Area Forecast Discussion
Issued by NWS North Platte, NE
Issued by NWS North Platte, NE
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593 FXUS63 KLBF 292058 AFDLBF Area Forecast Discussion National Weather Service North Platte NE 358 PM CDT Mon Apr 29 2024 .KEY MESSAGES... - Thunderstorms return to the area tonight into tomorrow, and persist nearly each day into early this weekend. - Elevated to near-critical fire weather conditions are expected to develop across western Nebraska Tuesday afternoon with the combination of gusty northwest winds and low humidity. - Strong to severe thunderstorms will be possible both tomorrow afternoon and again on Wednesday, primarily across central (Wednesday) and north central (Tuesday/Wednesday) Nebraska. - Temperatures fluctuate around average (60s) through the workweek with the passage of a few frontal boundaries, before climbing above average into early next week (mid/upper 70s). && .SHORT TERM /THROUGH TUESDAY/... Issued at 400 PM CDT Mon Apr 29 2024 Currently, scattered showers have developed north of I-80, in a narrow corridor of elevated instability. Temperatures range from the low 60s in north central Nebraska to the lower 70s in southwest Nebraska. Aloft, an upper low was centered over ND/MN, with broad zonal flow on its southern periphery across the central Plains. For tonight into tomorrow, active weather returns to the area, as a quick moving upper low drops southeastward through the Intermountain West, reaching the northern Plains early tomorrow morning. At the surface, lee cyclogenesis begins across northeastern WY/eastern MT, dragging a warm front northward across the area into the Dakotas. The deep southerly flow will both boost lows tonight back into the 40s, and lead to increasing moisture return flow into the area. This also looks to generate at least scattered showers in the broad warm advection regime overnight, though any severe threat with this activity looks low. Surface dewpoints will climb into the low 50s for areas east of HWY 183 by early tomorrow afternoon, leading to increasing instability. For areas further west, the surface cold front should begin to push through the area from west to east, reaching the HWY 183 corridor by early afternoon. It is ahead of this boundary where convective development is anticipated, and a window will exist tomorrow afternoon for strong to severe storms, primarily east of HWY 11. Some uncertainty remains with respect to this however, largely tied to the speed of the aforementioned cold front and how much time is maximized in the warm sector during better diurnal heating. Deep layer shear profiles do support organized convection, with good speed shear aloft indicated in area forecast soundings. Large hail and damaging winds look to be the greatest threats, with initial discrete/semi-discrete updrafts presenting the best chance for hail before quick upscale growth leading to increased damaging wind potential. The threat locally will likely be brief, on the order of a few hours, and tied to the progression of the surface cold front. This will need to be monitored closely as mesoscale details become more clear. High temperatures will range from the 60s across northwest Nebraska where the surface front should pass in the morning, to the low/mid-70s in southwest and central into north central Nebraska. Elevated to near-critical fire weather conditions look to develop across western Nebraska in the wake of the surface cold front tomorrow afternoon as well, as dry air is ushered into the area. This will send relative humidity values falling into the upper teens to low 20s for areas near and west of HWY 61. More concerning, as we mix out during the afternoon, winds will quickly strengthen from the northwest, tapping into a belt of 30-40kts of H7-H85 flow aloft. This should promote wind gusts approaching 40 miles per hour across western Nebraska with ample downward momentum transfer in the well mixed boundary layer. The overlap of strong northwest winds and low humidity could lead to a period of near Red Flag conditions, considering current fuel conditions from recent greenup. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... Issued at 400 PM CDT Mon Apr 29 2024 The threat for strong to severe storms persists into Wednesday, as yet another shortwave is progged to cross into the Plains by late Wednesday evening. At the surface, the aforementioned cold front will quickly stall across central Kansas, with lee cyclogenesis beginning across southeastern CO. This places our area in postfrontal broad east-southeasterly upslope flow. The easterly flow will pull the moisture that was ushered out behind tomorrow`s cold front right back into the area, with dewpoints increasing through the afternoon. The exact degree of moisture recovery remains somewhat uncertain, and this will determine the areal coverage of any severe weather threat. Portions of central and north central Nebraska look to have the best shot at higher dewpoints/greater instability, in closer proximity to the surface warm front in central Kansas. Hodographs look more than adequate to support severe weather across much of the area as well, with ample curvature in the lowest few kilometers and increasing speed shear aloft. Synoptically, this does resemble a regime that is favorable for severe weather across western Nebraska as well, with convection initiating across the Front Range of Colorado in the broad upslope and pushing northeastward into the area. Should discrete storms sustain themselves into western and southwest Nebraska, a threat for large hail and damaging winds would be possible, again driven by the degree of instability with northeastward extent. The pattern remains active into the latter part of the workweek and into early this weekend, as multiple shortwaves look to push through the area in the quasi-zonal flow aloft. Nearly daily shower and thunderstorm chances exist through Saturday across much of the area. The degree of any severe weather threat will be driven by surface features each day, though mid/upper level flow does look strong enough to warrant at least some concern for severe weather. Mesoscale features will need to be watched closely, and additional threats for severe weather may exist as we wrap up the workweek. && .AVIATION /12Z TAFS THROUGH 12Z TUESDAY/... Issued at 1159 AM CDT Mon Apr 29 2024 High clouds will begin to increase later this afternoon from west to east across the area. Ceilings will be in the 15000 to 25000 FT Range for both the KLBF and KVTN terminals through Tonight. Look for clouds to thicken Tuesday morning, especially over northern Nebraska where broken ceilings of 7000 to 12000 FT are possible at the KVTN terminal. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...Brown LONG TERM...Brown AVIATION...Buttler