![National Oceanic and Atmospheric Administration](/build/images/header/noaa.d87e0251.png)
![National Weather Service](/build/images/header/nws.4e6585d8.png)
![United States Department of Commerce](/build/images/header/doc.b38ba91a.png)
Area Forecast Discussion
Issued by NWS Des Moines, IA
Issued by NWS Des Moines, IA
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
038 FXUS63 KDMX 101147 AFDDMX Area Forecast Discussion National Weather Service Des Moines IA 647 AM CDT Sat Aug 10 2024 ...Updated for the 12z Aviation Discussion... .KEY MESSAGES... - Continued dry and pleasant today, but potential for showers and storms increases late Sunday into early Monday morning - More typical summer pattern by the middle of next week with intermittent chances for storms and more seasonal warmth and humidity && .DISCUSSION... Issued at 347 AM CDT Sat Aug 10 2024 Today`s weather should be much like recent days with seasonally cool temps and low humidities. With mostly clear skies and light west winds early this morning, this cool, dry airmass has allowed 08z temps to approach record lows in a few spots with readings in the upper 40s to middle 50s. Mason City, Lamoni, and Ottumwa would be the more likely candidates, if they can cool sufficiently over the next few hours. Weak short waves along the PV gradient and jet segment from CO into NE will advance into the MO Valley later today with some mid and high cloudiness due to warm advection aloft, but surface high pressure along and west of the MO Valley will keep our airmass little changed. This situation will change later tomorrow however as Pacific NW short waves follow the aforementioned track into the Plains. This will sharpen the H85/H7 trough upstream, and resultant warm/theta-e advection into the state, with kinematic contributions also increasing lift and column saturation by the early morning hours Monday. MUCAPEs get to 1000 J/kg at most, and are generally lower, so overall the severe weather potential is low. However with 40-50kt effective shear and elongated hodographs, a few strong storms with hail can`t be ruled out if higher instability is realized. Much of this lift should exit into midday Monday with only spotty slight chances lingering into Tuesday as upper level ridging approaches the MO Valley. Confidence decreases for the middle to latter portions of next week however, especially in the details. However, there is good larger scale agreement that the flow will weaken, allowing more seasonal warmth and humidity to return. Recent EC/NAEFS ensemble output notes seasonally anomalous values of specific humidity and precipitable water back into the MO Valley by Wednesday into Thursday. The models are struggling with upper trough timing, strength, and location, as well as surface features, but the overall pattern suggests a few windows for MCS development midweek through the end of the period. This results in several days with slight to chance PoPs until confidence increases. Would not be surprised to eventually see some severe weather potential, but with models having difficulty aligning focusing mechanisms, and what the shear/instability parameter space would look like at those times, the severe weather potential would best be described as low for the time being. The latest Colorado State machine learning severe weather probabilities (09/00z) reflect that as well with little signal as of yet. && .AVIATION /12Z TAFS THROUGH 12Z SUNDAY/... Issued at 647 AM CDT Sat Aug 10 2024 Confidence is high that VFR conditions will persist through the period with varied degrees of mid and high level cloudiness, mainly south and west. W-NW winds will increase a bit into peak heating, but then become light again by evening. && .DMX WATCHES/WARNINGS/ADVISORIES...None. && $$ DISCUSSION...Small AVIATION...Small