6/15/23 HWT – AMA

What appears to be a nice distinction between sheared / lesser sheared convection across the Octane window. Stronger shear across SW OK producing much different appearance versus SW KS convection.  Nice quick visual distinction for operational use. The idea of a quantifiable divergence contour and/or grid would be welcome also.

Octane data from Goes west meso sector was zoomed in along the inflow region across the SW OK supercell (not our CWA but I had to look). The upper right panel is the directional component and the color scale was changed to highlight approximately 210 – 150 degree range. The increasingly warm colors represent a backing of flow at approximately 4.5 kFt. This level of storm integration (if appropriate) would be advantageous to warning operations.

ProbSevere time series plots do not sample. I would like sampling tied to the cursor as in the parent CAVE window. The element assignment within ProbSevere did cause a problem with the time series information with a storm that strengthened on the southern end of a developing line. The storm initially had a defined area for the region of interest but once ProbSevere assigned it to the larger line the probabilities became much less representative. This impacted ProbTor values which were being monitored ahead of an eventual tornado warning in the Tx Panhandle. I was the warning forecaster today and used ProbSevere extensively for my decisions. It is not the deciding factor but it certainly weighs into the decision process.

PHS model output was interesting and the Updraft Wind element was noted as something not usually seen with model output. It was viewed initially but I didn’t monitor the model output once storms developed and warnings were being issued.

NUCAPS forecasts were unavailable until the very end of the operational window. I did view the 19z overpass soundings and found the familiar  trends of errors at the boundary layer when compared to nearby surface observations. This limitation continues to impact my confidence in the product.

– jbm

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6/15 Feedback for AMA

PHS

The surface based CINH at 20z lined up rather well with the satellite imagery showing the slightly more stable clouds over the eastern CWA.

When sampling an image versus contours, the contour sampling has the entire product name in the readout

PHS captured the initial convection just east of AMA well, even though the convection started an hour earlier than PHS indicated.  Image on right is PHS SB CAPE and contours are PHS SB CINH.  Home is roughly where the storm is located.  Satellite image is around 1930z and PHS forecast is 21z when CINH dropped from 80j/kg to 40 j/kg.

PHS did a reasonable job predicting the general storm coverage by 21z from the 16z run.

Toward the end of the exercise, the storm coverage was well captured by the PHS 16z run.  Should have taken this into account for my public graphics when describing the storm evolution.

NUCAPS

This is a NUCAPS sounding in the TX panhandle near AMA vs. a RAP40 sounding at the same point.  The RAP has the same trend in the dew point profile as NUCAPS, but is lower.

Noticed the NUCAPS sounding didn’t have the lower dew points around 400 mb as shown in the special sounding.  NUCAPS did have a hint of the weak cap near the surface though.

NUCAPS 700-500mb lapse rates from the gridded data was a constant 34.17 C/KM across the map.

NUCAPS forecast for ML CAPE was slightly less than what SPC mesoanalysis had at the same time of 20z.

NUCAPS ML CINH was higher than SPC Mesanalysis for 20z, with some parts of the CWA having almost 90j/kg of CINH south of Liberal, KS.

The 700-500mb lapse rates matched well with SPC meosanalysis for 20z.

OCTANE

OCTANE showed the cumulus developing along the dry line and warm front well.  Can also distinguish which clouds are becoming taller.

OCTANE highlighted where convection was taller, and Lightning Cast started to show probabilities for those same updrafts.

ProbHail

Noticed what could be an above anvil cirrus plume with the storm in question.  Prob Hail only had a 35% chance for severe hail at the time.

Prob Tor

Noticed the Prob Tor jumped up depending on what cells it was encompassing.  Took three screen shots to denote the trend.  Seemed reasonable for it to increase since the end cell was ingesting the dry line at the time the probabilities increased.

-Rainman

Tags: None

SHV Feedback for 6/14 and some feedback from LZK CWA

NUCAPS

Noticed the SHV special sounding was very similar to the NUCAPS sounding done an hour later.  NUCAPS on the left and SHV on the right.  The surface and near surface environment did not match as well.

