Area Forecast Discussion
Issued by NWS North Platte, NE
Issued by NWS North Platte, NE
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044 FXUS63 KLBF 161801 AFDLBF Area Forecast Discussion National Weather Service North Platte NE 101 PM CDT Mon Sep 16 2024 .KEY MESSAGES... - Windy (30+ mph) conditions today and Tuesday ahead of a potent system pushing inland across the western US. - A cold front will bring increased precipitation chances (40-70%+) Tuesday night into Wednesday, with a threat for severe wind gusts for areas generally along and west of Highway 83. - High confidence (>90%) in above normal temperatures through the week ahead of a pattern change this weekend with cooler temperatures and a secondary threat for precipitation. && .SHORT TERM /THROUGH TUESDAY/... Issued at 413 AM CDT Mon Sep 16 2024 Today and Tonight...The aforementioned early morning activity currently developing is expected to orient itself along a north- south corridor east of Highway 183, waning through the early afternoon. At most these showers and thunderstorms may produce some gusty winds with hit-or-miss precipitation amounts of 0.5" or less. Outside of this, dry conditions are expected across the local area today. Surface high pressure will continue to hold strong across the eastern half of the US with a surface trough of low pressure deepening across eastern Wyoming into eastern Colorado. Southeasterly flow ahead of the surface trough will amplify with a tightened surface pressure gradient (SPG) between the two surface features. As a result, southeasterly winds will increase with widespread gusts up to 35 mph and locally higher gusts up to 40 mph across northern Nebraska. High temperatures will warm into the above normal range from the mid-80s to low-90s. Although low level moisture will be prevalent across the area, limiting overall fire weather concerns, any fire starts could spread quickly given the gusty winds. Another shortwave ejecting northeastward across the central Rockies combined with increased mid-level warm air advection (WAA) and a strengthening LLJ will present another opportunity for elevated shower and thunderstorm development late this evening/overnight. Thanks to the LLJ, gusty winds up to 35 mph will persist through the overnight period. Tuesday...Similar conditions as compared to today will be on tap for the area on Tuesday as the strong upper-level trough tracks northeastward into the Great Basin on Tuesday with continued amplified low-level flow. As the SPG tightens even further (~15+ mb gradient across the state), widespread southeasterly wind gusts will peak near 40 during the day on Tuesday. When looking at recent NBM Probabilities, an overwhelming 75%+ chance of wind gusts of 30 mph or greater exists across all of western and north central Nebraska. However, when looking at probability of wind gusts exceeding 40 mph, probabilities drop to 30% or less across much of the area though pockets up to 60% exist across northern and southwestern Nebraska. Given this, locally higher gusts up to 45 mph cannot be ruled out for portions of northern and southwestern Nebraska. Daytime temperatures warm into the upper-80s mid-90s which is 15 to 20 degrees above normal for the middle of September. Dry conditions are expected through the day ahead of an approaching cold front which will bring an increased threat for precipitation Tuesday night into Wednesday. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... Issued at 413 AM CDT Mon Sep 16 2024 Tuesday Night and Wednesday...By Tuesday night, a strong negatively tilted shortwave will lift into the northern Rockies and northern Plains with strong lee-cyclogenesis across far northeast Wyoming and southeast Montana, driven by mid-level height falls and upper-level divergence. This will force a cold front to advance west to east across the area. At the same time, a strong (40+kts) southwesterly LLJ will ramp up over the northern Plains. Not only will the LLJ support continued breezy winds through the night, it will also help aid in the development of scattered to widespread shower and thunderstorm development along and ahead of the frontal boundary. Buoyancy will lack across the local area with more favorable low-level moisture and mid-level lapse rates residing much further north across Montana and North Dakota. Recent forecast soundings show deep mixing and an inverted-v profile with DCAPE values of 1,000-1,500 J/kg present across the area, suggesting that strong to severe wind gusts will be the primary concern with this activity. Convective initiation is expected to begin across the higher terrain of Wyoming and Colorado forming clusters of thunderstorms, tracking west to east across western and north central Nebraska beginning around 00Z. Greatest severe threat timing is from 6 PM to 3 AM CT with storms exiting the area through sunrise on Wednesday. When looking at precipitation totals, NBM Probabilities indicate a 40 to 60% chance or greater for 24 hour (12Z Tue through 12Z Wed) 0.25"+ liquid equivalent precipitation across all of western and north central Nebraska. Fortunately we will get another shot at widespread meaningful precipitation as we head into the latter end of the week into the weekend. The frontal boundary will also bring an end to the gusty winds for Wednesday as the low-level flow relaxes. Thursday and beyond...The upper-level shortwave exiting into Canada will be replaced by another trough of low pressure that will drop southward across the west coast, pushing inland across the Desert Southwest on Thursday. Additional frontal boundaries advance through western and north central Nebraska through the weekend resulting in unsettled conditions continuing and ushering in cooler temperatures, falling into the 70s by Saturday. && .AVIATION /18Z TAFS THROUGH 18Z TUESDAY/... Issued at 1250 PM CDT Mon Sep 16 2024 An area of broken MVFR ceilings extends south to north along the Hwy 83 corridor. These should gradually lift this afternoon. Otherwise VFR conditions should prevail through tonight. Low level wind shear will once again be a concern overnight tonight, especially to the east of Hwy 83. Winds will also be gusty from the south to southeast this afternoon through tonight and into Tuesday. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...Viken LONG TERM...Viken AVIATION...Taylor