Area Forecast Discussion
Issued by NWS Wichita, KS
Issued by NWS Wichita, KS
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
486 FXUS63 KICT 291740 AFDICT Area Forecast Discussion National Weather Service Wichita KS 1240 PM CDT Sat Jun 29 2024 .KEY MESSAGES... - Scattered storms this morning, especially across the Flint Hills - Another hot and humid day across south central and southeast KS - Storms possible this afternoon/evening across southern KS; better chances tonight across portions of central/south-central KS - Active weather pattern into next week with roller-coaster-like temperatures && .DISCUSSION... Issued at 308 AM CDT Sat Jun 29 2024 As of 3 AM, zonal midlevel flow was positioned across the central Plains with a northern stream shortwave trough moving across the northern Plains. A meandering surface trough extends from portions of southwest KS to near Dodge City to McPherson to near Topeka. A modest temperature gradient and wind shift reside along the frontal zone. Two zones of convection were ongoing at this hour with the first across northwest KS into central KS. This convection is positioned on the midlevel lapse rate gradient, which extends from eastern CO into central KS. Midlevel WAA has been weakening and leading the this convection weakening as well. The second zone resides across the Flint Hills and within a zone of WAA rooted near 850 mb. The focal point for development thus far has been on the nose of the jet or generally along Highway 50. RAP and HRRR forecast soundings suggest parcels originating between 800-700 mb have up to 500 J/kg of instability. Effective shear values are in the 20-30 kt range and should mitigate any potential for severe storms. More notably, PW values remain near 2" and will support heavy rainfall. As the LLJ weakens towards sunrise, convection should dissipate. Transitioning into the daytime hours today,the frontal zone will sag further south before stalling near the OK state line. Temperatures north of Highway 50 should be notably cooler this afternoon with highs in the 80s to near 90. Areas along and south of Highway 400 are likely to see another afternoon of hot temperatures and humid conditions. One of two scenarios (or a combination of both) are likely to play out this afternoon. Boundary layer mixing will ensue shortly after sunrise today. Forecast RAP and HRRR soundings seem a bit overzealous with mixing heights and subsequent surface dew points (and were yesterday as well). Their raw outputs suggest temperatures will surge near 100+ degrees along the OK border with dew points in the mid to upper 60s. Even so, this still sends heat index values near 105. Should dew points hold near 70 into the afternoon, which seems plausible, heat index values near 110 would become likely. Immediately behind the frontal zone (generally along Highway 400), boundary layer mixing will be greatly reduced with dew point values likely to surge back into the low-mid 70s. Combing this moist boundary layer with temperatures in the mid-90s will create heat index values near 105. As a result, have opted to expand the Heat Advisory northward to include Sedgwick, Butler, Greenwood, Elk, Wilson, Woodson, and Allen counties. See the latest Advisory for further detail. In regards to the convection potential this afternoon, large scale ascent will remain meager through the daytime hours, although weak convergence along the front may yield a few storms. Confidence continues to increase for convection tonight, mainly across portions of central and south central KS. This appears to be the zone where a 25-30 kt LLJ will overspread the stalled frontal zone. Severe weather appears unlikely but heavy rainfall is probable with any storm as PW values remain near 2". Heat relief is expected area-wide Sunday as the frontal zone sinks further south into OK. In addition, showers/storms may linger into the afternoon, especially across central/south- central KS. Afternoon high temperatures near 80 are expected. The heat will return area-wide Monday and Tuesday as the front retreats northward and midlevel ridging amplifies overhead. Temperatures will once again approach the 100 degree mark. A northern stream trough will shunt the frontal zone southward into our area late Tuesday into Wednesday. This will set the stage for another break from the heat and additional storm chances through Thursday. && .AVIATION /12Z TAFS THROUGH 12Z SUNDAY/... Issued at 1150 AM CDT Sat Jun 29 2024 VFR conditions will start at all terminals but thunderstorms later in the TAF period will make for difficult flying conditions. Showers and thunderstorms with wind potential into the 45Kt range are possible in the KCNU area between 23Z and 03Z tonight but after that time, VFR conditions are expected to rule. The remaining terminals, VFR conditions are expected until close to 09Z to 11Z. KRSL and KSLN will likely see some showers with embedded thunderstorms during this time while KHUT and KICT will likely see this activity later in the 11Z to 14Z time frame. The main terminal of concern will be KGBD which could have several hours of thunderstorm activity. Very heavy rain is likely but winds are not expected to be severe. This heavy rain risk will significantly reduce VSBY conditions as a result. AFter 16Z to 18Z tomorrow, VFR conditions will return to all terminals. && .ICT WATCHES/WARNINGS/ADVISORIES... Heat Advisory until 8 PM CDT this evening for KSZ069>072-083- 091>096-098>100. && $$ DISCUSSION...BRB AVIATION...ELM