Probabilistic Hazard Information (PHI): Highlighting the Benefits via New Verification Techniques for FACETs

The extended manuscript entitled, “Probabilistic Hazard Information (PHI): Highlighting the Benefits via New Verification Techniques for FACETs” by Stumpf, Karstens, and Rothfusz, is available on the program of the American Meteorological Society 3rd Conference on Weather Warnings and Communications, Raleigh, NC.

The information in the PDF manuscript summarizes a lot of the content in this blog.  It also includes new work to apply the verification scheme to severe weather warning-scale Probabilistic Hazard Information (PHI).  These thoughts will be expanded upon in the blog in the near future.

Greg Stumpf, CIMMS and NWS/MDL

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MRMS Data and Information Sources

MRMS Data Sources

MRMS Web Browser:

MRMS Google Maps:

Past Hail and Rotation Tracks:

NWS Enhanced Data Display (EDD):

RealEarth (U. Wisconsin):

MRMS Information Sources

Warning Decision Training Division training courses:

NOAA Virtual Laboratory MRMS Community:

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NUCAPS Sounding between RAOBs

North Central Kansas was one of the prime areas for severe thunderstorm development this afternoon, but with the the nearest RAOB soundings being Topeka and Dodge City, it was difficult to assess the evolution of the thermodynamic environment. Neither of those sites launched an 18Z balloon today, so the area was lacking any observed thermodynamic profiles. The NUCAPS retrieval at 1828Z occurred when the storms were beginning to develop, and a retrieval point was available on the Kansas-Nebraska border (circled below).

Surface METAR data was overlaid to determine a representative temperature and dewpoint for modifying the lowest levels of the sounding. The sounding was modified for a surface temperature of 69 and a dewpoint of 61 based on nearby METAR observations.  A broken cumulus field was evident on the visible GOES image at 1830Z. There was some concern for the data quality in the cloudy areas, but the quality appeared to look reasonable.  The retrieval indicated a CAPE of 1705 J/KG with no CINH… which supported the breaking of the cap and additional thunderstorm development.

-Daniel Nietfeld


NUCAPS-vis NUCAPS-vis-mtr NUCAPS-skewT

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Forecaster Thoughts – James McCormick (2013 Week 3)

1.  Introduction

I was granted permission to attend the Hazardous Weather Testbed Warning Forecast Experiment at the National Weather Center in Norman, Oklahoma for the week of May 20 – 24, 2013.  In particular, my focus was to be on high resolution analysis and model forecasting products as well as their applications for forecasting and warning for deep moist convection.  Increasing my knowledge of storm analysis and forecasting helps with the detailed verification of various FSMT forecast products and brings cutting edge research back to our squadron.  In return, I provide feedback and discussion about the success of products to the National Severe Storms Laboratory (NSSL).

The week, as one can imagine given the dates and location, did not go as planned.  Strong tornadoes, including a strong EF-4 tornado near Shawnee, had affected central Oklahoma on the day before the testbed; this storm had created a need for storm surveyors from the testbed.  On Monday, shortly after the first shift began on Monday, a devastating EF-5 tornado developed just to the northwest of Norman, affecting the city of Moore particularly hard.  The event took a significant physical toll on many of the people working for the testbed, as I believe every NSSL employee with the testbed took part in surveys during the week, and the event took an emotional toll on everybody in the project as well.  I know people worked very, very long, hard days this week, and that work is greatly appreciated and admired.

We did the best we could with the resources available to us for the week.

2.  Pre-Course Material

I read all material provided describing experimental products to be tested prior to attending the testbed.  I appreciate all of the material being prepared, and I think, given the reality that I don’t have an AWIPS machine to work with exercises on, I got caught up to speed very quickly even in the chaotic conditions of the week.

It had also helped that I had attended the testbed last year, and I had a general idea of what to expect from the project layout and what type of products to expect.

3.  Schedule

3.1 Monday, May 20

Monday’s shift began at 1 PM.  I arrived at the Weather Center at noon to have lunch with colleagues participating in the other half of the experiment.

At 1 PM, we met as a group in the development lab.  We briefly did introductions and we quickly ran through goals and product sets hoped to be evaluated during the week.  We knew convection was going to fire rather early in the day in Oklahoma, perhaps by 2 PM.  Mr. Gabe Garfield gave a quick discussion about the expected weather conditions.  A stout atmospheric cap was quickly eroding with rapid daytime heating, and the atmospheric conditions were very favorable for severe weather with thunderstorms likely to begin developing at any moment.

The plans for the day quickly became very ragged.  Storms fired quickly just west of Interstate 35 in central Oklahoma before we were even really settled into the lab.  I worked Mr. Jeremy Wesely for the first portion of the afternoon.  We looked quickly at the OUN WRF products, which suggested immediate initiation.  The reflectivity developed a very large cell in central Oklahoma that on the OUN-WRF appeared to be a left moving storm, which clued me to the threat of hail.

Three storms very quickly fired, so we only spent a few moments in forecast mode.  Among the analysis products we were able to see early on included a strong reflectivity core at the -20 C level.  Though we weren’t issuing warnings for this early portion of the testbed, we certainly would have started with the storms forming west of the OKC metro area.  A storm southwest of Norman quickly grew dominant – along the suggestion of the OUN WRF – and began moving to the metro area.  We noticed the updates had stopped, as power glitches began to affect data flow at this point.

