GOES14-SuperHiResVisible Shows Convective Trends 5/12

The Super Hi-Resolution Visible Satellite Imagery below depicted a differential heating boundary over northern Illinois, denoted by the green line.  Very little cumulus was observed north of the green line where cirrus cloud cover was thicker, while enhanced cumulus congestus was occurring south of the green line.  With low level south to southwest flow, cumulus that developed south of this boundary had a tendency to dissipate when moving north of the green line/boundary. A severe storm denoted by the orange circle in southeast Iowa was moving east northeast and seems to be moving along this boundary.  It will be interesting to see if this storm will continue to be severe over the next few hours.

Michael Scotten

ProbSevere Model Good Lead Time NE Missouri/SE Iowa border – Missing SRSOR Images

The ProbSevere Model indicated an 83% probability of a severe storm within an environment of 2968 J/Kg of MUCAPE and 34.6 kts of EBShear at 2020Z. It also indicated MESH of 1.07inch at this time. The following 2-minute resolution updates continued to show 80+% prob and 1 inch+ MESH as the storm tracked northeast from the NE Missouri/SW Iowa border into SW Iowa except for one frame at 2028z where it showed a 64% prob. WFO DMX issued a SVR at 2037z. ProbSevere may have helped give up to 17 minutes additional lead time if the warning was issued once the ProbSevere crossed above 80%. At the time of this post there were not yet any confirmed hail reports.

Visible satellite data started to show a resemblance of an enhanced updraft on this storm at 2015z with a developing anvil and anvil shadowing at 2025z.  SRSOR VIS data was missing between 2011z and 2030z so had to use conventional visible images for the attached screen captures.

Shawn Smith

EDIT: Missing GOES-14 SRSOR images were due to "daily housekeeping" - BL

NOAA/CIMSS ProbSevere model at Week 2 HWT

The second week of the 2014 HWT is underway, with visiting forecasters evaluating a number of GOES-R products, including the new NOAA/CIMSS ProbSevere model. Forecasters are learning how to use this product today within their warning operations.

The ProbSevere model is probabilistic guidance from a statistical model, which fuses together data from the Rapid Refresh NWP model (RAP), growth rates in GOES-derived cloud products, and Multi-Radar Multi-Sensor (MRMS) Maximum Expected Size of Hail (MESH). Storms are identified and tracked in both satellite and radar imagery. Time trends (normalized vertical growth rate and glaciation rate) are extracted form satellite objects/storms, and shared with overlapping storms, present on radar. The probability of severe in the near future (~0-60 min) is computed using these satellite time trends, the MESH, and MUCAPE and effective bulk shear derived from the RAP.

This storm in south-central Iowa had a 90% probability of severe prior to producing a 64mph wind report. All of the surrounding storms had probabilities generally less than 30%.

A storm that developed in the warm sector also had a strong probability of severe well before 2" hail was reported in north-central Illinois.

With sampling turned on (see image below), we can see the AWIPS-II readout for ProbSevere. The probability of severe is of course displayed, as well as the values of the individual predictors. If the satellite growth rate predictors read 'N/A', that means that the storm is not discernible in satellite imagery, and thus growth rates can't be computed. Work is ongoing to try to associate mature satellite features with individual storms on radar. ProbSevere will still operate with radar+NWP, however, lead time to some severe hazards may not be as great as when the satellite growth rates are incorporated.

-Cintineo

Expanding Overshooting Tops Increase SVR Lead Time in Southern IA

The following images depicted the expansion in overshooting tops depicted by the CIMMS Auto Overshooting Tops Detection Algorithm 2015 to 2045 UTC May 12 across southern Iowa.

The first image had a small red blob in southwest Davis county at 2015 UTC, which greatly enlarged in area by 2025 UTC in the second image.   By 2030 UTC in the third image, the area split up into three blobs.  By 2037 UTC, the fourth image indicated four blobs with the two blobs to the northeast representing the fastest growth and expansion of the storm.  By 2045 UTC, the last image, three blobs were with this storm, possibly indicated that storm was intensifying or at least maintaining intensity.

A SVR was issued for Van Buren county, on the southeast part of the enclosed circular area, with the overshooting tops blobs at 2037 UTC.  A 60 mph gust along with heavy rainfall and low visibility was observed in the warned area at 2127 UTC. The great expansion and splitting of blobs indicated by the Auto Overshooting Top Detection Algorithm could have increased SVR lead time another 10-30 minutes.

Michael Scotten

EWP Status for 12 May 2014: 11:45-7:45 pm Shift

In contrast to last week, the start of this week has come with some very active weather. A fresh batch of forecasters are quickly getting spun up on  all of the experimental products as we look forward to another great week. Today, Shawn Smith (WFO Buffalo) and Michael Scotten (WFO Norman) are forecasting for the Davenport CWA, while Kevin Deitch (WFO Louisville) and Erica Grow (WUSA) are in the St. Louis CWA. Today’s shift will run from 11:45 to 7:45.

