Area Forecast Discussion
Issued by NWS Sioux Falls, SD
Issued by NWS Sioux Falls, SD
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607 FXUS63 KFSD 012345 AFDFSD Area Forecast Discussion National Weather Service Sioux Falls SD 645 PM CDT Mon Jul 1 2024 .KEY MESSAGES... - Below normal temperatures continue through most of the week with high temperatures on the order of near seasonable to 5 to 10 degrees below average. - Severe weather remains possible this evening, with hail to the size of ping pong balls and damaging winds up to 60 MPH expected to be the primary hazards. - Heavy rain also remains possible tonight through Tuesday morning. Those along and southeast of a line extending from Tyndall/Sioux Falls/Marshall could see anywhere from a tenth to 1.5 inches. Locally higher amounts (2 to 3 inches) may still occur, especially in the presence of training storms. Thus, a Flood Watch has been issued for portions of our area. - Active weather pattern aloft supports periodic chances for showers and storms for the remainder of the week, with a brief lull possible Wednesday. && .DISCUSSION... Issued at 251 PM CDT Mon Jul 1 2024 CURRENT THROUGH TONIGHT: Scattered showers and storms remain ongoing across the region, with latest observations showing mostly cloudy skies and temperatures in the mid to upper 60s. Broad WAA and an increasing LLJ have also resulted in fairly breezy southeasterly winds across our area, with gusts currently ranging between 25 to 45 MPH. Expect much of the same throughout the afternoon, with gusts lessening to 15-25 MPH near sunset. Heading into the evening, our attention turns to an advancing upper level wave progged to push eastward across the Northern Plains. Have already noted dewpoints in the lower 60s as far north as the MO River Valley ahead of an advancing sfc warm front. Given the efficient moisture transport in place, expect showers and storms to redevelop near/shortly after sunset in areas west of the James River. While a few of these storms could become strong to severe, expect this initial wave to fizzle out as they push eastward into dry/stable air near the sfc. Better chances for severe weather looks to occur along the MO River Valley and along/south of Highway 18 between 00-06Z. While a few discrete storms may be possible initially, expect storms to favor a linear storm mode - with ping pong ball size hail and gusts up to 60 MPH being the primary hazards. In addition to severe weather, also want to emphasis that heavy rain will also be possible, especially with PWATs near/exceeding 2 inches. While there has been a slight decrease in rainfall totals through Tuesday morning, still expect amounts to range between a tenth to 1.5 inches along and southeast of a line from Tyndall/Sioux Falls/Marshall. That being said, could still see pockets of locally higher amounts (2 to 3 inches) occur, especially in the presence of training storms. Thus, given the recent rains and saturated soils in place, have decided alongside neighbors to issue a Flood Watch for portions of our area, which will be in effect from 7 PM tonight through 7 AM Tuesday. As always, we encourage you to have a way to receive warnings. In the meantime, be sure to clear gutters and street drains of all debris and make sure your sump pump is working. And remember, if you encounter a flooded roadway - turn around, don`t drown! TUESDAY AND WEDNESDAY: Sfc cold front dives across the region Tuesday in the wake of the aforementioned upper level wave. A bit of uncertainty still exist concerning how quickly this boundary will advance across our area, which will in turn effect the odds of seeing strong to severe storms. Latest CAMs would suggest a quicker solution, thus, keeping the threat for severe weather largely southeast of our area. However, if the cold front advances slower than expected, can`t rule out the possibility of seeing a few strong to severe storms across NW Iowa. Will continue to monitor trends in the meantime. Otherwise, look for afternoon highs to rise into the upper 70s to lower 80s. Should see dry conditions return late Tuesday night and continue for much of the day Wednesday as sfc ridging slides overhead. 850 mb temperatures will warm to the upper teens which will result in seasonable high temperatures in the low to mid 80s. Lows during this time will also remain fairly mild, as temperatures only fall into the lower 60s. WEDNESDAY NIGHT AND BEYOND: Precipitation chances return to the forecast Wednesday evening as yet another upper level wave takes aim at the region. While some fluctuations in timing may still occur, expect showers and storms to be possible late Wednesday through Thursday afternoon. As alluded to in the previous discussion, ensembles continue to show high probabilities (near 100%) for exceeding a tenth of an inch of rain. However, their probabilities drop to about 30-50% for exceeding a half an inch of rain, with the higher amounts generally across south-central South Dakota. Will certainly need to keep an eye on things in the coming days, as it will not take much rainfall to cause additional flooding concerns. Periodic chances for showers and storms continue for the remainder of the week as an active weather pattern lingers aloft. Temperatures look to be a touch cooler Thursday and Friday, with highs largely in the 70s and lows in the upper 50s. Drier conditions could make a return this weekend as upper level ridging builds into the western CONUS but too early to say if any ridge riding waves will bring continued chances for rain to the area. && .AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/... Issued at 644 PM CDT Mon Jul 1 2024 Breezy south-southeasterly winds will diminish this evening ahead of an incoming cold front, with showers and thunderstorms expected to develop and move through the region from southwest to northeast over the next 12 hours. MVFR to IFR cigs and visbys are expected, with a stratus deck likely hanging around behind after the showers/storms have moved through. As alluded to in the previous discussions, confidence is highest for preciptation occuring in locations along and southeast of a line from Tyndall/Sioux Falls/Slayton. A few storms could become strong to severe, with hail and damaging winds being the primary hazards. Tuesday will see the cold front finish pushing through the region causing winds to shift out of the northwest, with another round of scattered showers and thunderstorms in the afternoon. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...Flood Watch through Tuesday morning for SDZ070-071. MN...None. IA...Flood Watch through Tuesday morning for IAZ012>014-020>022-031- 032. NE...Flood Watch through Tuesday morning for NEZ013-014. && $$ DISCUSSION...SST AVIATION...APT