The northern supercell quickly developed a large wall cloud.  A tornado warning including Norman was issued by the OUN weather office shortly afterwards.   Seeing the storm moving to our northwest, we decided to continue to work instead of seeking shelter By 2:40 PM was producing a tornado to the northwest of Norman.  Screens in the room were tuned to live coverage of this tornado and everybody – both on our side of the room and the SPC experiment side of the room – quickly grew gravely concerned with the unfolding tragedy to the north.  Several people began calling loved ones and taking care of personal business.  Warnings for this particular storm – and now the storms to the south – were clearly and obviously tornado warnings.  After a few moments of shell shock (I can’t think of another word), we continued to work.  I was particularly impressed with the calm, resolved demeanor in the room even in the face of the enormous tragedy and personal stress.  Power glitches in the area due to the thunderstorm continued to affect the data flow, and it was only around 3:30 PM that data began coming into our systems.  The data, an hour behind or so, allowed for a delayed real time analysis of the Moore tornadic supercell.  By this time, the devastation to our north was quite apparent.

The first product that jumped off of the screen at us was the tornado debris signature.  As one might expect, a violent tornado hitting a major metropolitan area creates a lot of debris, and the radar algorithm quickly picked that signature up, carrying it through the city.  We certainly did not expect to see this signature in other storms, but it was interesting to see the levels reached by the Moore tornado.

We also took a look at low- and mid-level rotation tracks.  Mid level rotation increased dramatically near the city of Bridge Creek.  If one wasn’t paying attention to the supercell and tornadic potential of this storm before, they were certainly needing to do so after the rotation passed Bridge Creek.

We also began paying more attention to the southern storms around this storm, which also were producing severe weather.  A “cloud top cooling (hereafter CTC)” rate of -28 C was noted in Wichita County, TX, at 1902 Z.  The radar data would later show a 2.5 to 3 inch hail icon with that storm, and the storm would be responsible for golf ball sized hail by 1920Z.  In an environment where storms were developing rapidly and producing severe weather unusually quickly, the CTC product allowed for 18 minutes of lead for the first hail report.  Baseball sized hail would later be reported with this storm.  We also noted a tornadic debris signature in Jefferson County, OK, as the storm moved to the east.  While I don’t know if any tornado was ever officially reported with this storm, it sure seemed likely that this storm was producing a tornado, and the tornado debris product would have helped confirm confidence in a tornado warning.

Around 5 PM, I was able to take over my own forecast station with the departure of one of the local testbed participants, working next to Jeremy.  We were switched to the Fort Worth coverage area to follow the supercell traveling along the Red River, moving out of the Norman counties.  The other group continued to work severe storms north and east of Oklahoma City.

Analysis of the storm showed a hard right turn with the supercell looking at the mid level rotation tracks.  The volatile environment suggested all modes of severe weather from supercell thunderstorms, and this rotation track product indeed confirmed that this storm was still a rigorous supercell.

I took a break around 6 PM just to breathe.  The tornado must have hit national news around this time because my phone went off several times.  I didn’t spend much time with the phone; we were requested to leave cell phones for emergency calls in the area because the entire infrastructure had in central Oklahoma had been compromised with several towers damaged or destroyed, but I called my mom at home, as I felt it was very important that she knew that both myself and my brother in law were safe.  This time was also around the time when the initial CNN fatality count was reported, which hit the entire office pretty hard.  Again, I was really impressed with the how the office kept working even in the presence of such difficult news.  We took no breaks for dinner; Greg graciously ordered pizza to the office.

I began to look again at the OUN WRF to see if any other activity was to be expected.  The OUN WRF lit up down to I-20 with storms as the night progressed.  While the coverage was a bit much, another strong thunderstorm producing several tornadoes and strong hail was located very close to I-20.  The geographical extent of convection in the OUN WRF did well for this particular event.  (This storm was located just to the south of our radar product area, so we did not focus on this storm initially.)  I did issue one severe thunderstorm warning for a small updraft west of the DFW metro area, though that storm came down quickly with no reports.  I issued the warning based on cloud ice values noted as similar to other rigorous updrafts.  I would cancel the warning after a few scans when it became clear the updraft had collapsed.  I would issue a couple of warnings on the southern supercell, even without experimental data, just to make sure I knew how to use the software properly and to finish the day off on a somewhat normal note.

After a long and difficult day, we dismissed after completing a short survey a little after 8:30 PM.

3.2   Tuesday, May 21

Tuesday’s shift began after lunch, at 2 PM, with a strongly worded moderate risk in northeastern Texas.  I arrived at noon to have lunch with colleagues and to catch the briefing from the other testbed, the Experimental Forecast Program group.  Their overview focused on a wind threat in northeastern Texas.  Mr. Andrew Zimmerman and I were paired as forecasters for the Shreveport office; we decided to sectorize our forecasts based on Interstate 20.  I would forecast and warn for south of the Interstate; he would cover all products for north of the interstate.  Because we were the eastern CWA, we were able to take a look at some forecast products.  The other group was the Fort Worth CWA; they had convection fire very quickly and immediately went into analysis and warning mode.

The convective pattern went in three main rounds per the OUN-WRF:

1)       East-west oriented convective line pushing north along the Louisiana/Arkansas border.  Elevated in nature due to relation with lifting boundary, we expect these storms to primarily be a hail threat.  Updraft helicity product indicates some potential for these storms to be supercellular, giving the threat for destructive hail.

2)      Pre-frontal squall line pushes in from eastern Texas from west to east.  Based on the OUN-WRF, a strong signal for rotation within updrafts in the line is noted.  Strong winds and potential tornadoes are noted as the threats with this squall line, and we expect this line to be our biggest severe weather maker.   We also note a more isolated storm well to the southwest of our CWA, down by San Antonio with good supercell signatures in the helicity product.  That storm would have the best potential in the model to produce all forms of severe weather, but it is well out of our CWA.  We also noted some negative helicities within this line, suggesting that this line wouldn’t be a pure squall line, but that the line would have some embedded supercells as well, with an environment favoring splitting.  This would introduce a hail threat in this squall line while diminishing the tornado and straight line wind threats a little bit.

