Area Forecast Discussion
Issued by NWS Sioux Falls, SD
Issued by NWS Sioux Falls, SD
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786 FXUS63 KFSD 251817 AFDFSD Area Forecast Discussion National Weather Service Sioux Falls SD 117 PM CDT Sat May 25 2024 .KEY MESSAGES... - Scattered showers and southwest winds gusting into the 30s may be a minor nuisance to outdoor activities this afternoon and evening. - Another round of scattered showers and storms slides in near the Missouri River Valley and the U.S. Highway 20 corridor overnight. A strong to briefly severe thunderstorm or two cannot be ruled out with hail up to quarter size and wind gusts up to 60 mph. - Periodic scattered showers and storms continue through Sunday and Monday. - Dry, seasonal conditions develop Monday night through Wednesday. && .DISCUSSION... Issued at 318 AM CDT Sat May 25 2024 The leading edge of a weak piece of mid level energy will move into the area this morning but not bring much with it. For the most part the atmosphere is very dry below 700 mb so the only thing available to produce precipitation is moisture in the dendritic layer, which is very high, and any instability in the EML, which is pretty weak. So, for the most part just expecting some sprinkles with a small chance for a hundredth or two if some slightly higher instability comes around. This potential will mainly be this morning into early afternoon and north of I-90. By late this afternoon and tonight showers and a few thunderstorms will be possible but right now instability looks pretty weak. Both the GEFS and EC Ensemble showing about 20% chance or lower of 500 J/kg CAPE near the Missouri River with almost no chance for 1000 J/kg CAPE anywhere. The slightly better chance for the higher CAPE values will be central SD late this afternoon then down the Missouri River into northeast NE and northwest IA later tonight. Not too dissimilar to Thursday night, just less instability and a weaker wave. Suspect with the decent little wave moving through NE tonight some showers will develop with the best chance for the better ingredients for storms and very isolated severe weather to come together in northeast NE and northwest IA from about 10 pm to 5 am. Once again, chances look pretty low but a couple of stronger updrafts not out of the question. One thing to watch out for is with a pretty dry sub cloud layer there could be some wind that sneaks north out of the potentially stronger convection in NE. Otherwise for today it will be warmer but once again windy. Not as windy as Friday but still some stronger winds this morning into early afternoon. Suspect some gusts of 35 to 40 mph. Sunday should see roughly two areas with potential for showers and thunderstorms. The first will be the wave moving through NE which should bring some forcing and moisture north towards northeast NE into northwest IA, especially in the afternoon and evening. Overall the instability is pretty weak so right now not concerned about severe weather. The other area will be a wave moving through southern ND which may spark some showers or isolated thunderstorms in central SD late afternoon and evening then mainly north of I-90 during the evening into Sunday night. This area also appears to pose no severe weather threat. Once this wave passes on Sunday night a cooler pattern with below normal temperatures is expected Monday and Tuesday. A wave passes by through MN on Memorial Day and could allow for a few showers and isolated thunderstorms mainly east of the James River. Upper level ridging builds into the area Wednesday and Thursday which should bring back normal to above normal temperatures. Wednesday should be dry, but with troughiness developing over the Northern Rockies on Wednesday night Thursday into Friday will likely see the next chances for showers and thunderstorms. && .AVIATION /18Z TAFS THROUGH 18Z SUNDAY/... Issued at 109 PM CDT Sat May 25 2024 VFR conditions prevail through this evening. Scattered showers lift north of the I-90 corridor this afternoon into early this evening, mainly impacting Huron, with gusty south winds. An area of scattered showers and perhaps a few storms is expected to develop in south central SD and central NE, tracking east through the evening and may impact Sioux Falls and more likely Sioux City overnight. Behind this, winds shift more north or northeast tonight behind the passing wave. While an isolated strong to severe storm with large hail and strong wind gusts cannot be ruled out, the main threat will be gusty erratic winds near storms tonight. MVFR stratus may develop Sunday morning. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. IA...None. NE...None. && $$ DISCUSSION...08 AVIATION...BP