23 Feb 2019 Case – AzShear

The single radar AzShear provides good continuity with persistent mesocyclones. It also highlights well meso handoffs. The single radar AzShear is far superior to the merged product. The merged product does not provide as smooth of a track and suffers from obvious different depictions of the circulation from varying ranges and sample times giving a more blotchy appearance and larger overall signal.

— S Coulomb

AllSky & TPW Check

Did a quick check of the merged TPW and AllSky products and as previously advertised/anticipated, the convection has been riding right along the gradient of the higher instability, but there is some discrepancy as to whether it’s right in the heart of the higher PWATs or along the leading edge, depending on if you’re looking at the AllSky or TPW, respectively. Noticed quite a bit of a latency in the availability of these products (up to an hour), which wouldn’t be good in an operational setting. Compared the values of the TPW and AllSky PWAT with the RAP, and the AllSky matched up much closer to the RAP. However, with the amount of cloud cover in the region (for obvious reasons), the GFS is the predominant data type (basically a model-to-model comparison). Either way, the general idea/trend is helpful if serving as a mesoanalyst in an operational environment.

~Gritty

(CAPE)

(AllSky PWATs)

(Merged TPW)

Layered TPW Shows Arrival Of Moisture

We’ve been monitoring a boundary on both the KEOX and KEVX radar, likely associated with weak surface convergence per surface obs. The layered TPW product shows a tongue of moisture approaching the region. It looks like a line of towering cumulus developed over the Gulf of Mexico as this moisture interacted with the convergence line.Sandor Clegane

Tracking Meteogram Tool With AzShear

One of the discussion points that has come up about the Merged AzShear product is monitoring the trends of the AzShear as storms progress. One way to do this that is built into AWIPS is the Tracking Meteogram tool. The following are a  GIF and PNG for a MCV just off of the MOB CWA. The radar image is above. The GIF shows the tracking tool and AzShear and then the plot showing the trends. In this case you can see general increase in AzShear values. There are some limitations of the Tracking Meteogram took like only being able to track one feature at a time, there is a lot of things to edit and modify with the Meteogram (the position and size of the tracking area), and this would not be an easy tool to modify and update while trying to focus on other warnings.

-Alexander T.

Merged AzShear for Strength Trends

An example where AzShear data can show storm trends in one image without looping. As SAILS cuts come in you’re able to view rotational strength trends before the entire image is replaced by the next volume scan. Although this image is looping you can see the times when sails cuts would be overlain on one image.

NMDA Struggles To ID Mesocyclones On QLCS

A severe thunderstorm pushed through the northern portion of the CWA and I had a tornado warning in effect in anticipation of tornadoes along the eastern most portion of the bowing line. Unfortunately, the NMDA was not initially identifying mesocyclones along that portion of that line. It was only until well after the warning was issued that the NMDA identified anything along that portion of the line.Sandor Clegane

GLM Assist In DSS

The below image shows GOES-16 day cloud convection (DCC) beneath GLM Minimum Flash Area (MFA). Point F is a DSS event. DCC shows clouds glaciating a county upstream of our DSS event, with the storm becoming electrified shortly after glaciation per MFA. This prompted a call to the emergency manager providing support for the DSS event letting them know that lightning was imminent.

ENI total lightning also shows lightning (white points), but the point data fails to show the extent of the lightning, which may lead decision makers to think that they have more time to react to the approaching lightning than they actually do.Sandor Clegane

AllSkyLAP CAPE – Trends

Noticed the trend of AllSkyLAP – CAPE was interesting – and bucked the trend of the GFS background.

2157 UTC:  LAP seemed to have a good handle on higher CAPE trends at this timeframe with over 1000 J/kg in a wide area – which seemed to match convective trends.

2227 UTC:  LAP reduced CAPE over much of the area – even in areas that did not see storms.  Skies were generally were generally partly/mostly cloudy – but the trend appeared to reduce values too quickly.

2258 UTC:  LAP CAPE appeared boost again somewhat – but still less than the GFS CAPE.  These sort of “bouncy” CAPE trends will be examined the remainder of the week – to see if this trend continues.