3)      Cold frontal squall line pushes in from eastern Texas from west to east a couple of hours after the first squall line.  This line is expected to primarily be a straight line wind producing storm.

I then began to review the thunderstorms pushing north in the southern portion of Arkansas.  We consider a tornado warning for a supercell in Miller County based on base reflectivity apperance, but we decided against this warning.  While the OUN-WRF had suggested supercells, we immediately note a strong outflow boundary pushing south of these storms.  We consulted with some of the MRMS products to help with this decision.  Some low level shear was noted on the shear track history, but nothing real was noted on the mid level track.  Any tornado threat we might have considered early is likely gone.  We’ll keep watching, but the environment just doesn’t seem favorable for surface based storms.  No severe weather was reported with the storm we chose to leave unwarned.  One storm developed a large hail signature, but this storm was north and east of our county warning area.

We quickly coordinated with the Experimental Forecast Program; their final graphics had a very strong risk for winds in northeastern Texas, as they indicated in their briefing.

With the elevated storms moving harmlessly away from our CWA, we turned our attention to the weather in the Fort Worth CWA to see what would be coming our way.  We noted a couple of very strong “Cloud Top Cooling” product values – one of -27 C and one of -41 C, each for 15 minute periods.  Each of these storms was well back into the Fort Worth CWA, so we would not be handling warning responsibilities for either, but we were clued into the fact that some pretty explosive storms might be developing out to our west.

The first squall line first approached our CWA in far southeastern Oklahoma.  The storm was on the far edge of our CWA on the far edge of radar coverage.  Very small values were noted on the “MESH” algorithm, and vertically integrated ice values were smaller than storms in Texas yesterday evening.  We also noted a little bit of potential for large hail in the “HSDA” produt – the dual-pol radar product designed to detect large hail – but we chose not to warn for these storms.  Either by good analysis or by the luck of these storms being in extremely rural, river valley regions, we received no reports from these storms.

We also noted that outflow from the initial Arkansas storms was pushing definitively to the south.  In contrast to what mesoscale models were suggesting, this feature would cause any storm to its north to become elevated, decreasing the threat for all modes of weather.

Storms later approached in my sector from the west.  I issued a handful of warnings and I actually found that the MESH product was doing a good job of finding wind damage reports in addition to the hail reports.  We also got damage reports from an advancing outflow boundary, but we didn’t consider those reports to be of particular interest to the testbed detail.  As the threat shifted to wind with the approaching squall line from the west, we began to get nasty wind signatures aloft.  I began issuing broader severe thunderstorm warnings for wind for the entire line.  The atmosphere, somewhat stabilized from the outflow, still seemed capable of producing damaging winds.  In that regard, the storm structure indicated by the OUN-WRF succeeded; in another, no threat for embedded supercells existed because of the outflow, a weakness that even a short range model could not account for.

At 7:10 PM, with the severe threat turning solely into a marginal wind threat, we decided to switch regions of the country, up to New York, where storms were a bit more isolated and had the potential to produce hail.  Andrew and I were placed in the Binghamton CWA.  We again sectorized our coverage area; this time along the north/south boundary of I-81.  I took responsibility for storms east of the highway.  By 7:30 PM, I was confident enough in hail signatures northeast of the radar to issue my first warning.  I would warn on the radar “Hail Size Discriminator” in addition to the MRMS products.  Giant hail was suggested at 7:55 PM.  I continued the warnings for the next 90 minutes as the storm evolved and moved east ward.  I didn’t receive a single report from any of the storms I warned for, though I do not regret the warnings.  I immediately checked the Binghamton office warning history after the shift ended; they too had been warning for these storms.  I really, really believe that these storms produced severe hail and that the HSDA algorithm did a nice job of analyzing the storm detail.  We just didn’t get the reports in the nighttime in rural New York.  That’s my story and I’m sticking with it.  I was admittedly a little bit exasperated by the end of this event, not having a ground truth to say one way or the other what had happened for the sake of the testbed and whether or not the products had indicated severe weather or not.   Such is life.

Again we did not take a dinner break; Gabe graciously delivered from a local restaurant, which was much appreciated.

We took a short break around 9 PM as a CNN reporter and camera came to our office following an interview in the Weather Forecast Office.  Mr. Travis Smith was interviewed about our testbed, discussing some of the products we were testing on Monday during the Moore tornado.

As of 9:15 PM, I let all of my severe thunderstorm warnings go, happily giving the storm off to the Albany CWA desk.  Shortly afterwards, we finished for the evening, completing surveys and wrapping up for the night.

3.3   Wednesday, May 22

On Wednesday, I participated on the Mesoscale Analysis desk with Mr. Andrew Zimmerman.  Our job was to analyze the performance of high resolution products, monitoring the local storm environments and providing updates to the warning desks about the environments that their CWAs would be experiencing.  We issued mesoscale discussions at roughly 3 PM, 5 PM, and 7 PM.

We were promptly greeted with the unpleasant news that the GOES-13 satellite had suffered a major failure, and that we would be without all of our satellite based products for the rest of the week unless we could completely rely on the western domain, which would require a forecast day in Montana or the intermountain west.  (We would have no such day.)  Our forecast interests again took us back to New York.

We were particularly interested in evaluating the LAPS products on this day to see how our mesoscale environment was being represented.  Temperatures were quickly warming in central New York in the upper 70s and lower 80s.  Storms formed along the theta-E maximum just south of Lake Ontario, where a lake breeze was also pushing slightly southward.  An initial squall line was pushing out of the area through the eastern portion of the Albany CWA and into New England; we were more interested in convection potential behind the initial line.  The SPC mesoanalysis confirmed a deep stable layer in the convective outflow.

