GLM struggling with intensifying supercell

The first CI of the day occurred just after 19Z. The radar appearance of the storm remains healthy and the ground-based lightning networks are as strong as they’ve been, but the GLM strength has (erroneously) dropped off dramatically.

-Atlanta Braves

All-Sky LAP PW Showing Rapid Low-Level Moistening

A comparison of the All-Sky LAP derived PWATs with 12z RAOBs shows that the LAP product is depicting PWAT quite well.

The PW retrievals were done mostly in clear skies (blue colors):

A four-panel plot of total PW and PW at different layers from 12-18Z shows rapid low-level moistening over OK and AR (upper right and bottom left panels).

The moisture return, in combination with diurnal heating, is resulting in a rapid increase in CAPE as suggested by the all-sky LAP product:

Ron Dayne

Here comes the moisture

The AllSky Layer Precipitable Water clearly shows the moisture return this morning into southern Texas and Central Oklahoma. PWATs across the Red River were ~0.5 inches early this morning and have now increased to ~1.5 inches this afternoon.

This product is a great situational awareness tool to survey the pre-storm environment. -Atlanta Braves

AzShear Depicting Highest Tornado Threat

The 0-2km AzShear product is depicting the highest tornado threat along the convective line. There is a maxed-out area of 0-2km AzShear along this line.

This makes sense given extreme low-level shear values in this area with easterly winds at the surface lengthening the hodograph. According to the RAP, 0-1km SRH values are in excess of 400 m here.

Ron Dayne

Difficult Warning Decision as Storms Enter LSX CWA

The northern extent of a line of storms that has produced sporadic wind damage is approaching the LSX CWA from the south. One of these storms has good reflectivity structure with a tight front reflectivity gradient and a rear inflow notch. However, these storms appear to be entering a more stable airmass. This is reflected in the ProbSevere probabilities of the storm in question compared with one just a bit further north:

The northernmost storm with the cool contours has only a 22% ProbWind and is in an environment of only 715 J/kg MLCAPE (per the sampling feature). Meanwhile the storm in question to the south in the warmer contours has a 90% ProbWind with 1220 J/kg MLCAPE. These storms are moving to the northeast toward the more stable air. Incidentally, the All-Sky LAP CAPE does not depict as sharp of a gradient in the CAPE compared with the RAP-derived ProbSevere values:

I am not sure which is more accurate but I suspect the model-derived values are more accurate in this situation.

Furthermore, a weakening trend in the Flash Extent Density is observed on the northern end of the line:

This storm still deserves a warning, but we will see how quickly it weakens.

Ron Dayne

GLM Storm Intensification

Storms are trending sub-severe across most of our CWA at this hour, but 1 cell behind the initial line started getting its act together. Here is the GLM Flash Extent Density (top left), GLM Minimum Flash Area (top right), GLM Total Optical Energy (bottom left), and KLZK base reflectivity (bottom right) before the cell started intensifying:

The large FED and MFA bullseye imply the updraft is intensifying on this storm. This proved to be a useful proxy because this was the result 8 minutes later:

This suite of products has a lot of utility for pulse severe events and DSS on-site weather events. -Atlanta Braves

Precipitable Water Comparisons

The Blended TPW product (top left) shows promise in creating an all-observations precipitable water product in AWIPS. The polar-orbiter PW data in cloudy areas produces artificial gradients and inaccurate values compared to modeled fields (GFS top right and HRRR bottom left), but its attempt to generate an all-observational PW product is successful. I am unsure of how to suggest improvements in the cloudy areas but would encourage these model-free fields continue to be developed.

The AllSky PW product (bottom right) looks really good. The inclusion of GFS data in cloudy areas is a neat idea and the partly cloudy areas seem to be well-computed. This is a tool I will definitely use for situational awareness. -Atlanta Braves

AllSky Overview – Big Help

The AllSky products seem to do a really good job of providing timely and relevant environmental data with higher spatiotemporal resolution than other means. Representative model soundings and the SPC Mesoanalysis page are nice tools, but the AllSky products add a helpful third point to interrogate environmental evolution. Perhaps the most helpful application is tracking of fronts and boundaries. As the dry line advances it is easy to see its eastward extent. In addition, the extent of the warm air is very clear as it pushes into Missouri.

This 4 panel display with cloud type in the lower right is a useful tool for identifying potential causes for inconsistent data from pixel to pixel. I like these products and look forward to their operational implementation at the end of this month! -Atlanta Braves