Best moisture comes over western Wyoming when snow levels are still fairly high during the day on Wednesday.

Certain areas in Western Wyoming will be favored as this large Low pressure Trof appears to split up as it moves across the Rockies, with the main center of that Low going north into Montana and eventually Southern Canada by the end of the week. And the southern part swinging across Nevada & Utah and eventually Colorado.

The higher elevations of Yellowstone Park (especially the SW corner of the Park) and the Wind River Range will potentially receive the most snowfall. As snow levels lower progressively Wednesday thru Thursday in western Wyoming, the lower elevations pick up some snow, as well. I also expect the Tetons will see a brief period of enhanced snowfall when that Low is over us and moving across Southwest Montana.

Who Gets It?

This is also a good looking set-up for Central Idaho’s Mountains, as they get into the colder air sooner, when the storm is still intact as it moves inland Tuesday night/Wednesday. And then another swath of snow will be likely across Southwest and Central Montana, initially with a SW flow as the Low approaches for west of the Divide, and then east of the Divide (central Montana) with decent upslope flow once the Low moves into eastern Montana.

A variety of different computer models depict the variability of the snowfall accumulation & distribution across the Northwestern US and NW Wyoming with this storm, and a few of those are shown below for comparison. Note that they each cover a different time period. So, which one is correct?

(Hint: A skier will pick the one that shows the greatest amount of snow where they like to go, every time!)

Don’t pull on your snow pants just yet, it will warm up over the weekend and melt a good portion of what accumulates in the mountains this week.

NAM 48-hour Total Snow Accumulation Tues. a.m thru Wed. p.m.

MFF Total Snow Accumulation Tues. a.m. thru Fri. a.m.

WRF Total Snow Accumulation Tues. a.m. thru Thursday evening.

Same Map as Above (WRF) zoomed in on Western Wyoming

Post by meteorologist Jim Woodmencey
Graphics courtesy of LEADS On-Line
and USDA-FS Fireweather

Meteorologist Jim Woodmencey

The First Day of the Fall Season doesn’t get here until Sunday, September 22nd,  but we will see a change in the weather pattern from what has been relatively warm to relatively cooler beginning Wednesday.

There will be a series of storm systems of different sizes and shapes working out of the Gulf of Alaska and moving across the Northwestern US over the course of the next 7 to 10 days, and each of these will be cold enough for some white stuff in the higher elevations, at least above 10,000-ft.

The first Low pressure system moves thru Tuesday night and early Wednesday. Then a break in the weather and warming Thursday & Friday. Next weather system looks weak but may bring some showers to the mountains later Saturday and on Sunday. Then another break between weather systems Monday & Tuesday of next week, with a larger and even colder looking Low pressure system moving into the Western US Thursday and Friday of next week, with snow levels may be down even lower.

Not to the valley floor, and not huge amounts of snow up high, but enough for a reminder that it ain’t summer anymore.

We also could see below freezing temps in the Jackson Hole valley this week, especially Friday morning with clearer skis overnight Thursday.

Wednesday Sept. 18 Weather Map

Sunday Sept. 22 Weather Map

Freeze-free Days in Jackson

With high temperatures still reaching into the 70’s this week (78 in town on Monday!) and lows only in the 40’s most mornings, it may seem like we have had a long “frost-free” season this summer. But actually it was probably not as long as you might think.

According to the thermometers at the Jackson Climate Station the last day below freezing overnight low temps in the Spring was on June 23rd (28 degrees). And the next time it got below freezing was on September 1st ( 30 degrees). That’s 69 days, by my math, of “frost-free” or “freeze-free” days.

Although, there was one day in mid-August that it got down to 32 degrees for a morning low……if that qualifies as a “freezing” day, then our growing season was split in two!

Post by meteorologist Jim Woodmencey
Maps from NWS

Meteorologist Jim Woodmencey

Big Rain in parts of the Western US this week, with the Four-Corner’s States seeing the brunt of the precipitation all week long, in Arizona, Utah, New Mexico, and Colorado. Then the Front Range in Colorado was hit especially hard the last two days.

