Week 2 complete!

Week 2 (of 4) of the Hazardous Weather Testbed 2016 GOES-R/JPSS Spring Experiment is now complete! Week 2 was a relatively active week allowing participants to test the products in various regions of the US. After starting in Milwaukee and Chicago on Monday, participants worked primarily in Norman and Wichita on Tuesday, where widespread severe weather took place. Forecasters moved to the Kansas City and St Louis CWA's on Wednesday, before finish the week on the East Coast in the Raleigh and Blacksburg CWA's.

Bill Line, SPC/HWT Satellite Liaison

From left; Kristin Calhoun (OU/CIMMS and NSSL), Monte Oaks (WFO New Braunfels, TX), Ben Herzog (WFO Milwaukee / Sullivan, WI), Bryan Jackson (WFO Sterling, VA), Bryan Schuerman of WBOY-TV (West Virginia), Tiffany Meyer (OU/CIMMS and NSSL), Bill Line (OU/CIMMS and NOAA/SPC).

Bryan Schuerman, our broadcaster participant for the week, shot live stories on Wednesday for stations in West Virginia.

Week 2 (25-29 April 2016) Summary and Feedback

On Thursday, the final day of operations for 2016 week 2, participants operated primarily in the Raleigh and Blacksburg CWA's.

GOES-R LAP
- GFS underdid CAPE values all week.
- These fields are useful for situational awareness, especially for getting a quick look at the environment when you are just sitting down.
- Would it be possible to use RAP for these retrievals over CONUS?
- I liked being able to see what moisture was doing at the different atmospheric layers. It worked well to overlay the satellite-derived winds on the layer PW.
- The other day, it was really helpful to see the drier air moving in at the upper levels, with increasing moisture at the lower levels. It is nice to have this in a 4-panel display.

 GOES-R CI
- In most cases this week, I could diagnose from the cloud evolution where CI was imminent. But severe CI, when it works, is very useful
- Severe CI would be more useful in warning operations than regular CI, but it was pretty bad in most situations.
- Both CI's did really well in Lubbock this week. CI picked up on a broad area where convection developed, and severe CI focused in on where the best storms ended up developing.
- CI was good when we were in Missouri. It didn't always target the exact cells, but it usually did give us the general area where CI was imminant.
- If it highlights the general area of future CI, that is good enough for me. I don't need to know exact cloud.
- As a broadcaster, I would love to have this in my office. Often I don't have as much time to analyze the weather before my broadcast. This is something I could have up when I begin my day. I see it being very beneficial to the broadcast community.
- This would be more useful for the shift coordinator, and for DSS, over the warning forecaster.
-  I liked setting all values below 30% to be transparent. It decluttered the image a lot. I like being able to see the satellite imagery.
- The product display did not bother me.
- I'd like to see products like this be based off of the 1-min data. Something that could alert us to imminent development, since there is so much data.

ProbSevere
- In general, I really liked it. It sometimes gave me a false sense of security. When it trended down, this gave me confidence to focus my attention on other storms
- It is a limitation that it struggles with linear modes.
- Every office has the capability to change the color table. Various offices might want a different break point. it is a preference.
- I like the outline, I think that is the way to display these things.
- For contours, when using with radar, the contour is displaced. I recommend having it loaded on a seperate display with MRMS
- I would have wargen display with radar and a seperate display with MRMS and ProbSevere.
- I think it covers wind threats very well, but wind was difficult.
- We would definitely like to have probs by threat, in addition to total severe
- If this helped us with wind, it would be even more valuable than it is now
- It provides a nice comprehensive overview
- I foresee having a 4-panel with probsevere, probwind, probhail, and probtor
- For the hail threat, maybe look at including -20C reflectivity - this could help with area of storm and magnitude
- For tor, somehow including information about the presence of an RFD could help. Also, LL SRH, 0-1 km shear, storm motion, streamwise vorticity

SRSOR
- This week sold me on the value of 1-min imagery. At first I was like, it's really pretty. The storm over Kirksville was in a data sparse region and had explosive growth evident in the 1-min data. This visualization pushed me over the edge to warn. There was a similar case yesterday where convection developed rapidly so I warned early. This is something I will use in my warning decisions in addition to looking at radar.
- Broadcaster: I would definitely show this on TV, either by itself or under radar. Viewers like to see interesting stuff. I would also use this for diagnosis behind the scenes.
- The lack of data along the Mexico border hurts, but the 1-min data will help to fill this gap.
- I see utility for the parallax-corrected imagery. It appears to properly make the correction.

