Area Forecast Discussion
Issued by NWS Sioux Falls, SD
Issued by NWS Sioux Falls, SD
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609 FXUS63 KFSD 062258 AFDFSD Area Forecast Discussion National Weather Service Sioux Falls SD 558 PM CDT Sat Jul 6 2024 .KEY MESSAGES... - Increasing coverage of showers and thunderstorms through this afternoon to mid evening, diminishing again by midnight tonight. A few strong to severe storms are possible with large hail and damaging winds the primary threats. - Patchy fog again possible tonight-early Sunday. Widespread dense fog is not expected, but isolated visibility below a mile is possible. - Unsettled weather continues early next week with spotty afternoon to early evening showers/storms Sunday-Wednesday. Severe weather is not expected. - Cooler than normal temperatures for early July through the early part of next week, but trending closer to normal by the end of the week. && .DISCUSSION... Issued at 208 PM CDT Sat Jul 6 2024 Afternoon/Evening: Focus will be on the wave currently evident on WV imagery diving through the central Dakotas as of early afternoon. This will be entering an environment characterized by MLCAPE values of up to 1000-1500 J/kg. While deep layer shear is weighted south of I-90 away from the better dynamics, up to 30-35 kts of EBWD is progged north of I-90 and may allow for some organization of thunderstorms. Additionally, fairly straight hodographs may allow for splitting cells in any of this more organized activity. Large hail up to ping pong ball size appears to be the primary risk with wind gusts up to 60-65 mph possible with an occasional sounding showing a modest dry subcloud layer and DCAPE values approaching 1000 J/kg. While an extremely low potential, a muddled low level wind profile can at times lend to a low end landspout potential with non-supercell parameter between 0.5-2 through the deeper convergence zones. In terms of rainfall, PWATS around 1.25 and 850 mb dewpoints exceeding 10C will likely allow for efficient rain rates in any healthier thunderstorms, although activity looks progressive enough to prevent any widespread issues. HREF PMM/LPMM do show the potential of localized pockets to around 2-2.5 inches with most locations less than that. While unwelcome in flood stricken areas, don`t suspect we`ll see any significant river rises from the more isolated amounts and instead focus for any problems will likely be in urban and poor drainage areas. Overnight: As has been the case the last couple of mornings, very well could see some patchy fog in low lying areas. Have introduced this mention into the forecast through the daybreak hours Sunday morning. Sunday: Another day where forecast soundings suggest the potential for some scattered showers and thunderstorms in the afternoon and early evening hours as the cooler upper low swings overhead. Lack of a stronger wave likely keeps activity non-severe and less organized than today. Will keep chance level POPs in the afternoon and early evening hours. Temperatures again in the mid 70s to lower 80s. Monday thru Wednesday: No real significant changes for the early to mid work week as occasional weak waves slide down the backside of the upper trough lending to occasional afternoon/evening shower chances. At this time, the focus looks to be near and east of I-29. Thursday and Friday: West coast ridging tries to build eastward and should provide for drier conditions and warming temperatures. && .AVIATION /00Z TAFS THROUGH 00Z MONDAY/... Issued at 555 PM CDT Sat Jul 6 2024 Scattered thunderstorms will be possible across the area through the evening, and there will be a risk of isolated severe storms. Thunderstorms end from west to east by late evening, and with very light winds there will be a possibility of patchy fog. Additional shower and thunderstorm development will be possible on Sunday afternoon and evening. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. IA...None. NE...None. && $$ DISCUSSION...Kalin AVIATION...JM