The large area of Low pressure that has been hanging over Nevada, Utah, & Colorado this week is responsible. And that Low has circulated a lot of moist and unstable air up from Mexico and the Gulf, deluging many areas with record rainfall, along with resultant mudslides and flooding.

One Day’s Rainfall Totals September 12, 2013

Colorado
In the 24 hour period from 6am Thursday Sept 12 to 6am Friday Sept 13 Burlington Colorado had 4.72 inches of rain. Centennial Airport had 2.44 inches, Colorado Springs 1.85 inches, and Denver Airport 1.30 inches.  That’s more than a whole summer’s worth of rainfall for some of these places! Map above shows precip totals from Sept. 12.

Wyoming
Southern Wyoming and into parts of Central Wyoming had between 3/4 and 1 inch of rainfall Thursday. Cheyenne 0.65 in. Lander 0.73 in. Laramie 0.91 inches.

Northwestern Wyoming and Jackson Hole meanwhile measured rainfall in hundredths of an inch. So, no whining about how wet it seems we have been lately, compared to Colorado anyway.

Jackson Hole Summer Rainfall
Total precipitation for June-July-August in the Town of Jackson was 1.65 inches. That is not even half of what our average summer precip would be, 3.85 inches.
However, September has been a little wetter, as of Thursday, Sept. 12th, we have received just over 1 inch of rainfall during September 2013. Starting to make up for the generally dry summer. And a huge difference in teh weather from this time last year whe we were warm & dry and had the Little Horsethief Fire raging.

Post by meteorologist Jim Woodmencey
Graphic from NOAA

Meteorologist Jim Woodmencey

This past week I have been caught using the “F-word”, a lot. I try to refrain, but I suppose it is inevitable, after all, “Fall” is just around the corner.

It is still August, and technically still the Summer Season for another 3 weeks. However, the last few days it is not the “F-word” that people are dropping as much as they are asking, “What kind of winter are we going to have?”

Seems way too early to be thinking about snow, but the main reason I get inundated the last week or so of August about the outlook for the coming winter is because around September 1st the price of a season pass at most ski areas goes up.

It’s simple psychological economics, if you hear it is going to be a “big” winter, then you are more likely to throw down now for the goods. Goods that haven’t even been manufactured yet. I suppose everyone is just looking for a little assurance that there will be plenty of snow this winter.

On the other hand, if you hear that is is supposed to be a “dry” winter where you ski, you might not be willing to make an investment in the product until it comes on the market and proves itself by out-performing the forecast.

You’re betting on the futures market. It’s commodity trading in the white stuff. I don’t do any trading, personally. I don’t even think I own any stocks, and my IRA has about $250 dollars in it (since 2008). Basically, my retirement plan is, I have to work until I am dead.

But I do follow the weather, and I do love to ski powder. So, I do follow the snow market, and for those of you who just gotta have the early forecast, the insider tips, I offer my analysis of how the snow futures market is looking ….before the price of a Season Pass goes up in the next few days.

If you want to skip all the analysis and get to the bottom-line, then just scroll to the bottom of this blog…..

Farmers Almanacs

There are several different Farmer’s Almanacs out there to consult. These, in my opinion, are the least useful and least accurate indicators of long range weather. But I have to admit, I keep one within arm’s reach of my toilet every year.

There are three different Farmer’s Almanacs that you can consult:
1) Farmer’s Almanac, in print since 1818.
2) The Old Farmer’s Almanac, in print since 1792.
3) Harris’ Farmer’s Almanac, claims to have been around since 1692.

That means that Harris’ Almanac is actually 100 years older than the Old Farmer’s Almanac. Hmm……

To paraphrase that guy from the Dos Equis commercials, “I don’t often read a Farmer’s Almanac, but when I do, I prefer the Old Farmer’s Almanac“. Unfortunately, that one is not available yet (release date is Sept. 2nd). So, I’ll give you what info I could decipher from the other two almanacs.