10-min Satellite-derived winds
- I see utility for marine areas, special marine warnings, seeing flow at low levels, warning decisions in marine areas.
- I would like to have seen more upper-level winds
- I used the LL winds to verify the low shear environment and to project the movement of storms. They were helpful in showing which direction the storms would move.

Lightning Jump
- I tried playing with the transparency, but it didn't really work out for me.
- I would have benefited from a cheat sheet to know what exactly to look for.
- It was nice seeing the jumps yesterday, and that the storm strength did fluctuate with jumps. I wouldn't use it alone, but would use it in tandem with other tools.
- Training with this product will be important
- I imagine people will want a threshold to go off of
- An issue is when multiple storms merge and cause a false trigger.
- With ProbSevere and LJ, I liked having them in a SA display, with MRMS composite or -20C reflectivity underlay. I found this helpful to get a big picture view, highlighting areas of interest. Certainly something I would use in operations.
- I think warning coordinator would be best to monitor these products, distributing the workload.

PGLM
- I think having lightning contoured as opposed to the image would be less obtrusive.

NUCAPS
- For the Plan view: theta-e, CAPE, LRs, dew points, DCAPE.
- I will compare NUCAPS with RAOBs when available to help improve my understanding of NUCAPS.
- I would like to analyze this in the evening, for diagnosing transition of events from severe to heavy rain/MCS.
- Although I would like the surface modifications to be modified, if this does occur, I still want to be able to view the original profile.

Other:
- I would look at an improved OT (and enhanced-V) detection product from GOES-R. Summary products are good. There is so much data coming in, this would help.
- I liked having the product sheet there in front of me so I remembered what to look at and how to view it.
- We did not feel like there were too many products to evaluate.
- Broadcaster: The training beforehand was extremely helpful. Not ever having AWIPS experience, it did help a lot to get exposure beforehand. This was an eye-opening experience to what folks at the NWS do every day, I am blown away. I think every broadcaster should get to do something like this. I can't wait until these products become available. I am going to sit down with Baron and ask how they are going to do this.
- It was nice to have experience forecasting in different regions of the country.
- For the most busy days, it was hard to focus on evaluating the products. On these days, should have all forecasters in the same CWA.
- Having more developers here would be helpful.
- All forecasters indicated they enjoyed their experience.

High Density Satellite Winds Confirm Radar Cell Motions

Monitoring severe cell motions over the Raleigh WFO was a bit confusing at first with easterly to northeasterly motions in the southern storm clusters, and southeasterly to easterly motions tracking from the storm clusters to the northwest. High density satellite winds at 2240z were able to confirm these differences in cell motions.

Forecaster: Manbearpig

Severe CI A Disappointment Today

There were zero severe CI clusters over 30% today until 2230z, despite numerous severe storms across the CWA. The one cluster that did finally exceed 30% died out within an hour of the identification.

CI seemed to do reasonably well. At the beginning of the day, we had some cumulus bubbling and light returns on radar. CI was identifying these storm with high CI probabilities, and within a few hours, there was widespread storms across the area.

-Toki Wartooth

LUB Severe CI

Severe CI looks pretty good from LUB today. Below is routine visible, Prob Severe, and Severe CI.

 

BAJ

Storms pulsing up and down in Raleigh

Storms pulsed downward briefly after moving east of Raleigh and the eastern flank of strong to severe cells all weakened, leading to a couple of warning cancellations without severe reports to back them up.  However, the ProbSVR parameters on these cells fell no lower than 31 percent before each rose again, leading to warning reissuances. Storms again strengthened into 3 discrete cells, after it appeared they were about to merge into a multicell cluster.

Forecaster: Manbearpig

Rapid Storm Intensification Evident On Super Rapid Scan

The super-rapid scan visible imagery clearly showed a rapid intensification of a few storms across the CWA. This intensification corresponded with intensification in radar parameters. Within 15 minutes of this feature on the satellite imagery, ProbSevere had jumped to 97% and there were several 2-3 sigma lightning jumps. A significant TBSS was also evident in the half hour after this satellite feature.

-Toki Wartooth

PGLM LUB

Trends in PGLM with SVRs plotted for reference.  the northern cell has lightning quite far east of the actual cell.

 

BAJ

ProbSevere and Lightning Jump Help In Decision To Let Warning Expire

A warning on a severe storm in the western RAH CWA was nearing its expiration. Radar signatures were marginal leading up to the expiration time and I was not confident on my decision to re-issue. However, ProbSevere, total lightning activity, and the lightning jump algorithm were all declining leading up to the decision time. This nudged me to not re-issue the warning, and shortly after the warning expired, the storm all but died.

