DISCUSSION
Issued at 400 AM CDT Sat Jul 27 2024

TODAY: Early this morning, a line of elevated showers/sprinkles continues to track slowly north-northeast through central SD. Model sounding profiles and nearby observations suggest only sprinkles, if any, will reach the ground with clouds based around 10 kft, but have introduced a chance for sprinkles from Gregory to Chamberlain to Huron through late morning.

Aside from this, the region remains under the influence of dry split flow aloft today with minimal weather impacts aside from the continued hot, humid weather. High resolution models continue to favor wildfire smoke aloft through tonight. This coupled with potential diurnal cumulus development and deep mixing through the nocturnal inversion should still bring high temperatures similar to Friday, in the mid 80s to lower 90s. Mixing should bring breezier south winds with gusts in the 20s to mid 30s and also slightly lower dew points, bringing heat index readings a touch cooler than Friday.

TONIGHT AND SUNDAY: A few weak waves in warm air advection via southwest flow aloft bring a low chance for showers and storms tonight near and west of the James River Valley in SD. Further east, the better chance for isolated showers and storms holds off until near sunrise and later Sunday morning. After temperatures fall to near 70 degrees early Sunday, expect a slightly less hot but more humid day with deterministic models favoring the return of 70s dew points. Should see increasing mid to high level clouds Sunday with a breezy south wind once again, but largely expect strong capping to inhibit any severe weather until Sunday night.

SUNDAY NIGHT: A stronger mid level wave ejecting into the Northern High Plains should trigger the initiation of one or several MCSs late Sunday afternoon through Sunday evening. There is low confidence in exactly where this will develop (i.e., north central SD vs central NE). Strong capping suggests this activity would be more likely to track into our area from the north or west than initially develop, but strong instability and steep mid level lapse rates favor isolated strong to severe storms with high resolution guidance showing potential for bowing segments. Suspect the main threats would be large hail up to golf ball size and up to 70 mph wind gusts, with threat increasing into the overnight hours as mid level winds strengthen.

MONDAY: Any storms should exit the region by sunrise Monday morning, but hot, humid weather lingers. Highest dew points in the mid 70s are most likely in northwest IA, where heat index readings may flirt with 100 degrees Monday afternoon.

TUESDAY AND BEYOND: Hot, humid weather typical of late July continues well into next week as ridging reinvigorates in the Southern Plains with highs in the 80s and 90s and robust humidity continuing to impact sensitive groups, such as those doing prolonged work outdoors and the elderly. Additionally, will be monitoring periods of low to moderate storm chances returning Tuesday night through Wednesday night via shortwaves riding in zonal flow aloft.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/
Issued at 632 AM CDT Sat Jul 27 2024

Mid level ceilings slide in near Chamberlain to Huron this morning with a chance for brief sprinkles. Expect VFR conditions to prevail through at least this evening with wildfire smoke continuing to stream through aloft. Southerly winds ramp up after sunrise, gusting in the 20s this afternoon, highest at Sioux Falls and Huron. Isolated thunderstorms are possible near Huron late in the TAF period but confidence in timing and location of storms is low.

FSD WATCHES/WARNINGS/ADVISORIES
SD...None.
MN...None.
IA...None.
NE...None.