The first day of the EWP has been pretty intense but very interesting. I focused on a couple of storms in Texas: the first just west of Houston died pretty quickly but the second, north-west of New Orleans, proved more interesting. One of my favourite products so far is ProbSevere but I’ve found that it can be inconsistent with the polygons and probabilities.

At 21:00Z (below) there’s a 55% probability polygon highlighted in a high 0.5 Reflectivity area. To the northeast of this is a 5% polygon shown.By 21:20Z(below) these two polygons have merged with an 82% probability. The 0.5 reflectivity does not back this up, neither do the dangerous thunderstorm alert tracks.

Twenty minutes after at 21:40Z(below) the polygon has split again: 65% to the south and 5% in the north.It is proposed that this may be due to the thresholds used to create the polygons and the proximity of polygons to each other (i.e. polygons cannot appear to overlap). This is also just one case study so further study is required!

Minnie

The three thunderstorm alerts (Thunderstorm, Significant, and Dangerous) are nice to look at, but don’t add much value to the warning process because the polygons change every few minutes.

The East and WEST ENI DTA 10 min Motion Projections are nice references, but aren’t needed for warning purposes.

The East and West ENI DTA Rates are very useful for tracking the lightning trends in thunderstorms.  However, the algorithms “jump around” too much in lines of storms, splitting storms, and merging storms.  This makes it difficult to follow these algorithms at these times.

The East and West ENI DTA Cell Polygons seem too small given the size(s) of the storms.  This leads to smaller East and West ENI DTA Cell Flash Rates than is realistic.  Plus, these algorithms “jump around” too much in lines of storms, splitting storms, and merging storms.  This makes it difficult to follow these algorithms at these times.

The 1 km ENI Total Lightning Grid is very messy and is hard to use for warning purposes.  The 3 km grid seems to be the most useful.  5 km and higher seems to “wash out” the details of the storms.  This is using the 5-minute data, that is more likely to capture the current lightning trends.

The ENI Total Lightning Plots show the lightning as points (where the strikes/flashes/pulses occurred) and as a total count for each in the corner of the screen.  It would be nice to have the capability to turn the “points” off, but leave the count on.

5-minute data seems to be the most useful for the various lightning algorithms.  With 1-minute data it’s easy to miss trends.  With 10 and 15 minute data, they don’t update fast enough for rapidly evolving storms.

Champion

In this example there are way too many DTAs issued. As a forecaster, this many polygons over the same area would likely not provide useful information.

It appears this is a result of the ENTLN cell track algorithm grouping then ungrouping then grouping cells, which leads to new DTAs (which last for 45 min) for what was really the same cell.

Ertel

Currently, lightning is not considered for special marine warnings. However, lightning on the open waters can be deadly to boaters.

Here is an example (from the Texas coastline) of  5 minute cloud-to-ground lightning from the ENI Total Lightning Grid density at 5 km resolution:

With the addition of this data set into AWIPS2, the special marine warning criteria could be modified to use the density of cloud-to-ground lighting.  In the end, this will better meet the National Weather Service’s mission to protect life and property with regard to marine interests.

Polarimetric Researcher

While this is not the best example I have ever seen, the lightning data did a pretty good job of capturing the storm split and keying in on the stronger more dominant right mover.

Ertel

Broadcast meteorologists operate under a number of constraints in developing severe weather situations. As a broadcast met forecasts in real time, products that display easy to understand forecast information are more likely to be used and incorporated into breaking severe weather coverage. Prob Severe as CI Probability are elements that can be easily incorporated to on-air analysis, as they guide the broadcast meteorologist and the conversation he or she has with the viewing public.

UFFSU

One of my favorite things today about the ProbSvr is the ability to make it a “quick look.” This image is after marginally severe weather a little earlier, so environmental wise in general, it isn’t favorable. But what if it was favorable and I was just glancing, waiting for things to pop? Like the example below, I can quick glance at this mess and see that all the ProbSvr is under 10% so I shouldn’t be worried for severe weather without having to look through various levels of radar data.

Lauren13

A special 18Z radiosonde launch was done at Wilmington, Ohio. The special launch allows for direct comparison to a dervived NUCAPS sounding.

Here is the observed radiosonde data:

Here is a NUCAPS sounding from nearby:

Note that the NUCAPS sounding is not representative, especially near the surface. The surface temperature is 77F and the dew point is 55F on the derived sounding. A nearby METAR close by the NUCAPS sounding was 85F/61F.

However, if the boundary layer temperature and dew point profile is modified using nearby METAR observations (85/61), the SBCAPE is more representative to the observed sounding (1761 vs. 1688 J/kg):

Therefore, it is critical to look at the near-surface temperature and dew point profile when using NUCAPS derived soundings.

Polarimetric Researcher

Day 1, two words: Data. Overload. So many new products to look at. However, once you dig into each individually, there is a lot of cool stuff there. Just getting an initial look and feel for all the GOES-R and ENI products available to us today.  Decided to focus mainly on the ENI stuff today. The ENI total lightning counts are really eye-opening. The addition of the in-cloud component reveals a lot more activity that we weren’t previously aware of.

The ENI Cell flash rates and cell polygons are really interesting as well. The two combined would give a better indication of which cells to focus on. Especially in the West, for fire weather/dry lightning situations, this will be very helpful. Due to the pop-up, nearly stationary nature of the storms over terrain, the cell tracking and motion projection features may not be very useful, but can be turned off or simply not used. Need to remember if you are using the cell flash rates and comparing to the ENI total lightning counts, to use the 1-min TL counts since the cell flash rates update every 1 min – compare apples to apples.

Loving the ENI time series plots. It’s helpful to see the trends with a particular cell. Is it strengthening/weakening electrically, and a visual distribution of the different flash types and how they vary over time. These would be especially helpful in the Southwest in the warning process, as a component in whether to warn or not based on the overall upward or downward trends in flash rates. The storms there tend to be short-lived and more isolated in nature, which this product seems geared for. Interesting to note and a caveat with the time series is trying to pick out possible lightning jumps with it. The “jump” on the time series could be tied to an increase in cell polygon size, not flash rate, caused by mergers of two or more individual cell polygons.

First impressions of the ENI Thunderstorm Alerts…jury is still out on the usefulness of these alerts. I tended to use the time series if looking at a specific storm or the Cell Flash Rates if looking more generally at which cell is more active.

Still trying to figure out which products among all the ENI and GOES-R can be overlaid or used together (taking into account what goes into each product); that is, if you can overlay Lightning Jump with cell flash rates and have them be compatible.

~ Regina Phalange

One of the pitfalls of automated warnings (regardless of what they are based on) is they tend to “hold on” to warnings too long, since they cannot be expired early. Here is an example where a cell had been weakening for some time (>20 min), yet the 45 min Dangerous Thunderstorm Alert (DTA) from ENTLN was still valid. I imagine a forecaster in this situation would expire the warning long before the DTA expired.

Ertel