-Toki Wartooth

Paralax correction good/bad

Raw visible satellite data over VA showing cu towers with lightning flashes.

 

Note the parallax corrected puts the tower right where the lightning flashes are!

 Here's an example from NC. Again with OT and lightning. Shadow is displaced well north of the lightning cluster.

Parallax correction win!  Note the shadow right around the flash cluster!

That was the good.  Now for the bad.  Chunky display, particularly with anvil next to clear skies.

 

Here's the raw vis:

 

BAJ

How Much For That Doggy In D2D?

The pink poodle shaped lightning jump illustrates the weaknesses in having storm interrogations not able to separate cells in a multi-cluster environment if using the wrong Lightning Jump scale.

Forecaster: Manbearpig

ProbSevere Reduced Situational Awareness

A pair of severe storms were approaching our CWA from the north. Just before these storms entered the CWA, the ProbSevere began to fall, dropping to 60% and 48% respectively. At this same time, traditional radar signatures remained elevated and a warning issuance was appropriate.
Due to the rapid increase of convective activity across the CWA at this time, I was relying on ProbSevere to highlight storms of interest while I was interrogating or warning on other storms. Because of the drop in ProbSevere, on the storms mentioned in the previous paragraph, I did not further interrogate those storms until they were right on the border. As soon as I saw the traditional radar signatures, a severe warning was issued.
In this situation, ProbSevere actually reduced my situational awareness and the lead time on the warning on these storms. That said, I was working sort of a "worst case" scenario, because several storms were reaching severe criteria at the same time I was was issuing warnings on my own (partner was writing a blog post). I all likelihood, multiple people would have been working this event and I would have had a more manageable workload, so I wouldn't have missed this storm. However, I feel like these "worst case" scenarios are exactly when ProbSevere can help, by identifying which storms require further interrogation.

 -Toki Wartooth

2 Severe Storms Issued in the Raleigh Area

The loop here shows rapid trending of ProbSVR values, and each storm showing sigma jumps of at least 3.0.  In subsequent scans, the northern storm approaching Raliegh had ProbSVR values jump from 54 to 67 to 94 percent, and a solid hail core aloft to justify severe potential. The second storm made a similar jump in ProbSVR as 48 to 56 to 60 to 82. The rapid jumps in ProbSVR coinciding with the Lightning jump anomallies occurring with each cell showind the ProbSVR parameters in the middle of these jumps (60 to 70 pecent) gives this forecaster a chance to build upon speed of analysis and increase lead time. In addition, the northern storm was moving near the cone of silence and could have had lost data that may have delayed a warning in real time.

Forecaster: Manbearpig

GOES-R CI targets convective initiation in Texas Panhandle

GOES-R CI (top left) probabilities increased to over 50% in the Lubbock CWA at 1900 UTC. At 1930 UTC, probs over 75 were sampled, and at 1945 UTC, increased to over 80. Convective initiation was apparent in visible imagery beginning at 2000 UTC.

Severe CI probabilities over 70 were sampled at 1945 UTC.

Storms associated with this development produced 1 inch hail at 2124 UTC.

CI Review for 28 April

CI worked well in RNK today, April 28. The highest CI (orange and red) developed into the severe weather.

 

However, nothing registered in Severe CI.  This is interesting since ProbSevere increased to high ranges first from cloud growth rates. Why did Severe CI not register with this?

 

BAJ

Lightning Jump and ProbSevere Give Some Leadtime On Likely Severe Weather In RAH

A storm in the northwestern portion of the RAH CWA began to display borderline severe radar signatures around 2015z. At time time, there had been no lightning jumps and ProbSevere had yest to exceed 50% on this storm. Given the ample instability available to this storm, I decided to pull the trigger on the warning despite the lack of support from the lightning jump algorithm (LJA) and ProbSevere.
At 2023z, there was a 2-sigma lightning jump followed by a 5-sigma jump at 2025z. By 2033z, ProbSevere finally jumped above 50% to 65%, eventually making it to 99% by 2041z.
As of this writing, no severe reports had been reported on this storm. However, at 2037z, a significant three body scatter spike (TBSS) was apparent, so I am confident that this storm produced severe hail shortly after this time. Assuming this storm did not produce severe hail before the TBSS appeared, the LJA provided a roughly 15 min lead time on the severe hail, and ProbSevere provided about 5 minutes lead time (using 60% as a warning trigger). Forecaster lead time on this event was around 20 minutes.

