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
500 FXUS63 KTOP 190523 AFDTOP Area Forecast Discussion National Weather Service Topeka KS 1223 AM CDT Wed Jun 19 2024 .KEY MESSAGES... - Thunderstorms continue across the area overnight with locally heavy rainfall leading to some instances of flash flooding and river flooding. - Above average temperatures will stick around into the weekend and next week. && .DISCUSSION... Issued at 219 PM CDT Tue Jun 18 2024 This afternoon, the surface analysis shows a 997 mb low in SW Kansas and a 997 mb low in E South Dakota, connected by a cold front which roughly runs from Smith Center KS to Scott City KS. Convergence is increasing, and storms are beginning to fire on the front in Nebraska very quickly. Current mesoanalysis indicates that surface based CAPE values range from 2000 to 4000 J/Kg, which is quite significant and will result in rapid storm development further west on the aforementioned boundary. Effective bulk shear ranges from 20-30 kt ahead of the front, which is quite low. Current thinking is that thunderstorms that form on the front will become linear and grow upscale rather quickly, due to strong convergence in the low levels, weak shear, and storm motion parallel to the boundary. The storms are forecast to enter the area by roughly 6 pm tonight in the NW portions of the area, and reach the KS/MO border roughly by midnight. These storms will have the potential for strong winds and large hail, as well as heavy rainfall. The severe weather threat will diminish from west to east as instability weakens and an inversion begins to form at the surface. One significant short term change to the forecast is in the QPF field, which now shows less rainfall than previous iterations of the forecast. Generally speaking, the boundary which was expected to stall around the KS/NE border, now appears that it is stalling further south. Additionally, there is stronger convergence further SW in Kansas, and most models are indicating the heaviest rainfall in southern Kansas. Forecasts have been adjusted to account for this trend, and the axis of heaviest rainfall in our area now runs across central portions of the area. A majority of the area will likely fall in the 1-2" range. With this southward shift in the guidance, totals have increased a bit along the turnpike, closer to 1", with lower amounts south. Scattered thunderstorms will continue overnight and into Wednesday. The widespread storms and cloud cover means that temperatures will fall well below normal, with some areas along the Nebraska border struggling to reach 80. More normal temperatures will be realized further south, where the boundary won`t reach all the way. The upper level ridge builds significantly to the west on Thursday, and the boundary finally leaves the area. Warmer and drier weather are likely to return for the end of this work week, and temperatures will return to the 90s across much of the area. A trough further to our north will likely bring back a chance of storms Saturday afternoon and evening, and daily storm chances will likely continue into the start of next week. Taking a minute to look at the long term forecast, it does appear that we will be warming up yet again next week. The NBM temps are approaching 100 across portions of the area, with heat indices well into the 100s for Monday and Tuesday. For a 6 or 7 day forecast, this is just a sign that above average temperatures are likely to be the norm for the majority of the period. && .AVIATION /06Z TAFS THROUGH 06Z THURSDAY/... Issued at 1223 AM CDT Wed Jun 19 2024 Watching storms build towards KTOP/KFOE while exiting KMHK early this morning. Think thunderstorm activity winds down over the next few hours. Models indicate MVFR cigs impacting sites after 12z, but upstream observations remain VFR, leading to uncertainty in timing and longevity of MVFR conditions. Confidence is low in how additional showers and embedded storms evolve through this afternoon; much of the daytime hours could feature off and on showers/storms. && .TOP WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Montgomery AVIATION...Flanagan