textproduct: North Platte

KEY MESSAGES

- Isolated to widely scattered severe thunderstorms will be possible tonight.

- A cold front will tend to focus the severe potential more across Kansas Tuesday

- Strong to severe thunderstorms are possible again Wednesday. Locally heavy rainfall will also be possible given the moist environment.

- Warmer and drier conditions return Friday into the weekend as an upper-level ridge strengthens across the region.

SHORT TERM /THROUGH TUESDAY NIGHT/

Issued at 339 PM CDT Mon Aug 17 2026

Appears to be a residual outflow boundary from earlier convection that has settled across the southern Sandhills this afternoon. This will be one area to watch for possible convective initiation late this afternoon. The other area to watch will be development across southwest into south central South Dakota. CAMs have been more aggressive with this activity, and move it into northern Nebraska this evening (mainly east of Highway 183). This would be round one, with another potential late night round tracking virtually across the same area of north central Nebraska. If two rounds do indeed occur across the same area will have to monitor for some locally heavy rain potential. As far as severe, deep layer shear is more than adequate for storm organization. A couple of initial supercells could emerge out of a deepening CU field late this afternoon into this evening near the aforementioned outflow boundary. CAMs have struggled with the evolution of this scenario. The storm organization across southern South Dakota is more certain, with multiple runs of the HRRR showing at least a couple of rounds of potential intense convection. The main risks would be from damaging winds and large hail. The overall tornado risk is low.

A cold front will sag southward into Kansas Tuesday. Although some isolated shower and thunderstorm activity will be possible during the day, the better focus for afternoon development would be south of the area nearer the cold front across Kansas. Other storms may move off the higher terrain into northwest Nebraska during the evening...and these could continue eastward overnight. At this time, this activity doesn't look like it will be overly strong, with the better focus remaining to the south overnight.

LONG TERM /WEDNESDAY THROUGH MONDAY/

Issued at 339 PM CDT Mon Aug 17 2026

Wednesday, an upper-level longwave trough will become established across the Great Lakes and Hudson Bay region, resulting in northwest flow aloft across the area. Along the southwestern periphery of this trough, a weak disturbance will move through the region. Surface dew points in the mid to upper 60s, combined with sufficient mid and upper-level forcing, will support shower and thunderstorm development across portions of the area. In terms of severe weather, MUCAPE values of 2000 to 3000 J/kg combined with 40 to 45 knots of deep-layer shear should support organized convection, with large hail and damaging winds the primary threats. The SPC currently has much of the forecast area in a Marginal Risk for severe weather Wednesday, and this period will continue to be monitored closely over the next several forecast cycles. Moisture profiles will also remain quite impressive, supporting efficient rainfall processes and the potential for locally heavy rainfall with stronger thunderstorms. Temperatures Wednesday will remain on the cooler side, with highs generally in the mid to upper 70s across much of the area.

Thursday, the longwave trough across the Hudson Bay region will continue to shift east as an upper-level ridge builds across the western United States, maintaining northwest flow aloft across the region. Warm air advection will begin to increase as the western ridge amplifies, with 850-mb temperatures returning to the 20 to 25C range. This will support warmer surface temperatures, with highs returning to the mid 80s across much of the area. Another weak disturbance is forecast to move southeast through the northwest flow on the backside of the departing longwave trough, potentially providing sufficient lift for scattered showers and thunderstorms Thursday afternoon and evening. Severe weather may again be possible given sufficient instability and deep-layer shear. However, strengthening 850-mb warm air advection may result in a stronger cap, potentially limiting convective initiation. This period will continue to be monitored over the next several forecast cycles.

Friday into the weekend, the upper-level ridge across the western United States will amplify and gradually shift east toward the region. Increasing subsidence associated with the amplifying ridge should favor drier conditions, while the stronger upper-level flow and better forcing remain north and east of the area. Temperatures will also trend warmer, with highs returning to the lower to middle 90s across western portions of the forecast area through Monday, while north-central Nebraska remains somewhat cooler with highs generally in the lower to middle 80s. By early next week, the upper- level ridge is forecast to begin flattening, resulting in a transition toward more zonal flow and potentially allowing stronger upper-level flow to return to the region.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 1258 PM CDT Mon Aug 17 2026

VFR conditions will prevail across all of western and north central Nebraska through tonight and into Tuesday morning. There is a signal for some lower MVFR ceilings to develop west of departing thunderstorms across central and portions of north central Nebraska early Tuesday morning. Otherwise scattered thunderstorms should develop this evening, and as mentioned, depart the area later tonight.

LBF WATCHES/WARNINGS/ADVISORIES

None.