Call to chasers Greg Stumpf and Jim LaDue confirms that storm is outflow-dominant, still a very HP-looking supercell.
Travis Smith (EWP Weekly Coordinator, 19-23 May)
Live Blog – 22 May 2008 (7:02pm)
Forecasters are issuing PAR-based warnings using the Prob Warning tool. The way to interpret the data is that they are encircling the storms of interest with the polygon tool and selecting either “Severe Thunderstorm” or “tornado” warning.
Dealiasing is an issue, but not just on the PAR.
Storm is moving into higher dew point air.
Travis Smith (EWP Weekly Coordinator, 19-23 May)
Live Blog – 22 May 2008 (6:33pm)
Low HWT staffing today, so Live Blogging is slow…
PAR IOP is up, with all forecasters participating. SteveH is also doing Prob Warn.
Gate-to-gate right now has good continuity that cannot be seen in the KTLX velocity data.
Travis Smith (EWP Weekly Coordinator, 19-23 May)
Outlook – 22 May 2008
SPC has higlighted a MODT Risk of severe storms, with emphasis on long-tracked tornadoes, in their 1630 UTC outlook, across portions of Western KS, and adjacent areas of CO and NE. A SLGT Risk extends along a progged dryline into Western Oklahoma. Concerns for the southern target include cap strength and weaker low-level shear. Plans are to conduct a ProbWarn IOP for the KS area, unless storms develop in Western Oklahoma, where instead we’d conduct PAR operations, since there haven’t been live PAR operations yet this week.
Greg Stumpf (EWP Operations Coordinator)
Summary – 21 May 2008
SteveR — working with the new software and probabilities was easier tonight. Would be easier to combine wind/hail in some instances. Maybe a way to “paint” on the warning rather than having slider bars. Call to action based on probabilities — higher probs communicate stronger language. Forces you to think more about how the threat is changing/evoloving with time.
Jonathan — worked with SteveR, similar comments. Felt more comfortable. Had fewer threats tonight, so that may have contributed.
SteveH — knew what the threats were since it was in his backyard. Did a lot more analysis tonight even though he was working by himself. Updated every five minutes, 2 threats per storm, 3 storms. Was prety easy. Could work 7-8 storms if he was more comfortable with it. Storms moving same direction made it easier. Could work a lot more if it was the only thing he had to do.
Dave — finds it easier to work with ellipses than polygons. Really important to have a good measurement of the speed. Tonight we had development and decay of storms, and it would make it more challenging. No need to fine-tune areas when the storms are more “pulse” in nature.
Mike — larger your polygon the less you have to do…. modulates the work load.
Ryan — would like to make a “flexible ellipse” that could be stretched at one end. Would really like to see a preview.
Jonathan – WarnGen-style warning would be nice.
SteveR — would like the probability ticks every 5%. Several people agree.
SteveH — maybe tornado every 1%
Probabilities:
SteveH — when storms start rotating, you should put out a low-end probability
Jonathan — how will the ublic react to these low probabilities?
SteveR — how do we verify in this new paradigm? Verification is a huge workload at his office as directed by his region.
Jonathan — would like independent verification.
Discussion turned to the value of SHAVE-type verification and independent verification.
Another question: should GPRA goals be directly guide the probability threshold at which people should take action? Probably a WAS*IS question.
Travis Smith (EWP Weekly Coordinator, 19-23 May)
Live Blog – 21 May 2008 (8:15pm)
SteveH is adding a tornado threat based on increasingly favorable environment (backed winds, better moisture, and the southern end of the cell taking on supercell properties (WER, notch, low-level meso).
Travis Smith (EWP Weekly Coordinator, 19-23 May)
Live Blog – 21 May 2008 (7:47pm)
SteveH is letting his two northernmost storms keep low probabilities in case they re-intensify. Southern storm is still going strong.
Travis Smith (EWP Weekly Coordinator, 19-23 May)
Live Blog – 21 May 2008 (7:36pm)
Dave and Ryan have updated their storms. For their southern storm, hey have two cells encompassed by one threat area. An issue they struggled with in this approach is that they felt that the differing updrafts had different probabilities.
Dave said that it is tough to track so many updrafts, even if he was more comfortable with the software.
Dave and Ryan have traded off at 0037z – Ryan is now drawing polygons.
Kevin Manross (Gridded Warning Cognizant Scientist)
Live Blog – 21 May 2008 (7:33pm)
SteveH has some large wind threat areas (some with high probabilities), based on the already-strong synoptic winds combined with evaporatively-driven downdrafts. “Any 50 dBZ core has the possibility of producing strong winds.” Currently most concerned with the storm to the SW of KGLD.
Travis Smith (EWP Weekly Coordinator, 19-23 May)
Live Blog – 21 May 2008 (7:26pm)
SteveR/Jonathan would like some way to see if the polygons have been saved while they are waiting for the threats to be processed, as well as a way to quickly see a list of current probabilities for each threat.
KGLD needs to change PRF!
Travis Smith (EWP Weekly Coordinator, 19-23 May)