All posts by Jim Woodmencey

Fire Weather & Air Quality

Mountain Weather Blog
Photos below show the quick progression of the Horsethief / Wilson Canyon Fire as it blew up on Sunday afternoon, between 2:00 pm & 3:15 pm. Most of these photos were taken from the ridge on Munger Mountain, along the Wally’s World Trail. Munger Mountain is located to the Southwest of the fire. 
This series of photos shows how quickly a fire can blow up during the afternoon heating, even in September. Time between the first and last photo from Munger was a little over 1 hour and 15 minutes. 
Final photo was smoke plume viewed from the Rodeo grounds in Jackson, looking at north side of Snow King, around 5:00 pm.
Horsethief Fire September 9, 2012
 First shot from Munger @ 2:00 pm
Last shot from Munger @ 3:15 pm
 Taken from Rodeo Grounds in Jackson @ 5:00 pm

Where to Find Fire & Air Quality Info

I have had many requests for good sources of both fire information and air quality information, therefore, you can now find many links to both on www.mountainweather.com under the Jackson Hole drop down on the menu bar, by clicking to the Jackson Hole Information Page……some National fire info & air quality info is also available here.
Unfortunately, getting real-time and real specific info on fires and air quality is not like getting satellite photos & radar images that are updating automatically, all the time. So, my advice be patient and take some time to click around to gather the info you are most interested in. Like with most weather related stuff, there is rarely just one button you can push to get all the info you want.
Text submitted by meteorologist Jim Woodmencey
Photos by Jim Woodmencey

Winter Weather Outlook 2012-13

Mountain Weather Blog


With temps near 90 degrees the last two days in Jackson Hole it is hard to even think about snow and the coming Winter Season. But it happens every year in late August, the questions begin as to, “What kind of winter are we going to have?”
With the start of the Fall Season still three weeks away and Winter officially another three months beyond that, it seems silly to even start worrying about it while still in my shorts and flip-flops.
The reason the question gets raised this early in ski towns is because people are trying to make that decision of whether or not to buy a season ski pass, at the discounted rate, before the prices go up in September.
(Reminder: Prices increase Sept 1st for the Jackson Hole Mountain Resort. After Sept. 16th for Grand Targhee).
My standard answer to this annual question is, “It will be a great winter!”
After spending most of the last 30 of them here in Jackson Hole, I can tell you that a lean winter here still beats a good winter almost everywhere else! Sure, we’ve had our BIG winters that everyone would like to see repeated every winter (2010-11, for instance), but even when we have had lower snowfall winters, we’ve still had some tremendously great skiing.
So, let’s look at what the long range forecasts are saying for the upcoming Winter Season 2012-13.

Long Range Outlooks

A sneak peek at the Old Farmer’s Almanac, which comes out this week, tells a tale of warmer than normal temperatures for the Northwestern U.S. with below normal snowfall. They could be wrong, as they were way off on last winter’s prediction, after all.
The Climate Prediction Center (a division of NOAA and the National Weather Service) does show the start of the season, October-November- December with warmer than normal temps and “equal chances” for above or below normal snowfall.
(See maps below and keep up with all the latest short & long range outlooks on the
NWS Discussions Page of mountainweather.com)
3-Month Outlook Maps for October-November-December 2012
Temperatures
Precipitation

El Nino Year

The fluctuation in the Equatorial Pacific that we commonly refer to as “El Nino & La Nina” is technically known as the “El Nino Southern Oscillation (ENSO)”. This is what the Climate Prediction Center focuses a lot of their time on when making these long range forecasts.
Last Winter (2011-12) we were also in a La Nina year, weaker than 2010-11’s, and the storm track went way north to Alaska most of the Winter & Spring of 2011-12. That is one of the things that can happen in some La Nina years. Or, it can get locked in over the Northwestern U.S. and Northern Rockies, like it did two winters ago, 2010-11, when winter didn’t end until June!
Most of the Summer of 2012 we have seen a “Neutral” condition with the ENSO, and now we are trending towards a weak to moderate El Ninocondition that is expected to persist for the Fall & Winter of 2012-13.
Usually, during El Nino winters, the storm track coming out of the Pacific favors a more southern route, and the Southwestern U.S. gets more precipitation. The opposite of a “normal” La Nina, where the Northwestern U.S. is favored and the Southwest is dry.
Don’t let that scare you, because statistically El Nino for us is a 50/50 proposition. Half of El Nino Winters in Jackson Hole produce below normal snowfall and half produce above normal snowfall.
The last time we had “weak” El Nino conditions was during the Winter of 2006-07, with below average snowfall. The last time we had moderate El Nino conditions was the Winter of 2009-10, and we saw above normal snowfall.
A 50/50 bet seems like decent odds to go ahead and buy that Season Pass!
 Chart below of ENSO Index 
(El Nino years in blue and La Nina Years in red.)