Keep in mind, the wording they use is purposely vague, like many weather forecasts. What you have to realize is, a forecast is an expression of “uncertainty”. It is not exact. As I tell students in weather classes I have taught, use any forecast as guidance, not gospel. That said, here is what they said……

Farmer’s Almanac

Pacific Northwest: Cold & below normal snowfall.

Rockies: “Piercing Cold” & normal snowfall.

Sierras to Wasatch: Cool with normal snowfall.

Harris’ Almanac

Cascades & Sierras: Cold December & January with normal snowfall. Warm February & March with below normal snowfall.

Intermountain West & most of the Rockies: Cold December & February. Warmer January. And showing above normal snowfall December, January, & February. March was shown to have normal temps & snowfall.

In general the theme seems to be a colder than normal winter throughout the West, with relatively normal snowfall across the board, a little below in the Northwest perhaps, and a maybe little above normal in the Rockies. Overall nothing too remarkable….pick whichever one sounds better for where you ski, and run with it!

From the Farmer’s Almanac, not the Old Farmer’s Almanac

Climate Prediction Center (CPC) Forecasts

The CPC will give you trends for temps and precip broken down in 3-month increments, for the next year. They are very general in their depiction of the actual weather you might experience, but they do put long hours into dissecting the atmospheric trends and the work these guys do is as cutting-edge as you can get, and their maps are based on a lot of different models and exhaustive inputs, including the El Nino/La Nina situation, which I will address lastly in this blog.

When I flipped thru the maps and looked at the overall picture for the Western US from November thru March, it seems to carry a similar theme through the winter months, here’s my take on what the CPC is showing. (Refer to DEC-JAN-FEB maps shown below).

Temperatures: The Colorado Rockies  & Utah have a higher probability of experiencing warmer than normal temps. The Sierras, Nevada, and Wyoming had a little lower probability of warmer than normal temps, but were still “in the paint”, to steal a basketball phrase. The Pacific Northwest and Montana fell out of the paint, and had what they refer to as “EC”, Equal Chances of being warmer or colder than normal. Should we just call that “normal”? You make the call.

Precipitation: In general, the entire Western US fell under the category of “EC”, Equal Chances of having above or below normal precip the entire winter. For we simple-folk, that’s a coin flip, Bubb!

However, there was one exception to this overall outlook, and that was during the early part of the winter season. The Oct-Nov-Dec & the Nov-Dec-Jan map sets showed an area of Above Normal Precipitation over the Idaho panhandle, all of Montana, and across Northwest Wyoming. Why? I have no idea.

You can view all the maps on the Long-Range Outlook Page of mountainweather.com
then go to the CPC’s Seasonal Outlook Page.

3-Month Outlook Maps for December-January-February 2013-14
Temperatures	Precipitation

ENSO

The El Nino Southern Oscillation (ENSO) situation has been in a “Neutral” phase all summer, and the big boys who analyze all that ocean temperature stuff all agree, to a certain level of confidence, that these conditions will hold through the Winter of 2013-14. That means we will be in neither an El Nino nor a La Nina, but rather a “No Nino”, if you will.

The implications for that bear out in the long-range forecasts from the CPC that I just described above. “Equal Chances” for above or below normal snowfall almost everywhere in the Western US. It’s a coin flip, Bubb!

Summary

So far, the Farmer’s Almanacs and the CPC are not in agreement on temps in the Rocky Mountain Region, at least. One is saying colder and one is saying warmer. The farmer’s seem to have more of an opinion on the precip amounts. Maybe they too foretold “EC” in their prognosticating formulas and decided to flip a coin?

Don’t get too hung up on trying to hang your hat on one forecast or another. I’ll guarantee that wherever it is you ski in the West, there will be snow this winter.

How much, how many awesome powder days you will get, will always vary from year to year, season to season, month to month, week to week. Parts of the winter may see glorious dumps. Parts may see what seem like interminable stretches of drought. But you know you are going skiing, no matter what the weather does. My mantra is, “All skiing is good skiing, some skiing is better!” That’s a pretty good outlook, is it not?

