Now the pre GCK storm is the western end of a squall line moving southeast with a dominant cold pool.

Craig’s considering removing the current hail threat area for the western cell. Maybe they’ll consider dropping probabilities.

Craig would issue a severe warning for the entire line for the wind threat but would consider keeping hail threat more cellular based.

Greg suggests at 0056 UTC to create new threat area for the cell to the east so that they can practice polygon threat areas.

Overview: The warning valid times are still equivalent to legacy polygon warnings. There’s considerable uncertainty about when to think multicell-based threat area vs. individual cell. When to transition is a big question.

Jim LaDue (EWP Weekly Coordinator, 5-9 May)

Brian wanted to add an interior, enhanced probability hail threat area but we’ll stick with simpler issues for now.

The storm is now more merged with the line to the east and is now nor N-S oriented.

There’s a storm to the east in the line with enhanced MESH. Bill’s wondering whether to add a new threat. For now he’ll want to keep it simple.

Updating western, pre GCK, storm which acquired a N-S dumbbell configuration. Do they go with a second threat for the south dumbbell? Bill sais the VIL’s continuing downward and they’re satisfied with the drop in probability trend from earlier. Brian thinks the inflow is weakening the storm and there’s contamination.

Greg asked if they feel confident the probability will be zero by the end of warning time? Bill sais no. Brian agrees. But now at 0048 UTC the MESH dropped further. So Brian’s going with 30 min validation time. Initial prob =70% lowering to 45%. The storm’s out of the previously created threat area and so they just saved at 0050 UTC.

Jim LaDue (EWP Weekly Coordinator, 5-9 May)

Brian is now on the WDSS-II. Bill is on D2D. Craig and Cynthia are contributing in the background.

Jim LaDue (EWP Weekly Coordinator, 5-9 May)

Storms east of the GCK storm appear highly elevated according to Brian. He’s also thinking High downdraft CAPE and dewpoint depressions would depress the tornado threat.

Craig and Brian’s correlating VIL with the report. The VIL’s come down a bit and the latest report is 1″ . Cynthia’s worried the worst hail threat is now too far north of the threat area centroid. But Craig sais the tendency is for propagation to occur to the south.

Brian is also thinking the squall line segment to the south may eventually cutoff inflow to the storm.

Bill’s coming over to help Cynthia update the threat area. Bill’s interested in pulling the north extent of the threat area a little north and rotate the ellipse N-S and stretch it out. Oh, a new MESH product came in and they had to reposition the reshaped threat area to the east a bit.

Upon reconsidering after looping the MESH, they’ll consider a 50 min warning time. Motion uncertainty has been set to 10deg from 277, speed 10kts – uncertainty=5kts. Peak (trend) probability to be set to 55% in 30 min from 95%. So the trend is lower.

Done by 0027 UTC

Jim LaDue (EWP Weekly Coordinator, 5-9 May)

Initial hail prob = 100% and slowly dropping off to 75% in 10 min. They’ll be updating.

Main concern is if it’ll move off the boundary. Right now it’s not.

Jim LaDue (EWP Weekly Coordinator, 5-9 May)

We have Cynthia on WDSS-II drafting the threat areas for hail while Bill monitors radar data on D2D. We decided to approach the workload like this in order to reduce the cognitive load of trying to handle new software.

Brian will be working the environmental data.

The GCK storm appears to be a high-based supercell with a significant TBSS as of 20 min ago. Softball hail was observed in GCK 30 min ago.

Jim LaDue (EWP Weekly Coordinator, 5-9 May)

Greg has done a walk-through on a live supercell in Woods county, OK for a hail threat. Slow motion of the storm means lots of variation in storm motion direction between the forecasters.

Jim LaDue (EWP Weekly Coordinator, 5-9 May)

The storm merger has occurred but there are still distinct inflow notches aligned east-west on the south side of a >50dBZ contiguous low-level core. We’re seeing the strong SR inbounds in the core but no outbounds south of the core due to poor signal.

Liz’s binary TOR threshold is 30% so she dropped the probabilities to just above that level. This means absolute probabilities will not be consistent between forecasters. Should they be relative to a personal TOR warning threshold?

Oh, when Liz made a loop, the edit polygons dialogue box also looped in an annoying way.

The end. NO tornado observed yet though dust was rising in some chaser’s streaming videos.

Jim LaDue (EWP Weekly Coordinator-in-Training)

Live stream from a chaser east of GLD shows a wall cloud northest of Thomas, KS.

Liz took over prob warn and as expected, is experiencing a big learning curve. Warnings may not be totally accurate. We’ll need at least an hour for each forecaster to get up to adequate skill in WG.

Jim LaDue (EWP Weekly Coordinator-in-Training)