Comment from Steve H., Dave, and Jonathan (via Mike M.):
If the threat area seems to be advecting downstream with an acceptable motion, they would like to be able to just update the probabilities without worrying about moving the polygon (that is, the polygon moves by itself).
Travis Smith (EWP Weekly Coordinator, 19-23 May)
The team of Steve H., Dave, and Jonathan have been working the South Carolina storms in the Charleston area, along with Mike M. (probwarn coordinator). So far, they’ve been exclusively issuing hail and tornado threat areas. The cancelled the threat areas for the first storm as it moved offshore in the last 20 minutes. They may begin issueing wind threat areas as well as they begin focusing on a new storm.
We’ve had live streaming video from Charleston channel 5 for the duration of the event, although it hasn’t resulted in too much addition information about ongoing storms.
Travis Smith (EWP Weekly Coordinator, 19-23 May)
There are several issues preventing SHAVE from keeping up with the storms of interest in order to provide real-time reports. Becaues the LSR’s are pretty timely today, we’ve decided to go ahead and collect high-density reports on the storms that the forecasters are focussing on although it will be delayed. This will let us do a nice comparison in post-analysis although it’s not really helpful for real-time decision-making.
Travis Smith (EWP Weekly Coordinator, 19-23 May)
SHAVE is working North Carolina and Georgia this afternoon, and will link up with the Prob Warning exercise in another hour or two.
Travis Smith (EWP Weekly Coordinator, 19-23 May)
There is already a Severe T-Storm Watch box out for N. Carolina/Virginia at briefing time, and it looks like we’ll let the storms mature and have a Prob Warning Guidance IOP beginning at 4pm CDT. This is a good region for SHAVE verification as well, so we will try to coordinate the two projects in order to maximize verification of the PWG grids.
The forecasters will split up and work on PAR and CASA playback cases until then.
Travis Smith (EWP Weekly Coordinator, 19-23 May)
We examined some storms SW of Brownsville for the PWG training. No IOP this evening — any data collected are just for training purposes. No strong convection anywhere in the CONUS today.
At the end of the training, conversation ensued about the role of automated algorithm guidance in the warning decision-making process, how to calibrate probabilistic information for different threat type, and the value of advecting warning grids.
Travis Smith (EWP Weekly Coordinator, 19-23 May)
Good day for training! The SPC outlook for today is “See Text”, with a 2% tornado probability over the S. Illinios/Kentucky/Tennessee area and 5% hail probability over three different areas (Upper Midwest/Central Plains/Ohio Valley). There is big 500mb trough in the east with generally NW flow over the risk areas.
Today’s plan(afternoon):
In the evening, we will do a Probabilistic Warning Guidance training exercise, in real-time if storms develop, or displaced real-time if not.
Travis Smith (EWP Weekly Coordinator, 19-23 May)
Since some of the damage from last night was across the street from my kids’ school, I set off from there this morning with only a Nokia N95 as assistance. For those who don’t know, this cameraphone is pretty nice:
I basically drove around and took pictures with the phone and then uploaded them. It seemed great! Only, when I got back to NSSL, I discovered that it didn’t really go so well:
The practical upshot is that the GPS Logger / regular digital camera survey method will still work better, unless you want to auto-upload your results to a web site.
(Travis Smith)
A quick look at the PAR data indicates two separate short-lived circulations that passed through Oklahoma County and were scanned by the PAR.
Survey photos KML from Piedmont to Meridian and NW Expressway are attached. There was an almost continuous narrow path between the two locations, though part of it would have been over Lake Overholser.
Too bad there is no EF-scale DOD for movable metal bleachers. I saw loads of those tossed around. One of them badly bent a steel-braced awning at the baseball fields.
A photo from newsok.com was in the back yard of someone’s house in Yukon, so I didn’t get in to see the damage myself. The only other stuff I saw in that area were some stockade fences blown down and some limbs removed (no uprooted trees or anything). So that part of the path could be EF1 based on the picture, but EF0 based on everything else.
Kiel and Angelyn surveyed the Edmond / NOKC circulation. Kiel writes:
I’ll use tornado lightly here…radar really helped pick this guy out. Anyways, attached is Angelyn’s and my survey. Gonna go EF0 on this bad boy…sporadic damage that eventually lined up into a path (2.8 miles long by 20 yards wide).
DI/DODs:
Trees (hard/softwood): DOD 3
Single family home: DOD 2
Aparment building: DOD 2Given the last DI/DOD, winds up to 82 MPH.
(Travis Smith)