Area Forecast Discussion
Issued by NWS Omaha/Valley, NE
Issued by NWS Omaha/Valley, NE
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507 FXUS63 KOAX 241111 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 611 AM CDT Mon Jun 24 2024 .KEY MESSAGES... - Moderate to near Major flood stages are expected along the Missouri River from Blair to Rulo this week, rivaling stages that were last experienced in 2019. - Flooding is ongoing along the Platte, Ponca Creek and Clear Creek. Flooding is expected to recede along the Ponca and Clear Creek later today. - The hottest temperatures of the year so far are forecasted for today, with heat indicies from 106 to 111. The heat may extend into Tuesday afternoon across southeast Nebraska. - Isolated to widely scattered thunderstorms will be possible Monday and Tuesday evenings. A Slight Risk for severe weather is present both days. - More widespread chances for rain and thunderstorms return Wednesday night through Friday night. && .DISCUSSION... Issued at 222 AM CDT Mon Jun 24 2024 Short Term (Today and Tomorrow) Scattered thunderstorm development is currently ongoing across western Iowa as a weak mid-level disturbance slides across the area. Weak instability (MLCAPE around 500 J/kg) should keep away any chance of severe weather with these thunderstorms as they push off to the east. Upper level ridging across the central CONUS will help to bring some of the warmest temperatures so far this year across the area. 850 mb temperatures will be in the mid to upper 20 degree Celsius range today, bringing a boost to temperatures this afternoon. High temperatures are expected in the 97 to 104 range. Dewpoints in the low 70s will bring heat index values in the 106 to 111 range this afternoon. Given the elevated heat related concerns, a Heat Advisory will go into effect from 1 PM to 8 PM today. Record high temperatures will be within reach at Lincoln this afternoon (current record high of 103 set in 1988). Severe weather potential returns this evening as a weak cold front pushes into the area. Scattered thunderstorm development is likely in the late afternoon into the evening. MUCAPE of 2500-4000 J/kg along with 25 to 35 kts of bulk shear should support a few high based thunderstorms. A decent CAP is place should keep coverage scattered to widely scattered. The relatively weak shear in place should make it difficult for updrafts to remain organized for long. Therefore, the primary hazards will be a brief period of hail and strong wind gusts as storms quickly become outflow dominant. SPC has much of the area in a slight risk (level 2 out of 5) for severe weather this evening. Much of the area will continue to experience above average temperatures on Tuesday. However, a cold front orientated from the northeast to the southwest will push to the southeast from South Dakota through Tuesday. This will limit high temperatures near 90 by the NE/SD border with highs increasing near 100 as you approach the NE/KS border. With dewpoints still lingering around 70 degrees, heat index values in the 100 to 105 range will be possible south of Interstate 80. A Heat Advisory has been issued for our southern counties on Tuesday afternoon (1 PM to 7 PM). Another round of severe weather is possible late Tuesday afternoon into the evening as scattered thunderstorm development is likely along the aforementioned cold front. Plentiful instability will be present ahead of the front (MLCAPE of 2500-4000 J/kg) with marginal bulk shear (30-35 kts). A brief period of isolated storm development is possible before upscale growth takes over. Primary hazards will include strong winds and hail although a brief tornado can`t be ruled out. SPC has placed a slight risk (level 2 out of 5) for severe weather into eastern NE and western IA. Additional flooding concerns remain low as the bulk of the QPF associated with this event remains south of Interstate 80 with values approaching 0.25" near the NE/MO border. Long Term (Wednesday through Sunday) Wednesday remains the only day this work week without precipitation chances. Northwesterly flow returns to the area, bringing high temperatures down into the 80s into Thursday. An upper level low tracking across southern Alberta/Saskatchewan will push multiple disturbances into the central and northern Plains towards the end of the work week. A prolonged period of PoPs greater than 30 percent enters the area Thursday afternoon and continues into the weekend. The best chance for severe weather will be Friday afternoon/evening as a cold front pushes through the area. CSU Machine Learning highlights much of eastern NE/western IA for severe weather potential on Friday. Flooding concerns will need to be monitored as an extended period of rainfall is possible over an already sensitive area. WPC has places a slight risk for excessive rainfall over northeast NE and northwest IA on Thursday. Widespread PoPs of 30 to 50 percent continue into Saturday morning. && .AVIATION /12Z TAFS THROUGH 12Z TUESDAY/... Issued at 604 AM CDT Mon Jun 24 2024 VFR conditions expected through the TAF period. Winds will be out of the south today with wind shear this morning ending around 15Z. A weak front moving through this evening could lead to a few thunderstorms developing this evening between 23Z-03Z which could impact the terminals. Chance of storms impacting terminals stays down around 20-30 percent. Winds will weaken again this evening and shift to southwesterly. && .HYDROLOGY... Issued at 105 PM CDT Sun Jun 23 2024 A number of forecast changes occurred for the Missouri, Platte and Little Sioux Rivers during the morning round of updates. Water flow from Missouri River tributaries down stream of Gavins Point dam remain in major flood, with minor impacts beginning along the Missouri River between Sioux City and Decatur. Minor to moderate flooding is expected to occur along the Missouri between today and next weekend, with a 5-25% chance of flood levels reaching major stages downstream of Plattsmouth due to additional water flow from the Platte River. The Platte currently is flooding between Leshara and Ashland, with minor flooding expected from Louisville to the confluence with the Missouri tonight into early Monday. Minor to moderate flooding is anticipated along the Little Sioux River Monday and Tuesday, with historic crest levels being reached in northwest Iowa. Flooding is abating along Ponca Creek to its confluence with the Missouri in Knox County. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...Heat Advisory from 1 PM this afternoon to 8 PM CDT this evening for NEZ011-012-015>018-030>034-042>045-050>053- 065>068-078-088>093. Heat Advisory from 1 PM to 7 PM CDT Tuesday for NEZ068-088>093. IA...Heat Advisory from 1 PM this afternoon to 8 PM CDT this evening for IAZ043-055-056-069-079-080-090-091. Heat Advisory from 1 PM to 7 PM CDT Tuesday for IAZ090-091. && $$ DISCUSSION...Wood AVIATION...McCoy HYDROLOGY...Fortin