Chinook

Convection-allowing models show a localized tornado threat tomorrow.

Here is a NAM 3-km cross-section east-to-west through the dryline tomorrow. The warm moist sector will have the moisture confined to being below 800mb. This dryline has very low relative humidities west of it. You can see the slight increase in potential contours to 307K-310K. (lines on this plot). It's also cool to see the high-res models have elevations above 700mb (roughly 10000 ft) in SW Colorado, built into the land system. You can also see the evidence of the cooler air coming in to the Rockies, as the -12C isotherm dips from above 500mb's elevation to around 600mb. several storms could develop with over 2000 J/kg of CAPE and 0-3km storm-relative helcity of 300-400m2/s2 and 0-6km shear of 50 kt (sounding near west Oklahoma)

The GFS analyzed this as 943 mb

tornado in northern Missouri

I am going to post these because it may be the last interesting day to post updraft helicity tracks for the Midwest for the year. There seems to be some agreement on the updraft helicity tracks in central IL, but my own idea is that the higher tornado threat might be SE Missouri.

Dew points of 60-70 will exist southeast of the cold front on Sunday, with a low pressure in Iowa/Missouri. In general, the models have strong winds at 850mb-500mb, leading to some areas of 0-3km storm-relative helicity of 250m2/s2 or better. Models have 40-60 kt of wind at 500mb over Arkansas/ Missouri, leading to 0-6km shear in that range of values.

It's now 10/17. And Raindance was... right. A compact 500mb low is cutting off right now near the Sierra Nevada, and will track through Wyoming, bringing snow to some areas of the Sierra Nevada to Wyoming. Winter storm watch for some areas of Wyoming

Here are some more maple leafs. Well, not Toronto Maple Leafs. 2nd picture: ash. 3rd picture: some type of bush where the leaves resemble maple leaves.

mountains partially clouded (Wednesday)

My area had a few minutes of rain, graupel, and lightning, and even thunder somewhat close by. Then, today turned out to be pretty nice, not too windy like Cheyenne.

TDS about 7 mi from Dodge City

confirmed tornado near Copeland KS

Interesting weather note this evening. The upper level low over the Southwest is bringing in so much wind, the flags are flying at Dodger Stadium, the likes of which I've almost never seen for a southern California baseball game.

location of two confirmed tornado warnings several minutes ago (3:53pm Central), also, prelim. tornado report near Jacksonville IL

This is a 12z HRRR run for tomorrow night. The afternoon-evening SBCAPE should be a narrow area of possibly 500 J/kg to 1500 J/kg in western Kansas and down into the Texas Panhandle. Models show convective development. I wonder if the deep layer shear could be too powerful for supercells, given the limited CAPE. As in, the shear could be so great it disrupts updrafts.

might as well post this. NWS point forecasts for RMNP have 4"-8" at high elevations

confirmed tornado at Johnson, OK (0157z radar showed a TDS)

new confirmed tornado warning east of OKC

new tornado warning extends about 35 miles east to west

tornado that was reported at Cooperton

1st supercell of the day in the process of developing now in SW Oklahoma.

The 15z HRRR has some big updraft helicity tracks right through Norman and other areas!

Believe it or not, this is an oak tree. Many of the cottonwoods haven't changed to bright yellow yet.

NAM-3km cross section through the cold front and directly through the severe thunderstorms. Huge differences in upward motion mess with the isentropic surfaces. You can see a slight reduction of the 0C isotherm going towards the left side of the plot.