Area Forecast Discussion
Issued by NWS Sioux Falls, SD
Issued by NWS Sioux Falls, SD
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
090 FXUS63 KFSD 071739 AFDFSD Area Forecast Discussion National Weather Service Sioux Falls SD 1239 PM CDT Fri Jun 7 2024 .KEY MESSAGES... - Scattered showers and isolated thunderstorms return to the area today into tonight. There is a low probability of a strong to severe storm along the Missouri River during the afternoon/evening. - Slightly cooler temperatures with relatively light winds for the upcoming weekend. - Low confidence in precipitation chances for Sunday into the beginning of next week with significant model differences. - Chances for above normal temperatures return late next week as a ridge of high pressure builds across the south. && .DISCUSSION... Issued at 325 AM CDT Fri Jun 7 2024 Clear skies across the region early this morning with weak surface high pressure situated over our area. The surface ridge will shift eastward into the central Mississippi Valley during the day, this as a surface low deepens over western NE and KS. In response, calm winds this morning will increase a bit by afternoon - out of the south as the high moves to the east and the surface pressure gradient tightens up slightly. Even so, winds will be much lighter than the past couple of days with much lighter winds at the top of the mixed layer. Otherwise, an upper level shortwave slides eastward across southern SD during the day. With that, scattered showers and isolated thunderstorms are expected to develop across the area as midlevel warm air advection overspreads the region. Although SPC has outlined portions of the MO River Valley in a Marginal convective risk, think that the potential for severe storms is low. While there will be plenty of effective bulk shear (50 kts+) in place across the region this afternoon and evening, almost all models (with the exception of the NAM) indicate the more significant instability (1000 J/KG +) remaining well to the south and west of our CWA. If the NAM were to verify - with CAPE of around 1000 J/KG through south central SD, then the potential for a stronger to severe storm would be greater over that area. As for precipitation amounts for today, they would be on the lighter side (a tenth of an inch or less) with model soundings indicating a layer of dry air below 700 mb. As for temperatures today, they will remain seasonable in the mid to upper 70s. While any showers and storms will most likely diminish by late evening, there could be additional light showers over the eastern portions of our CWA later tonight as another upper level impulse drifts across the region. Lows tonight will drop into the 50s once again. Surface high pressure slowly builds across the region for the upcoming weekend. This will bring slightly cooler temperatures with highs generally in the low to mid 70s. Northerly winds will be relatively light on Saturday, with a touch more of a breeze on Sunday - though not out of the ordinary with sustained winds of 10 to 15 mph. Most models would indicate a dry weekend ahead - with the exception being the GFS which becomes a significant outlier as we move into the beginning of next week. While the ECMWF/Canadian/and NAM all begin to build an upper level ridge over the region by Sunday, the GFS wants to drop an upper level low into the Northern Plains on Sunday and Monday. If that were to occur, then rain chances would increase on Sunday into Monday. At this point, will ignore that solution since it is an outlier from the rest of the models. These same trends are displayed in the respective 00Z ensembles. For Tuesday through Thursday, while the GFS continues to be an outlier early in the period, our next chance of precipitation could come on Tuesday as both the ECMWF and Canadian bring an upper level trough into the region. By mid and late week, models (and ensembles) trend to toward a broad upper level ridge building over the central CONUS. This is reflected in warming temperatures as highs climb into the 80s to near 90 during this period - which is supported by both NAEFS and ECMWF ensembles which indicate 700/850 mb temperatures into the 90th percentile with respect to climatology by the end of the week. && .AVIATION /18Z TAFS THROUGH 18Z SATURDAY/... Issued at 1238 PM CDT Fri Jun 7 2024 Scattered showers continue across the region, with accumulations remaining on the lower side given the dry air still in the lower levels. Will see coverage increase through the afternoon and evening, with a few strong to severe storms possible west of the James River and along/south of the MO River Valley. As a result, could see cigs/vsbys briefly drop to MVFR/IFR levels. Additional showers will be possible along and east of I-29 near/after daybreak, followed by a narrow band near the MO River late morning. Otherwise, expect S/SE winds to continue, with direction becoming more northerly by daybreak tomorrow. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. IA...None. NE...None. && $$ DISCUSSION...JM AVIATION...SST