Area Forecast Discussion
Issued by NWS Omaha/Valley, NE
Issued by NWS Omaha/Valley, NE
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390 FXUS63 KOAX 020434 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 1134 PM CDT Sat Jun 1 2024 .KEY MESSAGES... - Daily storm chances starting by this evening and lasting through at least Tuesday. - Increasing chances for a strong wind storm moving into the area after 9 PM tomorrow. - The highest chances for strong to severe storms are on Sunday and Tuesday, but confidence is low on exact timing and how widespread the severe weather threat will be. - Slightly warmer through next week with highs in the upper 70s and 80s. && .DISCUSSION... Issued at 413 PM CDT Sat Jun 1 2024 Tonight through Tomorrow: Water vapor imagery this afternoon features largely zonal flow with ridging in place centered over New England while several shortwaves litter the remaining CONUS, including a more potent one moving farther into the Ohio River Valley. Looking closer at a recent surface analysis, upper 50s to 60s dewpoints continue to linger in Nebraska and Iowa with a drier airmass on the northern side of a very weak boundary at the NE/SD border. Light northerly are in place currently with highs being realized in the upper 70s to low 80s, with a few patches of cirrus left over from morning convection in western and central Nebraska. After sunset, low- level wind speeds associated with the nocturnal jet are expected to pick up largely over western and central Nebraska, with jet nosing and shortwave PVA allowing for instability rooted at 700 mb to be realized. Latest runs of the CAMs move this activity into northeastern Nebraska after 1 AM before pushing it off to the east by mid-tomorrow morning. By tomorrow afternoon, strong warm air advection and moisture transport will be in full force in the forecast area. CAMs have been divided on producing storms after 1 PM across eastern Nebraska, owing most of the uncertainty on weaker shear, and limited moisture to fight the cap. Sufficient instability and shear are in place so that if scattered storm activity develops, quarter-sized hail is a possibility through 6 PM. The main concern of the day comes later in the form of what is expected to be a large bowing MCS that progresses out of convection starting in the Panhandle. Earlier runs of the extended CAMs have been showing impressive low-level and surface wind fields and has warranted an increase to an Enhanced Risk (level 3 out of 5) just into northeast Nebraska. While this system is expected to move into our area, weaker shear and increased capping will limit its severity as it moves east. The main concern continues to be the damaging winds, with quarter-sized hail possible and heavy rains falling on saturated soils (especially in northeast NE). Monday and Tuesday: Monday and Tuesday are expected to continue the active trend precipitation-wise, with continued shortwaves moving through the zonal flow. Machine-learning storm outlooks for day 3 and 4 continue to clip southeast Nebraska and Iowa with Tuesday holding our best chances for stronger storms. Driven by better shear and a stronger front, more focus for ascent will sweep through Tuesday afternoon and evening with scattered storms in central Nebraska expected to form a larger line of showers and storms by the time it reaches Iowa. Wednesday and Beyond: For the rest of the week, the main upper jet moves south and becomes northwesterly, guarding eastern Nebraska and Iowa from any of the good moisture to the south. Despite the northwesterly flow, highs are still able to old healthily into the lower 80s, making for a really nice stretch of weather to be outside in going in to the weekend. && .AVIATION /06Z TAFS THROUGH 06Z MONDAY/... Issued at 1133 PM CDT Sat Jun 1 2024 VFR conditions are anticipated through the forecast period with a chance of thunderstorms through much of the 24 hour period. Scattered thunderstorm activity in central Nebraska may affect any of the 3 TAF sites, but confidence was only high enough to include at OFK from 09Z to 10Z Sunday. More storms are possible in the afternoon hours, but again confidence in timing and location have lead me to leave them off this TAF issuance. All three sites could be affected. Best chances and highest confidence of storm coverage comes with the line of storms forecast to work west to east late on Sunday night from about 03Z to 06Z Monday. Wind gusts over 50 knots are possible. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ DISCUSSION...Petersen AVIATION...Nicolaisen