Note from the EWP coordinator:
The NE TX activity was mostly a “wind bag”, with very little hail or tornado threat any more. So we have opted to complete our shift up in the Empire State. Our new CWAs: Albany and Binghamton
Tuesday, May 21, 2013
Mesoscale Update - 00z WRF Simulated IR and Nearcast
I was very impressed with the accuracy of the WRF simulated IR (top left panel) given that the image valid at 23z is a 23hr forecast and was very close to verifying (second image below). See the two images below.
This NearCast shows a very unstable environment (bottom right image...valid at 0630Z) through the night, which should sustain the convective bow as it tracks across Louisiana. The instability and environment actually seems to improve based on this nearcast model. Will see if this verifies.
Wesely
Wesely
EWP2013 Mesoscale Discussion 21 May 2000 UTC
LAPS 2.5 Theta-E advection was strongest from central TX near more isolated/discrete severe storms from Burnet, Brady, to Hamilton Texas and northeast through Corsicana to Clarksville along the Red River Valley. GOES-R cloud top cooling (CTC) and Convective Initiation (CI) forecasts just an hour or so ago indicated the increase in the isolated severe cells over central TX well. However, GOES-R positioning was off, but not too far off regarding the tail end of the linear MCS across north and northeast TX.
CIMSS NearCast Layer GOES Theta-E and PWAT differences did show maximums right where the Brady and Burnet convection in central TX was occurring and handling maximum stripe just ahead of the linear MCS moving east across I-35 further across north and northeast TX.
OUN_LAPS SBCAPE appeared to be well in line with current SPC mesoanalyis real-time values and can be trusted for the next 1-2 hours. During the late afternoon and early evening hours, we expect the linear MCS to continue to progress east with potential for embedded meso-vorticies and weaker tornadoes along the leading edge, while larger discrete supercell storms both ahead across the east Texas Piney Woods and southwest into the eastern Texas Hill Country and central Texas to contain more intense modes. These storms will likely see better inflow of rich Theta-E air from the Gulf of Mexico leading to lower LCLs, and the potential for very large hail and longer track tornadoes, if the tail-end of the upper level forcing from long wave trough over the Plains can extend that far south.
CIMSS NearCast Layer GOES Theta-E and PWAT differences did show maximums right where the Brady and Burnet convection in central TX was occurring and handling maximum stripe just ahead of the linear MCS moving east across I-35 further across north and northeast TX.
OUN_LAPS SBCAPE appeared to be well in line with current SPC mesoanalyis real-time values and can be trusted for the next 1-2 hours. During the late afternoon and early evening hours, we expect the linear MCS to continue to progress east with potential for embedded meso-vorticies and weaker tornadoes along the leading edge, while larger discrete supercell storms both ahead across the east Texas Piney Woods and southwest into the eastern Texas Hill Country and central Texas to contain more intense modes. These storms will likely see better inflow of rich Theta-E air from the Gulf of Mexico leading to lower LCLs, and the potential for very large hail and longer track tornadoes, if the tail-end of the upper level forcing from long wave trough over the Plains can extend that far south.
CI/CTC AWIPS2 Loop
Tried to manually loop a 4 panel image of CI/CTC/Radar/Vis and with a 40 plus frame count it was too slow to be useful. It took over 20 seconds for all parameters to load. However, at a frame count of 12 it was much faster and of more use for following trends.
Wesely
Wesely
HWT EWP Status for 21 May 2013: 2-10 pm Shift
Note from the EWP coordinator:
Moderate Risk again for portions of SE OK, AR, NE TX, and NW LA. Convection will be ongoing in the late morning, and is expected to continue well into the late evening and overnight hours. With better convective initiation opportunities to occur later this week, and to allow for some time in the morning for damage survey activities in Moore, we are opting to capture the later portion of this event.
Likely CWAs: Shreveport, Fort Worth, Little Rock, Tulsa, and Norman
The blog will be updated after 2pm CDT with appropriate GOES-R posts.
Moderate Risk again for portions of SE OK, AR, NE TX, and NW LA. Convection will be ongoing in the late morning, and is expected to continue well into the late evening and overnight hours. With better convective initiation opportunities to occur later this week, and to allow for some time in the morning for damage survey activities in Moore, we are opting to capture the later portion of this event.
Likely CWAs: Shreveport, Fort Worth, Little Rock, Tulsa, and Norman
The blog will be updated after 2pm CDT with appropriate GOES-R posts.
Monday, May 20, 2013
Welcome to HWT Week 3
Welcome to week 3 of the HWT. The forecasters are busy trying to get spun up on using all the demonstration products in a short amount of time since storms have exploded over OK earlier this afternoon. Once this takes place, the blog will explode as well. :-)
Forecasters are here from Wakefield, VA, Fort Worth, TX, Huntsville, AL, Upton, NY, and the Norman, OK forecasters will join us tomorrow hopefully. Most of the Norman folks were out completing storm surveys this morning from yesterday's tornadoes...which very may well occur again tomorrow. GOES-R support this week at HWT includes myself (Chad), Jim Gurka, and Lori Schultz.
