Area Forecast Discussion
Issued by NWS Omaha/Valley, NE
Issued by NWS Omaha/Valley, NE
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445 FXUS63 KOAX 212325 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 625 PM CDT Sat Sep 21 2024 .KEY MESSAGES... - 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. && .DISCUSSION... 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. && .AVIATION /00Z TAFS THROUGH 00Z MONDAY/... Issued at 623 PM CDT Sat Sep 21 2024 All TS have developed southeast of TAF sites and are not expected to impact TAF sites in the near term. After 05Z, expect showers, with a small chance for a thunderstorm, to develop and impact LNK/OMA off-and-on for several hours. Do expect VFR conditions to be dominant during this time, and -SHRA should eventually dissipate, but there is uncertainty regarding the exact ending time as it could persist longer into Sunday. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ DISCUSSION...Kern AVIATION...Barjenbruch