The bottom-line is ….there are just two things you need to do right now, shut up & buy your season pass. While it’s cheap.

Post by meteorologist Jim Woodmencey
Graphics from NOAA

Meteorologist Jim Woodmencey

We have had an interesting cycle of thunderstorms over the past week, not always of the typical afternoon variety that we normally associate with summer. Some have developed early in the day, before noontime.

A good example was yesterday’s thunderstorms which perked up pretty rapidly just before noon and then hung over the Teton Range for a few hours. Nothing too extreme, but if you were up climbing in the Tetons (and about to summit) it would have been frightening, I am sure!

A photo of Monday’s thunderstorm when it was in its early stages of development is shown below. Followed by what it looked like within another two to three hours. I also included satellite & radar images to get a feel for the relative size of this little cell as it merged with other cells and reached its peak development.

Growth of this cell was aided by very light wind flow aloft (from West-SW), some orographic lifting from the Teton Range itself, and an unstable atmosphere on Monday.

SAFETY NOTE: Here is a link to a sheet you can print out about thunderstorm & lightning safety……… THUNDERSTORMS & LIGHTNING SAFETY

Taken before noontime Monday Aug. 12, 2013, from south of town, by John Patton

Webcam shot from Spring Creek at @ 1:20 pm

Visible Satellite Photo at 1:00 pm (cell over Tetons in red circle)

Pocatello Radar at 1:15 pm (Cell over Tetons in red circle)

Text by Jim Woodmencey
Photos from John Patton and Spring Creek Webcam

Meteorologist Jim Woodmencey

The “Dog Days” of Summer will be coming to an end soon (see definition at end of article), as we have now reached the midway point of the Summer Season in early August.  Much like Groundhog’s Day in early February marks the midway point of the Winter Season, we are currently sitting halfway between the Summer Solstice (June 21)  and the Autumnal Equinox (Sept. 22). And so far, the first half has been really dry, but maybe not quite as warm as you might have thought!

Sunny July day 2013, Photo by Doris Hargrave

Refer to the Summary table below for a quick rundown of June and July’s weather. Data is  from the newly relocated Jackson Climate Station instrumentation, formerly located at the USFS Office and currently located just a short distance north of the old location, at the Jackson-Greater Yellowstone Visitor Center.

Historic data for the “normals” comes from the newly updated, and more complete, climate record for Jackson, encompassing data from 1905 to 2012. However, beware that there is an awful lot of missing days, months, and years in this data set prior to about 1949. Our most complete and accurate climate data in Jackson, WY is from about 1950 to 2010.

June
Temps were about as normal as can be and the hottest day,officially, was 86 degrees, although many thermometers hit 90 in town at the end of the month.
Precip though was more than an inch below normal in June 2013.

July
Temps were again right about normal for July, with average highs for the month a degree cooler than normal, and average lows for the month a degree warmer. Hottest day was also 86 degrees in July. We also broke a record for a cold high temp on July 28, 2013 with a high of only 67 degrees in town. Previous record for that date was 68 degrees back in 1950. 
Precip came up short again, by about a half an inch.

Total precip for both June and July in town was 1.10 inches. “Normal” precip total for those two months would be 2.79 inches, which means we are behind by 1.69 inches.  My sense is that there were areas that receive more rainfall in July, depending on where the thunderstorms dispensed their rain.

(Note: The “Dog Days of Summer” are considered to be the hottest part of the summer between July 3 and August 11, the period of time that extends from 20 days before to 20 days after the conjunction of the dog star Sirius and the Sun.).

Post by meteorologist Jim Woodmencey
Photo by Doris Hargrave

Meteorologist Jim Woodmencey

After 6 days in a row of nearly perfect summer weather around Jackson Hole…..sunny skies and highs in the valley in the upper 80’s……from last Thursday (July 18) through Tuesday (July 23), we are finally going to see some changes over the next 6 days. Nothing radical, but we will go from absolutely no chance of thunderstorms to at least a possibility of some thunderstorm activity in the coming days.

