Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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169 FXUS63 KOAX 212034 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 334 PM CDT Sat Sep 21 2024 .KEY MESSAGES...
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- Marginally severe storms generally along and south of I-80 through 8pm. Hail and strong winds the primary hazards. - Much cooler and breezy with widespread showers diminishing by Sunday afternoon and evening. - More seasonable temperatures for the work/school week with mostly dry conditions.
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&& .DISCUSSION...
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Issued at 324 PM CDT Sat Sep 21 2024 Tonight into Sunday: Latest water vapor imagery and subjective upper air analysis shows a strong low moving toward the Four Corners region with a low amplitude shortwave ejecting out ahead of the main wave across the Central Plains. Meanwhile, a cold front continues to slowly drift south and currently has made it through the northwestern half of the CWA and appears to be directly overhead at our office as of this writing. The boundary is showing up well on radar, likely pinging off particulates. This boundary continues to move into an unseasonably warm and muggy airmass with temperatures in the upper 80s to low 90s and dewpoints in the upper 60s to around 70. We have seen an increase in northwesterly gusts behind the surface boundary in the 35-40 mph range. There remains a brief window (through 8 pm) for marginally severe storms to develop along the boundary as we approach convective temperatures this afternoon and large scale forcing from an approaching mid-level shortwave moves into the region late this afternoon and early this evening. SPC continues our Marginal risk of severe storms where hail and possibly some wind would be our primary hazards. Latest SPC mesoanalysis shows around 3000 J/kg of mixed-layer CAPE and around 35KTS of deep layer shear are available ahead of this boundary. Severe window should be relatively short-lived with much drier/cooler and somewhat breezy conditions behind the front. Meanwhile, large-scale forcing for ascent will continue over the area as the above mentioned low over the Four Corners region begins to eject into northwestern Kansas and southwestern Nebraska. This forcing should be sufficient to produce widespread showers with a few embedded rumbles of thunder possible. Lows tonight will drop into the 50s with highs on Sunday remaining in the lower to mid 60s under mostly cloudy skies with off and on showers. Monday through next week: Monday through Thursday look dry after the departure of the above mentioned low. After the much cooler day Sunday, temperatures are forecast to rebound to more seasonal levels for this time of September, with highs in the 70s and lows in the 40s and 50s. Some uncertainty remains late next week in regards to the evolution of the a large upper low that is forecast to drop through the Northern and Central Plains and potentially become cut off as it moves into the Southern Plains. We have maintained some very small (20%) pops late this week into early next week but forecasters confidence is quite low due to the uncertainty.
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&& .AVIATION /18Z TAFS THROUGH 18Z SUNDAY/... Issued at 1232 PM CDT Sat Sep 21 2024 VFR conditions are expected through much of the period at all three TAF sites with the exception of a few showers and thunderstorms, mainly at KOMA and KLNK. Latest runs of CAMs indicate that a few thunderstorms could develop near KOMA and KLNK around 21z and continue through 00z before pushing southeast of the sites. A few strong wind gusts and small hail are possible with this initial development in addition to heavy downpours. Widespread showers with a few embedded non-severe thunderstorms will spread over much of southeast Nebraska and southwest Iowa after 04-06z and continue through much of Sunday. Although VFR conditions are expected for much of the time, we could see some deteriorating condition down to MVFR or even IFR in stronger storms. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ DISCUSSION...Kern AVIATION...Kern