Text submitted by meteorologist Jim Woodmencey

Graphics from NOAA

Cool Cumulus Clouds

Mountain Weather Blog

Late afternoon and early evening (between about 4:30 and 8:30 pm) on Friday July 27th there were some very cool looking cumulus clouds associated with thunderstorms around the Tetons & the Jackson Hole area.

Most of these would be classified as Cumulonimbus Mammatus Clouds. That is, they were of “cumulo-form” (tall & puffy)…… They produced some rain, so they also get the suffix “nimbo”…. And, they had the mammary shapes extending from their bases, thus “mammatus”.

Photo by Scott Guenther

The bulbous extensions beneath the clouds are indicative of strong updrafts and downdrafts within the thunderstorm. Whether or not the thunderstorm spits out rain or hail at that point depends on if the falling precipitation within the clouds can overcome the updraft speeds.

Below is a collection of photos sent to MountainWeather after the storm, and some that I captured while on a long hike through the Tetons that day, while on a patrol with some old Jenny Lake Ranger friends of mine.

Posted by meteorologist Jim Woodmencey


 
 
 


Looking West Towards Alaska Basin, Photo JW
Looking NW from near Static Peak Divide, Photo JW
Looking WNW from Static Peak Trail, Photo JW

Thunderstorms Add Needed Water

Mountain Weather Blog

Downpours associated with thunderstorms that moved over Jackson Hole on Sunday produced about a half an inch of rain in town. That actually put us over the top for July’s precipitation and we are now above normal for the month, with another week or so to go.
Normal precipitation in town in July is 1.05 inches and so far this month we have received 1.23 inches. That goes a long way towards making up the deficit we have been in, and we are still below where we should be for the year so far, by a little over an inch of water (-1.13 inches). Especially after  below normal rainfall in May & June.
Looking at our total precipitation to date for the year (through July 22, 2012), we now stand at 8.21 inches of water. Historic average would be 9.34 inches for January through July.
Compare to Year’s Past
Back in 1988, the year of the Yellowstone Fires, we only had 6.99 inches for the year, through the end of July.
Looking back through the last 10 years or so, I found three other years that we had even less precipitation  than what we had in 1988, between January 1 and July 31. They were 2001, 2003 and 2007. Another thing to consider is that we just had three years in a row with above normal for precip at this point in the year. See table below.
Total Precip January 1 through July 31
Year
Precip Inches
2000
9.06
2001
5.54
2002
7.63
2003
6.57
2004
8.79
2005
10.15
2006
9.44
2007
4.92
2008
9.09
2009
13.93
2010
10.74
2011
12.82
2012 so far = 8.21 in.
Historic Average Jan.-July = 9.34 in.
Data in this table is taken from the Jackson Automated rain gauge, for comparison.
These current numbers are coming from an automated instrument near the site of the historic Jackson Climate Station, which was manually read by U.S. Forest Service employees up until February 2012, when they stopped taking manual readings. The historic numbers used for establishing our monthly averages were all read manually, for over 60 years.
Back to Those Thunderstorms

The thunderstorms went up the west side of the Tetons and directly over town Sunday did not distribute rainfall evenly in all locations.  The automated rain gauge near the old Jackson Climate Station recorded 0.48 inches. The Town of Jackson gauge at the County building showed 0.50 inches. And the automated gauge at the Driggs, Idaho Airport showed 0.52 inches of water.
Grand Teton National park gauges recorded only around 0.10 inches, and even all the way up to Old Faithful, just 0.13 inches. All much less than in town.
Drought or no Drought
The current U.S. Drought Monitor Map shows that most of Wyoming is in a “moderate” to “extreme” drought, while Northwest Wyoming, including Teton County is “abnormally dry”. Areas of southern Wyoming, especially between Rock Springs & Rawlins have some of the worst conditions. See map below.

