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
405 FXUS63 KTOP 230900 AFDTOP Area Forecast Discussion National Weather Service Topeka KS 400 AM CDT Sun Jun 23 2024 .KEY MESSAGES... - Slightly less hot today, but heat indices of 105-110 degrees are forecast Monday and Tuesday. Heat Advisory has been issued for Monday. - Storm chances increase late Monday night through Tuesday with the greatest focus on Tuesday night in eastern KS. - Mainly overnight storm chances midweek through the weekend with lower temperatures, except Friday when triple digit heat indices may return. && .DISCUSSION... Issued at 400 AM CDT Sun Jun 23 2024 Early morning water vapor imagery shows the upper ridge encompassing the southern CONUS with a shortwave trough over southern Manitoba followed by another trough off the coast of British Columbia. This places the main westerlies north of the forecast area where they are expected to remain throughout the forecast period. At the surface, high pressure sits over central NE behind yesterday`s front which has now passed to the southeast of the CWA. This sfc ridge is progged to move across the area throughout the day, turning winds from the north back to the south this afternoon under sunny skies. Slightly lower temperatures in the 90s and dew points in the 60s should give us a short reprieve from the triple digit heat indices today. Low-level southerly flow increases into Monday with a strengthening pressure gradient over the area, as a lee sfc trough develops in response to a subtle perturbation rounding the periphery of the upper ridge. This in addition to deeper mixing should allow for 850mb temps of 24-28C to mix down, yielding highs in the upper 90s to low 100s, hottest toward central KS where mixing is deeper. Heat indices of 105-110 are forecast area-wide, so have issued a Heat Advisory for Monday afternoon. The aforementioned perturbation in the flow aloft looks to pass near or north of the area late Monday night into early Tuesday, so have low-end PoPs for this after midnight through Tuesday morning. Similar temperatures and dew points to Monday are forecast for Tuesday, so heat headlines may again be needed. Consideration was given to issuing an Excessive Heat Watch spanning Monday and Tuesday with a few places possibly seeing heat indices near 110 both days and Tuesday morning lows only falling to the mid to upper 70s, providing little nighttime relief. However, confidence in reaching warning criteria is not high enough at this time, especially if there is enough convection or cloud cover in the morning to keep temperatures lower than forecast on Tuesday. Trends will continue to be monitored to determine what type of headline would be needed. Greater chances for thunderstorms come Tuesday evening as a shortwave moves through the Upper Midwest and drags a cold front through the region. The best forcing looks to be north and east of the area, leading to higher PoPs (50-60%) focused in eastern locations Tuesday evening. Still, a very unstable air mass with deep- layer shear around 30 kt leads to at least some potential for any stronger storms to have damaging wind gusts. This risk should diminish later in the evening as inhibition increases. The pattern Wednesday through the weekend favors periodic thunderstorm chances mainly during the overnight periods as upper ridging holds to our south and embedded perturbations move through the flow aloft. Exact timing and placement with each of these waves is uncertain this far out due to the low-predictability nature of this type of pattern. High temperatures look to hold in the 90s Wednesday onward behind the front, with the exception of Friday when a thermal axis may move overhead and bring heat indices back into the 100s. && .AVIATION /06Z TAFS THROUGH 06Z MONDAY/... Issued at 1218 AM CDT Sun Jun 23 2024 VFR conditions are forecast with light north winds in the first half of the period veering to the south-southeast for the second half of the period. && .TOP WATCHES/WARNINGS/ADVISORIES... Heat Advisory from 1 PM to 7 PM CDT Monday for KSZ008-KSZ009- KSZ010-KSZ011-KSZ012-KSZ020-KSZ021-KSZ022-KSZ023-KSZ024-KSZ026- KSZ034-KSZ035-KSZ036-KSZ037-KSZ038-KSZ039-KSZ040-KSZ054-KSZ055- KSZ056-KSZ058-KSZ059. && $$ DISCUSSION...Picha AVIATION...Picha