299 FXUS63 KLBF 071124 AFDLBF Area Forecast Discussion National Weather Service North Platte NE 624 AM CDT Wed Jul 7 2021 .SHORT TERM...(Today through Thursday) Issued at 407 AM CDT Wed Jul 7 2021 A small convective cluster early this morning has moved down from the WY/SD border along a frontal boundary where some lingering instability is pooled. Radar trends indicate that the convection has weakened considerably and expect any lingering outflow will ride up and over the dense stable air at the surface delineated well by low stratus clouds in nighttime microphysics satellite imagery. Otherwise, the abundant low stratus has spread just about across all of central and eastern Nebraska, and locations just outside of the cloud edge are experiencing some patchy dense fog. Once diurnal heating mixes the boundary layer enough, the shallow clouds will break up and fog will dissipate after daybreak. Temperatures this afternoon east of highway 183 where clouds hold on longest will top out only in the upper 70s, while readings in the sandhills reach the middle and upper 80s. Return flow behind a departing area of high pressure will push a warm through central Nebraska tonight into Thursday. The best dynamic support with frontogenetical forcing along the boundary will slide by just to our north but will be close enough to mention a slight chance of thunderstorms up along the NE/SD border overnight. The oven door then opens up on Thursday as southerly winds amplify and brings a surge of hot air back to central Nebraska. Moisture is limited so do not expect oppressive heat index values, but as winds become gusty and minimum relative humidity values dip below 20 percent toward the panhandle will have to monitor fire weather conditions especially for locations that did not receive a significant wetting rainfall on Tuesday. Look for triple digit heat near the Colorado border tapering to readings around 90 up near Oneill. .LONG TERM...(Thursday night through Tuesday) Issued at 408 AM CDT Wed Jul 7 2021 Main concern in this period is convective potential Friday into Friday night. Lingering warm front boundary/developing dry line across the region will become a focus for convection as the upper level jet provides diffluence aloft and a good amount of short wave energy slides down the face of the western ridge. Bufkit shows hodographs lengthening with low amplitude and ensemble mean CAPE values approach 3000J/Kg over central and eastern Nebraska. Combined with 0-6Km bulk shear values exceeding 50kt by later Friday afternoon that have a shallow angle of incidence to the expected position of the boundary, expect robust multicell convection to develop and consolidate into an organized MCS with a primary wind threat associated with DCAPE values around 2000J/Kg as it moves into eastward late Friday afternoon and evening. Confidence in this expected evolution is growing and SPC day 3 outlook of a slight risk seems well placed, though there is still uncertainty in specifics. Will be keeping a very close eye on evolution in guidance over the next 2 days. Precipitation may linger into Saturday as the upper trof pulls through and allows high pressure to build in for Sunday with quieter weather heading into the first part of next week. && .AVIATION...(For the 12Z TAFS through 12Z Thursday morning) Issued at 614 AM CDT Wed Jul 7 2021 MVFR to briefly IFR conditions will be possible this morning with low stratus lingering through mid morning. There is also some patchy fog across portions of western Nebraska and the river valleys, but is expected to diminish shortly after daybreak. After mid morning only high clouds are expected to remain and VFR conditions will prevail the remainder of the forecast period. Winds will be light over the next 24 hour period, out of the southeast around 5 to 10 kts. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...MBS LONG TERM...MBS AVIATION...Gomez