In a relative sense, we aren’t so bad off here in Northwest Wyoming, all one has to do is look around and we still have some pretty green hillsides. Not too many other places in Wyoming have that going for them right now.
Text & Analysis by meteorologist Jim Woodmencey
Map from NOAA

July 11, 2012 Thunderstorm Summary

Mountain Weather Blog

A large thunderstorm cell developed over Southeastern Idaho late Wednesday morning (July 11, 2012) and drifted slowly east over Northwestern Wyoming at around noontime. This thunderstorm cell grew to roughly the size of Teton County,WY and produced a fair amount of lightning as it moved overhead.
The images below are from the height of that thunderstorm as it was moving over Jackson Hole & the Tetons, with the heaviest concentration of lightning was across the southern part of Jackson Hole. One of those bolts that hit the top of Snow King managed to fry one of the components in the computer that runs the lightning detector, hopefully that will get repaired in the next day or so. (You can access this via the Lightning Map Page on mountainweather.com).
Lightning Image is a bit complicated to explain, but you get the idea, there was a fair amount of lightning. Red & orange dots are bolts hitting the ground, green & yellow rings are the instrument trying to discern parts of the thunderstorm that are producing the most lightning strikes. Instrument also can detect in-cloud lightning, depicted by blue plus/minus symbols.
Snow King Lightning Detector Image
(From MountainWeather )
Pocatello Radar Image
(Courtesy of NWS)
Infra-Red Satellite Photo (NOAA)
Visible Satellite Photo (NOAA)
Radar image & Satellite photos also show the aerial extent of this thunderstorm very well. These images are all taken from very close to the noon hour.
This was a slow moving thunderstorm, due to very light winds aloft, which contributed to its ability to produce a large amount of lightning over a concentrated area. Some gusty winds were produced in some places and there was a downpour of rain in other places, beneath this thunderstorm.

Weather Observations

Wind Gusts: In the valley winds gusted up to 31 mph at Timbered Island weather station in Grand Teton National Park. Unfortunately, the Town of Jackson instrument was down during this event, so no data was available from there.
In the mountains at the Raymer wind station near 9500-ft. at the Jackson Hole Mountain Resort recorded a wind gust of 45 mph at around 12:15 pm. At the same time on the Lower Saddle of the Grand Teton at 11,600-ft. there was a wind gust of 52 mph.
Rain: Phillips Bench Snotel had 0.10 inches of rain, the USFS instrument in Jackson had 0.11 inches. Areas north of Town in Teton Park and over in Driggs, ID only reported a trace of precipitation. The Raymer precip gauge at around 9300-ft. showed 0.08 inches.
Keep in mind that anytime you hear “thunderstorms” in the forecast, that should imply the potential for gusty downdraft winds, and/or brief downpours of rain, and of course, lightning!
Post by meteorologist Jim Woodmencey
Graphics from MountainWeather & NOAA

June 2012 Weather Review

Mountain Weather Blog

To no one’s surprise, June 2012 was warm & dry. It was not the hottest June ever by any means, but it was certainly one of the driest on record. I will review temperatures first and then the precipitation, or lack thereof!

Temperatures
The average high temperature in the Town of Jackson during June 2012 was 75 degrees, or about 3 degrees warmer than normal. The average low temperature was 38 degrees, and only about 1 degree warmer than normal.
That would make for an average “mean” temperature for the month of 56.5 degrees, which is about 2 degrees warmer than the historic average for June.
Although we had 10 days in June that were 80 degrees or warmer, we also had a number of days that were well below normal, with highs only in the 50’s. That certainly prevented June 2012 from being ranked among the hottest. There were many other years, especially in the 1990’s and early 2000’s that experienced warmer Junes. None of those were able to top the warmest June ever, which was June 1988. The average mean temperature back then was 61.4°F.
Precipitation
You would have to go all the way back to 1935 to find a drier June in Jackson Hole, when only 0.17 inches of rainfall was recorded. This June we had 0.20 inches.
Even June of 1988 saw more precip, with 0.35 inches of rainfall for the month. But that summer went on to be the hottest & driest on record, with no precip in the entire month of July and a scant 0.45 inches in the month of August.
That 0.20 inches this June was way below our normal June precip of 1.65 inches, by almost am inch and a half!
June 2012          vs.      June Historic Averages
Avg. High Temp = 75°F
Normal High = 72°F
Avg. Low Temp = 38°F
Normal Low = 37°F
Avg. Mean Temp = 56.5°F
Normal Mean = 54.5°F
Total Precip.= 0.20 inches
Normal Precip = 1.65 inches
Look Ahead to July
The latest 30-day Outlook for July indicates above normal temperatures and equal chances of above or below normal precipitation (see maps below). The Pacific Northwest is expected to be below normal and areas to the south of us, like the southern and central Rockies, are expected to see above normal precip. That will likely be due to an active monsoon season, which is beginning this week. (See blog post from last summer about the Monsoon).
For more info about long range weather forecasts, click here and go to the bottom of the  : MountainWeather.com Outlooks Page
http://www.cpc.ncep.noaa.gov/products/predictions/30day/off15_temp.gif
July 2012 Temperature Outlook
July 2012 Precipitation Outlook
Text by meteorologist Jim Woodmencey
Graphics from NWS
Data for June 2012 is from the USFS “automated” weather station, and is compared to the old historical record which was all taken “manually for the last 70+ years.