We begin to make the switch from an extremely dry and stable airmass to one that is a little moister and more unstable. This new mass of air is a combo of some leftover disturbances that have been causing thunderstorms & heavy rainfall in parts of Arizona & Southern California (where they needed it!). And there may be a little remnant of the monsoon mixed in there also. That airmass has made it over Nevada and Utah will drift closer to us and provide the necessary ingredients to produce some thunderstorms.
(See Sat Photo and today’s weather map below).

This is not a true “monsoon” flow, which would be coming up more directly from the South. This moisture has basically drifting up around the periphery of a Ridge of High pressure that has been over the Southwest US this past week. That is now working itself into a very light Westerly flow aloft over Southern Idaho and Western Wyoming. That will bring an end to the extremely dry and cloudless conditions we have seen.

How Dry Was it?

The instrument at the Jackson Hole Airport bottomed out at 7% relative humidity on Monday. The Town of Jackson weather station showed 9 % RH. And I had a guy named Joe, who lives in a van down by the Hoback River (who happens to have a nice home weather station!) and he reported a Relative Humidity that registered as low as 0.04%.

Trust me, that is about as dry as you can get, even by desert standards. That extreme dryness was part of the cause of the haze we have had around here, in combination with dust and pollen in the air, and a bit of smoke mixed in from forest fires in Idaho that has drifted over us.

Infra-Red Satellite Wednesday morning, July 24, 2013

Surface Weather Map Wednesday, July 24, 2013

Meteorologist Jim Woodmencey

The weather we had this past Saturday morning caught me a little by surprise, with a line of thunderstorms moving over NW Wyoming and directly over the Grand Teton at around 8:30 a.m.

I was actually expecting that kind of weather Friday morning, not Saturday. When it didn’t materialize, I thought,  “oh well, it must have dissipated or not be as moist and unstable as I thought”.

The reality was, that moist and unstable air, what looked on Thursday to be an almost “monsoon-like” surge moving up from Arizona, didn’t make it to us until early Saturday morning. That is a lot of time to be “off” by.

This very small surge of  moisture that originated down in Arizona on Thursday, and was evident way down there on satellite and radar, and lightning maps, and then it crept its way north thru Utah with very little fanfare.

As with a normal surge from the monsoon, thunderstorms are possible anytime of day or night and they don’t need the afternoon heating to get them going. This case was eerily similar in nature. The only other indicator for the possibility of seeing earlier-in-the-day type thunderstorms was the presence of a stationary front in NE Idaho & NW Wyoming. I generally discounted that because it had been there the previous two days and did not seem to lend any additional boost to thunderstorm development on Thursday, or even on Friday. We had no thunderstorms here Thursday of last week, and only a few isolated strikes around the region Friday.

Re-Analysis

A series of maps (satellite, radar, & lightning maps) that I saved from this event illustrates how innocuous it looked and how quickly this developed. There were no lightning strikes evident over northern Utah or eastern Idaho prior to about 6:00 am, after that, things developed very fast that morning.

There was little to no indication on the computer models I looked at on Friday morning, after analyzing dozens of different products to give me an indication of moisture and instability. I had the thunderstorm potential at zero in the am Saturday, 60% in the pm for Saturday on my forecast that I issued on Friday morning.

I checked the NWS forecast at 8:00 am and it said “Slight Chance of Thunderstorms”. And once the lightning started, they issued a thunderstorm warning. So, apparently the NWS saw no early indicators either.

A bad forecast from my end, as I see it. And that’s why I re-analyzed that morning. My conclusion was, that it was one of those smaller features that would easily slip thru the cracks in the model resolution that was not picked up. Especially 24 hours ahead of time when I made my last forecast on Friday morning. But the rub is, there was little or no sign of developing activity overnight as that airmass moved up thru Utah, and then once it got over SE Idaho, and maybe got better orographics or closer to that stationary front, it really kicked in.

