EWP Blog

Classic BWER with the Brule County right moving supercell. Seeing the best azimuthal shear with this storm with  nearly 15^s-1. Just got a funnel cloud report a little before 8 pm.

Beautiful heart satellite signature with the splitting supercells in SD late this afternoon.

Update — just got a report of a funnel cloud at 750pm south of Kimball with this storm. Still shows very strong azimuthal shear and the mesh is up to 1.65. Continue to see large updraft values as high as 17.

00 UTC OUNWRF intialization of composite reflectivity and surface updraft helicity over Dallas, TX

Corresponding radar reflectivity from KFWS at 0000 UTC

SNELSON/TY

3DVAR 5km updraft helicity showing some enhanced values with the western supercell in the last 10 minutes.

MRMS 0-2km azmuthal shear confirms what we see in KFWS 88D base data that any rotation is above 2km.

SNELSON/TY

Went with another TOR for Brule County. The storm turned right and the low level circ increased/tightened up. Also saw an increased updraft (around 15 ms^-1) and increase in updraft helicity.

We have warnings out on a few storms to the SW of Midland.  Storms have increased SW of Midland past couple of hours and this is semi-inline with the OUNWRF forecast of increasing tstm coverage over the central and eastern zones through the course of the evening hours. The model has been consistently too robust on the coverage of storms and too east with the timing of storm placement.

Latest model run still shows some strong Surface Max Hourly Wind Speeds near 30 m/s in the first 1 to 2 hours but then indicates a broad weakened wind field around 20 m/s or less in the 3 to 6 hour forecast.  Radar data suggests main threat with these storms would be large hail, and the OUNWRF has Max Hourly Column Hail around 64 kg/m3 just east of where the storms currently are in the next hour…which is verifying fairly close to current radar observations…just a bit too far to the east.   Most WRF parms seems to be indicating a potential for stronger storms through 9 PM then a weaker trend with tstm intensities by 11 PM as the storms move east into the eastern zones.

Tim/JeffG

Looks like the MESH has been a little low today at least with the Beadle County storm. Been getting golf ball reports although the MESH max has been 1.8 inches. In fact, got a report of golf balls near Broadland at 725pm, but only got a 1.2 inch MESH. Interestingly, the old school Hail Algorithm from the 88D suggested 1.75 at this time.

This storm took it’s time developing but maintained a persistent circulation throughout Brule County. Opted to go with a TOR based on the persistence and depth of the circulation combined with the az shear product. 3dvar also showed an increasing updraft. Storm is very far from the RDA, so there are some velocity quality concerns.

Switching WFOs was the trick. A pair of supercells over north Dallas were just putting out large hail about the time we swtiched. 15Z SREF composite indicators such as Prob of STP > 1 and SCP > 3 have bullseyed this area around 00Z, nice verification.

MRMS MESH shows a nice hail core in the eastern storm. Numerous reports of hail to tennis ball size have been received. The western storm, in spite of MESH values < 1.25″, had a report of golf ball size hail in Grapevine.

3DVAR has good updrafts (~13 m/s) and even better upper level divergence (11 s-1). Not seeing much in the wind or helicity fields yet.  88D velocity from KFWS not showing well defined mesocyclones as of yet. Though we did see a really pronounced 3-body scatter spike.

SNELSON/TY