Fire Weather Season

Mountain Weather Blog
June is shaping up much like it did back in the Summer of 1988, with hot, dry, and windy weather rapidly escalating the fire danger. Big, rapidly growing fires this season already in Colorado, Utah, and Southwestern Wyoming should be all the reminder we need to be extra careful this Fourth of July Week. (See link to big fire map below). You can follow the progress of this fire season and these big fires by clicking on this link to:
The U.S. Forest Service’s Active Fire Page

 

Jackson Hole has been spared so far, with no thunderstorms this past week to spark any fires. We’ve been sitting under a dry & stable Southwesterly flow. But the weather not too far to the south of us over eastern Utah & western Colorado has had a few thunderstorms as a relatively narrow tongue of moisture in the upper levels of the atmosphere has extended from Arizona, northward to parts of southern Wyoming.

Upper Level Map at 500mb (@18,000-ft.
To the West of us, the Pacific Northwest has seen some very cool & wet weather as a series of Low pressure systems has hung along the Coast and then taken a track inland that keep the precipitation to the North & West of Wyoming.

Some indication that the weather pattern may change by the middle or end of next week, with what looks like some monsoon moisture creeping up from the South, which would likely bring us some thunderstorms. 


Posted by meteorologist Jim Woodmencey
Map images from USFS & UCAR

Wind in June

Mountain Weather Blog

Back on June 4, 2012 we had wind gusts in Jackson Hole of 51 and 59 mph recorded at the Airport and in town, respectively, at around 4:30 p.m.
These gusts were due to a few dry thunderstorm cells that moved up from northern Utah and southwestern Wyoming, traveling from south to north, over Snow King Mountain and up through the Jackson Hole Valley and on towards Yellowstone, before dying out in the evening.
(See Lightning Strike Map below).

 

These gusts were very brief, and were strong enough to topple some large trees around town. Strong downdraft winds from dry thunderstorms that exceed 50 mph are known as “microbursts”, which these were. Microburst winds originate from the base of the thunderstorm and come straight down, impacting the ground, and then spread out in all directions. (See photo below, courtesy of Charlie Craighead).
 

Father’s Day Wind

On Sunday, June 17, 2012 we had gusty winds that began around 10:00 a.m. and remained strong throughout the day and into the nighttime hours, topping out with peak gusts at around 5:00 p.m.
These winds were the result of a strong jet stream that stretched across the eastern Pacific and into the Northwestern U.S. on Sunday. At 30,000-ft. this jet stream was running at over 100 mph over Washington State & Montana.
(See jet stream map from Sunday afternoon below).

Down here at ground level in western Wyoming & eastern Idaho, we experienced wind gusts in the Town of Jackson of 34 mph. 40 mph at the Jackson Hole Airport, and a 53 mph gust in Grand Teton National Park, just east of Jenny Lake. At the Driggs Airport they recorded a gust of 51 mph. These winds were more of a straight-line wind, consistent in direction, from the West-Southwest, primarily.
One thing that makes the jet stream so strong is a big difference in temperature from north to south, at all levels in the atmosphere. For example, at the surface high temps over southern Canada and the Pacific Northwest on Sunday were only in the 60’s, whereas high temps over California, Utah, and Colorado were in the 90’s, to low 100’s in the Desert Southwest.
Look for that cooler air from the north to arrive on Tuesday!
Text submitted by meteorologist Jim Woodmencey
Lightning Map from MountainWeather
Photo by Charlie Craighead
Jet Stream map from NWS

May & Early June Running both Hot & Cold

Mountain Weather Blog

Almost 80 degrees yesterday and likely topping 80 degrees in Jackson today, calling for a double-take on the calendar to make sure it is really only early June.

