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

Thunderstorms developing north and east of Abiline lose their CI fairly quick. 22:00Z – storm just east northeast of Abiline has 60-70% CI.

2230Z – Storm ENE of Abiline looses its color tag. Next developing storm just north of Abiline showing 20-40% CI.

23:00Z – Now both storms no longer have color tags.

23:45Z – A new cell goes up between and just to the north of the 2 original storms – and does not receive a color tag.

Scott Rudge.

At 00:08Z, the northernmost storm just ahead of the dry line has just entered the OUN CWA. Prob severe was sitting at 66% with estimated hail size of just under an inch.

Scott Rudge

It’s the evil “inverted bow echo”.  Actually a storm splitting just north of CYS 23:48Z

Update 00:30Z  looking at total lightning along this storm…the following image represents total ltg. at the time of the above image.  Lightning dropped off quickly shortly after…at the same time the storm weakened as it went through a split/reorganization.  By 00:15 ltg had picked back up as the storm reorganized.  Storm as strong as it has been at 00:30 (74% on ProbSevere, 1.10″ MRMS MESH) but lightning as not picked back up to its previous high levels before the previous split…

Shortly before 2300Z, development of t-storms took place just E of CYS.  A few CGs, intensifying, and moving NE.  Instability remains marginal in this area…higher to the north…and in western NE where the atmosphere has heated up after losing an earlier cirrus deck.  Will closely monitor available tools as this storm crosses the area.

Update:  strong, not svr, storm continues now just NW CYS at 23:40Z.  Has shown slight weakening.  ProbSevere has matched that pretty well…down to 57% from a high of 66%.  Maximum MRMS MESH was near 1″ at 66%, down to .88″ at 57%. db

All output of Prob severe model are white text.  Change font/color based on certain thresholds. For example, MESH output changes to yellow once 1 inch hail is predicted etc.

Convective initiation has once again lined up pretty well with the instability depicted on the theta-e difference graphic in the nearcast. I have now seen this in a couple of cases. The nearcast forecast brings some instability north into Oklahoma later this evening. It will be interesting to see how this lines up with the convection at that time, as the HRRR model has shown some decent development across portions of North Central Texas and Southwestern Oklahoma.

Jared Maples