Two storms would develop to the north, one early in the forecast period, one a couple of hours later.  Both would be severe, both would track just south of Lake Ontario, and both would be warned for by the respective CWA desks.  We kept noting the theta-E maximum to the north, well represented by the LAPS imagery.  At the Mesoscale Discussion desk, we focused more on the potential for convection elsewhere, as the environment remained fairly similar along the path of the northern supercells.  We also knew that the respective warning desks would likely be more focused on the ongoing storms, benefitting more from having another set of eyes on where new storms might form.

We grew more and more concerned as the day went on about the dry air filtering into the rest of the Buffalo and Binghamton CWAs from the southwest.  We kept seeing dry air signals represented in the environment, and kept noting that convection was going to struggle anywhere in western New York outside of that boundary in the northern portions of the respective CWAs.  We also noted that simulated satellite imagery cleared out convection to the east and left a dryer, stable environment over much of western New York.  Andrew very astutely noted that the dryer air meant that south of the northern supercells, the main severe threat was transitioning quickly to a downburst wind threat instead of a hail threat.

That trend really defined the day.  I really thought the LAPS products did a great job of holding fast to the idea that dry air – characterized by 30 degree dew point depressions – was firmly in place, and that any convection trying to go up would struggle mightily.  We kept seeing storms try to fire on radar but never sustain themselves.  (It was noted that we dearly missed the chance to evaluate satellite-based convective initiation products from UAH.  We would have loved any help we could have gotten with the developing cumulus clouds.)  Even in the presence of other high resolution models suggesting convective development in western New York, the LAPS products really made it clear that nothing substantial was to be expected.  I also thought the LAPS products did a terrific job of representing moisture boundaries well.  If I had a recommendation, I would love to see a dew point depression trend chart – how the DPD changes from hour to hour is quite interesting to me and would show areas where dry air is mixing out the boundary moisture.

We kept waiting for the upper level forcing to arrive to give elevated convection a chance to develop, but that forcing arrived after our shift ended.  The most significant activity in terms of development was terrain-induced convection in Pennsylvania moving towards the southern counties of the Binghamton area.  We did note a little area of higher moisture in the far southern counties, but these storms barely approached the CWA as the shift was ending.  I do believe a couple of warnings were issued, though I don’t know if we stayed long enough for verification.  We ended around 8 PM after completing surveys.

3.4   Thursday, May 23

On Thursday, I again participated on the Mesoscale Anlaysis desk, this time with Ms. Ashlie Sears.  Our shift began after lunch.  I again had a chance to catch the briefing from the Experimental Forecast Program, which talked about the Texas panhandle and a very uncertain convective evolution in the presence of very light wind shear aloft.  A mesoscale complex was expected to develop, but which direction the convection would ultimately move, we did not yet know.  Different models, including the AFWA ensemble members, were showing different solutions.

Forecast interests for our group were back in the plains, this time in the Texas panhandle.  Again, GOES-13 remained out of operations, meaning satellite data was limited, but we were far enough west that we were able to use some of the products in a limited capacity.  For the fourth time this week, convection had already fired by the time we got to the lab and set up, which made model analysis and pre-convective environment identification somewhat difficult.  We did quickly run through OUN WRF data to see what we could gain from the model runs.  We noted scattered storms along the Colorado/New Mexico front range to be forecast, though nothing terribly robust.  To the east, convection was noted by 19Z, which was accurate, with stronger helicity signals near I-40 suggesting a supercell threat with all modes of severe weather possible.  The OUN WRF projected this complex to move eastward into Oklahoma maintaining a severe threat almost to the OKC metro area.

Our first storm of interest quickly came out of the Lubbock area, where a cloud top cooling value of  -17 C/15 minutes was noted.  With the GOES-13 still out, we were using satellite products that were completely reliant on the western imagery, which made values a bit different than usual given that we were on the edge of the domain where we could use the imagery at all.  Our LAPS mesoscale analysis noted a rich theta-E maximum through the I-27 corridor along the boundary, and convective initiation occurred very close to this maximum (within a county).  LAPS updraft helicity was more bullish in western Texas than what we saw on the OUN-WRF – I thought maybe this product’s forecast was too aggressive.  Basically this product was expecting, it appeared, mesocyclones along the entire dry line during initial convective development.  Both the OUN-WRF and the LAPS products gave us the idea that storms that went up initially would threaten with all forms of severe weather, and the Lubbock area storm quickly gave each of the threats, including extremely damaging winds in excess of 100 MPH.

The first storm in the AMA area developed a massive circular outflow that extended all directions, including back to the northwest along the dry line.  We noted that it took the LAPS an hour or so to catch on to the colder, more stable air infiltrating the AMA area.  What was seemingly a prime area for convective development has now become much more stable due to mesoscale influence.  After a couple of weak convective attempts on the outflow boundary, a storm showed a -18 C/15 minutes cloud top cooling value in Potter County.  This storm did become severe for a couple of scans.  Chad Gravelle had asked us to watch the CTC product near radars – this storm was very near the AMA radar, and the algorithm performed quite well.  This storm, with large scale winds working directly in opposition to the motion of the low level forcing, had a motion of nearly 0, contrary to the projection of a progressive complex that several models had advertised.  This storm lasted for a couple of warnings before dissipating.  Away from the forcing of the outflow boundary, the storm could not exist in the ouflow cooled air.

