


Area Forecast Discussion
Issued by NWS North Platte, NE
Issued by NWS North Platte, NE
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388 FXUS63 KLBF 061743 AFDLBF Area Forecast Discussion National Weather Service North Platte NE 1243 PM CDT Sun Jul 6 2025 .KEY MESSAGES... - Strong to severe thunderstorms are probable each day Sunday and Monday with a Slight Risk (level 2 of 5) and an Enhanced Risk (level 3) in place for each respective day. - Locally heavy rainfall is possible both Sunday and Monday with total rainfall amounts for the 48 hours of 1-2" likely across central Nebraska. - Seasonable temperatures and recurring rain and thunderstorms chances continue through the extended forecast with the threat of severe weather returning on Thursday. && .SHORT TERM /THROUGH MONDAY NIGHT/... Issued at 424 AM CDT Sun Jul 6 2025 Early this morning, progressive outflow from Saturday evening convection across western South Dakota was tracking south and east into the Sandhills. This boundary was providing enough low-level lift to overcome the stable low-levels and lead to scattered showers and thunderstorms. A few storms, particularly near Valentine as of 0815z (315am CDT) were noticeably stronger and perhaps contained some small hail but overall the threat for severe weather is low with MUCAPE of around 1000 j/kg and lapse rates aloft fairly marginal. Aloft, fairly zonal flow was in place as shortwave troughing departed to the east into the Mississippi Valley and another notable shortwave was apparent along the Montana/Saskatchewan border. Placement and evolution of the low- levels with respect to this outflow will have large implications on how the threat for thunderstorms, including the threat for severe, plays out today. Sunday/Sunday Night...Early morning model guidance is already struggling with placement and progression of outflow currently located near a VTN to AIA line. This feature will continue to shift south but will likely stall across the central Sandhills closer to daybreak. This will result in a fairly notable spread in daytime highs with upper 80s to low 90s across southwest Nebraska but only upper 70s along the Nebraska/South Dakota border. Through the late morning, surface winds will back to the south and then southeast ahead of the boundary and this will maintain a ribbon of richer moisture as dew points in the lower 60s persist within a relatively narrow corridor. Warming temperatures in the mid-levels will promote steepening lapse rates with magnitudes climbing to around 7.5-8.5 C/km. Within the narrow moisture tongue and as daytime temperatures climb, moderate to strong instability will develop. As the shortwave along the international border tracks east, enhanced mid-level flow will overspread the Central and Northern Plains creating a strongly sheared environment with ample instability. Latest Day 1 Storm Prediction Center outlook maintains a Slight Risk (level 2 of 5) for much of the area. A few flies in the ointment regarding the setup: 1) Outflow remains progressive and already appears to be further south than what many CAMS suggest. This casts doubt on deterministic solutions and taking their direct output as reliable. 2) Placement of eventual boundary stalling also remains somewhat uncertain and could trim areas out of the severe threat should this continue to shift south. 3) Recent trends have suggested that capping may not fully erode and with fairly weak forcing in the warm sector, discrete storms may be limited or not materialize whatsoever. Given these lingering questions, have kept PoPs on the lower end through the daytime Sunday. Should a storm develop this afternoon, it`ll likely remain fairly discrete and all hazards of severe weather will be in play with greatest concern being very large hail, perhaps exceeding 2", damaging wind gusts of 70-80 mph, and a tornado or two. It`s worth emphasizing this is likely the worst case scenario and current confidence in this scenario materializing is low. Later today though, within the southeasterly moist flow, believe storms are more likely to develop off the topography to the west of the forecast area. Reasonable theta-e advection off the surface should fuel a complex of thunderstorms that quickly grow upscale with merging cold pools. Given high DCAPE values focused across southwest Nebraska, believe damaging winds gusts would be the main concern. Given recent heavy rains from July 4th activity, did briefly consider hoisting flood headlines in our southern zones. Opted against this eventually as uncertainty with evolution of storms today casts doubt on magnitude of rainfall amounts. On top of that, storms should remain progressive and the threat for seeing more than one round in the areas that saw heavy rain the other day