EWP Blog

Initial thoughts focus on the Tulsa (TSA) as well as the Springfield (SGF) and Little Rock (LZK) CWAs for convective initiation and storm maturity. Latest visible satellite imagery depicts congested cumulus field over southeast Oklahoma in response to continued low-level moisture transport and broad ascent with analyzed speed maximum across northeast Texas.

• Watching two potential scenarios unfold late this morning into the afternoon hours. First, monitoring broad cu field over the next several hours for initial convective development over eastern Oklahoma or western Arkansas as further low-level destabilization transpires and increasing deep layer shear arrives across the area. Model guidance suggests robust activity maturing over northeast OK into northwest Arkansas by early/mid afternoon, and therefore watching the TSA/LZK CWAs.

• To the west, a more conditional scenario exists along the cold front during the afternoon from Ardmore to Tulsa. Clearing has been noted ahead of this boundary from Graham, TX to Duncan, OK. Stratus deck to the northeast of the corridor appears to be thinning along I-44. Will have to also monitor this area later this afternoon across the TSA CWA for additional robust activity.

Main severe weather threats will likely be large hail up to golfball size and damaging winds in excess of 60 mph with well-organized multicell storms or a few supercells. Tornado threat appears low today with marginal low-level shear within the 0-1 km layer. However, any unresolved storm-scale boundaries from early morning convection within the warm sector of far eastern Oklahoma or western Arkansas may locally enhance isolated tornado threat.

Blair/Curren

Today was an active day for our visiting forecasters, but not in the way we were originally expecting at the end of the previous shift with models initially forecasting development of supercells along the dryline in central and western Oklahoma.  As the CI forecasters began their morning forecast, it was already evident that the ongoing convection in western Oklahoma had greatly modified the forecast from the day before.  Initially, none of the high-resolution models had a handle on the overnight convection, but the OUN-WRF and HRRR were beginning to modify with each successive run, keying in on the development of MCS moving across Oklahoma and the possibility of rotating storms further north near the CO/KS border associated with the closed Low.

The split of forecasters between these two regions seemed to work out well.  Forecasters focusing on the Oklahoma region were able to examine both the pGLM over the Oklahoma LMA network and 3D-VAR data as the MCS reached its peak strength.  Meanwhile, GLD and DDC forecasters monitored CI and later were able to incorporate 3D-VAR data in their analysis as things wound down in central Oklahoma and we moved to the floater domain.  While none of these storms produced tornadoes, the vorticity product from the 3D-VAR was easily incorporated into the analyses and seemed to prove useful in the warning decision process.

-K. Kuhlman (weekly coordinator)

As we watched the storms move through central Oklahoma today a small, isolated cell developed over Lawton, Oklahoma. This storm conveniently gave us the opportunity to show the effectiveness of total lightning observations in helping gain lead-time ahead of the first cloud-to-ground lightning strike. This small cell turned out to be even more interesting as the PGLM observations gave a 29 minute lead-time over the first cloud-to-ground strike. This was pretty remarkable as the lead time is usually on the order of 5-10 minutes. Below are three images showing the event.

-Geoffrey Stano (NASA/SPORT)

Central Oklahoma had several strong thunderstorms move through the region and the forecasters at the Spring Program had the chance to check out the pseudo geostationary lightning products derived from the Oklahoma lightning mapping array. Most of our time was spent investigating the products and discussing the various pros and cons. The figure above shows a good use for these data in a lightning safety perspective. The 1-minute PGLM flash extent density (and the corresponding NLDN cloud-to-ground lightning data) are tightly clustered with the the stronger convective regions, indicated by strong radar reflectivity. However, unlike the NLDN data, the PGLM flash extent density still showed that lightning flashes were extended anywhere from 8-32 km into the stratiform region. This shows the advantage of seeing the spatial extent of lightning activity available from total lightning observations. This is further emphasized with the PGLM maximum flash density in the upper-right which shows the maximum PGLM for each grid box for the past 60 minutes. This shows that most of central Oklahoma has had lightning activity within the past hour, indicating that the threat of a cloud-to-ground strike still exists.

-Geoffrey Stano (PGLM Principal Investigator)

Brandon has been comparing the 3DVAR data with the regional radars across OUN, specifically max vorticity from  3DVAR vs radial velocity data.

Below is a screenshot from 2111 UTC including max vorticity of  about 0.01 s^-2 to storm relative velocity (at 1.8, 2.4, and 3.1 degrees elevation) from KTLX:

-K. Kuhlman

Brian is noting a good relationship between the 3DVAR  vorticity field and low-level radial velocity data on the tornado-warned storm in NE Cleveland/Pott. Counties.