-Toki Wartooth

Experimentation with ProbSVR Color Schemes

When it comes to viewing algorithm and derived products, this forecaster prefers more dramatic jump points to new colors over a slowly changing color scale.  In most cases a ProbSVR jump value going of 20 percent would be enough to get the forecaster's attention for further inspection, but the association of colors to specific range of number would be easier to monitor, especially for a shift-coordinator that would prefer a more simplistic view of things.  The color scale shown in the lower left attempts to reflect radar reflectivity, but could be modified to be more compatible with color overlays used for the Lightning Jump overlays.

Forecaster: Manbearpig

Vis Satellite shows boundary for possible TOR

Cold Air Damming is retreating across the VA piedmont. A look at the 1445Z scan shows the back edge of the low stratus over the central part of this image. At that time there was strong heating south and stable clouds north. Around 18Z, cu developed along this line. the cell that then moved over this area and produced a mesocyclone and possible tornado. There would have been a boundary.

BAJ

NUCAPS Analysis May Slightly Overestimate CAPE in Clear Skies

As the Visible loop above indicates mostly sunny skies an 18Z NUCAPS sounding arrived for diagnosis over South Central NC. Surface obs near Richmond County Airport near Rockingham, NC suggested a temperature and dewpoint of 77 and 62 degrees respectively, which lined up well with the surface report of 80 and 64 degrees respectively.  As the Rockingham report increased to 85/65 by 1930z, the NUCAPS plot was modified to include the surface obs, leading to a CAPE estimate over 3600 J/kg as shown in the modified sounding above. Given that the unmodified sounding from 18z illustrated only 1708 J/kg, the continued mixing of mostly sunny skies and southwest winds should mean the boundary layer moisture profile should be drier. It would be nice to have a model-based tool that could automatically factor in low level mixing influences to save time in an operational environment.  Still the midday CAPE assessment with temperatures climbing should suggest realistic CAPE values in Southern North Carolina to be in the neighborhood of 2500 J/kg. Interestingly enough, the 20z SPC Mesoanalysis surface based CAPE revealed a CAPE contour of 2500 J/kg within 80 miles of Rockingham (to the west), and values just over 2000 J/kg on top of this same area.

Forecaster: Manbearpig

Lightning Jump and Drop

Severe Thunderstorm along NC/VA border was potent with high cloud flash rates in the 30s and 40s per minute then dropped into the teens.  This produced a negative lightning jump (or lightning drop/ease) of -8 sigma. Lightning then increased and there were 1 and 2 sigma jumps.

 

BAJ

NUCAPS Shows Increasing Instability Across RAH CWA

The mid-day NUCAPS (top below) profile shows an unstable atmosphere across the RAH CWA with MUCAPE around 2500 j/kg. This is especially helpful as the latest LAPS data to come in is over 3 hours old.

The upper levels in the NUCAPS sounding appears to show a much drier profile than the observed sounding from GSO this morning (bottom above). In the upper levels, this seems reasonable, especially after looking at the latest upper level LAP layer PW (below). A substantial dry layer is clearly moving into the region, so this upper level drying is believable. I'm not sold on the much drier lower levels of the NUCAPS sounding because; a) NUCAPS does poorly in the lower levels, b) the LAP layer PW shows moistening in the lower levels, and c) were it not for a few very moist obs around 550mb in the observed sounding, the lower portions of the two soundings would look very similar. Perhaps the moist layer around 550mb in the observed sounding contained bad data?

-Toki Wartooth

Satellite influence on ProbSevere

As storms fired in the Blacksburg CWA, the particular influence of the satellite fields on a developing storm was noted. The storm of interrogation devleoped along the VA/NC border, and was first tracked by ProbSevere at 1750 UTC, with a probability of 3%, no MESH, lightning or satellite growth.

At 1844 UTC, MESH was up to .22 in, lightning to 27 fl/min, and weak satellite growth had been sensed, all bringing the probability up to 20%.

Six minutes later at 1850 UTC, the probability had jumped to 51% as MESH increased to .37 in and lightning to 42 fl/min.

By the next scan (1852 UTC), new values for the satellite fields were ingested into ProbSevere, with strong growth and moderate glaciation rates being measured. This had the effect of bumping up the probabilities to 76%, which really attracted the attention of the forecasters.

 A warning was issued on the storm at 1908 UTC as probabilities continued to rise to 88%.

This case shows the significant impact of the satellite fields have on the probabilties.

Altrenate Color Table For CI Probability

The default CI probability color map creates a very cluttered looking image, hides many interesting features in the satellite imagery with inconsequential, low probability clusters, and the gray-blue color (second lowest) blends in with the gray scale color map used in satellite imagery.

