Area Forecast Discussion
Issued by NWS Sioux Falls, SD
Issued by NWS Sioux Falls, SD
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311 FXUS63 KFSD 091711 AFDFSD Area Forecast Discussion National Weather Service Sioux Falls SD 1211 PM CDT Thu May 9 2024 .KEY MESSAGES... - Afternoon isolated showers and storms are possible into the evening hours, mostly west of I-29 with little to no accumulation expected. - Warmer and mainly dry conditions Friday into Sunday. Continued warm with renewed rain chances by early next week. Best chances currently expected mid week. && .DISCUSSION... Issued at 322 AM CDT Thu May 9 2024 CURRENTS THROUGH TONIGHT: Showers continue to pivot from northeast to southwest over the area this morning. Rainfall amounts since midnight have been less than 0.10" with a few sites in northwestern IA over 0.25". Additional rainfall amounts through the rest of today and into tonight should be less than 0.25". Cloud cover and rain are keeping temperatures in the upper 40s to mid 50s, and we`ll fall into the 40s by daybreak. We`ll continue to see the mid/upper level low flatten and shear out as it slides south through today. This will drag the bulk of the rain and isolated storm chances toward the Hwy 20 corridor by the late morning/early afternoon. However, expect some additional and isolated showers/storms to pop up over the forecast area. Soundings indicate some weak elevated instability (at or less than 200 J/kg) at the top of the mixed layer, which will serve as the catalyst for this development. May see more virga than bonafide showers or sprinkles with a fairly robust dry sub cloud layer and thus limited coverage of pops. A mix of clouds and sun is anticipated with highs in the 60s to lower 70s. Breezy north to northeast winds today may gust around 25 mph. Isolated gusts are possible with showers and storms. Another wave grazes the eastern portions of the forecast area late this evening through tonight but without much moisture to work with, expect dry weather overnight. Lows fall into the 40s. TOMORROW THROUGH THE WEEKEND: Mostly dry but somewhat unsettled weather through the weekend. A mid level trough dives across MN Friday afternoon and evening, which may bring some isolated showers and possibly a rumble of thunder or two to areas along and east of Hwy 75. Elevated instability is less (around 100 J/kg), and dry sub cloud layer may once again limit precipitation. Temperatures Friday warm into the upper 60s and lower 70s although breezy northwesterly winds will probably make it feel a touch cooler. Sustained winds Friday will be around 15-25 mph and gusts to 35 mph. Warmer on Saturday, with more low level westerly flow and WAA. Highs in the 70s, with some folks along/west of the James River possibly approaching the 80 degree mark. A low pressure system is expected to move across the south central Plains late Saturday into Sunday which may bring some isolated rain/storm chances to the area as the wave lifts north. Confidence is a bit low in the coverage of these rain chances, given how varied the track of the low is by Sunday evening (09.00z models show the center of the mid level low anywhere from north central NE to western KS/eastern CO. Highs on Sunday again in the upper 70s to lower 80s. Lows through the weekend in the 40s and 50s. EARLY TO MID NEXT WEEK: Aforementioned low pressure continues to move across portions of the Plains into early next week, with models showing another wave progged to move through mid week. This keeps periodic rain and storm chances in the forecast, but with the timing/track differences of each of these lows, confidence is too low to narrow pops more from the NBM. Best chances do look to be with the stronger wave/trough axis mid week. Precipitation chances may be more diurnally driven given the timing of the waves and increasing afternoon instability. Temperatures remain near to above normal - warmest early in the week. Highs in the 70s to lower 80s continue, with lows mainly in the 50s. Periodic breezy conditions expected. && .AVIATION /18Z TAFS THROUGH 18Z FRIDAY/... Issued at 1210 PM CDT Thu May 9 2024 Largely VFR throughout the period, though some spotty MVFR cigs are currently occuring along highway 71 in NW Iowa, but that should lift up into VFR throughout the afternoon hours. This afternoon will likely see a cu field develop at around 8kft, with some spotty weak showers possible west of I-29, though little to no accumulations are expected. After breezy northerly winds throughout the day, winds will weaken as they turn westerly overnight, switching back to northwesterly Friday morning as they increase in strength. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. IA...None. NE...None. && $$ DISCUSSION...SG AVIATION...APT