appears low. While a few locations could see 1-2" of rainfall from activity tonight, belief is this will be rather spotty and not present widespread issues warranting headlines. Storms should quickly dive southeast into the strengthening LLJ. Believe most if not all thunderstorm activity should exit the area around or shortly after midnight. Monday...a greater severe risk appears likely for tomorrow. Latest SPC Day 2 Outlook has added an Enhanced Risk (level 3 of 5) for much of the forecast area. Inherited PoPs from the model blend painted extensive Chance (25-55%) and even Likely (55%+) categories across the region. Following collaboration with neighboring offices, opted to trim these up somewhat as the day is not anticipated to be a "wash out". As northern stream troughing translates east, a surface cool front will settle south into the area by late in the day. Southerly flow ahead of this feature will reinforce low-level moisture and push afternoon highs into the low to middle 80s. Timing of this front appears to favor late afternoon and early evening into our northwestern zones. While broad warm air advection storms appear possible ahead of this feature, forcing will be maximized along this boundary and therefore have highest PoPs later in the day. An approaching mid-level speed max will interact with this frontal boundary around peak heating as moderate to strong instability develops. Flow aloft exceeding 30 knots will support a strongly sheared environment with 0-6km BWD of 35 to 45 knots. Forecast hodographs exhibit long straight hodographs initially, elongating through the evening as LLJ increases. This significantly increases low-level curvature and bolsters 0-3km to around 200 j/kg. Given shear vectors largely orthogonal to the surface boundary, believe discrete storms may be sustainable for a few hours into the evening. This increases concern for very large hail (2"+), damaging wind gusts approaching 75 mph, and a tornado or two. Eventually though, with ample unstable air feeding into the frontal boundary, upscale growth appears likely and a transition to primarily damaging winds is probable. SPC`s Enhanced Risk outlook is mostly driven by the damaging wind outlook and believe this is valid. Given strong forcing and anomalous moisture quality, believe heavy rain is also possible though confidence in magnitude of rainfall is limited at this time. Storms once again should depart to the southeast around or shortly after midnight leaving the remainder of the overnight dry for the area. && .LONG TERM /TUESDAY THROUGH SATURDAY/... Issued at 424 AM CDT Sun Jul 6 2025 Tuesday and beyond...temperatures are likely to climb towards the middle of the week as upper ridging across the Desert Southwest surpasses 595 decameters. Though this is fairly anomalous values for the area, the warmer air appears likely to remain bottled up in closer proximity to the feature. Northwesterly flow will overspread the Central Plains through the middle of the week. Highs will climb into the middle to upper 80s for Tuesday and upper 80s to middle 90s for both Wednesday and Thursday. While precipitation chances will continue for both Tuesday and Wednesday, greater probabilities will come Thursday as ridge breakdown begins during the day with a stronger disturbance tracking out of the Pacific Northwest. Given the expected warmth and an approaching cool front, have higher-end PoPs in the forecast with Chance and Likely categories (45-60%) in place. The SPC also highlights a Day 5 Outlook encompassing our northern zones. Outlooks for Day 5 from SPC are fairly uncommon for the local area, with a quick look showing the area averages maybe one or two instances of this occurring a year. Active weather continues through the end of the week as broad troughing remains in place across the northern Plains through Friday and Saturday. This should help maintain cooler temperatures through the time frame. Temperatures should moderate by the start of the following week, however, as mid-level heights build and ridging strengthens once again across the west coast. && .AVIATION /18Z TAFS THROUGH 18Z MONDAY/... Issued at 1243 PM CDT Sun Jul 6 2025 VFR conditions are expected outside of convection today. Lingering light rain will impact KVTN for the next hour or so with the departure of the morning convective complex across north central Nebraska. Later convection this afternoon is largely expected to miss the site, however impacts are expected at KLBF. The line of storms is anticipated around 02-04z with at least MVFR restrictions. Near-term amendments later today will account for most recent trends. Site will quickly return to VFR behind the storms. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...NMJ LONG TERM...NMJ AVIATION...Hagenhoff