EWP Blog

Overall – impressed by Inst AzShear.  Think this could be a real game changer.  Would like to see this fast tracked into AWIPS.

1.  When used in conjunction with other base and DP products – really supplements storm structure evolution – e.g. gust fronts, UDCZ, RFDs.
2. Areas of highest values > 0.01 are easy to see – and give forecasters an easy method to triage what storms need attention.
3. Focused much of my time with Inst AzShear at 0.5 deg.  Did tilt up on a number of occasions to find values near cloud base – and often times very similar to lowest cut.  Would be interesting to see how this performs with mid-level mesos – for things like hail production
4. Only real drawback I see is the “noisy” appearance to data – especially in areas of ground clutter, wind farms, etc.  But I think forecasters would get used to it quickly.
5. Merged products also useful – both individual and tracks – mainly from an SA perspective – trends, tracks of meso, polygonolgy, etc.

Merged products end up showing trend information as new sails cuts come in. In the cases below, notice that the northern storm’s AzShear is weakening over time and the southern storm is increasing.

Above, you can see on the northern storm that the last tile shows weaker leading AzShear. At the same time, note that the leading AzShear signature in the southern storm is increasing.

The northern storm continues to dissipate as the upper tilts catch up to the sails cuts that were weakening earlier. While the southern storm continues to increase in AzShear intensity as the sails cuts would suggest.

At this point the northern storm is gone and the southern storm is quite strong and large.

So not only does AzShear provide a situational awareness of the strength of a couplet, it can also show rotational trends in a storm over time assuming that SAILS is turned on. Plus, the more sails the more information you’ll get in these plots. In the case above it appears SAILS2 was on as you’d get two leading signatures before the data merged back into one storm.

–FLGatorDon

Around 2120Z – interesting structure on a storm SE of KMXX.   Can see in Azshear – inflow from the south immediately ahead of the gust front.  However, behind this feature – can see an area of enhanced Azshear.  Question would be – how much would the PBL be worked over – cooled – and how might that influence tornadic potential?  Yet – another easy depiction on what is going on with storm evolution.

The single radar AzShear product continues to show utility in diagnosing storm structure and trends which leads to higher confidence and earlier warning decisions (in addition to the overall SA nature of the product).

In this case you can clearly see the line segment transition from (see captions):

— FLGatorDon

Not in this event – but would be interesting to note the trends in Inst AzShear for Sig Hail producing storms – e.g. mid-level mesocyclones.

Using a combination of Z, Zdr, inst AzShear from KMXX – can see development of low level mesocyclone quicker than V/SRM alone.  Can see the “white” > 0.01 s1 show up as early as 2000 UTC on the main TOR- while Z/SRM shows mainly a convergent signature.

Looking down the convective line – south of KMXX – examining the Azshear around 2040 UTC.  Area near the county border does trigger above 0.01 – whereas areas further south are slightly weaker (see image).  Would be interesting to know which of these produced tornadoes.  Reminder – plotting the tracks would be great!

First time looking at these products (Single Radar AzShear, Merged AzShear 0-2km, and Merged AzShear 3-6km) and I’m already liking how quick it is to pull my eyes to areas I should be paying close attention to. The most obvious feature is the circulation well to the SW of the radar site (close to 115km out), but what I find to be even more useful is watching mid-level rotation tighten into a low-level circulation closer to the radar site (around 51km away). In the first screen capture below, the Single Radar AzShear product highlighted the RFD bulging out, which is very useful in being able to fully diagnose the developing case. In an operational setting, having the full suite of AzShear products available to supplement traditional radar products could raise confidence when making a warning decision. Both of the merged products increase my confidence in the vertical depth of the circulation, but is also useful when diagnosing shallow circulations, at least in this one case I’ve been looking at. I’ll be interested to see how these products perform in other cases, particularly ones that involve the more shallow QLCS TOR-scenario.

All that said, I will say that there are enough false positives appearing in the AzShear product suite, particularly the Single Radar one, that caution should be taken if using solo, without reference to the traditional radar products. In an even more active scenario, I could potentially see false positives taking the warning forecaster’s attention away from features that need closer attention.

~Gritty

The AzShear products seem to accentuate features such as the RFD which could allow for a better assessment of RFD strength and the potential for new tornado genesis in cycling supercells.

In this specific example the initial tornado weakens or dissipates, and when faced with a decision whether to continue or re-issue a warning, the enhanced RFD signature would have prompted me to continue the warning. Sure enough, several scans later a new circulation developed that would have prompted a new tornado warning on its own.

— FLGatorDon