There have been problems with data ingest earlier...but now things are slowly coming back online.
Since I started this post...a devastating tornado tracked 8 miles north of the National Weather Center. Its a chilling reminder that one of the GOES-R goals is to assist in increasing lead time for tornado and severe thunderstorm warnings.
Forecasters are here from Wakefield, VA, Fort Worth, TX, Huntsville, AL, Upton, NY, and the Norman, OK forecasters will join us tomorrow hopefully. Most of the Norman folks were out completing storm surveys this morning from yesterday's tornadoes...which very may well occur again tomorrow. GOES-R support this week at HWT includes myself (Chad), Jim Gurka, and Lori Schultz.
There have been problems with data ingest earlier...but now things are slowly coming back online.
Since I started this post...a devastating tornado tracked 8 miles north of the National Weather Center. Its a chilling reminder that one of the GOES-R goals is to assist in increasing lead time for tornado and severe thunderstorm warnings.
Friday, May 17, 2013
Week 2 Debrief
While week 2 of the HWT Spring Experiment started out fairly quiet it certainly didn't end that way. Wednesday night's tornadoes in N. Texas ended up being the highlight of the demonstration so far and a lot of good feedback was collected from that event as well as the rest of the week. Check it out...
GOES-R CI
- 'On days where convection in more questionable it may be nice to have the ability to filter out the lower values to get rid of the confetti-like display, however on days where convective initiation is much more likely, those lower values provide some valuable information and help in keying in on particular growth.'
- 'Values of 57% or greater seemed to do fairly well on identifying initiation throughout the week.'
CTC
- 'The CTC is useful but does have trouble in areas of cirrus.'
- 'Most of the storms that developed did have a high POD, but also had some FAR.'
- 'In operations we're looking for which storms have potential. This is where the CTC would definitely be useful.'
- 'For situational awareness the CTC is a big thing. It identifies which storms to watch.'
- 'It would have been a better experience on Wednesday night if we'd had Rapid Scan Operations for GOES-13.'
Nearcast
- 'The CAPE field was good to compare to other CAPE fields though it can be hard to wrap your head around exactly what you're looking at and how it was computed.'
- 'The color scheme was a bit confusing. With the theta-E difference I'm used to thinking that green, yellow, and red values, are values to key in on, but in this case it was the darker blues and pinks.'
- 'The GOES-E and GOES-W images were definitely different, they didn't match, so I wasn't sure which one I should look at. It would definitely be useful to have a seamless overlap.'
- 'CAPE is conventionally what we're used to looking at, but the theta-E difference was also very useful.'
- 'Yesterday I looked at the theta-E and PW values... there were no high PW values [in west KS] and so it made sense why the storms there weren't growing. This information was very beneficial to have.'
- 'Then on Wednesday the storms in OK and TX formed right on the low-level and mid-level maximums of theta-E, so it did very well.'
RGB Airmass
- 'Yesterday the RGB showed showed drier, cooler air behind the convection which is what you would expect, but as the day went on you could see the moisture return to the area... because of this I kept my eye on what was going on there.'
- 'On Wednesday the dryline structure in OK and TX was very visible and we keyed in on this area.'
- The RGB gives you more information about the airmass source, it's composition, etc. It's very helpful information to have for situational awareness.'
- 'I liked the RGB as an overview, especially when you first sit down to see where airmasses are setting up. Though once you get into the nitty gritty of warning operations I didn't use it as much.'
Simulated Imagery
- 'We'd use it as a comparison to the actual IR to see what was influencing the model later.'
- 'It doesn't seem to handle anvils very well, but this may be a good thing because you could see where the storms were developing without the anvil getting in the way.'
- 'It's fairly remarkable what this imagery can do, giving you a satellite image so many hours in advance.'
- 'It did very well this past Tuesday in holding off on convective initiation up in the Western GL.'
PGLM
- 'Add the number or percentage of sensors currently working... for testing purposes it's crucial that we have this information so that we can use the product accurately.'
- 'Perhaps the 30 flashes/min threshold should be colored different so that it stands out more.'
- 'I used this product to identify which storms were starting to intensify and what cells I should key in on.'
Well that's a wrap for the week 2 debrief... but don't forget, our 'Tales from the Testbed' webinar will be beginning within thirty minutes and will cover the use of all of our experimental products during the N. Texas tornado event on Wednesday night. It should be a very interesting discussion!
GOES-R CI
- 'On days where convection in more questionable it may be nice to have the ability to filter out the lower values to get rid of the confetti-like display, however on days where convective initiation is much more likely, those lower values provide some valuable information and help in keying in on particular growth.'
- 'Values of 57% or greater seemed to do fairly well on identifying initiation throughout the week.'
CTC
- 'The CTC is useful but does have trouble in areas of cirrus.'
