FXUS63 KLBF 111145 AFDLBF Area Forecast Discussion National Weather Service North Platte NE 645 AM CDT Sat May 11 2024 .KEY MESSAGES... - Generally near or above normal temperatures for the next week with no widespread frost anticipated - A few showers/storms south today, then more widespread tomorrow afternoon with little to no severe weather threat - More low end (<30%) chances of precip throughout the week, although a greater potential for more widespread thunder (60%+) Tuesday evening && .SYNOPSIS... Issued at 405 AM CDT Sat May 11 2024 An upper level closed low spins near Las Vegas, while Nebraska lies on the western periphery of a more prominent trough digging through the Great Lakes and the Chesapeake. At the surface, high pressure has settled onto the Great Plains in the wake of a quick-passing cool front. && .SHORT TERM /THROUGH SUNDAY NIGHT/... Issued at 405 AM CDT Sat May 11 2024 Today and tonight... The surface high drifts east, resulting in downslope west flow early in the day to become more southerly later on for the region. The southerly low level return flow will help pull moisture into Nebraska, as shown by dew points rising into the mid/upper 40s by tonight. A developing lee side surface low will add to the forcing ahead of the approaching upper low, and an isentropic upglide regime takes hold. While the bulk of the rain shower activity will take place in CO/KS, some showers and perhaps a storm should be able to spread into southwest Neb toward sunset. A few showers will also continue into the overnight hours as the upper low eventually reaches eastern CO. Thunder parameters are very weak, and severe weather is not anticipated, as MUCAPE will be limited to 500 j/kg and deep layer shear 20 kts. For max temps, bumped values up a couple degrees over the previous forecast to account for fair skies for at least the first half of the day and modest warm air advection at H85. Guidance has trended slightly warmer, reflecting the 24 hr temp changes of 3-4C at H5. Highs range from mid 70s in the panhandle to near 80F in central Neb. Increased cloud cover tonight should hold lows to the mid 40s (west) to lower 50s (east). Tomorrow... The main upper low, as well as the surface low, cross into western Kansas by the afternoon. Meanwhile, a clipper-like system comprising a low and attendant cool front, race south from the Prairie Provinces and reaches the SD/NE border by sunset. Low level flow flips to southeasterly, which increases the moisture advection further. Despite a weaker shear profile, instability seems to increase across the Sandhills with mid-level lapse rates near 7 C/km and MU values nearing 1000 j/kg in spots. Short term model guidance locks on to iso/sct showers becoming more widespread in the afternoon. The severe weather threat still appears low, but pockets of heavier precip is definitely in play. Recycled cool air at H85 and thicker cloud cover will keep max temps cooler in the south compared to the north. The NBM envelope spread widens, so stayed near the median values given the higher uncertainty. Highs should range from upper 60s south of I-80 to near 80F along the SoDak border. && .LONG TERM /MONDAY THROUGH FRIDAY/... Issued at 405 AM CDT Sat May 11 2024 Continued forcing and remnant moisture near the upper low will keep a few rain showers around on Monday, but a stronger cool front presents a more significant and widespread shot of moisture on Tuesday. Will need to monitor for a window of strong or severe storms across the Sandhills during the afternoon and evening. Guidance points to a ribbon of higher CAPE values riding up the Hwy 83 corridor, while a newly approaching upper trough increases the deep layer shear component. To round out the week, upper flow becomes nebulous but a couple more surface boundaries slide through the region. The forecast maintains periodic low end (20-30%) PoP. As for temps, an H85 thermal ridge kicks into gear on Tuesday ahead of the cold front. Guidance ranges from 15-20C in the Sandhills, which could translate to lower/mid 80s in the south and upper 70s to the north. The front presents a brief setback Wed and Thu, but highs should rebound to the 70s/80s by the end of the week. Even with the frontal passage, morning lows really don't dip below 40F this week. && .AVIATION /12Z TAFS THROUGH 12Z SUNDAY/... Issued at 632 AM CDT Sat May 11 2024 VFR conditions continue over the forecast period. Winds will be out of the west to southwest around 5 to 10 kts throughout the day into tonight. Skies will remain mostly clear over the next 24 hours. There is a slight chance of a shower or thunderstorm across southwest Nebraska. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Snively SHORT TERM...Snively LONG TERM...Snively AVIATION...Gomez