I don’t like to miss stuff or be wrong about the weather, I take that personally, especially when it coincides with outdoor activities in Jackson Hole on a Saturday morning! However, that is also one of the things that I love about this game of weather forecasting, even with all the latest technology and sophisticated computer models, we still can’t see it all………and Mother Nature always gets to bat last!

 Post by Meteorologist Jim Woodmencey

Graphics From NWS & MeteoStar-LEADS On-line

Maps from around 6:00 – 7:30 AM Saturday

Satellite 7:00 am MST

Radar 7:30 am MST

Lightning Strike Map 6:15 am MST

Maps from around 8:00 – 8:30 AM Saturday

Satellite 8:00 am MST

Radar 8:20 am MST

 

Lightning Strike Map 8:30 am MST

Photos from Saturday Morning

Looking South from near Moose, WY  Photos by Rick Paul

Meteorologist Jim Woodmencey

For the past week I have been thinking about the tragedy that occurred during the wildfires in Arizona back on June 30th. Wildfires are perhaps one of the worst weather related disasters we can experience here in the Rocky Mountain West. They are no less violent, powerful, or unpredictable than the tornadoes of the Plains and Midwest.

Most wildfires are started by the weather with a lightning strike, from there the weather controls the fire’s behavior, wind & low humidity being the enemy. And it usually takes a change in the weather to get them under control.

My heart goes out to the families of the 19 firefighters lost in the Yarnell Fire in Arizona, and my praise and thanks goes out to all firefighters across the country. Thank you for what you do. We all appreciate it, especially here in the Western US.

 History Repeats

The Yarnell Fire tragedy is not the first of it kind in the Western US, and we should also remember those who were lost trying to fight other big fires in the past.

More recently was the South Canyon Fire on Storm King Mountain in Colorado, on July 6th, 1994 that fire blew u and made a rapid run up the mountain and killed 14 firefighters.

And back in August of 1949, there were 13 firefighters lost (some of this country’s first smokejumpers) in the Mann Gulch Fire in Montana. This incident was chronicled in Norman Maclean’s book Young Men and Fire, an excellent read.

You can keep up with the current wildfire situation locally and across the US by going to the the Jackson Hole Information Page and poking around the Fire Information section.

Meteorologist, Jim Woodmencey

Nearly record HOT in Jackson this weekend with the Town’s automated weather station reporting a high on Sunday of 90 degrees. Record high on June 30th in Jackson is 91 degrees set back in 1990.

FYI…Record high for July 1st is 92 degrees, also set in 1990.

Hot temps are courtesy of a big Ridge of High pressure that is sitting in place over the Western US. About as hot as it can be, for almost any summer month, but especially for late June in the Desert Southwest.

Looks like one or two more days of this before the Ridge breaks down a little and temps cool for the end of the week.

Some of the hottest high temperature records that were re-set this weekend are listed below.

Death Valley, CA…………..…….128 degrees on Saturday (ties highest June temp)*
Death Valley tentatively reached 129 degrees Sunday evening, and that breaks June record high. Which would tie for the hottest temp ever in the month of June in the US, set in Volcano, CA (not a town anymore!) back in June of 1902.

Las Vegas, NV …………117 degrees on Sunday  (ties all-time high temp record for Vegas)
Zion National Park, UT…….112 degrees (ties old record for the date in Zion)
Salt Lake City, UT………….103 degrees (ties old record for June 30th from 1979)

*Death Valley still has the distinction of being the hottest place on earth with their world record high temperature of 134 degrees, set 100 years ago, on July 10, 1913.

Weather Pattern Keeping it Hot

The Ridge of High pressure over the Western US is being held in place by two Troughs of Low pressure in the current blocking pattern that has established itself across North America. This Ridge is warm all the way up through the atmosphere. The air within the two troughs is much cooler.

This is a “blocking pattern”, which means it will be hard to change, kind of like a logjam in the river. The very cold trough off the West Coast will try and flatten this Ridge some towards the end of the week. And that will help cool temps, at least across the Pacific Northwest  & northern Rockies.

Upper Level (500mmb) Map showing large Ridge in Western US flanked by two Low pressure Troughs.