Forecasters will have access to a sector of GOES-14 1-minute imagery all week providing feedback on the utility of high temporal resolution imagery in a forecast environment.

- Bill Line, SPC/HWT Satellite Liaison and Week 2 EWP Coordinator

Week 1 Feedback (and 05/08 daily debrief)

After a relatively quiet start, week 1 of the 2014 HWT Spring Experiment turned out to be quite active by Wednesday and Thursday. Participants were able to utilize most of the experimental products in the simulated forecast/warning environment, writing numerous blog posts, and leaving valuable feedback to product developers.

Week 1 EWP Participants

Feedback feedback for week 1:

Simulated Satellite Imagery: Unfortunately, due to problems out of our control, this product was only available halfway through the day Thursday.
- The model didn't pick up convection in Texas. That can be very important: if its showing stuff that’s not there, why continue to use it?

NearCast System: 
- It seemed like a very useful product
- It allowed for the visualization of moisture and instability and tracked how it was moving. You can track where the fuel will be. It helped for CI and ongoing convection.
- One of the more consistent tools, it handled gradients well
- 30 minute model update would be fine, more often then that, there wouldn't be much change
- Might be useful to somehow interpolate data to fill gaps, perhaps this could be contoured, and one could turn it on/off
- I actually like the gaps, it tells the forecaster where we don't have data, instead of interpolating, a forecaster can interpolate in his head.
- I haven't seen anything like this in AWIPS; it is a unique tool
- This is the type of tool that you need to look at daily, and the more you use it, you'll be able to figure out how to correctly use it.
- The PW values at the low levels were not very deep last night, this could help a forecaster to update/remove pops
- This was the most consistent product throughout the week. It gave me confidence where the moisture boundaries would be in the near future, and convection consistently developed along those boundaries.

GOES-R Convective Initiation:
- A line of clouds formed in Nebraska. CI showed some higher probs on the northern end of the line, where storms would first initiate several scans later. Probs increased down the line before convection continued its development.
- It is ok. It can go from fantastic to not so good depending on situation
- One of those tools you have to use a lot to learn what regimes it's useful for, and not
- Applying it it non severe situations would be good
- I can see its usefulness in a forecaster being able to update pops in the near term
- it gives a forecaster a 5-10 min lead on starting to interrogate near storm environments where the      convection is firing
- I can see it in a procedure
- It was hard to get a feel for and get a handle on because of changing domains throughout the week (mountains to plains)
- Yesterday, there was a line developing, but it never showed probs
- Out of all of them, might have been the least useful
- Might have other applications, like fire weather out west in the summer.

Prob Severe Model:
- Later on in development, it had very high probs on storms that ci had missed
- It would be useful to change the color of the text when values reach certain thresholds (eg. MESH >1")
- Right now, it is kind of a short term initial storm development tool. I think there are other fields that could go into it that might be useful.
- Prob tornado, wind, hail would be nice to see
- Does have limitations in linear regimes
- It would take more than 4 days to really learn how to use the probs, develop thresholds in my head
- If there was an upward trend in prob severe, I would pay attention to that storm
- It was really good up until the last day in Iowa and Kansas, where many storms had high probs but didn't go severe. These storms had high growth rates but marginal MESH
- In some cases, this product may be enough to make me issue a warning (or not) when I am on the fence
- When I saw probs over 90% and they weren't going severe, I lost confidence
- I would look at these probs, then at other tools to verify it.
- I think, no matter what tools become available in the future, I will always go back and look at the raw data (dual pol, all tilts, etc) in addition
- I think it was useful in flagging areas where I should be looking. I would take a closer look at those storms with higher probs
- How I would use it: I've done my homework on the environment and the first cell is developing (with some sort of prob severe trend) and it is warned on. Any later storms that show the same trends in prob severe, I would likely also warn on. I would want to calibrate to the situation at hand.
- The ability to effectively use this tool would come with experience
- The color scale was fine. I like that the contours got thicker. Everything about the display was fine. I would just change the readout (by adding colors for certain thresholds)

Overshooting Top Detection:
- I like that it makes obvious where the overshooting tops are
- In areas where radar coverage is a little more sparse or when a radar is down, I see more utility, in helping to identify where the strongest updrafts are.
- I didn't get to see if monitoring trends in OT's would be useful (we didn't work late enough shifts), but I think it could have utility in the weakening stages of convection

