Lone cell southeast of Billings garners a pseudo warning

A lone cell over rural areas southeast of Billings developed into a persistent severe cell on the CIMSS Model (above 90 percent) for several consecutive radar scans along with significant to dangerous category total lightning values.  The cell centroid moved to the right of environmental flow on both radar and projected ENI motions.

John Pendergrast/Jason Williams

June 2 — Lightning Jump coincides with Large Flash Density (CYS)

Just a few minutes after my previous post on distant flash density, we got a lightning jump along with several CG lightning strokes AND a large flash density.  The lightning jump was up to 6 sigma!

Note the 6 sigma lightning jump on the left screen along with 4 CG lightning strokes, while the flash density was up to 16 per minute!

This cell persisted with its density rate as the severe probability quickly increased to 90 percent by 256 PM.  The overshootimg top algorithm also turned on with another supercell that developed near Lusk, WY.

CoonieCatEye

BIS CWA: Using NUCAPS and CIMSS to anticipate new convective development

Trying to anticipate future convective development. Looked at a CIMSS CAPE (fig 1) plot and seeing that the best CAPE is shifting into the eastern CWA. Took the available NUCAPS sounding and modified  it with a nearby metar with a 77/66 surface reading.  See plenty of CAPE (3,500 J/kg). May be too much just simply modifying the surface points along, but nonetheless it shows it is plenty unstable.  This was also in a mostly clear region.  Plan on testing CI-East to see if this clues in on potential development in this area. –Cattywampus.

Fig 1: CAPE shifting east along with surface low and southerly flow.

fig 2. Modified NUCAPS sounding over cloud free SE portion of the CWA. Still quite unstable.

–Cattywampus

June 2 — Flash Rates vs. CG Ltng outside LMA Range of Efficiency (CYS)

I had been noticing that the LMA Flash Density has been occasionally reporting outside the maximum range of efficiency well north of the sensor array in north central Colorado, over 200 km away.  Even though the flash rate is low (only around 1 flash/minute), it did pick up on one CG lightning stroke in the Douglas area this afternoon, which occurred coincident to the flash report.  See Figure 1 below.

Fig.1  One CG lightning strike near Douglas (KDGW) (L) and the Flash Density (R)

Appears this may be due to increasing cloud heights and possible glaciation rate aloft.

CoonieCatEye

CI Prob Success

The image below (please click to animate) shows an example of when the CI probability product successfully predicted the onset of convection. At 1845Z, a yellow CI polygon appeared southwest of Solen indicating a 60% probability of convective initiation. In the next frame (1900Z), the visible satellite imagery shows intense cumulus growth in the vicinity. I also compared this to radar, and a cell popped up at 1858Z.

-Helen Hunt

CI performs well on new Montana convection

CI product at 2020z climbed to 50% for the clouds south of BYZ. At 2027z, radar showed most of that zone had low reflectivity, with the exception of a northern cell that was resurrected from previous convection. However, by 2049z, much of the area that CI had indicated as a max had convection. Spatial area was very good!

Jason Williams

Low CI verifies

What looked visually like a potential source of a future storm in the south-central BYZ CWA was pegged by CI at 17% at 2000z. It never went on to develop and totally lost a CI value by 2036z.

There are increasing values of CI to the west, however, where LAP also indicates higher instability.

Jason Williams

Radar evolution compared to LAP in Montana

The four images show the progression of the storm cluster in the BYZ CWA in relation to the GOES LAP CAPE (upper-left panel). The storms appear to have intensification as they move NE; while one could look at the better proximity to the radar for this, the increase in lightning would suggest that there was indeed intensification (see previous post on lightning rate).

The northern end of the line has become stratiform and has been completely without lightning since 2011z; the southern cell started losing lightning at about that time and has since had very little (if any) on the one-minute ENTLN data. The ENI DTA went away at 2023z and no alert boxes have been present since then.

It appears the LAP CAPE product performed well in relation to how the storms evolved as they moved NE.

Jason Williams

CI and outflow boundaries

Noticed how the CI was pegging on the outflow boundaries.  Decided to overlay the radar and CI.  This image shows how the CI and outflow boundaries are marked out well.  Noticed that it did a good job picking up these boundaries, but did not do well with actual CI from boundaries interactions.  This was GOES-West…in SE WY.

 Now using GOES-East, it did an excellent job.

MacGyver

SSRO and boundaries

The one minute data, by far, has been extremely useful.  The data has lead me to find small boundaries, like in this GIF.  It also has lead me to think outside of the box and find fine mesoscale features like small jets that will help strengthen and initiate convection.

MacGyver