We again wrote a mesoscale discussion around 5:30 PM, which became very complicated, because storms in each of the three CWAs of interest were behaving differently.  Basically, we broke the MD down into the three sections to reflect the local influences at each region.  After this MD, outflow continued to ruin the AMA environment, the lone supercell continued to do its thing in the San Angelo area as it slowly weakened, and terrain convection in the Midland area struggled to organize away from the source of its origin in the hills.  Ms. Sears and I kept an eye on the various environments, but little changed over the last couple of hours.  Again, outflow really wrecked the “expected” severe weather environment, especially north of the highway 82 corridor.  I love the OUN-WRF, but a forecaster really has to get rid of any pre-conceived notions of what the day “should” look like in the face of rapidly changing conditions that models are still hopelessly outmatched against.

We ended the day a bit early to save images and collect our thoughts for the webinar on Friday.  We were each assigned an individual topic to discuss for 2-3 minutes during the webinar.  I was assigned to talk about using MRMS products in the Shreveport area on Tuesday evening.  After collecting images, we completed the last surveys for the week, and then we dismissed for the evening.

3.5   Friday, May 24

Friday began at 9 AM with a detailed discussion and review of the week’s events.  We each gave considerations about some of our favorite products and how we used those products in simulated forecasting and analysis environments.  Thoughts and considerations of products were discussed with points of contact for each product.  We then went through a practice run of our webinar before the ‘real deal’ went live at noon.  After our presentation, the group took questions from the live listening audience from around the country.  We dismissed shortly after 1 PM.  I spent the afternoon and evening with colleagues, enjoying the quiet weather at a grill out.

4.  Final Comments/Random Thoughts

Given what happened on Monday, simply getting through the week – much less as productively and seamlessly as the testbed went – seemed like a minor miracle.

I thought ordering dinner in the office was a great way to keep working while getting a bite to eat.

5.  Thanks and Acknowledgements

I would like to thank UCAR and NG for allowing me permission to attend this testbed.

I would like to my deepest thanks to all of the workers at the testbed, including Mr. Greg Stumpf, Mr. Gabe Garfield, Mr. Darrell Kingfield, Mr. Jim Ladue, and Ms. Kristin Calhoun, for continuing the great work of the testbed in the midst of such extraordinary tragedy and chaos.  I know that each of these individuals worked extremely hard in the face of storm surveys to keep the testbed running as smoothly as possible.  There are not words for how well each of these individuals did their jobs this week.  I also want to thank all of the testbed members for professional, considerate behavior during the week.  We all hurt from the tragedy in Moore, but we all were able to continue to work all week long.

James McCormick
UCAR Associate Scientist I
Aviation Hazards Team
16th Weather Squadron, Air Force Weather Agency.
Offutt AFB, Nebraska



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Forecaster Thoughts – Ashlie Sears (2013 Week 3)

The 2013 EWP was held for three weeks in May, with 6 participants per week attending from Eastern, Central and Southern Regions. I had the opportunity to attend in the third and final week. Unfortunately, many issues arose during my week which affected the initial timeline/plan laid out for us to follow. The first of two EF5 tornadoes to hit the OKC area ravaged Moore, OK on the Monday. We also were limited on the tools to test Wed-Thurs with the loss of GOES-14.

The test bed was arranged to where there were two forecasters on a meso desk for the duration of the shift each day. They would provide hourly updates on the environment or determine if the area of concern needed to be shifted. There were then two teams of two who were given responsibility of different CWAs and providing warnings for their respective area.

Timeline for the Week

Sunday – Arrived in Oklahoma.

Monday – Introduction to the test bed, overview of the week, discussion of expectations for the week. The Moore tornado occurred at the beginning of this shift and with many people helping to run the test bed being affected by the storm (i.e. their kids in the path) along with technical issues we were dealing with, there was a lot of confusion to the first day, limiting to what we were able to accomplish. We were unable to use any of the test bed products in real time to analyze the tornado that occurred, though we were able to go back later in the evening and analyze the day.

Tuesday – Warning Operations over Fort Worth and Shreveport CWA early on, followed by Albany CWA in the evening.

Wednesday – Warning Operations over Buffalo and Binghamton CWA.

Thursday – Warning Operations over Amarillo, Lubbock, San Angelo and Midland CWA.

Friday – Week wrap up, with a 30 minute national call discussing things learned during the week.

Lessons Learned

With a shortened testing period this year, each week was asked to analyze all the tools to be tested, though focusing on two primary areas. We presented nationally for the “Tales of the Testbed” webinar on the last day covering these two specific topics, discussing best practices and how we found we could utilize in the tools in our own office operations. The focus for my week covered the Multi-Radar Multi-Sensor (MRMS) and the Hail Size Discrimination Algorithm (HSDA). In addition to the tools/experiments, we were asked to provide feedback on the usage of AWIPS 2 and the whole warning generation.

Mesoscale Analysis Tools

There were two things we were asked to utilize in determining the mesoscale situation. Unfortunately, these tools are restricted to their domain of Oklahoma and Northern Texas and that general vicinity. However, talking with the representative for the LAPS forecast, I was informed that they eventually would like to spread to the rest of the country, depending on the success they find in the southern Central Plains.

OUN-WRF and LAPS 1km and 3 km forecasts cannot be utilized up here in the Northeast. However, the LAPS 2.5 km analysis is available to be used at this time. I found during our warning situations that using the Theta-E values from LAPS was a best practice in figuring out where the convection was going to initiate and continue to form. The ability of AWIPS2 to allow multiple layers to be easily overlaid and the easy access with zooming in and out without constantly having to reload  the frame allowed the forecaster to analyze the situation at a much quicker pace as well as obtain a much clearer picture. I found it beneficial overlaying the analyzed 2.5 km CAPE values with the latest reflectivity images then comparing to how the LAPS 1 and 3 km forecasted these parameters over the next few hours. Overall, the LAPs had the better grasp of the type of storm development and the location though the timing was off by up to 1-2 hours. It also is run at 15 minute intervals, allowing a more up to date version of what is occurring. The OUN-WRF had a better handle of the timing of the development, but was off on the location.

