textproduct: North Platte

KEY MESSAGES

- Following morning general thunderstorms, Tuesday afternoon and evening thunderstorms including the threat for severe will be possible with large to very large hail, damaging winds, and perhaps a tornado or two possible the main concerns.

- While most locations remain dry, an isolated thunderstorm or two will be possible in the afternoon and evening Wednesday for portions of west central Nebraska.

- A warmer, drier pattern sets up mid week through the weekend and into early next week. Highs remain above seasonal averages, with little to no precipitation expected.

SHORT TERM /THROUGH WEDNESDAY NIGHT/

Issued at 217 AM CDT Tue Sep 1 2026

Early this morning, rain and thunderstorm coverage was increasing across western and southwestern Nebraska early this morning. This was occuring in advance of an approaching mid-level disturbance. Broad warm air advection and DCVA were the primary sources for lift. Monday evening RAOB data from KLBF showed modest MUCAPE, at or around 1500 j/kg. Early morning mesoanalysis shows little change to this outside of a northward advection of some greater instability. Mid-level flow was fairly strong, observed at 40 knots with this RAOB sample and though some fluctuations are noted in short-term guidance, a rebound in the early morning hours is expected with the arrival of the h5 trough. This will maintain adequate deep-layer shear for storm organization. The Storm Prediction center maintains a Marginal Risk through 12z (7am CDT) and isolated severe wind gusts and/or severe hail will be possible in the strongest storms.

Tuesday/Tuesday Night...a fairly active day for rain and thunderstorms appears likely for western Nebraska. Aloft, the mid- level wave will continue to lift north and east with a weak surface low developing early in the day. This will form on the warm front across northwest Kansas. To the east, southerly flow will strengthen as the warm front begins to lift north. Earlier outlooks suggested a closed low forming just off the surface but trends have been to make the system more progressive with a lower amplitude. This has allowed for a further northwest placement of the surface boundary. This places the area deeper into the warm sector where ample diurnal heating, with afternoon highs in the middle 80s to lower 90s, beneath steep mid-level lapse rates will promote moderate to strong instability of 1500-2500 j/kg MLCAPE. Given strongly veering wind profiles and slightly backed surface flow into the boundary, deep layer shear will be strongly supportive of organized convection. Uncertainty remains regarding where storm initiation occurs with two distinct camps: further north into south central South Dakota or further south across the central Sandhills. The lingering difference between these two solutions is placement of the frontal boundary in the afternoon. The HRRR and RAP depict a northward push through the day and a final placement closer to I-90 with the NAM lagging considerably south as elevated convection early in the morning over South Dakota reinforces the further south placement. The latter of these outputs would prove to be favorable for severe weather locally with the lingering boundary serving not only as a focus for development but also perhaps a source for low-level vorticity which could promote more supercell storm modes and perhaps a non-zero tornado threat. HREF ensemble outlook favors the northern zone where it paints the highest QPF probabilities. Even if the greater coverage remains north, warm air advection in an unstable environment could lead to more isolated development further south with large to very large hail and damaging winds the main concerns, especially with any supercell structures. The SPC has introduced a Slight Risk (level 2 of 5) for north central Nebraska and agree given the potential advertised by a few CAM solutions. Training of storms along the surface boundary, should the further south scenario play out, could lead to locally heavy rainfall as well with the further south NAM12 solution depicting localized rainfall amounts of up to 2". The going forecast resembles HREF output which allows most if not all activity to depart the area by mid to late evening. This will leave the bulk of the overnight hours dry with lows falling to the upper 50s to lower 60s.

Wednesday/Wednesday Night...high pressure across the northern Plains will nose into the area by early in the day. Within the southwesterly flow aloft, the next disturbance will overspread the Intermountain West. Lee troughing through the day will support increasing southerly and southeasterly flow which will drive the high pressure out of the area by midday. A dryline feature will set up over the Panhandle and serve as the dividing line between richer low-level moisture and increasingly dry air anchored to the higher terrain. While the dryline appears likely to be fairly sharp, convergence along the boundary will likely remain weak through the day. Afternoon highs will reach the upper 80s to lower 90s. The lack of greater forcing for ascent casts doubt on thunderstorm potential for the afternoon and evening. Deep layer shear and moderate instability would support a strong to severe threat but confidence in development is too low to message any appreciable severe threat. The SPC highlights low predictability with only a General Thunder outlook (no severe). Will keep PoPs low but maintain a Slight Chance mention (~15%) in our west. Further north and east later in the evening, as a stronger low-level jet forms, do anticipate some development to extend south into north central Nebraska. Though the focus should remain over eastern South Dakota, believe enough forcing exists to lead to at least widely scattered development. The stronger winds off the surface will keep the boundary layer mixed further east where lows will likely hold in the lower 70s with general 60s expected elsewhere to the west.

LONG TERM /THURSDAY THROUGH MONDAY/

Issued at 217 AM CDT Tue Sep 1 2026

Upper level ridging persists late week into next week. This will continue to favor a warmer, drier pattern through the holiday weekend into next week. Temperatures are expected to remain above seasonal for early September. For reference, the first week of September the average high drops from 85 to 83 degrees. However, current forecast highs remain in the upper 80s to mid 90s, with potential for upper 90s across southwest Nebraska. The cooler highs, in the upper 80s to lower 90s, are generally expected to remain across northern Nebraska and remain consistent with the 75th percentile compared to climatology. So, while these highs are warmer than usual, these are not too unusual. Further to the south, where highs remain in the 90s, highs remain consistent with the 90th percentile compared to local climatology, which is less usual. By early next week, some uncertainty begins to build into the forecast, though. GEFS spaghetti plots suggest most solutions still favor upper level ridging to continue across the region, however, some of the more progressive solutions begin to track an upper level trough across the Northern Plains. If these solutions come to fruition, then we could see the upper level ridge begin to break down early week, potentially bringing slightly cooler highs, yet still remaining above seasonal averages.

The upper level ridging is also expected to help limit precipitation potential late week and through the holiday weekend. Ensemble guidance continues to remain pessimistic on precipitation chances, generally keep a less than 10 percent chance of exceeding one tenth of an inch of precipitation through the weekend. However, ensembles do still suggest around a 20 to 40 percent chance for light rainfall, exceeding one hundredth of an inch. Deterministic guidance suggests a few shortwaves tracking through the upper level flow, though given the forecast positions, would expect this to keep surface lows across the Dakotas. With this in mind, cannot completely rule out some slight chances for very light precipitation, but not expecting any wetting precipitation through the weekend. For what it is worth, latest NBM guidance does keep some slight chance PoPs, generally less than 20 percent, each evening this weekend. However, based off the ensemble guidance, would expect any precipitation that may occur will be very light.

AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/

Issued at 616 AM CDT Tue Sep 1 2026

Rain showers are tracking across portions of the region this morning, bringing localized low end VFR conditions. These showers are expected to track out of the region in the next few hours, with additional showers and thunderstorms redeveloping during the morning and early afternoon hours. These storms may bring localized impacts to ceiling and visibility, as well as gusty and erratic winds. At this time, still expecting VFR conditions to prevail at KLBF and KVTN. After this second round of thunderstorms, expecting light and variable winds to prevail across the region. With the light winds and recent moisture, there is is a possibility of patchy fog to develop across the region. Confidence is low in how far fog may spread at this time, so will continue to monitor today.

LBF WATCHES/WARNINGS/ADVISORIES

None.