Chinook

With a 986mb low over Iowa, and 60-65F dew points from Louisiana up to Springfield IL/Davenport IA, I believe the SPC will have to give a slight risk outlook for the entire cold front and adjacent areas. Especially with 75 kt winds at 500mb over this region.

Anybody know if there has been any confirmed damage at Triana to Owens Cross Roads AL?

As for now, this is a radar-confirmed tornado warning at Sewanee.

There is likely going to be some mixed rain/snow for our area on Friday/Saturday morning, with the potential for heavy snow at Estes Park.

It looks like this storm north of Huntsville is trying to develop a stronger rotation

The southern supercell near Vina, AL is ramping up with stronger rotation and a tornado warning.

Thunderstorms near Tupelo MS seem to be increasing in intensity quickly.

It seems quite likely that scattered severe storms will move across Tennessee and Kentucky, as well as adjacent areas of Mississippi and Alabama. According to most CAMs, the storms may be quite late in the day, with some stronger storms at 00z (8:00PM eastern/7:00PM central). With strong wind fields aloft, these storms will have fast movement, and I would expect a wind/tornado threat

It looks like my area got 3.9" of snow and 1.35" of total precipitation (nearest CoCoRAHS observers.)

Today has been kind of low on the storm report total, given the two different enhanced-risk areas. This is a radar-confirmed tornado north of Little Rock.

This tornado-warned storm has tracked northeastward from Fort Smith metro area. (near Mulberry, AR)

My place has about 2" on grass, and just some slush on the streets.

A storm near Essex, IA is already starting to show signs of being a discrete supercell with 1-2" hail.

latest radar, with p-type. we have snow here, maybe 1/2" on rooftops.

I don't know if this is going to accumulate. At Fort Collins, there has been 0.77" of liquid equivalent since yesterday. There is only a trace of snow right now. I guess I can deal with that. I did plenty of shoveling in February. I'm not sure I want to do more shoveling today or tomorrow.

Why not use math? The 10% tornado area is 113,928 sq mi, the 5% tornado area is 140,381 sq mi, and the 2% tornado area is 168,806 sq mi. The SPC system forecasts a probability that any one point in a certain zone will see a report within 25 miles. That means that each point in space is something of a 25 mi radius storm-report-detector. A 25-mi radius circle takes up (pi)*(25)^2 square miles of area. Aside from using more advanced methods of statistics, let's just apply simple math. The number of 25 mile circles covered by the 10% outlook is 58.02, and likewise, 71.50 circles, and 85.97 circles. Then (58.02)*(0.10)+(71.50)*(0.05)+(85.97)*(0.02) = 11.1 tornadoes. 11 seems like a possible number of tornadoes. Qualitatively, I think it's reasonable to say the 10% risk for a large section of the Ohio Valley/Mississippi may seem too much. Otherwise, using real statistical methods may calculate a different number of expected tornadoes.

Tiny tornado vortex signature (near Albany TX)

we've had two tornado reports here. The current tornado warning is not directly over the velocity couplet (unless the radar is delayed somehow)

Storm-relative velocity shows about 75kt on the right hand side, 35 kt on the left hand side. (same storm as the last post)

This storm near Maryneal, TX has ramped up its rotation in the last couple of scans.

My place is getting 1/4" hail and some lightning right now. We haven't seen hail for a really long time!

As for the 20z HRRR, there is really only one major thunderstorm with a helicity track, and that's 2-4 counties west of Fort Worth. I expected the HRRR to have more of these.

Models have been pretty inconsistent with this storm, which should be starting tonight. The 12z GFS has a QPF of 1.85" for downtown Denver, with 12.3" of snow (Kuchera ratio.) It also has this heavy snow at 33 degrees F, with 20kt winds at the surface and 40 kt winds at 1km above ground. I would imagine that yesterday's winter storm watch for 3-7" and gale-force winds, is pretty reasonable, given the uncertainties. The NWS still could upgrade/downgrade the headlines as needed. As with fall/spring storms, this one may be rain, then transitioning to snow, which brings some uncertainty with it. Blizzard warning for Weld County, east of DIA, Castle Rock --this text valid for Greeley

The SPC has increased the wind risk to 30% and tornado risk to 10% into southern Indiana and Illinois. Some of the convection-allowing models show updraft helicity tracks in IN/IL late at night, well after 00z.

we have a winter storm watch for 3-7" across the Denver CWA, low elevations, 8-16" for over 9000ft.