Figure A (NUCAPS Modified sounding points 1915Z
Figure B (NUCAPS Modified sounding point near KOZA, in the moist sector)
Figure C (NUCAPS Modified sounding point near KFST, behind the dry-line)
This is a comparison of NUCAPS modified sounding for locations west/east of the dry line.
Figure C NUCAPS Modified Temp/Dew….82/27 KFST Metar Temp/Dew….86/35
Figure B NUCAPS Modified Temp/Dew…75/62 KOZA Meter Temp/Dew…79/66
-Jake Johnson
Compared several NUCAPS soundings across the pass to determine usefulness of the modified versus unmodified data. In each example, the modified is on the left and unmodified is on the right. 
The example above was quite dramatic. This was an example over my home CWA. The modified sounding on the left captures the true mixing likely taking place over the point to the north of GJT airport, the right has a vastly different temp/td profile. This would have dramatic impacts for fire weather and smoke dispersal forecasting in remote areas, which is a critical task provided by our office. 
Moving south, the above example is well west of the dry line in New Mexico. Unmodified does capture a well mixed BL, but the modified shows this feature more pronounced. Clear skies were present throughout the entire day leading up to this point. 
This sounding above was from just slightly west of the dryline
This sounding was a bit farther east, in the vicinity of increasing moisture east of the dry line. 
Finally this sounding was from well east of the dry line in the vicinity of intense thunderstorm development. Note the odd structure in the lower levels in the unmodified sounding on the left, these strange temp readings are eliminated in the modified sounding which greatly changes the CAPE values and other parameters.
-Dusty Davis
Perfect conditions to utilize NUCAPS soundings today in the FWD CWA. FWD did a special release at 18z and I was able to compare that to a 19z NUCAPS sounding immediately west of FWD, ahead of the ongoing convection north and west of the CWA. They are remarkably similar from the boundary layer upward with very similar MUCAPE/SBCAPE values around 4600-4800 J/kg.
This highlights how important these NUCAPS soundings can be in the absence of any 18-20z special balloon releases. I’m very impressed with how well it lines up with the observed 18z launch and have more confidence in using these in pre-convective environments.
–Stanley Cupp
18z FWD sounding:
19z modified-NUCAPS sounding ~25 miles west of FWD
NUCAPS location (green dot above mouse cursor) vs. FWD location (yellow home cursor) and 1 minute vis imagery
Wichita Falls tornadic environmental data using NUCAPS Modified Sounding. NUCAPS sounding surface data had temp/dewpoint of 73/68, looking at surface obs temp/dewpoint range near the NUCAPS point sounding was 74-76/69-70. Therefore modified numbers were in the ball park.
NUCAPS 700-500mb Lapse Rate Gridded Product did a decent job with mid lapse rates across southwest Oklahoma showing a favorable environment for severe thunderstorms.
While it is very easy to plot forecast soundings from whatever model you may choose, NUCAPS provides yet another resource as an alternative to NWP. A strong thunderstorm formed in Mexico around 22z today, almost due west of Del Rio, TX. SPC mesoanalysis showed approximately 2000-3000 J/kg of MUCAPE in the vicinity prior to convection initiation (CI). A quick look at a 20z modified-NUCAPS sounding corroborated the SPC analysis, with ~2400 J/kg of MUCAPE at 20z. The NUCAPS data allow for a detailed analysis of the resulting profile and can be a useful alternative to model soundings, especially the modified products as they attempt to more accurately represent the boundary layer based upon RTMA data. The 20z NUCAPS had ample CAPE in the hail growth region along with 700-500 mb lapse rates in excess of 7C/km. Effective bulk shear in excess of 40 knots coupled with favorable thermodynamic environment likely resulted in this storm producing large hail as KMAF radar sampled greater than 60 dBZ at greater than 32K feet. ProbSevere hail output peaked at 97% (MRMS Mesh = 1.87″) roughly 40 minutes after CI.
–Stanley Cupp
20z NUCAPS sounding near storm in Mexico
20z SPC Mesoanalysis MUCAPE and 0-6km shear (dot indicates point of CI)
The modified NUCAPS sounding over Brewster Co TX was more representative of the actual conditions at 20Z versus the regular NUCAPS. A dryline was positioned very near the point of interest and convective initiation eventually occurred near the boundary in ~1000 ML CAPE air around 22Z. 
Modified NUCAPS sounding w/ surface Td near 47F. MLCAPE ~ 1000 J/kg.
Regular NUCAPS sounding w/ surface Td near 54F. ML CAPE ~2000 J/kg.
RTMA Td analysis. Point H is where the NUCAPS sounding was taken from.
GOES-16 RGB at 2150Z showing CI occurring near the dryline.
Compared the NUCAPS sounding today (4/25) over WFO TAE. See the point evaluated below (labeled point A below):
This is the “unmodified sounding.” Overall the thermodynamic profile looked realistic. Looking in the PBL – noticed it was about 2C too warm and about 2C to dry.
This is the “modified sounding.” As expected, no change to the mid level thermo profile. The PBL did have the “correction” applied – not the “cliff” in the temp profile. Overall, I was expecting a more sophisticated PBL nudging scheme. In reality – it just appeared to force the T/TD from the nearest METAR, with maybe some minor smoothing. This is something a forecaster could do in about 30 sec – so didnt gain much.
BETTER OPTION: employ a more sophisticated nudging scheme to the nearest RAP/HRRR. If you going to modify the sounding – might as well nudge it to a model analysis – which have a long history of being used in severe wx research.
Forcing and storms remain well to the west of our CWA, but the atmosphere is becoming primed for strong to severe storms later this afternoon. LAPS All Sky retrievals show that ML instability has been steadily building, reaching roughly 500 J/kg along the Gulf coast.
An 8 hour loop shows how the instability has built and gives more confidence that instability will continue to build ahead of the storms to our west. 
We did feel that LAPS CAPE seemed a bit underdone given the intensity of the downstream of the convection, so we took a look at the latest NUCAPS retrievals. We examined the point in the extreme SE of our CWA.
The boundary layer on the unadjusted sounding required some adjustment to match the nearest obs, but overall, seemed to capture the general profile well. I was initially skeptical about the warm nose just above 700mb, but a similar feature was evident on the 12z sounding from TAE. This feature may have an impact on storm intensity and potential hazards, and it would be particularly helpful to see how this feature changes over time.
Sandor Clegane
Storms are approaching the HGX CWA. GOES-16 imagery shows amply cumulus development across much of the CWA. With temps in the upper 70s and dew points in the upper 60, I expect there to be ample instability in this environment.
All Sky LAPS retrievals indicate ML CAPE just shy of 1000 J/kg, but with this environment, I would expect instability to be higher. 
The modified NUCAPS shows a profile more in line with what I would expect to see. In this profile, the surface dew points were close to what surface obs show, but the surface temp did need to be adjusted up a bit. This sounding, coupled with analyzed deep layer shear, leads me to think severe weather is a possibility in this area.
Sandor Clegane
One way to increase NUCAPS sounding data usage is to improve the ability to display “mouse over” soundings using the PoP-Up SkewT. See the example below – I was able to mouse over the various points and display the NUCAPS soundings.
However, the PoP Up SkewT display is small, crude, and cannot be enlarged. If a version of NSharp could be integrated into the PoP Up SkewT (e.g. larger SkewT with thermodynamic variables below) – then forecasters might use it more often. The current PoP Up SkewT is probably 10 yrs old – and needs improvement.