- 'Most of the storms that developed did have a high POD, but also had some FAR.'
- 'In operations we're looking for which storms have potential. This is where the CTC would definitely be useful.'
- 'For situational awareness the CTC is a big thing. It identifies which storms to watch.'
- 'It would have been a better experience on Wednesday night if we'd had Rapid Scan Operations for GOES-13.'
Nearcast
- 'The CAPE field was good to compare to other CAPE fields though it can be hard to wrap your head around exactly what you're looking at and how it was computed.'
- 'The color scheme was a bit confusing. With the theta-E difference I'm used to thinking that green, yellow, and red values, are values to key in on, but in this case it was the darker blues and pinks.'
- 'The GOES-E and GOES-W images were definitely different, they didn't match, so I wasn't sure which one I should look at. It would definitely be useful to have a seamless overlap.'
- 'CAPE is conventionally what we're used to looking at, but the theta-E difference was also very useful.'
- 'Yesterday I looked at the theta-E and PW values... there were no high PW values [in west KS] and so it made sense why the storms there weren't growing. This information was very beneficial to have.'
- 'Then on Wednesday the storms in OK and TX formed right on the low-level and mid-level maximums of theta-E, so it did very well.'
RGB Airmass
- 'Yesterday the RGB showed showed drier, cooler air behind the convection which is what you would expect, but as the day went on you could see the moisture return to the area... because of this I kept my eye on what was going on there.'
- 'On Wednesday the dryline structure in OK and TX was very visible and we keyed in on this area.'
- The RGB gives you more information about the airmass source, it's composition, etc. It's very helpful information to have for situational awareness.'
- 'I liked the RGB as an overview, especially when you first sit down to see where airmasses are setting up. Though once you get into the nitty gritty of warning operations I didn't use it as much.'
Simulated Imagery
- 'We'd use it as a comparison to the actual IR to see what was influencing the model later.'
- 'It doesn't seem to handle anvils very well, but this may be a good thing because you could see where the storms were developing without the anvil getting in the way.'
- 'It's fairly remarkable what this imagery can do, giving you a satellite image so many hours in advance.'
- 'It did very well this past Tuesday in holding off on convective initiation up in the Western GL.'
PGLM
- 'Add the number or percentage of sensors currently working... for testing purposes it's crucial that we have this information so that we can use the product accurately.'
- 'Perhaps the 30 flashes/min threshold should be colored different so that it stands out more.'
- 'I used this product to identify which storms were starting to intensify and what cells I should key in on.'
Well that's a wrap for the week 2 debrief... but don't forget, our 'Tales from the Testbed' webinar will be beginning within thirty minutes and will cover the use of all of our experimental products during the N. Texas tornado event on Wednesday night. It should be a very interesting discussion!
Thursday, May 16, 2013
Slow Day in CI/CTC Land
Shown below is a classic example of CI/CTC spoilage by upper level cirrus clouds. Note the rather mature convective system over the GLD CWA. All of the SPoRT CI algorithm detections (upper left) are all in the cumulus field on the outer fringe. CTC detections, when they occur (upper right), are similarly absent from the main complex. This has been the case the entire shift. Perhaps without the cirrus, we would be able to see strength fluctuations in the convective line, but the constant presence of cirrus over the top does not allow the satellite to sense updrafts. While there have been improvements to CTC over the last year to two to deal with thin cirrus, even that work would not help here. Cirrus contamination is clearly the main drawback to these otherwise excellent and useful products.
 |
| 051613 2230 UTC CI (top left), Visible Satellite with CTC (top right), NLDN lightning (bottom left), and Reflectivity (bottom right) |
CL
20Z Nearcast Analysis of CAPE Trends Through the Afternoon
The 20Z Nearcast model shows slow but steady weakening of instability fields through the afternoon. Ribbon of 800-1000 J/KG along the CO/KS border between 20-22Z with a theta-e diff of 8-11K decreases through the late afternoon and evening to roughly 600-900 J/KG. There is a similar trend in theta-e difference with 6-9K theta-e difference in this region through the early evening…along with about 30kts of 0-6 km shear. Further east into central Kansas…CAPE and theta-e difference significantly drop off…so from this forecast one can expect any storms that develop within the convergence zone along the KS/CO border to move east and have some marginal strength and organization before dissipating as they approach central Kansas.
 |
| 051613 2000Z Nearcasting CAPE |
Sad Storms so far in SE CO/NW KS - No juice in the Nearcast
 |
| 051613 22:31 Nearcast Precipitable Water Difference and Reflectivity |
This image depicts CIMSS-NRE 700-300 mb precipitable water values overlaid with 0.5 Reflectivity from KDDC. These struggling high based storms are over an area with precipitable water values only 0.05 to 0.11 inch between 300 and 700 mb. It seems very unlikely these storms will do anything, unless they can quickly move east in the next few hours where much higher precipitable water values exist.
Scotten
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