000 FXUS63 KLBF 170002 AFDLBF Area Forecast Discussion National Weather Service North Platte NE 702 PM CDT Thu May 16 2024 .KEY MESSAGES... - Hot and dry tomorrow with highs approaching 90 and elevated/near critical fire weather conditions - Thunderstorms appearing more likely (60%+) Sunday and Monday with severe weather possible, including all hazard types - Brief stint of cooler/milder temps early in the week, then warming again by midweek with continued low end (<30%) moisture chances && .SYNOPSIS... Issued at 352 PM CDT Thu May 16 2024 The heart of an upper trough has moved downstream of the forecast area today, with its axis roughly lining up with the Missouri River, and placing western Nebraska into broad northwesterly flow aloft. A closed upper low in the process of getting absorbed into the main flow also lies to the southwest, currently centered over New Mexico. Toward the surface, high pressure has gained control of the central and northern Plains in the wake of a cool front. A weak boundary or surface trough stretches along the High Plains, cutting across the panhandle. && .SHORT TERM /THROUGH FRIDAY NIGHT/... Issued at 352 PM CDT Thu May 16 2024 This evening into tonight... The surface high edges eastward, transitioning low level flow to more return southwesterly. WV/IR imagery indicate a couple rounds of mid/high clouds upstream, likely associated with weak PV anomalies. A weak low level jet also develops with guidance generally suggesting 30 kts at H85 in the Sandhills. The combination of the strengthening southerly flow and a thermal ridge will jump start the warm air advection scheme, shown by 6-7C rises over the last 24 hours. Went with a general blend for min temps, which lines up near the median of the NBM envelope. Forecast lows range from upper 40s panhandle to mid 50s north central. Tomorrow and tomorrow night... Upper flow briefly becomes quasi- zonal across Nebraska as the trough over the Great Lakes evens out and a new trough digs upstream in the northern Rockies. A surface low also spins up near the Black Hills and drags a cool front through the Sandhills after dark. In the meantime, fair skies and southwesterly low level flow will help accelerate warm air advection further. Guidance is in good agreement with H85 temps ranging 20-25C across the forecast area, which is a good 5C warmer than today. Again used a general MAV/MET/ECS blend for max temps, which resulted in a subtle upward trend over the previous forecast. While new forecast highs sit in the upper 80s, these values correlate to the lower end of the NBM envelope. Would not be surprised if later forecasts need bumped up another degree or two, especially with NAEFS ensembles suggesting 97%ile of climo. The cool front is progged to cross overnight, primarily 06-12z. Questions remain whether forcing can overcome marginal moisture to result in precip. Left forecast dry as of now, but CAMS suggest iso/sct light rain showers or sprinkles. && .LONG TERM /SATURDAY THROUGH THURSDAY/... Issued at 352 PM CDT Thu May 16 2024 The weekend starts with northerly flow behind the cool front, resulting in relief from Friday's heat. Highs should generally stay in the 70s, accompanied by nearly full sunshine. Attention quickly turns to Sunday when the pattern turns much more active. Another lobe in the large scale upper trough tilts the axis to negative, transitioning the flow to southwesterly for the Plains. Southerly low level flow is basically unimpeded from the Gulf, which helps to push dew points well into the 50s. A lead mid-level shortwave intersects a warm front passage early in the day and a dryline and cool front later on. Parameters seem to be pulling together for a severe weather scenario for western and north central Nebraska. Abundant energy in the form of 1500+ j/kg MUCAPE and very steep mid- level lapse rates (8+ C/km) combine with strong deep layer shear of 40+ kts. Preliminary forecast soundings resemble "loaded gun" profiles, while hodographs indicate consistent veering in the low levels. While convective evolution may be fuzzy, initial mode would likely be supercellular for any development. Agree with the SPC assessment of all hazard types are on the table. The bulk of the forcing shifts east on Monday, but the post-frontal environment on Monday could still comprise steep lapse rates and strong shear, despite the fairly limited instability. Depending on precip coverage during Sunday's event and Monday's new development, may need to monitor excessive rainfall risk. The heart of the deep trough crosses the central Plains on Tuesday, then a ridge gradually builds in over the Rockies heading into midweek. Low end PoP persist into Wednesday, while temps range from coolish Mon (60s north/70s south) to seasonable by Wed (70s/maybe 80). && .AVIATION /00Z TAFS THROUGH 00Z SATURDAY/... Issued at 701 PM CDT Thu May 16 2024 Thunderstorms upstream coming off the Black Hills are moving toward Nebraska but are expected to diminish with loss of heating after sunset, so will not include any mention at KVTN but will monitor closely and amend if needed. Otherwise, VFR conditions will persist across central and western Nebraska through the valid period. A low level jet will become established southwest to northeast with the axis roughly from KIML to KONL. Will include a mention of low level wind shear at KLBF but expect KVTN will remain far enough from the jet axis to necessitate a mention in the TAF. After daybreak Friday once diurnal hearting becomes established, expect some gusty conditions with southwest winds gusting to around 22kt. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Snively SHORT TERM...Snively LONG TERM...Snively AVIATION...MBS