OCTANE

Neat to see OCTANE highlight the taller clouds that are developing behind the main storm activity over the western CWA.  Lightning Cast started highlighting this area too for a lightning threat.

Very nice divergent signature on the updraft.  However, the 80 kts of divergence seems underdone given the MESH of 1.51”.  I know the speeds are dependent on the environmental winds, but just seemed odd given the hail potential.  Calibration would be helpful to help determine the hail size potential based on updraft divergence.

OCTANE captured two updrafts from a splitting storm over LZK’s CWA.  This helped to see the potential split earlier than when viewable on Radar.

Here is when OCTANE first denoted the split vs. what radar had at the same time.

PHS

Handled the storm location and timing rather well at the start of the exercise for SHV.

Noticed for the LZK CWA PHS was about 2-3 hours early with the storm activity, but had the location correct.  Radar image at 21z, PHS image at 19z

– Rainman

Tags: None

Verification of NUCAPS Soundings

Using the 1930z pass of the NUCAPS soundings during an SPC Moderate Risk was quite exciting.  The environment was primed for significant severe weather and having NUCAPS soundings available at the time of convection out of ahead of storms was beneficial. It provided additional confidence in the severity of the environment. 

As you can see from the satellite, soundings were unusable further north due to the ongoing convection and cloud cover. Thankfully clear skies prevailed from Jackson and southeastward providing some impressive sounding data to compare to SPC Mesoanalysis.  Sounding A was well in the warm sector and sunny skies and thus had the highest CAPE values and lapse rates. Sounding B was just to the southwest of the DSS event and was beginning to see some anvil over that location, but it still provided reasonable data and compared well with SPC mesoanalysis.    

Figure 1: Location of the NUCAP Soundings chosen to view and compare to SPC mesoanalysis. For reference, the range rings outline the 5 and 10-mile radius around a DSS event in Jackson, MS. 

Figure 2: Sounding A with a surface-based CAPE of 6004!

Figure 3: Sounding B with a modest 4079 surface-based CAPE.

Figure 4: SPC mesoanalysis Surface-Based CAPE and CIN at 20z on June 14, 2023.  The star is the DSS event location and the two dots are the estimated location of the soundings analyzed.

Figure 5: SPC Mesoanalysis 0-3km lapse rate (C/km) depicted lapse rates from 7.0-8.0. Once again, both soundings matched up well with SPS data.

– Podium

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6/14/23 HWT – SHV

Operational window encompassed ongoing severe storms at the start of the period which moved eastward out of the CWA by mid afternoon. The resultant outflow boundary / cold front intersection to the west of the CWA become the focus regions for potential for renewed storm development.

NUCAPS 6/14/23 19z sounding south of the outflow boundary of interest compared to nearby surface observation showed a large discrepancy in observed surface conditions (90/72 at nearby ASOS). This raises considerable questions on how these soundings are to be best utilized in operations.

OCTANE was useful in monitoring the attempted updrafts along the outflow boundary. It seems to show updraft growth more clearly than the day cloud phase product. I would like to see these data incorporated into the LightningCast model as this product is also very good at highlighting potential areas for CI.

OCTANE output was also viewed  in a region of a splitting supercell across western AR. Good conversation with developers on further development of the wind retrievals with observational data constructed hodographs being an operational request.

Utilized LightningCast to highlight the region of concern for new storm development. The storms did develop but it was a more gradual evolution. The highlighted region did verify as the region of development.

ProbSevere did a great  job as a safety net for radar warning operations. The element trend window is a helpful addition.  Talked with the developer on potential marking times along the time series where the element changes ID or grows in area to show when ProbSevere has merged or separated elements as this impacts resultant probabilities.

PHS model output from the 16z run was viewed online and compared to the corresponding HRRR. At the time of the exercise conclusion its solution had verified better on composite reflectivity than did the HRRR. A product in AWIPS highlighted regions where the fusion data is different than a zero hour model output would be beneficial for situational awareness and potentially for model output utilization.

