Northern Denver cell SVR reissuance

2317z radar

2316z PGLM

2319z PGLM

2333z radar

Time series of the northern cell. PGLM had a sharp increase in total lightning over three minutes, strongly boosting confidence to reissue SVR.

Jason Williams

Cyclic slow moving cell growing in eastern KS

A very slow moving cyclic cell exhibiting some mesocyclone character has persisted for nearly an hour. CIMSS Severe Model indicated around 50 to 60 precent with the cell over the past hour with modest total lightning activity.

John Pendergrast

More PGLM near Denver

Cell south of Denver had an increase in total lightning (20 to 44). Still waiting for an LSR to see if that intensification resulted in hail reports (there have been a handful from storms thus far). That southern storm had not looked particularly great for a little while but the increase in lightning caught our eye.

Jason Williams

CIMSS CAPE

I decided to take a look at the CIMSS products to see how the environment was evolving through the afternoon. I noticed that the CIMSS CAPE products appeared cellular in nature in the southern portion of the Jacksonville FA and smoother further north at 21Z and 22Z. Initially, I thought that the smoother part was more accurate and that the cellular values further south were some sort of noise associated with the satellite. However, when I compared the CAPE values from the SPC meso-analysis to the CIMSS CAPE, I realized that the cellular values were actually closer to the SPC values (near 1500 J/kg) and were more representative of the actual environment. This is likely due to the cloud cover (seen in IR imagery) that is over the northern part of the FA. The GFS is probably being used in this area, so the data appears smoother and is actually less representative of the actual environment. Further south where there’s less clouds, we’re probably seeing more of the satellite data which may be why it’s more cellular, but more representative.

21Z

22Z

-Helen Hunt

Increase in total lightning

Had a cell split SW of Denver (the larger mass of total lightning; SE of Denver is a separate cell entirely); the northern one had initially had more total lightning, but the southern storm ended up becoming the stronger one. The total lightning dropped in the northern cell while it quickly increased in the southern one. About five minutes later, reflectivity really began to show the intensity increase. Storm chaser video also showed a possible funnel cloud.

New updraft, increase in PGLM

West side of northern storm had new growth that occurred coincident with an increase in the total lightning on the PGLM.

If an area had an absence of 1 min vis imagery, the total lightning data still gives an alert that growth is (re)occurring.

Jason Williams

Cycling Supercell: SRSO and Lightning Jumps.

Using SRSO suspected that a supercell would become long lived as it seems to have a continued low-level, moist inflow into the storm visible via low level cu field and surface obs. The storm exhibited a cycling of pulses through Douglas Co which were evident via SRSO (Fig 1) and and  subsequent lightning jumps (Fig 2). This provided some validation that this cell would cycle and it could be seen in the lightning jump pulsing. –Cattywampus.

Fig 1.  (gif loop) Super-rapid scan, with pulsing super cell through Douglas Co.

Fig 2. (gif loop) Lightning jump with the supercell.

PGLM and vis sat

Click for loop. You can see updrafts go up and goes along with the increase in lightning on the PGLM.

Jason Williams

Concerns with CI Product

This is an example where I feel like there is so much going on with the CI product that it’s difficult to draw many solid conclusions. Looking at the zoomed out image, you can see just how many different individual areas that the CI product has picked up on. The product appears much too cluttered in this situation to really be helpful in my opinion. Even when I zoom in and focus on the highest area of CI (94% shown in red), I feel like it’s still difficult to track the development of that individual area and the nearby yellow and green areas. This is probably because the CI product and satellite imagery are every 15 min. When we get the 5 min data, I think the CI product will be much more useful.

Zoomed Out (Click image to see animation)

Zoomed In (Click image to see animation)

-Helen Hunt

Lightning jump and another updraft

Lightning jump nearly coincident with yet another updraft (sat images are five minutes apart from one to another).

Radar reflectivity increased shortly thereafter. An aside: MRMS VII also jumped.

Jason Williams