Chinook

Guess what? Maybe time for a winter thread. The models have some agreement on this cold air mass and higher chance of snow for the mountains on Thursday night, with some possibilities for snow on the Plains.

Major Hurricane Roslyn is close to the coast, near Puerto Vallarta. Intensity is 115 kt. Here is a segment of the discussion from 3:00PM Mountain time today (Oct 23)

A long, long time ago, the GFS predicted this 982 mb low in Nebraska. It's amazing how close it looks to the forecast for tomorrow. It's also amazing the GFS existed so long ago.

There are less than 10mph winds at Fort Collins this afternoon, with summer-like temperatures. Meanwhile, it is snowy, rainy and windy in parts of the Mountain West today. There are high wind and fire weather concerns for tomorrow on the Plains. The first snow, and by that I mean, only a winter weather advisory, has been posted for areas over 9000 ft at the Front Range in the near future. I guess the forecast has finally gotten to the point where there are winter storm warnings for the west, i.e. San Juan Mountains. say goodbye to summertime-type views like this

Wow, I actually didn't see this storm until today because it's south of the normal USA maps, and I assumed nothing was happening in the tropics.

You guys can feel free to start a winter discussion, but as of right now, only a dusting of snow at 12000 feet means it's hardly much of a winter discussion yet. In Ohio today, the freezing level is 2950 ft above sea level, as we are in a polar air mass that is nearly the worst weather we could have at this time of year.

We have a late-fall type polar-air trough in Canada. I wanted to point out that the plot of the 500mb wind speed and heights always hides the subtropical jet. The second plot is the cross-section from western Ontario to the Yucatan area of Mexico. The significant change in the altitude of the -12 degree C isotherm occurs at lower altitudes than the polar jet, which maxes out its wind speed at 300mb. The subtropical jet has its max speed at 200mb and the stronger winds are almost entirely at higher altitudes than 500mb. The 0 degree C, -12 degree C, and -18 degree C isotherms dip much closer to the ground in Ontario, perhaps much closer to the ground with any of our normal-ish jet stream patterns.

This velocity bulge was a reported tornado at Frankville, next to Racine. When I was 5 years old, my parents rented a place outside of Racine. And that's where and when I actually survived a -30 degree temperature by staying inside.

reported tornadoes reported tornado near Burlington Wisconsin

Confirmed tornado warning North Prairie, WI

Potential Tropical Cyclone 13 - Here is the first section of Discussion #1

there could be blue skies west of the tropical storm

The wind speeds are the bright colors, regardless of wind direction. in this case, it is a slice from west to east across the hurricane, so west is to the left. The 64 knot winds (hurricane force) are purple and higher, and the 96 knot winds (category 3) are light pink and other pink colors. The isotherms (0 degree C, -12 degree C, -18 degree C) are the small dashed lines that bump up in the middle of the storm. Hurricanes concentrates the warmer air at the eye, due to the latent heat release at the eyewall. The solid black lines are a little confusing as it represents potential temperature. When they dip down, then it is warmer. The 96 knots to maybe 115 knots on the east side of the eye reach very high into the air, about 35000 feet. Winds weaken at 40000 feet. The west side of the storm has some slightly different qualities in terms of how the winds change with height. The gray bump is due to the fact that the sea level pressure is around 950 mb, which is much different than the typical 1000mb. The highest winds are above the surface, but certainly winds of up to 120 knots are not far from the surface. This is a 12 hour forecast from the HWRF, for 06z

Buoy 42026 with 63mph gusting to 85mph wind (time: 0135z)

latest storm cross-section

first gust of 46 knots at Key West

18z cross-section of this storm (HWRF)

storm cross-section for tonight (00z)

western Caribbean composite radar

Here is some info you didn't want to hear: #3 Hottest summer at Denver, #3 Fort Collins, #1 Cheyenne

I hope this doesn't sound dumb, but Super Typhoon Haiyan set a record, I believe with satellite-estimated 195mph winds, (with 1-minute winds, JTWC-American style) and it directly affected Tacloban city, with a storm surge that came in almost as fast as a tsunami. So, yeah, I can't think of anything more devastating. according to Wikipedia: Syper Typhoon Noru--I don't believe I've ever heard of a storm that went from 50mph to 155mph in official (satellite) analysis in roughly 24 hours (correct?) I watched a 16-hour loop on Tropical Tidbits yesterday and that showed pretty much the entire development cycle.

I think I see some yellow aspen trees

Observations now with post-tropical Hurricane Fiona

peak wind gust 84 at St Paul Island

Hours ago, Sydney airport had to estimate the sea-level pressure to be 949.5mb edit: also 940.0 mb (Grand Etang, on the Cape Breton penninsula)