Area Forecast Discussion
Issued by NWS Topeka, KS
Issued by NWS Topeka, KS
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653 FXUS63 KTOP 011956 AFDTOP Area Forecast Discussion National Weather Service Topeka KS 256 PM CDT Mon Jul 1 2024 .KEY MESSAGES... - Heat becomes more widespread Tuesday, with Heat Advisory in effect mainly south of the Hwy 36 corridor. - Low chance for storms near the KS/NE border tonight. Greatest risk for organized severe risk comes Tuesday afternoon/evening, which could also bring another round of heavy rainfall. - Periodic chances for storms continue through the 4th of July holiday. && .DISCUSSION... Issued at 256 PM CDT Mon Jul 1 2024 Two areas of sfc low pressure are noted as of 19Z, one centered in SD and the other near the CO/KS border, both in response to the upper trough slowly advancing across the western US. Meanwhile the upper ridge holds steady over the south central CONUS. Cloud cover has been slow to scatter out, but recent satellite imagery indicates it should do so more quickly over the next hour or two. Clearing should still allow temperatures to heat up, but likely not as much as originally anticipated. Heat indices may still reach triple digits in parts of north central KS in the few hours left of peak heating, so will keep the advisory going in those areas today, though they may fall just short of criteria. The greater heat concern comes Tuesday as low-level moisture builds in and WAA commences overnight into tomorrow. A cold front approaching from NE by midday should help keep temperatures around 90 for counties along the KS/NE border, while most areas south should see deep enough mixing with warm 850mb temps to bring highs to the mid 90s to around 100. Have kept Tuesday`s advisory as is. Regarding storm chances through the next 24-36 hours, there remains a low chance for a few showers or storms to clip northwestern counties of the CWA, if enough energy from the slowly advancing upper trough can get far close enough to the area. The better forcing will be to our northwest closer to the trough itself, and better shear will be that direction as well with the LLJ being stronger as you head north into NE tonight. If an isolated storm were to make it into the area, damaging wind would be the main threat, but again it is a low probability. As the trough continues to approach the area heading into Tuesday, the associated cold front will also move closer through the morning. The RAP/HRRR show spotty showers potentially in north central KS ahead of the boundary, while most other models stay dry until the front itself moves in. Have storm chances increasing along this front in northern areas early to mid afternoon, while most places should see the best chances for increasing storm activity during the late afternoon to evening. Forecast soundings show an eroding cap during the late afternoon, and CAPE is progged to increase to 2000- 4000 J/kg with 30-40 kt of deep-layer shear (strongest along and behind the boundary). With flow being parallel to the boundary, storm mode could get messy as interactions occur, so the window of opportunity for any tornado risk looks rather brief and more towards far northeast KS as the front moves in and storms develop. Damaging wind looks to be the main severe risk with a well-mixed BL and inverted-V profiles, though large hail can`t be ruled out with a strong enough updraft. Additionally, will need to watch out for heavy rain and flooding with Pwat progged to return to 2-2.5", and possibly training storms along the boundary. The front looks to stall around southeast KS Wednesday, resulting in cooler temperatures with highs in the 80s area-wide. Broad upper troughing across the northern CONUS with embedded shortwaves aloft keep chances for storms through Wednesday and Thursday, though the main trough axis looks to pass through the northern Plains Thursday and push another front through the area that day. Timing and placement of these waves and the boundary will become more clear as we get closer to each day, but overall will need to monitor severe and flooding risks until we get through the 4th of July holiday. It would be prudent to stay up to date with the forecast until then. Mainly dry weather is anticipated Friday and Saturday before return flow early next week brings potential for additional thunderstorms, although chances are low at this time. && .AVIATION /18Z TAFS THROUGH 18Z TUESDAY/... Issued at 1244 PM CDT Mon Jul 1 2024 Satellite has been showing clouds trying to slowly scatter, so will give it a couple more hours before VFR conditions return at all terminals. SE winds remain up around 12-15 kt sustained with gusts 20-30 kt through much of the period. Think gusts should hold during the overnight hours and keep LLWS to a minimum despite a strengthening LLJ. Looking ahead, winds may veer slightly to the SW toward the tail end of the period with increasing high clouds ahead of an approaching frontal boundary. Any storms tonight look to remain well north of terminals with the next chance coming after this TAF period tomorrow afternoon. && .TOP WATCHES/WARNINGS/ADVISORIES... Heat Advisory until 8 PM CDT this evening for KSZ020-KSZ021- KSZ034-KSZ035. Heat Advisory from noon to 8 PM CDT Tuesday for KSZ021-KSZ022- KSZ023-KSZ024-KSZ026-KSZ034-KSZ035-KSZ036-KSZ037-KSZ038-KSZ039- KSZ040-KSZ054-KSZ055-KSZ056-KSZ058-KSZ059. && $$ DISCUSSION...Picha AVIATION...Picha