Bizarre temperature extremes in Wyoming

[Tim Vasquez]

The temperature extremes across Wyoming are impressive. I haven't looked at any other data, so I can't tell whether this is downsloping or a sharp inversion that's been broken up in places. I'm inclined to think the latter since Wyoming's elevation is already quite high and the passes aren't that much higher. May also be that and an intrusion of a much warmer air mass from the intermountain region.

Northern Wyoming is particularly interesting.

 

[Tim Stoecklein]

I'd be curious to see the elevations of each site. Terrain definitely changes quickly in that area. My wife spent a semester in Powell, WY on an internship so I spent a little time up there.

Tim

 

[mikegeukes]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
230 PM MST THU JAN 6 2005

SHORT TERM...SNOW-EATER WINDS HAVE WARMED TEMPERATURES
SIGNIFICANTLY DUE TO KATABATIC WARMING.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
303 PM MST THU JAN 6 2005

TEMPERATURES TODAY ARE WARMER THAN ADVERTISED IN SOME LOCATIONS
DUE TO WINDS MIXING THROUGH THE SURFACE INVERSION.

Mike

 

[Mike Umscheid]

Originally posted by Tim Vasquez
The temperature extremes across Wyoming are impressive. I haven't looked at any other data, so I can't tell whether this is downsloping or a sharp inversion that's been broken up in places. I'm inclined to think the latter since Wyoming's elevation is already quite high and the passes aren't that much higher. May also be that and an intrusion of a much warmer air mass from the intermountain region.

Northern Wyoming is particularly interesting.

Here is a metar plot at the same time that Tim V posted, but with a Topo overlay. You can clearly see the effects of localized significant downward motion thanks to mountain wave effects.
<img src=http://www.underthemeso.com/wxmisc/WYmetartopo.jpg>

This next image is a cross-section I made across the northern Wyoming area of interest that Tim pointed out. The color image is Theta-E, as well as the dashed red lines. The blue contour is Omega (magnitude of vertical component of wind calculated in microbars/sec). You can visualize the mountain wave effect as parcels follow closely the red lines from west to east. Even though this is a dry adiabatic process, I find theta-e shows the distinction of cold airmasses from warm airmasses better than theta. Notice the sinks of cold air in the valleys. The high-res Meso-eta model does a very good job re-creating this terrain effect, and it matches up well with the observations.... where the -15F observations were recorded in the valley between the Absoroka Range to the west and the Big Horns to the east. Very neat mountain meteorology that is actually not unusual at all in the cold season!

<img src=http://www.underthemeso.com/wxmisc/WYxsctn.jpg>
downward motion is dashed blue, upward motion is solid blue, theta-e is image and dashed red. Terrain is highly exaggerated

Mike U

 

[Tim Vasquez]

Very neat graphics... thanks for posting those!

Tim

 

[Robert Dewey]

Originally posted by Tim Vasquez
Very neat graphics... thanks for posting those!

Tim

Mike's just trying to show off AWIPS, :wink:

 

[Bill Schintler]

Even though this is a dry adiabatic process, I find theta-e shows the distinction of cold airmasses from warm airmasses better than theta.

Neat stuff! For grins, could you plot the theta temperature for the same time and cross-section for comparison? Thanks - bill

 

[Mike Umscheid]

Originally posted by rdewey


Mike's just trying to show off AWIPS, :wink:

Heh, I need to stimulate the mind somehow at 4:30a.m. on the mid shift after the fcst goes out! To answer Bill, I'll do a xsctn of Theta compared to Theta-E, but since the atmos is lacking water vapor and is quite cold, you'll find thate ~ theta-E.

Mike U