Original NUCAPS vs Experimental NUCAPS in Dodge City, KS Area

A NUCAPS pass over the Dodge City, KS area occurred around 18 UTC on June 22, 2017. Here is a sounding from this region.

The experimental NUCAPS came into AWIPS about 30 minutes after the original data. Here is the sounding from the same location.

The original profile had limited CAPE, around 500 J/KG.  The experimental profile had much more when the surface observations were included. The CAPE value was around 3,300 J/KG. This value was much more comparable to what was seen on the SPC mesoanalysis in the Dodge City region.

One other quick note: The Baseline Derived CAPE at the same time as the NUCAPS pass was also much lower than the CAPE derived from the experimental sounding.

It appears the reason why the original NUCAPS sounding was more stable was because the surface dew point was in the mid 50s where as actual obs and the experimental sounding had dew points in the mid 60s.

Lastly, I noted there was a gap in the experimental data points with this pass, that was not seen in the original NUCAPS.

Experimental 

Original

-Ironman

NUCAPS Experimental soundings showed why storm diffrences in our CWA; also de-bunked earlier tornado worry

Again, we were working the Jackson, MS CWA where our strong storms were in the western sections of our CWA, and much weaker in our eastern counties.

Also as mentioned before, I have observed that the Experimental (modified) NUCAPS is essential.

The difference between the west NUCAPS Experimental between the western sections of our CWA and the eastern sections matched with what was happening on radar.  Storms were much weaker to the east.

West counties NUCAPS Experimental:

East Counties Experimental:

Meanwhile, these soundings de-bunked my worry of tornadoes due to dry air over-riding the tropical moisture I thought I was seeing in 4 Panel WV.

NUCAPS showed that instead of dry air mid level upward, it extended all the way down to 850mb.

Davis Nolan
WKRN Meteorologist

Gridded NUCAPS Issue .... followup...

I haven't noticed it until now, but when the ~18/19 UTC NUCAPS gridded data swath came into AWIPS today...it came in two different chunks.  This first image shows the northern part of the swath that came into AWIPS for the central/eastern US in the early afternoon.  Part of this swath was labeled 18 UTC and part was labeled 19 UTC (Image 1). 

Image 1.  Sample swath (925 MB Mixing Ratio, 19 UTC 22 Jun 2017)

The next swath along/near the West Coast came in at about 20 UTC.

Image 2.  Sample swath (925 MB Mixing Ratio, 20 UTC 22 Jun 2017)

However, once this last swath came in...part of the previous swath was no longer avaialble...the swath that was labeled 18 UTC and covered much of the remaining portions of the central/eastern CONUS.

So, this is a followup to the previous post where the forecaster noted the absence of available gridded data over the southern/central High Plains.  I'm not sure what is happening, as the purge rules are set lengthy enough to retain more than two swaths (in fact, it's set to 24).  It may have something to do with the domain matching.  Anyway, this is worth further investigation.

Kris W

Huge difference in modified NUCAPS (Experimental) from unmodified

We were working the Jackson, MS CWA east of Trop. Depression Cindy.  Our strongest storms were near the Mississippi River.  We checked out soundings there.  Here's one of the unmodified NUCAPS soundings.

It does not look unstable and has a sfc temp of 74F and DP of 63F.  All CAPE values zero.

However the Experimental modified sounding looked like what we expect to see after using a sfc temp of 85F, DP 74F.

Now much more unstable, and SB CAPE 2625, MUCAPE 2630.

The modification is essential.

Davis Nolan
WKRN Meteorologist

Gridded NUCAPS Issue

I was going to look at gridded NUCAPS data over the Dodge City, Kansas area. However, when I went to load the gridded fields it was only showing a pass to the north earlier and then jumping to a new pass off to the west.

-Ironman

GLM Selection

Throughout my analysis at the HWT, I have found no use out of loading any of the sources within GLM and GLM Grid. The GLM combined is the one I have gravitated to and I have chosen 5 minute Flash Point + Event Density (1-minute update).  I did not find any of the longer accumulation times useful during warning operations or during pre-storm environment. The 5 minute Flash Point + Event Density (1-minute update) gave me the most important information as storms were developing and as storms were maturing.

-Ironman

NUCAPS Soundings and a Tale of Two Air Masses...Part II

Ok, so now for some observations of gridded parameters in this same region.  I decided to take a look at mid-level lapse rates and see if the gridded data showed differences across these two areas on the eastern flank of the broad low and the western flank of the upper ridge.

Image 1.  NUCAPS gridded 700-500 MB lapse rates over the SE CONUS, ~18 UTC 22 June 2017.

First, let me note that the gridded data came into AWIPS here at HWT about 30 mins or so before the NUCAPS sounding data.  Notice that lapse rates were generally higher in eastern portions of the area over Georgia than they were over Mississippi.  Values were near 6 C/km over some areas.  All else being equal, this would suggest stronger convection shouuld be expected over Georgia than Mississippi...and indeed, this is what has occurred.

This next image shows mixing ratios over this scene at this same time...

Notice here too, that values of mixing ratio (g/kg) were also generally higher over Georgia than Mississippi, again suggesting better chances for convection over Georgia.

NUCAPS Soundings and a Tale of Two Air Masses

Sometimes, things don't work out the way you think they will.  The world of meteorology?  Well, do I REALLY need to state how different things can turn out?  Probably not.

So, today we initialized to the Jackson MS office with the through that better instability might develop in the swath of drier mid/upper level air entering portions of southern Mississippi. Here is a scene showing GOES-16 0.64 um imagery overlaid with partially transparent 10.34 um imagery and NUCAPS soundings (green, yellow, red dots).

An earlier blog post showed some sample soundings from this environment, and I'll show another here briefly for quick reference.  This NUCAPS sounding was taken from near Jackson, MS at ~1830 UTC, and was fairly representative of soundings in the area.  

 Meanwhile, here is another generally representative sounding from near Atlanta, GA at the same time...

Notice the much higher instability that was present generally in Georgia early this afternoon.  What has happened?  Well, there has been much more convection and impactful convective cells in central and northern Georgia so far today, with multiple tornado warnings.  the same goes for Alabama, but unfortunately, soundings were not really useful over much of Alabama due to the thick, more uniform cloud cover.

Next will be a post about some observations of gridded data in this region...stay tuned!

Kris W

GLM in Tropical Environment

There have not been many deep storms in the Jackson, Mississippi region today. However, for situational awareness I loaded the local radar with GLM flashes. I was able to quickly see where the stronger storms were based on where there were more GLM flashes.

I have found it easier to visualize the GLM data without the events in this type of display and it may be better to have the GLM event grid data on a separate panel.

-Ironman

ProbSevere Assists in Warning Decision Making in BOU

For a thunderstorm in east central Colorado, ProbSevere rapidly increased from 35% to 87% between 2056 to 2108 UTC:

Based on this trend, I went ahead and took a look at all-tilts to determine the thunderstorm was severe and issued a warning.

In this example, ProbSevere was an excellent situational awareness tool.

-Lost Met