textproduct: Aberdeen

KEY MESSAGES

- Winds out of the northwest will gust 30 to 40 mph today with locally higher gusts possible. Winds will diminish late this evening through tonight.

- Widely scattered rain showers or sprinkles are possible this morning through this afternoon with chances between 15 to 25 percent, mainly west of the James River. Little to no accumulation is expected.

- High temperatures Tuesday and Wednesday will run around 10 to 20 degrees below normal ranging in the mid 40s to the mid 50s. Early morning lows Tuesday through Thursday will drop into the upper 20s to the lower 30s (10 to 15 degrees below normal).

DISCUSSION

Issued at 110 AM CDT Mon May 4 2026

As of 1am, the low is currently located over western Ontario with its cold front draped from northwestern MN through central North Dakota. Its surface trough is just ahead of it with its axis positioned northeast to southwest over the CWA. Winds are out of the southwest between 10-25 mph, highest along the eastern slopes of the Sisseton Hill per downslope effect. Highest gusts so far have been between 30 to 35 mph for several locations along the east side of the Coteau. Over the next several hours as this low tracks east across Ontario, the fropa will track southeastward across the CWA with winds turning northwesterly behind the front (and ending the downsloping event). This is a pretty quick moving front as it is forecast to exit our far southeastern CWA around or just a little after 12Z and out of the state late morning.

The strongest CAA will be over north central SD, just behind the front around 12Z, where winds are expected to increase through the early morning and gradually increase over the rest of the CWA through 18Z as weaker CAA will be widespread over the CWA by then. Pressure rises during this time won't be anything spectacular but up to +6mb/6hr during this time. NAM/RAP soundings show steep low level lapse rates up to between 800-700mb with the top of the mixed layer momentum transfer between 25 to 35 kts over the CWA and even up to the lower 40kts over north central SD by the afternoon when we reach peak daytime mixing. Rap is the more aggressive model in showing lapse rates to 650mb, but luckily winds aloft aren't incredibly strong. Still, went ahead and stuck with a blend of NBM/NBM90th with gusts ranging from 30 to 40 mph from mid to late morning through the afternoon. Winds should stay below advisory criteria as EFI indicates values of only 0.5 to 0.7 for wind speed/gusts over north central and northeastern SD along the ND border. Probability of wind gusts>45 mph is 25-35% over Corson County and the Leola Hills with NBM 24 hr max potential wind gusts up to 50 mph here. So locally higher gusts to 45+ is possible mainly over higher elevations of north central SD with widespread 45mph+ gusts not anticipated. Winds will diminish this evening as pressure gradients relax and we lose daytime mixing.

Cams show the potential for a horizontal line of post frontal showers tracking southward and over the ND/SD border around 12Z, and tracking east/southeastward. However, most of the CAMs do show them fizzling out becoming widely scattered or very spotty. This is due to lots of dry air near the surface so any rain would be very light or sprinkles or virga. CAMs still show additional convective showers forming over the CWA behind this by the early afternoon to the early evening, with HRRR/HREF being less impressed. So overall pops this morning through the afternoon is 15-25%, mainly west of the James River and highest along and west of the Mo River. Again being high based and dry air below (little bit of elevated CAPE) not much QPF is expected. Any shower(or weak storm) or collapsing shower could bring a burst of gusty winds to the surface, up to 50 mph or so. However, no severe weather is anticipated. Probability of QPF>0.01 is only 20-40% along and west of the Mo River. Otherwise, the CWA will be on the southeastern side (within the inverted ridge) of a large high pressure system over far northwest Canada by 00Z Tuesday and ongoing high pressure will keep the forecast overall dry Tuesday through at least Thursday.

Highs for today will be cooler behind the front ranging in the mid 50 to the lower 60s, warmest over south central SD. We really see the colder air move in starting tonight with overnight lows in the upper 20s to the lower 30s. Highs will be 10-20 degrees below average Tuesday and Wednesday, only in the mid 40s and 50s and lows still ranging in the mid/upper 20s to the lower 30s as 700-850mb temps will be 1 to 2 standard deviations below climo per NAEFs during this time. Our coldest morning looks to be Wednesday morning as record lows will be within 5 degrees. May need to blend in some NBM25 for morning lows Tuesday/Wednesday. Otherwise, warmer air will move in from the west, under a ridge, gradually warming temps back up for the end of the week with highs for the weekend back in the upper 60s and 70s.

AVIATION /06Z TAFS THROUGH 06Z TUESDAY/

Issued at 1213 AM CDT Mon May 4 2026

Terminals KABR,KATY,KPIR,KMBG

VFR conditions will continue at all terminals during this TAF valid period. Southwest winds will become west to northwest through the early morning hours as a cold front pushes through the region. Increasing winds speeds are expected as winds shift directions with peaks gusts between 25-35 knots by late morning/midday and persist into early evening tonight. Low level wind shear will be possible at KABR/KATY through the pre-dawn hours this morning as strong winds just off the deck are expected.

ABR WATCHES/WARNINGS/ADVISORIES

SD...None. MN...None.