Outlook – 13 May 2008

Alrighty – this is our best chance for CASA this week (likely for PAR too), for severe weather. We will probably have convection in the CASA domain tomorrow, but I’d be surprised to have much in the severe category.

We have a front that has sagged into central OK and has recently initiated in Lincoln CO (~2145z). The line looks like it is trying to continue to initiate toward the SW in the CASA network. The boundary appears to be visible in the Ern part of the network.

CAPE values have been progged to be rather extreme (~4000 J/Kg), but the shear is not terribly favorable for significant tornado threat. However, with a boundary colocated with high CAPE, we might have some opportunity for tornadic storms. Nevertheless, shear is sufficient for supercells with large hail.

Kevin Manross (EWP Weekly Coordinator, 12-16 May)

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Summary – 12 May 2008

Given the dearth of severe weather today, we went ahead and had all the participants (Dan M. Dan P. Dave H., Eve G. and Ron P.) sit through the briefings for each project (CASA, PAR and PROBWARN) after the orientation.

This evening, Dan P. and Dave H. are running though a CASA case with Brenda and Ellen. Dan M. and Ron P. are working a PAR case with Greg S. and Arthur.

Greg has offered a few comments regarding the PAR playback case(s), in general. He notes that the incoming data may be arriving too quickly, effectively bogging down the display when viewing cross sections. [Note: this is something that I encountered trying to run/view the PAR in realtime over the past year or two.] We can certainly take care of this in the w2simulator, but Greg ponders whether this should be done for realtime viewing.

EDIT (by Greg): Since the PAR already updates so rapidly, we could consider updating a volume scan at a time. This would provide ~60s updates of all tilts at once, and only “lock up” the display one time per minutes, rather than every 5s which is the current wg polling interval.

Comments by Ron and Dan (as well as Greg and Arthur) suggest that getting 88D data (KTLX, KFDR, etc.) for the PAR playback cases would be very helpful.

Kevin Manross (EWP Weekly Coordinator, 12-16 May)

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Outlook – 12 May 2008

Nothing much to get excited about today. SPC has a slight risk issued for the DRT area based mainly for downstream of “old faithful”. Otherwise, the CONUS is dominated by a mid-continent ridge with an exiting upper-level low off the east coast and a trough digging through nrn NV. This west coast upper trough will be the weather-maker for the week. In fact, this trough is progged to become very positively tilted and progress only slowly eastward.

That being said, it appears that our best bet for *severe* convection in our CASA domain may be late tomorrow afternoon/early evening as a cold front drapes across OK. Therefore, we have performed all the intro seminars this afternoon and this evening, Dave and Dan P. are working through a CASA case. Ron P. and dan M. are working through a PAR training case.

Kevin Manross (EWP Weekly Coordinator, 12-16 May)

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Live Blog – 6 May 2008 (8:20pm)

Kevin M. blogging abouy Bryan and Crag’s PROBWARN experience. Quick synopsis – we are focused on the LBB area. Currently there is little/no TOR threat, so we’re warning on hail.

A few quick questions have already arisen: (since we are currently issuing low-prob warnings)

[Why] would we bother with low prob warnings in a higher end situation?

How best to approach a line of pulse severe? [Do we encompass the line and then issue individual smaller ellipsoids within the line? Decided against – too much work to keep track of all of those indivisual warnings.]

Apprehension to issue many small warnings instead or within the larger one. Mainly a workload issue. Also, these are low-prob warnings.

How do we split a warning into 2 warnings/ Keep and existing one and make a new one? Delete the existing and creat two new ones?

Quick little couplette appears SE of LBB. Do we consider an environmental change and start considering issuing a low-prob TOR threat with these storms?

0030z – issuing a ‘high’ prob warning anticipating a storm merger NNW of KLBB.

Workload becoming an issue – having trouble issuing new warnings and keeping track of exiting warnings in a timely manner. (May be due to storm situation, or software.)

After about 2 hours of running the PROBWARN, Bryan was getting pretty fatigued. Craig switches to PROBWARN issuer at 0046z.

Trying to issue simultaneous hail and wind warnings for the same storm is difficult. (Embedding one polygon within another gets somewhat problematic either w.r.t. drawing verticies, or simply having to redraw the warning twice which takes time).

GUI issue: I have seen multiple instances of people trying to draw polygons (non-ellipsoid) and they end up drawing a straight line.

~0110z, looking at storm to SE of KLBB. Good low-level convergence. TOR prob, non-zero – considering issuing a ‘pre-TOR warning’

Calling it a night for me. been an intersting and perhaps most involved PROBWARN exercise this spring. Should be a fun debrief tomorrow.

Kevin Manross (Gridded Warning Cognizant Scientist)

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Live Blog – 30 April 2008 (6:23pm)

Notes on Gridded Warning Archive Case

Stream of consciousness notes from Mike Cammarata’s exercise:

Getting used to the software. Mike has some experience with this from earlier this week.

“Calibrated” ourselves with the MESH.

Desire to hide/show products more easily.

Would like to know when the next update is expected in displaced realtime case.

Long list of products (mostly warning output grids) became cumbersome to deal with.

At one point, Mike realized that we were encompassing more than the *current* threat area, made that adjustment.

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Group discussion: Mike Cammarata and Patrick Marsh, warning participants (Kristin/Kevin M. pw coords.)

A more informed decision could be made with better technology and guidance tools. For example, storm-following loops and cross-sections (even automated).

Took longer to issue due to polygon drawing (hard to get used to different knobology)

How did we feel about issuing probabilities? Probability was very arbitrary. Mike: “At what level of risk are we going to have a tornado?”

Discussion ensued about difference between achieving GPRA goals and current paradigm of warnings.

Discussion about significant call to action. (Are probs the best way? For tornado?)

Every decision maker has their individual cost-loss ratio for each decision made.

Andy feels that the “public” needs to know when to be told to “duck”.

The big issue is how we can objectively calibrate forecasters to the verification and to each other, so that there is a consistent answer for each warning.

Kevin Manross and Greg Stumpf (Gridded Warning Cognizant Scientists)

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