– jbm

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Day 2 Review of Products & Operational Applications

I took on the DSS role during today’s operational period. There were no afternoon NUCAPS-Forecast runs and the morning runs provided minimal coverage over the AMA CWA. So, I opted for PHS data today (namely SBCAPE) with MRMS 0.5 km Composite Reflectivity and ProbSevere overlaid (Figure 1) to diagnose the environment. Much of AMA was socked in by stratocumulus at the start of the operational period, but severe storms just to the west posed a concern as they tracked eastward into a gradually destabilizing environment.

Figure 1

The assigned DSS event was a hypothetical RC plane show at Texoma Municipal Airport (denoted by a yellow star in Figure 2). I was instructed to alert the hypothetical POC for the event when either of the following hazards were expected within 20 minutes: winds or gusts of 15 kts at the airport OR lightning within 10 miles. I used LightningCast probability contours along with ENI 5-minute pulse lightning plots (reddish orange tick marks) to monitor the proximity of lightning to the event range ring (Figure 2). I issued a DSS update with “lightning likely” wording after the LightningCast meteogram depicted a steadily increasing likelihood of lightning at the airport within an hour (Figure 3).

Figure 2

Figure 3

A LightningCast observation: the footprint of the 75% probability contour was much larger than the actual area in which lightning strikes occurred (at least according to ENI 5-minute pulse lightning) mainly in the anvil region. That said, GLM Flash Extent Density did indicate low-value pixels in the anvil region, so perhaps I missed some anvil lightning strikes by looking at just ENI 5-minute pulse lightning.

– Vort Max  

Tags: None

DFW and TAE HWT Feedback for 6/13

General question overall, can the units be displayed in fraction form instead of with a (-1 or2)?  Such as m/s instead of m*s-1?

PHS

Can temperature units be in F or even C instead of K?

Is 0-1 KM bulk shear AGL?

Could the bulk shear be in knots instead of m/s?

Can the bulk shear vectors and mean cloud wind vector (or 850-300mb wind) also be plotted?  This can help with determining storm mode. 

The PHS had storm coverage well matched with radar when simulation started.  However it was about 3 rows of counties too far north than what actually was happening.  This led me to believe that all the other data with PHS was also shifted north for what was actually happening.

Could mixed layer CAPE/CINH be added to the stability menu?  I think SPC’s mesoanalysis page defaults mixed layer to 100mb.  We use mixed layer CAPE quite frequently at our office.

Having DCAPE as a viewable product would be very helpful to diagnose a severe wind threat from supercells.

Noticed the PHS surfaced based CAPE/CINH matched quite well with mesoanalysis except for the CAPE/CINH just north of FL.  Both images are from 21z.

LightningCast

Helped maintain awareness about the overall threat for lightning, especially on the outskirts of the storm.

NUCAPS

Noticed the ML CAPE was much further east than what happened.  Of course this was from the morning overpass, not the afternoon one.

Did notice that the ML CAPE was lower than the surface based and MU CAPE.  Was going to look at a NUCAPS sounding to determine why that may have been the case.  However was not able to do that due to no data aside from the morning run. ML CAPE is on the left, MU CAPE is on the right below.

Prob Severe

Is there a way to highlight which storm Prob Severe is showing the trends for?  When I am looping the radar with multiple storms on it (example image below), I quickly lose track of which storm I had the trend graph displayed for.  Really like the ability to look at the trends graphically through AWIPS instead of having to go to the webpage to do so.

Noticed the readout only displayed above the pointer, not below.  The right image is what happened when I tried to sample the Prob Severe data.

Could there be an option to select the different fields we want Prob Severe/Hail/Tor/Wind to show?  There is a lot of data there, good data, but at the same time too much to look at during storm interrogation.

Does ProbTor calculate QLCS tornado probability?  This would help build confidence for issuing these kind of tornado warnings because the environment can change so rapidly from one radar scan to the next.

OCTANE

This helped me really see the updraft divergence of the cells.  This was in deep layer shear environment of 20 kts.  Neat to see the divergence weakening on the middle bottom cell in the upper left pane weaken as the cloud top temperatures warmed for that cell, confirming that the updraft was weakening.

