Area Forecast Discussion
Issued by NWS Topeka, KS
Issued by NWS Topeka, KS
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397 FXUS63 KTOP 031954 AFDTOP Area Forecast Discussion National Weather Service Topeka KS 254 PM CDT Wed Jul 3 2024 .KEY MESSAGES... - Thunderstorms are forecast across the area late this evening and overnight, which could bring strong winds to central KS and heavy rainfall particularly across east central KS. - A few severe thunderstorms are possible in eastern KS for the late afternoon and early evening hours of Independence Day. - Another chance for storms Saturday night into Sunday, otherwise slightly below normal temperatures continue into next week. && .DISCUSSION... Issued at 254 PM CDT Wed Jul 3 2024 Upper air pattern hasn`t changed a lot in the last 12 hours with broad cyclonic flow over the northern tier of the US and the ridge over the southeastern US leaving us within southwesterly flow aloft. Sfc ridge has been slowly moving southeast from NE into KS today, while the frontal boundary from yesterday has remained stationary across southeastern KS. Scattered showers are still more robust southwest of the area with light rain slowly moving northward. Lapse rates are rather meager over the area, so thunderstorms should be pretty isolated the rest of this afternoon into the early evening with perhaps some dry time before the main round of storms comes in late tonight. A vort max passing through the flow aloft should initiate storms off the High Plains later this afternoon into the early evening, and CAMs remain in good agreement on those moving east into our area late tonight. Most places should stay dry until after midnight, except perhaps far western locations in the CWA. Generally speaking, these storms should also weaken as they move east as MUCAPE looks to remain under 1000 J/kg, but still can`t rule out a few damaging wind gusts toward central KS if storms remain strong enough when they enter the area. Heavy rainfall looks to be the bigger concern for most of the area. At this time, the moisture axis is progged to set up just south of the forecast area where PW is forecast to be 2+ inches. This area in southeast KS to southwest MO is also where the HREF shows the strongest signal for rainfall amounts exceeding FFG, with the 90th percentile having totals of 2-3". That said, the HRRR has not been nearly as aggressive on this as some other individual CAMs have. If more guidance starts to show some of these higher amounts creeping north just a little bit, a Flood Watch may be warranted for our far southeast counties. The overnight batch of storms should push east of the area around sunrise or shortly thereafter. A few additional showers and storms may develop in central KS mid to late morning before moving out or dissipating by afternoon. The main storm chance comes with a frontal boundary crossing the area during the day, although lingering cloud cover does lead to some questions about how well the atmosphere will be able to recover and destabilize ahead of that boundary. Assuming there is enough instability, thunderstorms look to develop near the KS Turnpike around 4pm and then move east/southeast. Damaging wind and heavy rainfall are again the main threats. Think the main time frame for this activity should last until around 8pm, so most can hope to see dry weather by the time fireworks celebrations begin. By Friday, the main upper trough is progged to be in the Upper Midwest and Great Lakes regions, leaving the area in northwest flow. Another shortwave ejecting through that looks to bring our next chance for storms Saturday night through Sunday. Otherwise, temperatures are forecast to remain slightly below average throughout the next 7 days with highs in the 80s and lows in the 60s. && .AVIATION /18Z TAFS THROUGH 18Z THURSDAY/... Issued at 1245 PM CDT Wed Jul 3 2024 Low clouds at TOP/FOE have scattered with mid/high clouds remaining over all sites. Have removed mention of VCTS for this afternoon, as scattered showers across the entire state have had very little lightning observed with them and with weak instability, would expect any TS to be too isolated to mention in TAFs for the next several hours. Better chances for convection are with storms coming in from western/central KS overnight, so have added VCTS associated with that. The signal for heaviest rainfall is well south of terminals, so any vis reductions should be brief if any. Restrictions expected to come with MVFR cigs during the morning following the storms. Some guidance shows IFR may be possible during that time, but confidence isn`t high enough to go that low with cigs just yet. && .TOP WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Picha AVIATION...Picha