I would really like to see the forecasted LAPS in our region of the country as it proved quite useful in determining where the most likely area of convection would be. In addition, in discussing other potential uses, the LAPS rep informed me they have found it useful in forecasting the rain/snow line, producing fairly accurate forecasts, during winter events which would also be very useful in the Northeast.

Convective Initiation Tools

Unfortunately I wasn’t able to test these tools as well as the other experiments. On Tuesday, we arrived after initiation had begun, so we were unable to do any pre-event analysis. On Wed, we lost these tools when the GOES-14 satellite was down and our warning domain was outside GOES-13’s track. Luckily Thursday we were able to analyze the CI tools for the storms that occurred over northern Texas, allowing some familiarity but not as much as I had hoped. One side note I would like to make, I have been analyzing these tools available via the web to see how each handle CI here in the Northeast. For the couple of convective events we have had in the past few weeks, I have found that the CI tool has given about 1 hour lead time for areas further inland, but is still having issues with capturing the potential for convective development along the coast. One issue these tools do have is cirrus contamination and this was noted in several areas we were analyzing during the test bed.

Warning Tools

The experiments that were the focus of the week were the MRMS and the HSDA. The incorporation of the MRMS and HSDA will be very beneficial in warning operations. These products combine data from multiple sources, doing a QC over the data and then producing a final result that depicts a clearer image of what is actually occurring, compared to the usage of just one radar/source.

One of the more interesting aspects of the MRMS was the ability to use something other than reflectivity and velocity to create your warning polygon. For the issuance of tornado warnings, using either the 30 minute or 60 minute tornado track allowed the forecaster to see the trend of rotation, the strength of it as well as the path it was taking. While we may have to have four panels or more up to see rotation throughout the vertical column, using the rotation track products allowed us to see general rotation strength in the lower levels as well as in the mid-levels, just by looking at two screens. The color coding of the product also gave us an indication of the severity of the situation and caught our attention easier than diagnosing an all-tilts product.  The same concept was used with the MESH tracks which allowed the forecaster the ability to see the track of the hail core producing severe hail as well as enabling the forecaster to just look at one product (or multiple depending on the time scale) versus having to have an all-tilts up, which takes space and time. One other aspect I found very beneficial with the MRMS was the ability to set up a four panel screen with reflectivity at the 0oC, -10oC and -20oC compared to the lowest level reflectivity scan. This allowed for a quicker diagnosis to determine if severe hail was being produced within the hail growth zones. All the while too, because these products are incorporating many different sources, it also allows the forecaster to not to have to trouble themselves on bringing up all the surrounding office radars in addition to their local radar. This could help in saving memory space within AWIPS, allowing for the program to run quicker as well as general diagnosing time for the forecaster.

The HSDA products also provided quite valuable in determining the hail potential of a storm. Once it is determine if an area of the storm is possibly producing hail, the use of the HSDA then informs you of the potential size of it. We had great success in verifying the large versus giant hail in the storms of the southern Central Plains. Unfortunately, we were able to use the product for the storms here in the Northeast due to a misunderstanding of the use of the product. But I would be curious to see how well the storms verify compared to the HSDA in storms up here as well.


Overall, I had great success utilizing AWIPS2 into the warning operations during the test bed. The one main issue that occurred when I was producing warnings was that if a warning polygon happened to overlap into a different CWA when I was first constructing it, even after hitting the Warned/Hatched Area button, it still issued the full polygon that overlapped into the other CWA. This was presented to the IT rep during the test bed to hopefully be corrected. Otherwise, the functionality of AWIPS2 really did speed up the analysis as well as warning process.

Ashlie Sears
General Forecaster
NWS Upton NY (New York City)
2013 Week 3 Evaluator

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EWP2013 Week 3 Summary: 20 – 24 May 2013


The National Oceanic and Atmospheric Administration (NOAA) Hazardous Weather Testbed (HWT) in Norman, Oklahoma, is a joint project of the National Weather Service (NWS) and the National Severe Storms Laboratory (NSSL).  The HWT provides a conceptual framework and a physical space to foster collaboration between research and operations to test and evaluate emerging technologies and science for NWS operations.  The Experimental Warning Program (EWP) at the HWT is hosting the 2013 Spring Program (EWP2013).  This is the sixth year for EWP activities in the testbed.  EWP2013 takes place across three weeks (Monday – Friday), from 6 May through 24 May.

EWP2013 is designed to test and evaluate new applications, techniques, and products to support Weather Forecast Office (WFO) severe convective weather warning operations.  There will be three primary projects geared toward WFO applications this spring, 1) evaluation of multiple CONUS GOES-R convective applications, including pseudo-geostationary lightning mapper products when operations are expected within the Lightning Mapping Array domains (OK/west-TX, AL, DC, FL), 2) evaluation of model performance and forecast utility of the OUN WRF when operations are expected in the Southern Plains, and 3) evaluation of model performance and forecast utility of the 1-km and 3-km WRF initialized with LAPS.


Our participants included Eric Martello (WFO Fort Worth, TX), Ashlie Sears (WFO New York, NY), Jeremy Wesely (WFO Hastings, NE), Kris White (WFO Huntsville, AL), and Andrew Zimmerman (WFO Wakefield, VA).  The GOES-R program office, the NOAA Global Systems Divisions (GSD), and NWS WFO Huntsville’s Applications Integration Meteorologist (AIM) Program have generously provided travel stipends for our participants from NWS forecast offices nationwide.

