Just before 20Z, storms have developed and the Throckmorton storm looks to be close to severe threasholds. Confidence is high that a warning will be needed for the storm. Prob severe has reached 99% with estimated hail size around an inch. Growth rate and glaciation are strong.

The storm weakened a bit as it entered the CWA, but then strengthened quickly. Growth rate and glaciation was strong. A warning was issued.

Scott Rudge.

Storm moving into our area out of Weld Co., CO.  Seems to have lost its rotational signature, but is already cycled a couple of times…and at the least has exhibited some signs of strong downdraft wind wrapping around.   Jared issuing SVR for wind at 2115Z

of interest…total lightning has been relatively steady on this storm over the past 15 minutes.  Only some ebbs and flows…nothing notable…

db

Upper level analysis has ridge shifting east with trof entering the four corners region. Upper flow is west to southwest across the southern plains with 120 knot jet across central Texas.

NAM/RAP 500/700 Heights/Vorticity not showing any strong upper waves coming through this afternoon and evening.

Satellite and surface data show some mid level cloudiness moving through the southwest portions of the CWA. Dry line resides across far western portions of OK. Moist southerly BL flow continues across central and eastern portions of the area.

Nearcast moisture fields indicate increased PW’s and higher Theta E moving into the area by late afternoon and early evening.

Convection has initiated just south of the forecast area and just east of the dry line.

Scott Rudge.

Some thunderstorms have already developed this morning and this trend should continue through this afternoon. Moisture is shallow now, but the column continues to moisten as we progress through the day. The main focus, I believe, will be just east of the region. Temperatures are currently in the 60s and 70s in Northeastern Colorado and Western Nebraska with a little better moisture content. The main low is hanging back over Southwestern Wyoming, but we will begin to see some energy rotate in and around this low later this afternoon. There should be better support for storms as the jet become better established over the region, as well. The tornado threat is on the lower end, while the hail and wind threat would be greater. Low freezing levels would suggest easy formation of hail, especially if we can get some better updrafts (especially outside the meager 40 and 50 degree temperatures we see in Wyoming/Colorado).

Jared Maples

I was focused on a storm south of Cheyenne that was developing just west of I-25. The first few scans showed some potential with the storm. The Prob Svr was indicating smaller values (~30% range) around 1930Z. I utilized the all-tilts and dual pol products to see the extent of the storm height and magnitude of the reflectivity. It was apparent that 60+ dbz were up to around 19,000 AGL at the time. A freezing level of around 4,000 AGL gave confidence that some type of hail was falling. It was only about ten minutes later than the Prob Svr jumped from the 30% range to the 70% range. This would have had a decent influence on any warning that was issued. Soundings depicted plenty of dry air aloft, which would have supported some wind associated with this storm. Approximately 15 minutes time passed before velocity returns showed interest features that may have signified some decent wind gusts.

Jared Maples

Severe t-storms are a possibility through the afternoon in the High Plains around WY, CO, NE.

NAM, GFS agree on a low on the E. Colorado/W. Kansas area strengthening some through the afternoon, increasing the easterly, upslope flow into the area.  This will also serve to advect higher moisture content from the east…something we see in the Nearcast precip. H2O analysis

Ongoing convection in WY in combination with plenty of cirrus over the area of concern has limited for now the use of the CI product.  Plenty of clearer air farther southeast in KS outside of the area of immediate concern.

The Nearcast vertical theta-e difference product shows a band if instability along the WY, CO border and on into western NE.  The model forecast shows a maximum in instability near the WY, NE border at 22Z.

As ongoing convection in WY emerges into warmer, ore unstable air to the east, there is an expectation that storms will intensify.  Also need to be on the lookout for any thinning in the cirrus shield over the next few hours in NE as we could see more development out here.

Storm motion should be to the northeast.  Low freezing levels may lead to very large hail.  Looking at the 22Z Nearcast forecast difference in PW between the low and mid-levels, higher values are seen in the area of concern…drier air aloft could assist in downdrafts and damaging wind production.

Will monitor impulses rounding the upper trough to the west for increased vertical motion through the afternoon/evening.-db

CI tagging cu field in western north Texas with 90 percent development. A few storms have already formed with strongest storm approaching Knox county with 27% on
prob severe model.

BT