GOES-14 SRSOR (1-minute Imagery): Was only available the final day of operations (Thursday)
- Is it useful over 5 minute imagery? It is hard to say at this point.  I would need more time to view the imagery and learn how to properly interpret it. But if it is made available to me, of course I am going to view it.
- This imagery is really cool
- It makes boundaries more distinct, and might give you a little extra heads up on cu development
- It was really detailed when convection was starting to go up in Kansas, you could see tops going up and their shadows. It made me think that I should watch over here.
- I looked at this more than the ci product because the movement was so fluid, I could see things as they were happening
- I could definitely discern areas where stronger lift was occurring
- I stick to a lot of the base data when I am interrogating storms, including satellite imagery
- When you depend too much on derived products, you become lazy and start missing important things

PGLM Total Lightning: There was limited use of the Lightning Products due to lack of convective activity within active LMA's
- I concentrated on it in the Cheyenne area. It really picked up on the storm with the density, I had flash count overlaid, and they matched.
- I like being able to interpolate the data in AWIPS. I switched between that and the gridded look

Tracking Tool
- I think this would be useful. I used it to track reflectivity, and you could clearly see the trend
- It could be helpful to show you where in the column the max reflectivity is (look through all tilts for you).
- I would like to see this track features like gate-to-gate and storm top convergence.
- I did not find the interface to be too intensive to use
- The meteogram takes up a lot of real-estate. It would be nice to have the option of bringing up the meteogram in a separate window.

- - Bill Line, SPC/HWT Satellite Liaison

OT Detection Assists on IR

If you refer to the first image, it is obvious that we have some cold cloud tops over Minnesota and Wisconsin. However, it wouldn’t be quite obvious where the highest tops exist and which of those are necessarily overshooting tops. The OTD (Overshooting Top Detection) tool helps! By detecting a cloud top that is less than or equal to -6K than its surrounding anvil, the OTD will mark the cloud top (seen by the dark blue marks in the second image). The anvil must also meet a temperature threshold. The anvil must be less than or equal to 225K and the top must be less than or equal to 215K. If these conditions are not met, no overshooting top will be detected. This prevents the tool from being over sensitive and creating false detections.

Jared Maples

DSM set-up update

22Z…a broken line of storms continues through western IA.  To this point, strong…but not strong enough to warrant warning.

The LAPS model forecast for 22Z is below

Catches the basic idea of the shape/character of convection to the west, but just a little off in location.

Here’s the Nearcast instability forecast looking ahead four hours…highest instability will lift northeast, and this batch of convection will move with it.  Notice lingering instability (relatively speaking)near the NE/IA border.

The CI product shows the potential for more convection to develop along the main cold front behind our initial line.  Expecting this activity, should it take hold, will be less of a concern with lower instability to work with compared to the first line.

db

Storms develop further southwest along dryline

Strong thunderstorms continue to develop along the dryline in Kansas on Thursday afternoon.  The first severe thunderstorm warning came out at 2152 UTC 8 May 2014 for a storm southwest of Topeka, Kansas.  Figure 1 shows the evolution of this storm up to the point of becoming warned.  The ProbSevere model jumped above 50% at 2146 UTC--good for 6 minutes of lead-time.

Figure 1. NOAA/CIMSS ProbSevere and MRMS composite reflectivity valid 2146 -2152 UTC 8 May 2014.

It will be interesting if storms further southwest become severe, as probabilities briefly went above 50%, but have been cycling a bit as the storms try to better organize.

-Sieglaff

Storms over western Iowa

Strong thunderstorms have developed along and ahead of the dryline over far eastern Nebraska and have moved into western Iowa.  Figure 1 shows the evolution of these storms--notice the ProbSevere values fluctuate--occasionally into the higher ranges (pinks > 70%).  These storms are in a favorable environment, have exhibited strong satellite growth rates, and have cycled in radar-estimated intensity.

Figure 1. NOAA/CIMSS ProbSevere and MRMS composite reflectivity valid 2014 - 2112 UTC 8 May 2014.

A question was posed to the pair of forecasters working the DMX WFO at the EWP:

"These storms have exhibited some high probabilities and have fluctuated as the radar intensity ebbs and flows.  How would you use the storms in these in this scenario and what would you suggest as data inputs into ProbSevere to improve the statistical model?"

"One forecaster replied, I like the fact that probabilities are fluctuating with radar intensity, it tells me the storms are cycling and may not be steady-state ready to produce severe weather.  Another forecaster said it would make it more difficult to use--but combined with analysis of radar tilts and the velocity data--it still tells me what storms are going to pose the highest threat.  We've seen storms that get high probabilities and don't cycle--they produce severe weather--but not these.  So that's the million dollar question.  Both added additional pieces of information that might add value would be melting depth (freezing height) (although they noted not in this case) as well as additional reflectivity information at higher levels."

This type of interaction does NOT occur when researchers are in their institutes and forecasters working a shift in their WFO.  It is experiments like these that facilitate the most rapid improvement in new products and the prospect of 3 more weeks of interactions is exciting.


-Sieglaff