Area Forecast Discussion
Issued by NWS Omaha/Valley, NE
Issued by NWS Omaha/Valley, NE
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205 FXUS63 KOAX 272256 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 556 PM CDT Thu Jun 27 2024 .KEY MESSAGES... - Moderate flooding is ongoing or expected to begin along the Missouri River the next day or two. It`s forecast to last into next week for Omaha and points south. - 5 to 15 percent chance of strong to severe storms tonight into Friday and again Friday afternoon into Friday night. Both rounds of storms could produce heavy rain and localized flash flooding, along with damaging winds, hail, and perhaps a tornado or two. - Quiet and cooler for the weekend, with highs in the mid 70s to mid 80s. Then warming back up and becoming more active for the holiday week. && .DISCUSSION... Issued at 349 PM CDT Thu Jun 27 2024 A weak shortwave was moving through early this afternoon and leading to some some scattered showers and a few isolated storms, though overall not amounting to a whole lot with some of the returns seen on radar likely not even reach the ground. These will continue to push east through the afternoon and then attention will turn to additional storm development for this evening and overnight as strong low level moisture transport starts pointing toward the area. Model soundings do reveal a very stout cap to contend with, but steep lapse rates above said cap (especially in northeast NE) and decent shear suggest some of these storms could be on the stronger side if they do get going. In addition, we`ll have to watch storms that form over western NE and approach our area around or just after midnight. They will be moving into a less favorable environment, so should generally weaken as they push in, but still could last long enough to give portions of eastern NE some strong to damaging winds and hail. In addition, precipitable water values approaching 2 inches and warm cloud depths of 4+ km suggest any storm that does move through will be an efficient rain-producer and potentially lead to some localized flash flooding. A few showers may stick around during the day Friday as additional shortwave energy moves through. In addition, a surface low will slide across the Dakotas and drag a cold front through our area bringing higher chances for stronger storms by late afternoon/evening. With the daytime precip (or clouds at the very least) instability may struggle to build as much as models suggest so storms could initially struggle to get going as the front moves through. However with strong southerly flow through the day, far southeast NE and far southwest IA will have more time for warm, moist air to move in so think those areas would have the highest chances for any strong to severe storms. In addition, those areas will see the strongest low level shear as the low level jet ramps up in the early evening, indicating at least some tornado threat. However, the environment will be conducive to at least some stronger storms almost area-wide if things are able to initiate earlier in the day (more likely if we see more sunshine during the day). Finally, once again the environment will be ripe for efficient rain- producing storms with continued increasing precipitable water values (2+ inches for some), leading to a localized flash flooding threat. All that said, overall a fairly low confidence thunderstorm forecast for Friday afternoon/Friday night. Otherwise, also of note Friday will be the warm, humid conditions with a few spots perhaps reaching triple digit heat index values with highs in the 90s and dewpoints in the mid 70s. Surface high pressure and upper level ridging will push in behind the front setting the stage for a pretty nice and mostly dry weekend. Expect temperatures in the mid 70s to mid 80s with dewpoints back down in the 50s to lower 60s. Some hints at a few spotty showers by Sunday evening, but those should be few and far between with ridging dominating. The break in heat and storm chances looks short-lived, however, as the ridge pushes east Monday with broad upper level troughing/zonal flow building in across the western and central CONUS Monday through the rest of the week. Various bits of shortwave energy look to slide through while a slow-moving surface boundary pushes south Monday and Tuesday (could even stall at times). The general setup would suggest potential for some training thunderstorms along that boundary which would bring a risk for heavy rain and additional flooding, but still lots of details to work out between now and then. Still, very much a time period to keep an eye on. Otherwise, we`ll see continued storm chances through the week with temperatures getting back into at least the mid 80s to lower 90s. With the potential for repeat rounds of thunderstorms, ongoing flooding may end up lingering a little bit longer than currently forecast, or rivers may remain elevated for longer at the very least. && .AVIATION /00Z TAFS THROUGH 00Z SATURDAY/... Issued at 552 PM CDT Thu Jun 27 2024 VFR conditions through the period. There could be a shower at KLNK/KOMA 00-01z, then several dry areas, then thunderstorm chances return 07-10z at these two locations. Will likely keep precipitation out of the KOFK TAF as confidence is too low at that location. Otherwise, southeasterly winds at 13-22 knots through much of the early part of the forecast. LLWS develops at KOFK 02-12z, at KLNK 07-12z, and KOMA 08-13z, with winds at 2000 feet from the south at 180-190 degrees at 45 knots. Winds do shift to the northwest at KOFK by 16-18z. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ DISCUSSION...CA AVIATION...DeWald