Other visitors included Jason Otkin (Univ. Wisconsin), Steve Albers (NOAA/GSD), Chad Gravelle (NWS Training Center GOES-R Liaison), James McCormick (Air Force Weather Agency, Omaha, NE), Lori Schultz (University Alabama – Huntsville), and Jim Gurka (NOAA/NESDIS/GOES-R).

Greg Stumpf was the weekly coordinator.  Clark Payne (WDTB) was the “Tales from the Testbed” Webinar facilitator. Our support team also included Darrel Kingfield, Gabe Garfield, Travis Smith, Chris Karstens, Kristin Calhoun, Kiel Ortega, Karen Cooper, Aaron Anderson, and David Andra.


20 May:  Norman (OUN), Fort Worth (FWD):  Post-Moore Tornado supercell storms in southern OK and northern TX.  NOTE: The Moore tornado occurred too early in the shift and network outages cut off our live data feed.  However, the historical track products (e.g., Rotation Tracks, Tornado Debris Signature Tracks) were viewed after the event.

21 May:  Shreveport (SHV), Fort Worth (FWD), Albany (ALY), Binghamton (BGM):  Severe storms with hail in TX and LA, followed by marginally severe storms in upstate NY.

22 May:  Buffalo (BUF), Binghamton (BGM):  Supercells produced large hail in upstate NY.

23 May:  Amarillo (AMA), Lubbock (LUB, Midland (MAF):  Supercells with large hail and a few weak tornadoes in the TX Panhandle.



  • A logical progression of the HCA product, but useful than the current version.
  • Works well with MESH products, although seems to underestimate the hail size versus MESH.


  • Likes instantaneous MESH / height about -20C / -10C (lightning)
  • Tracks difficult to use for slow-moving cells; best for fast-moving storms.
  • A lot of the MRMS stuff makes derived stuff obsolete.
  • Track orientations give a lot of utility.
  • MRMS was considered by some forecasters to be the most useful new products for warning ops.
  • One forecaster thought it was outstanding and will be heavily used in the field.
  • Rotation Track product for the Moore tornado could be used to help determine operational warning thresholds.
  • The 2-minute temporal resolution is advantageous, potentially buying lead time.  This could potentially keep forecasters from switching back-and-forth from radar to radar and saving time from looking at all-tilts so much
  • Helps with the overall SA and the efficiency of the warning process.  With multiple deep cells in the area, products like the MESH, and -20 C Reflectivity can be very helpful for determining the cells on which to focus.
  • Was useful during a temporary radar outage, as data from adjacent radars was used to fill in the storm without having to analyze separate radar feeds.
  • Offered a quicker diagnostic overview of the storm than having to look at multiple height scans as we commonly do with the Donovan method.
  • Storms near or over a radar within a cone-of-silence had data which was effectively filled in with other radars.
  • Verified that MRMS products matched very closely the values one would get using manual data interpretation using all-tilts and sampling.


  • 0-1 km SRH fields received a lot of praise.
  • Recommend adding an updraft helicity track.

Variational LAPS:

  • The 15-minute temporal resolution of the product can be very useful for diagnosing locations of continued convection especially in rapidly developing convective situations.
  • Overdid the storms and created too much outflow.

GOES-R Simulated Satellite:

  • Helps to better visualize how the model is creating and evolving convection.
  • Recommend a product or procedure that will facilitate a comparison to real data.

GOES-R RGB Airmass:

  • Training on RGB airmass needed to be made more adequate.
  • Best when used with other environmental products to see how conducive the airmass was for convective development and maintenance.

GOES-R Nearcast:

  • Theta-E fields pretty good for diagnosing where convection was most likely.

GOES-R UAH SatCast/UW Cloud-Top Cooling:

  • UAH CI started out well on one event, but then began to struggle near the boundaries.
  • Still unsure of the utility to issue advanced warnings with the CTC product.  However, could be used for significant weather advisories and pre-warning products.
  • Training/best practices need to be developed that match the use of the CTC and CI products to near-storm environment, as performance varies with varying NSE.
  • There is utility in CI product for situational awareness and cell maintenance with MCSs.

GOES-R PLGM and Lightning Trend Tool:

  • Recommend a “drag me to storm” type interface for the trend tool.
  • Trend tool still not user-friendly, is time consuming to use.
  • Works well for DSS of NWS issued a lightning product/forecast, but not necessarily hail or tornado warnings yet.


  • The Articulate training modules received a lot of praise.


Greg Stumpf, EWP2013 Week #3 Weekly Coordinator; EWP2013 Operations Coordinator

Travis Smith, EWP2013 Week #3 Backup Coordinator


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Another Warning…Almost…and Some Other Thoughts…

Ok, so it’s always important to have a good understanding of new products before going gung-ho so to speak.  I thought I’d blog about something different here.  On my warning screen today, I had been looking at the 30 minute accumulation MESH product (or so I had forgotten it was the 30 minute accumulation) and yesterday when we were “in” New York, I had a great deal of success using this product, in conjunction with others.  Initially, I noticed a >1 inch value over northern Andrews County as shown in image 1 below.

Image 1.  MRMS MESH at 2316 UTC.  Notice the >1 values over northern Andrews County.
Image 1. MRMS MESH (30 min accumulation) at 2316 UTC. Notice the >1 inch values over northern Andrews County.

