183 FXUS63 KOAX 092310 AFDOAXArea Forecast Discussion National Weather Service Omaha/Valley NE 610 PM CDT Tue Sep 9 2025
.KEY MESSAGES...
- Areas of fog are expected to develop tonight across,focused north of a line from Columbus to Harlan, Iowa where visibilities of 1 mile or less are possible.
- Highs return to the and lows to the 60s into the weekend. A few spots are expected to see lower 90s Friday and Saturday.
- Periodic chances for thunderstorms will be present between Wednesday evening and the end of the weekend, though expect much more dry time than wet. The highest chances (20-40%) are on Saturday night into Sunday.
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.DISCUSSION... Issued at 339 PM CDT Tue Sep 9 2025
Today and Tomorrow:
Water vapor imagery this afternoon features a shortwave trough exiting the Mid-Missouri Valley towards the Great Lakes region, a largely swept-out eastern third of the CONUS, and a longwave trough pushing further onto the Pacific shore. Taking a look at a recent surface analysis, we find the forecast area on the eastern periphery of a messy junction of surface boundaries that arc from Nebraska/ eastern Colorado where the main effective surface lows exist with a few tendrils extending into South Dakota and across Kansas/Oklahoma. The best moisture locally continues to be found across the forecast area and has resulted in a bank of cumulus clouds that are trying to limit how much we can heat up so far this afternoon. Mostly dry conditions are expected through the rest of the day, with only a few showers expected to drift through just to the north and west of the forecast area.
Overnight, winds that had been out of the southwest are expected to slow down and turn southeasterly. Only a few to scattered high clouds are expected to drift in from the west overnight, and that should allow for ample radiational cooling to occur and push temperatures below the afternoon dewpoints/crossover temperatures. Areas of patchy fog are expected to develop -- especially where winds are expected to become calm, which appears most likely north of a line from Columbus to Harlan, Iowa. For now, the most likely time for fog to affect those areas would be from 3 AM to 9 AM, with conditions expected to improve quickly thereafter. From there, light southeasterly winds will continue into the afternoon with skies clearing out by sunset after highs in the lower 80s are reached.
Thursday and Beyond:
Beginning Thursday, a warmup will be full swing as the aforementioned longwave trough anchors over the western third of the CONUS and helps prop up a ridge over the Central and Southern Plains. Highs are going to be in the mid 80s Thursday with a quick jump into the lower 90s Friday. Models guidance is aiming its hottest day of the forecast at Friday for Nebraska before shifting it into Iowa for Saturday. As of this forecast, highs for the hottest stretch are conservative compared to the deterministic/ensemble guidance, with bias-corrected output holding temperatures down, while the straight blends and deterministic output being 2-5+ degrees warmer comparatively. With a general lack of surface moisture/oppressive humidity, we`ll dodge dangerous heat indices. That being said, folks across the country have been enjoying highs in the lower 70s, and a 20-degree jump could be a shock to the system to many and could serve as a sneaky heat threat for those that may push it this weekend getting yard work done.
For the remainder of the forecast, we`ll thankfully see high temperatures begin to fall closer to but still warmer than the normal September range, with highs in the low-to-mid 80s anticipated. This will be kicked off by the ejection of the aforementioned trough to the west across the Central/Northern Plains late Saturday into early Sunday. After that feature pushes through, we may see an uptick of shower/storm activity as west-southwesterly flow kicks in and several mid-level shortwaves push through early to mid-next week.
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.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/... Issued at 558 PM CDT Tue Sep 9 2025
A swath of FL045-020 clouds along and west of the Missouri River is gradually diminishing. Winds will remain light and southeasterly tonight, allowing for the development of some patchy fog. Lowest visibilities are expected over northeast Nebraska between 10-15Z. Anticipate KOFK dropping to at least 4SM, with periods of IFR to LIFR possible. KOMA and KLNK remain on the edge of the fog, according to current model guidance. Expect visibilities of around 5SM possible, with the potential for lower, if fog manages to develop farther south. Fog should dissipate shortly after sunrise, with VFR conditions prevailing through the remainder of the period.
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.OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None.
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DISCUSSION...Petersen AVIATION...KG
NWS OAX Office Area Forecast Discussion