Ryan Vandersmith

"Brocken spectre" in the fog last week near Boulder! #COwx #wxsky

Another day, another dusty mid-latitude cyclone.
#wxsky #ilwx #mowx #inwx #coldcore #tornado #severeweather

Incredible satellite view of today's bomb cyclone.
Credit: College of DuPage
#wxsky #wavecyclone #severewx

This is caused by a mountain wave flattening a thin layer of clouds against the lower stratosphere:

Cloud iridescence near Boulder today #COwx

"Subsun" optical phenomenon this morning near Boulder, Colorado. #COwx

Above the clouds yesterday morning! #cowx #cloudinversion

It's worth noting that forecast models are all over the place in terms of timing, so the front could arrive earlier than shown in this visualization.

Forecast visualization of the cold front sweeping through eastern Colorado today.
#COwx @bianchiweather.bsky.social

Flatirons looking frosty this morning #cowx #boulder #co

Cross section view of the arctic front interacting with a mountain wave today, inverting the vertical velocity field. #cowx #wxsky

Visualization of the cold front moving through Colorado this afternoon through tonight based on HRRR forecast data. Blue lines indicate boundaries / horizontal wind shear.
#COwx #Colorado #WYwx #Wyoming #WxSky @bianchiweather.bsky.social

Freezing fog + downslope winds + Christmas lights = magical views.
#cowx #wxsky #cloudinversion #boulder #colorado #citylights #weather

Definitely!

Yet another sunset cloud inversion earlier today! Denver city lights in the background. #cowx #timelapse #freezingfog #cloudinversion #bouldercounty #denverco #photography #abovetheclouds

Time lapse of a winter shortwave trough passing above a cloud inversion yesterday on the Front Range.
#cowx #wxsky #cloudinversion #coldfront #snowstorm

Time lapse of fog above the city lights of Boulder, Colorado last night. #cowx #wxsky #cloudinversion

Reanalysis cross section of the mountain wave amplification during the Marshall Fire. Today's setup is less potent from a downslope wind standpoint but still worth taking seriously due to the elevated fire risk. #COwx #COfire

This photo lines up almost perfectly with the RAP cross section for today's mountain wave over the Front Range #cowx #wxsky

This will be an interesting test run for sure. Looks like the strongly surface-based inflow verified with the tornado north of Houston #txwx

An example of the new "stepwise" CAPE and CIN plot being tested for SounderPy in the bottom right. The left sounding is north of the front, the right sounding is south of the warm front.

Time lapse of rotor clouds spinning over the Front Range foothills yesterday, produced by a trapped lee wave. #cowx #wxsky #cofrontrange #colorado #mountainwave

Here's the PR! Feel free to suggest changes:
github.com/kylejgillett...

Comparison of this windstorm (left) and the one that occurred during the Marshall Fire (right). The resemblance is uncanny aside from a few notable differences in the temperature profiles.

Cross section of the mountain wave structure overnight. The ~100 mph gusts were suggested at least 4-5 hours ahead of time by the RAP forecast model, which showed extreme amplification with similar downward velocity to the windstorm which caused the Marshall Fire in 2021.
#cowx #wxsky

Awesome! I'll let you know once it's ready!

@wxkylegillett.bsky.social would you be interested in adding this to SounderPy if I opened a PR for it?

This is fundamentally just a way to visualize the Effective Inflow Layer (EIL), which is used in operational forecasting and determines how storms transition to becoming supercells.

Interesting read on how the EIL affects supercell updrafts:
journals.ametsoc.org/view/journal...

In this context, "inflow" refers to the vertical levels of the atmosphere which contribute to a storm's updraft. The historic Greenfield tornado this year had a thick layer of uninhibited inflow from about 0-2km, steadily increasing towards the surface. This is highly favorable for tornadoes.

The main benefit of seeing the full inflow layer is that instead of relying on SBCAPE / MUCAPE to determine if a storm is elevated, you can see the full spectrum of possibilities. All else equal, well-organized inflow tends to produce stronger, more predictable, and more photogenic storms.