When you consider that the average high temperature in Jackson is in the upper 60’s the first few days of June, upper 70’s or lower 80’s seems more like early July.
Nowhere near a record high though, as we have seen temps as high as 89 degrees this early in the year, back in 1988.
Probably feels warm compared to the start of June the past couple years, which were running much cooler than normal. (See table below)
High Temps in Jackson (°F)
June 2012
June 2011
June 2010
           June 1st
76
73
60
           June 2nd
76
60
59
           June 3rd
79
57
60
May of 2012 had 11 days with a high of 70 degrees or warmer. May of 2011 had just one day that hit 70. May of 2010 had one day it hit 73, only day of 70-degree weather that May. So, this May probably felt very unusual to Jackson residents.
Running Cold
It was just this past Memorial Day Weekend though that we had record cold temperatures here in Jackson. The high on Sunday, May 27th, 2012 was only 43 degrees! (The old record cold high temp on that date was 44 degrees, set back in 1954).
What a difference a week can make…..and it looks like we cool down mid-week this week, warm up a little by Friday, and then cool down even more this coming weekend, June 9th& 10th.
(See map of 6 to 10 Day Temperature Outlook showing a cooler Northwest U.S. early next week.)
That’s sort of the nature of “spring” weather in Jackson, some days feel like it’s summer already, then the next thing you know you’re pulling on the fleece jacket and watching it snow.
6 to 10 Day Temperature Outlook

Text submitted by meteorologist Jim Woodmencey
Map from NWS

Summer Weather Outlook

Mountain Weather Blog

After a nice warm and dry start to the normally wet and cool month of May, we are back to a cool and showery weather pattern for the Memorial Day Weekend in the Rockies.
At least through Sunday, rain or snow showers are to be expected each day here in Jackson Hole, with highs only getting into the 50’s the rest of this week. That’s kind of hard to take after already experiencing several days earlier in May that were up into the 70’s, and one day tagging 80 degrees!
By Monday, Memorial Day, we should be back to sunnier skies and temps warming back up above 60 degrees, and maybe edging back up around 70 by mid-week.
What lies ahead for this Summer?
What I hear on the street is that we are in for a “hot and dry” summer.  A look at the Farmer’s Almanac backs that prognostication up, as well. But I usually defer to the Climate Prediction Center (CPC), to see how the next few months are expected to shake out, at least in general.
The CPC is a branch of the National Weather Service or NOAA whose sole task is to analyze the weather out beyond the standard 3 to 7-day forecast, as it relates to temperatures and precipitation being above or below “normal”, over the long term.
These are the maps you see below, for June-July-August. The 3-Month Temperature Outlook for the Southwestern U.S., especially, is solidly in the “above” normal category. Most of the rest of the southern tier of the U.S. is expected to be warmer than normal, as is the northern Rockies, including Idaho & Wyoming.
http://www.cpc.ncep.noaa.gov/products/predictions/long_range/lead02/off02_temp.gif
 3 Month Temperature Outlook

http://www.cpc.ncep.noaa.gov/products/predictions/long_range/lead02/off02_prcp.gif
3 Month Precipitation Outlook
However, the only area of the country that has a high probability of seeing “below” normal precipitation is northern Idaho and western Montana. Southern Idaho and Northwestern Wyoming fall under a lesser probability category, and everywhere else in the country (with the exception of southern Florida), has an “Equal Chance” (EC) of being either above or below normal, or just normal.
For a little more insight into how the CPC determines all of this, go to this link:
You will see just how much data and how many different climate indicators these guys consider when putting these simple maps together. More than meets the eye!
One of the factors the CPC considers is the current ENSO (El Nino Southern Oscillation) or El Nino/La Nina situation in the equatorial Pacific, which is currently in a Neutral phase, by the way.
To follow the long range outlooks throughout the year and to hunt down more info about La Nina and El Nino you can go through the NWS Discussions & Outlooks page on mountainweather.com, direct link is here:
What’s My Take?
In the short term, the early part of June looks slightly cooler and more showery for Jackson Hole, beyond that, we’ll really have to wait and see as the summer goes on.
I do expect since the snow at low elevations has been gone awhile now, that the ground will heat up more readily and warmer than normal temps this summer would be likely.  But it only takes one or two good thunderstorms a month to bring us our normal, or even above normal, precipitation amounts. The problem with that is, that more thunderstorms could potentially lead to more forest fires.
 Text submitted by meteorologist Jim Woodmencey
Graphics from NWS