I created an alternate color table to mitigate the issues outlined above. In the new color table (below) All clusters with a probability less than 30 are transparent, and the gray-blue color has been replaced with a darker blue that does not blend in the the gray scale satellite imagery.

-Toki Wartooth

Fast 1-minute Data Loop Proves to be a Good Aviation Forecast Tool

The HWT monitoring the Raleigh forecast area, while waiting on storms to develop noticed a good signal for clearing and improving conditions over Southern Virginia.  Elevated convection moving over the area brought downdraft air which led to a drastic clearing over a small portion of the thick low cloud and fog bank.  This could be a useful tool in Aviation forecasting.

Forecaster: Manbearpig

Good Performance from the CI Program

As Convective Initiation predictors reached values over 50 percent, cells began to form in this low shear, moderate cape environment.

Forecaster: Manbearpig

Raleigh Pre-Storm Analysis

In terms of moisture and instability, the Raleigh CWA appears to be primed for convection this afternoon. Surface dewpoints are well into the 60s, while LAP data shows PWs around 1.3. CAPE in the 1000-2000 j/kg range on the latest LAP analysis, which is over two hours old. Of note are significant differences in the LAP CAPE field which are dependant on the retrieval method. In cloudy areas where the GFS was used, CAPE is largely less than 1000 j/kg, but where the clear sky retrievals can be used, CAPE values are easily double what the GFS is showing, pushing 2000 j/kg in some areas. These higher CAPE values are consistent with the mesoanalysis, so this leads me to believe that the GFS instability is significantly underdone. Largely clear skies over the area should allow the atmosphere to continue to destabilize thought the afternoon.

Lift in this region is not terribly strong, but there does appear to be a subtle shortwave pushing into the region and a weak surface low north of the region. This apparently is enough, as convective initiation is already underway near the surface low.

Shear is modest thanks to fairly weak flow through the atmosphere. There does appear to be some very weak turning in the satellite derived atmospheric motion vectors, especially from the surface to about 925mb. This turning is confirmed on the 12z sounding out of GSO.

Given the convective initiation ongoing to the west and the continued destabilization across the area, I'm expecting at least scattered severe activity across the area.

-Toki Wartooth

LAP PW analysis early

The GFS influence fared much better on LAP PWATs in the same region where LAP CAPE estimates fared poorly.  The selected location sampled on AWIPS is almost a perfect match.

Forecaster: Manbearpig

HWT Acknowledges CAPE Weakness Over the Operational Area of WFO Raleigh

A large area of CAPE went well underforecast over much of the eastern half of the Raleigh CWA by the LAP Thermodynamic  Product due to the dependence on the GFS based capes.  The SPC Mesoanalysis at 16Z shows 1000 to 1500 J/kg Capes, with only a small area of CAPE values over 1000 J/kg denoted by the LAP (clear sky sampling).

Note: these values were 2 hours old compared to updated sources (e.g. RAP).

Forecaster: Manbearpig

Early Afternoon Analysis - Blacksburg (RNK) - Virginia/West Virginia - Thursday Afternoon

As the latest feature has continued to shift Eastward, we are focusing on West Virginia and Virginia this afternoon where the Storm Prediction Center has focused a SLGT Risk for Blacksburg as well as part of Charleston (RLX)'s County Warning Areas.

Already this afternoon the Convective Initiation (CI) Model is forecasting high values for part of our County Warning Area, as we are breaking out into a little but of sunshine with a CU field moving into the area. Severe Convective Initiation (Severe CI) Values are all on the low side, will be keeping an eye on them this afternoon to see if they increase. Wind barbs are indicating that most of the winds coming into the region are westerly, which would go along with expected storm motion this afternoon.

Current 0.5Z Reflectivity from Blacksburg (RNK) is showing that thunderstorms are ongoing over parts of the County Warning Area, with more thunderstorm development expected into the afternoon.

Looking at different indicators this afternoon with the LAP Analysis, CAPE is extremely low, less than 1000 J/kg, would want to increase this, and Lifted Index (LI's) are 0 to -1. I do think these are a little underdone as when compared to objective analysis. Precipitatble Water Values are AOA 1.00", which I would believe for thunderstorm development, and lead to the potential of heavy rainfall.

Widening the view this afternoon, expansive CU field is noted on the satellite imagery from Virginia back through West Virginia, and into Ohio, Kentucky and Tennessee.

Will keep an eye on values to see if they increase as we work into the afternoon.

Moisture values we're increasing in the lower levels of the atmosphere, but it was noted that some drier air was working into the upper levels of the atmosphere (Upper Right Screen) and that would help with the instability factor as we go through the afternoon for thunderstorm development.

Forecaster: Schuerman