Area Forecast Discussion
Issued by NWS Topeka, KS
Issued by NWS Topeka, 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
43
44
45
440 FXUS63 KTOP 262237 AFDTOP Area Forecast Discussion National Weather Service Topeka KS 537 PM CDT Fri Apr 26 2024 .KEY MESSAGES... - Several rounds of thunderstorms are forecast through Sunday. - Severe weather with large hail, damaging winds and even tornadoes are possible with the greatest risk on Saturday. - Additional rounds of heavy rainfall may lead to flooding over east central and northeast Kansas. && .DISCUSSION... Issued at 145 PM CDT Fri Apr 26 2024 An upper low was seen on the 18Z water vapor imagery with a shortwave trough rotating through the base of the low towards northeast KS. At the surface, A warm front has lifted mostly through the forecast area with a dryline extending south through central KS. Towering CU and a couple thunderstorms have formed along the dryline. The question with thunderstorms this evening is the extent to the south storms form along the dryline. There are mixed results from the various CAMs with some failing to develop storms as far south as I-70 and others showing more widespread storms over northeastern KS. MUCAPE around 3000 J/kg 0-6km shear of 50KT will be supportive of supercell storms. These storms are expected to swing to the north and east quickly this evening which may limit the tornado risk for our area since storms would be exiting as the low level jet and SRH increase. The models show a continued warm air advection pattern persisting through the night allowing the dryline to return west. RAP and NAM show a narrow east to west axis of isentropic assent developing overnight within the moisture return. So have continued with some small POPs through the early morning to account for the chance some elevated storms develop. Forecast soundings still show around 2000 J/kg of elevated CAPE with 40KT of bulk shear. So there may be a hail and/or damaging wind risk through the early morning hours. Confidence in elevated storms is low since CAMs don`t really support the RAP and NAM forecasts. Saturday looks to be complicated by warm sector development ahead of the dryline. Forecast soundings show little in the way of inhibition by the afternoon as height falls spread east. So storm mode could be complicated by this activity if it develops. The environmental conditions look to remain favorable for supercell storms with plenty of CAPE and shear. So we continue to message the risk for severe weather including tornadoes which may have the opportunity to be strong. There is a little more confidence in another round of heavy rainfall over eastern parts of the forecast area through Saturday night. A few river points went into flood this morning and the additional rainfall will probably may flooding a more widespread concern. With this in mind, went ahead and posted a flood watch for Saturday afternoon through Sunday morning. The storm system responsible for all of the weather is progged to remain over the central plains Sunday with another shortwave trough rotating through eastern KS. A diffuse boundary is forecast to still be over eastern KS through peak heating so there remains a chance for one more round of thunderstorms Sunday afternoon and into the early evening. && .AVIATION /00Z TAFS THROUGH 00Z SUNDAY/... Issued at 537 PM CDT Fri Apr 26 2024 Looks like the terminals will miss the TS this evening. There is an outside chance for an isolated TS to develop overnight. Probabilities of 20 to 30 percent are to low to include in the forecast at this time. LLWS looks to be mitigated by a mixed boundary layer and unidirectional winds. Biggest impact from the weather will be the MVFR stratus returning towards 06Z and after. Similar to earlier, this should scattered out and lift above 3 KFT by early afternoon. && .TOP WATCHES/WARNINGS/ADVISORIES... Flood Watch from Saturday afternoon through Sunday morning for KSZ011-KSZ012-KSZ023-KSZ024-KSZ026-KSZ037-KSZ038-KSZ039-KSZ040- KSZ054-KSZ055-KSZ056-KSZ058-KSZ059. && $$ DISCUSSION...Wolters AVIATION...Wolters