My old warning had expired and I started to prepare a new warning (I was blogging and was late keeping up with things =P ), but then thought it would probably be proper to more closely scrutinize some other data. I switched over to the MRMS reflectivity at -20C and noticed the values were relatively low for this cell at the time, with vales generally below 45dBZ in this same area (image 2).

Image 2.  2316 UTC MRMS reflectivity at -20C.  Notice the relatively low values in northern Andrews County.
Image 2. 2316 UTC MRMS reflectivity at -20C. Notice the relatively low values in northern Andrews County.

So, what did I do next?  I went back to the data I knew best and was most familiar…the all-tilts.  At the nearest time (2318 UTC), I noticed relatively low values of dBZ even near the 20kft level in this area, which corresponded to the MRMS reflectivity at -20C data (image 3).

Image 3.  2318 UTC KMAF 5.1 degree reflectivity.  At this elevation angle, the radar slice was approx 22 kft AGL at this location in northern Andrews County.  Notice generally low dBZ values at this height.
Image 3. 2318 UTC KMAF 5.1 degree reflectivity. At this elevation angle, the radar slice was approx 22 kft AGL at this location in northern Andrews County. Notice generally low dBZ values at this height.

From there I went to my four-panel of MRMS data, which included the 0.5 degree KMAF HSDA (image 4 below).  I had gained familiarity with these products fairly well over the past couple of days and wanted a quick sanity check.

Image 4. 2316 UTC MRMS and  2318 KMAF HSDA data, overlaid with SVR warnings. Upper left - MRMS Merged reflectivity QC Composite, MRMS upper right - reflectivity at -20C, lower right - MRMS MESH, lower left - KMAF 0.5 degree HC.
Image 4. 2316 UTC MRMS and 2318 KMAF HSDA data, overlaid with SVR warnings. Upper left – MRMS Merged reflectivity QC Composite, MRMS upper right – reflectivity at -20C, lower right – MRMS MESH, lower left – KMAF 0.5 degree HC.

Notice in image 4 above, the low MESH values in northern Andrews County at the time.  What?  I thought there were values over 1 inch.  I went back to my warning screen and noticed that I had the 30 minute accumulation of MESH.  I had simply forgotten.  However, this had almost resulted in a faulty warning.  Now, it could have been the HWT environment.  Would I have been so quick to react and careless in an actual operational setting?  Probably not.  However, this does bring to mind the importance of making sure to look at products carefully, especially new products with which the forecaster may not always be familiar.  Yesterday, when we were “in” the BUF office, I had used this product in addition to the MRMS reflectivity at -20C to actually form my polygons, and it had worked pretty well I thought.  But those cells were tracking along nicely.  Today, the cells were moving quite slowly.  So, the 30-min accumulation product may not have been appropriate to use in conjunction with WarnGen.  It was hard to discern any movement or much change in the product since the cells were not tracking along much. That’s why it was hard to determine if the >1 inch MESH had happened recently or much earlier in the 30 minute window.  Lesson learned.  This product may have been fine for SA purposes and perhaps kept on my non-warning screen.  These are things to think about for proper warning strategies.



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50dbz Echo Top_MESH_HSDA North Texas

The 50 dbz echo top continues to be one of my favorite parameters for quick and easy interrogation should things get busy. It’s a nice way to see the approximate height of the 50dbz core. Height of the 50dbz core above -20C is also a nice touch to analyze those really big storms that may need more significant hail wording.50_60dbz_2310z

The MESH and HSDA were both doing a good job with this storm. We did not get any hail reports, but that is likely due to the rural locations where the storm was tracking. Seeing the MESH indication of 1 inch hail and the HSDA forecast of large hail added confidence in the warning decision making process and it only took a few seconds to glance at these products. Therefore, there was still time to go through a complete review of base reflectivity and SRM data in all_tilts. The algorithm hail trends reflected what one would expect based on all_tilts base data.MESH_HSDA_2313Z

The mid level rotation track was a nice way to view the life of this storm. Initially there was good mid level rotation, but this rotation begins to weaken with time and the warning was allowed to expire early. The decision to expire the warning early was based primarily on trends within MESH, HSDA, and 50dbz echo tops. But the loss of rotation was icing on the cake for letting the warning expire.  (Jeremy Wesely)


Jeremy Wesely

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Storms Along the SJT/MAF Border

An earlier cell merger helped enhance low-level rotation and produced a reported tornado near Rotan in Fisher County TX in SJTs area.  The mid-level meso would eventually track SW toward Scurry and Mitchell Counties in the MAF forecast area.  The LAPS streamline analysis at 2330 UTC indicated convergence over the northeast portion of the MAF CWA, which appeared to be concentrating higher theta-e values in the location likely allowing the stronger convection to translate west of south.


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Damaging Convective Wind Event To Affect Areas From Abilene to Throckmorton

Our first clue was the 2.5KM LAPS Theta-E image with LAPS wind and regional radar overlaid on it at 2245 UTC.2245ZLAPS_Theta-E_Wind*The tornadic Fisher Co storm was propagating southward toward the bullseye of Theta-E over Nolan Co, while the rest of the more linear convection with damaging to destructive winds was moving southeast toward an area of high Theta-E extending from Jones/Shackleford countis into Callahan/Brown counties.

There’s a chance this linear complex splits with the better tornadic part moving southward across western San Angelo’s CWA from Fisher south through Nolan and Coke counties where the OUN-WRF 0-1KM SRH forecasts values by 0200 UTC to increase over 200 m2/s2. Meanwhile, the linear activity moving toward Abilene/Throckmorton is moving into an area of 0-1KM SRH less than a 100 m2/s2 for the most part with likely more of a damaging wind/marginal hail threat.


Here is latest MESH and 60 min MESH swatch from the severe activity.


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