– Rainman

Tags: None

6/13/23 EWP Blog Post – SHV

Active CWA assignment today. Warning issuance followed by the log form entry was somewhat cumbersome and time consuming but I understand the reasoning. 

Great interaction with the subject matter experts and their insight and comments were much appreciated. 

Good discussion on the potential uses of the OCTANE data. My CWA partner mentioned constructing real time hodographs that could be sampled. This is a good idea. The mental exercise to visualize the wind profiles from the height / direction/ and magnitude data is taxing to me and I think would be too time consuming in operations. 

Developer stepped through the awips imaging method to highlight specific layer winds and I found this very helpful. A layered wind four panel procedure would be helpful. Also good discussion on reaching for storm scale signals in the wind fields and whether wind speed data bins could be higher resolution than radar at high elevations and distance from radar. An intense left moving storm during this exercise window across NW LA into far SE OK showed strong anvil level divergence that persisted for an extended period.

Screen capture of the ice machine and intense three body scatter spike that persisted for close to an hour at least. Probsevere was very good especially once the tracking element was assigned to just the primary updraft. I issued several warnings during the exercise window and utilized probsevere on each one. The time trend window is great and I hope it gets to the operational version soon.

The PHS idea of better utilizing sampled profiles seems good to me. I would prefer it not be solely validated by WRF model output. I like the idea of showing where the fusion data senses departure from model initial conditions similar to shown on  this website:   cas.hamptonu.edu/~adinorscia/InteractiveMap/FusionMap.html

NUCAPS data today  was from the previous run with the 10-12 hour forecast near the exercise valid time. I compared the 11 hour NUCAPS forecast to the zero hour RAP analysis for MUCIN across the exercise domain. There was a large discrepancy between the two. Due to convection that had spread across this region earlier in the day I discounted the NUCAPS data. In this instance the NUCAPS forecast would have been viewed as suspect and likely would not have been used.

– jbm

Tags: None

Monday 6/12 Initial Post

Lots of products to look at and test. It’s a daunting task to know if you are looking at everything enough and in the correct way.

Appreciate the interaction with the developers and the openness to questions.

Below is a quick screen capture of the 6/12 19z 0hr NUCAPS MUCAPE (image) with the 19z 0 hour RAP40 MUCAPE contours. The developer mentioned that NUCAPS was good at depicting gradients but in this instance the gradient in the image is more smoothed than the RAP data while also being much less value than the RAP data. This raises questions on which analysis is best? Why? Is that same reasoning valid across the entire domain?

I would like to see observational data used as check point against model initialization. Where could larger errors in the model initialization raise questions about future forecasts. Asking the operational forecaster to quality control initial conditions has been a common ‘task’ assigned to maintaining situational awareness. I would like to see computers help with that task.

Quick update. Captured this image in the OCTANE data of an ongoing storm (likely supercell) in far NE New Mexico. The narrow corridor of light wind speeds (circled in white) matches my conceptual model of where the forward flank outflow boundary would be located. If this is the correct interpretation I think it would be very useful application in warning operations.

-jbm

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Day 1 Review of Products & Operational Applications

OCTANE-Direction

  • Distinguish different air masses when they are characterized by different advection regimes
    • Stable cloud streets in magenta (Figure 1)
    • Agitated Cu and deep, moist convection in yellow/green (Figure 1)
  • Locate boundaries
    • Identify areas of convergence based on the depicted flow directions
  • Suggestion: it would be great to be able to sample the cardinal direction (i.e. NW, SE) in AWIPS in addition to the direction already given in degrees

Figure 1

NUCAPS & PHS

  • Attempts at convective initiation failed over Guadalupe County and De Baca County… but why? Isobaric analysis revealed supportive dynamics for ascent south of the already-occurring convection.
    • 700 mb relative humidity and 850 mb humidity data (Figure 2) reveal a sharp moisture gradient across northeastern New Mexico
      • SPC 850 mb Td mesoanalysis verifies this (Figure 3)
    • Dry air was already moving across both counties from the west and was progged to continue over the next few hours, thus hindering convective initiation

Figure 2

Figure 3

– Vort Max

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