Another CI Case

Just another brief example of using the GOES-R Convective Initiation Algorithm.

CZ (left) and GOES Vis and CI (right) at 1830Z. The orange areas show 81% probability of CI.

Convection did indeed initiate soon after, becoming severe by 20Z. There were several reports of golf ball sized hail associated with this storm between 20Z and 22Z.

As of  2312Z this cell is still going strong. A pair of weak cells has popped up just to the south and the CI algorithm is showing two more 80% areas with these cells.

We're about to start wrapping up for the day, but it'll be interesting to see how these cells evolve over the next 30 minutes or so.

-V. Darkbloom

Lightning Jump and Cell Intensification

Another significant lightning jump occurred in west Texas (Midland CWA) around 2134Z (434 PM CDT). The jump was 4 sigma - shaded red below.

 

A time series reveals this was the first in a series of jumps.

The second jump around 22Z was 2 sigma. A loop of the 0.5 deg reflectivity shows the cell intensifying after the lightning jumps occurred. The max Z at the 0.5 deg tilt increaed from around 63 dBZ to around 71 dBZ in 8 minutes, or two volume scans.

(click image to animate)

In this case, the lightning jump is a good indicator of imminent storm intensification.

-V Darkbloom

All set up

Procedures and perspective displays set up. Time to start watching current storms.

Warned on this storm with a 5 sigma lightning jump. It appears to be a right-mover. 

Lynford

3rd SVR for TOP area

3rd severe warning for a hail core over southwestern Ottawa county, moving northeast. Lightning Jump Algorithm jumped over 4 sigmas around the time when the hail core aloft looked the best. ProbSevere jumped from 69% to 92% with MESH building to over 1.50 inches. DTA came out well in advance though it overlaid with a 2nd, more appropriate DTA, related to the more intense storm approaching from the south. Although fairly large area of 60 dBZ above -20 C, and MESH at 1.50 inches, only used 1 inch hail in warning due to lack of large hail reports during the afternoon.

Brick Tamland

A Limitation of Prob Severe Algorithm

While observing the Probability of severe throughout the event today, I have noticed that it seems to do well when there are discrete or individual convective cells and was useful in the warning operations when combined with the base data we were looking at interrogating the storms.  The storm we originally warned on seen in the image below had high prob severe values and verified with a 60 mph wind gust report.

However, later in the event the convection became linear and looking at the base data interrogating the storm there was not evidence supporting a warning along the line as the 50dbz cores were relatively low and the line of storms had become outflow dominated with the outflow boundary pushing well away from the storms.  The probability of severe though was showing values near 85% along the entire line.

So I think it is important to note for the users of this product that when the convection becomes linear the probability of severe may not be as useful and should not be as relied on compared to individual convective storm environments.

Jack Bauer

ProbSevere and Lightning Jump - Great Match for Warning Confidence

Another cell developing to the east of the two previously warned cells provided another opportunity to use both ProbSevere and Lightning Jump Detection Algorithm in conjunction to issue a Severe Thunderstorm Warning.

Really started to see an increase in the mid level reflectivity on the storm and during that time the ProbSevere increased from 8% at 2204Z to 64% at 2208Z.

At that point, we were starting to think about issuing a SVR and as we were making that decision, there was a 5 sigma lightning jump noted. That data arrived before the next version of ProbSevere arrived but tied in with the increase shown in the previous couple scans. At that point, we decided to issue the SVR and our thought was confirmed by the next version of ProbSevere increasing to 84% with a MESH value of 1.25".

The warning was issued at 2217Z and the ProbSevere value reached 94% with a MESH of 2" as the warning was issued.

Although the experience with these two products has been limited thus far, they have shown to work well in conjunction with the radar analysis to lead to increasing confidence on issuing a warning during rapid intensification.

-SRF

KICT Experimental Severe T-Storm Warning

The Omaha team moved to Wichita, KS WFO and has focused on developing convection along a cold front.  The NOAA/CIMSS ProbSevere model, combined with analysis of base radar data, helped the forecasters issue an experimental severe t-storm warning at 2217 UTC 04 May 2005 on the cell centered in Figure 1.  The animation shows how the ProbSevere model probabilities rapidly increase as the observations of the storm intensify.  The forecasters commented they liked how the rapid uptick in ProbSevere output matched with their analysis of the 3-d reflectivity of the storm as well as 5 sigma lightning jump (not shown) increased confidence to issue a warning.

Figure 1.  NOAA/CIMSS ProbSevere and MRMS Composite Reflectivity valid 2200 - 2214 UTC 04 May 2015.

-Sieglaff

First Warning for the Project (ICT)

With the move to ICT we were able to issue our first warning of the project. The storm that was previously discussed re-intensified after splitting. The increasing reflectivity aloft led to the MEHS data to give a hail estimate of 1.55" and pushed the ProbSevere up from 58% to 95%.

Thus, a warning was issued for that cell.

To the northwest, a storm in DDC started to take a right turn right around the same time as a series of 2-3 sigma lightning jump values (orange in bottom left screen). Those values occurred as the storm intensified on radar and led to the ProbSevere values rising from 80% to 97% as it was nearing the cwa. Also, notice the overshooting top detection in the lower right screen.

With all of those values and the expected movement into the cwa, issued a warning for the ICT area for the storm.

-SRF

Convective Initiation Success!

Looking back at the big picture and focusing on the GOES-R convective initiation, there was not much showing in our area of responsibility (TOP) but further south in northern Oklahoma I noticed some increasing probabilities at 1900 UTC.

15 minutes later at 1915 UTC the CI probability jumped to 90% on the east side of a cluster of identified clouds while there were also 40% probs on the west side.

Immediately after this time it was evident there was convective development was occurring as seen in this 2000 UTC satellite image below.

By 2030 UTC some CG lightning strikes were noted seen in the image below.  Radar at 2030 UTC also included.

Jack Bauer

Moved to ICT

With limited convection in the OAX area, we have moved over to ICT. The ICT CWA is along the same boundary, but now is on the southern side.

Taking at the quick look at the radar, there is a strong thunderstorm over the north-western part of the CWA. I decided to use the ProbSevere data as a quick overview and found the MRMS MESH data (hail size ~1") to be very helpful in giving a quick look at the current expectations on the storm. I also found the satellite indicators to be helpful with the switch to indicate the current state of the storm (Mature).

Starting to see some increase in the eastern cell while typing this and will follow up this blog post with additional information. -SRF