textproduct: Sioux Falls

KEY MESSAGES

- Light rain and drizzle risks will arrive late Monday afternoon and continue into Tuesday morning. Rainfall amounts less than 0.10" expected. Temperatures likely remain above freezing, mitigating any large scale icing potential.

- Confidence is high in another extended period of well-above normal temperatures into next weekend.

- Confidence also remains higher than normal in returning rain risks Thursday into Friday during the passage of a front. A rumble or two of thunder could also be possible especially over NW Iowa.

- Precipitation amounts for the end of the week are still favored to remain low, with current probabilities of >0.50" only 20 to 30%. However this may mark the most significant precipitation chance we've had for some time.

UPDATE

Issued at 1043 PM CST Mon Mar 2 2026

Light rain showers continue to push eastwards through the forecast area late this evening. While the bulk of the showers will come to an end just after midnight, drizzle remains possible for the rest of the overnight hours as more expansive low level stratus develops. This stratus will prevent temperatures from falling too much more from where they currently are. Thus, freezing drizzle is still not expected through the overnight hours.

Tuesday will begin on the dreary side with low level stratus locked in place through the morning hours. Saturation in the dendritic growth zone (DGZ) will exit the area, leaving just the stratus. The good news is that the stratus will lift a bit and break apart some, returning peaks of sunshine to the area for the afternoon hours. However, with remaining low level moisture in place, the stratus looks to re-expand across the area. There could be some light rain showers along and south of highway-20 where better saturation and lift looks to lie. Otherwise, low temperatures will again be on the warm side, only falling to mid to low 30s.

The middle of the week continues to look warm and generally dry as an approaching stronger upper level wave results in more meridional flow across the Plains. This will result in persistent warm advection that will warm temperatures to the 50s and 60s on Wednesday and then up to the 60s to possibly low 70s on Thursday. Latest guidance still shows precipitation occurring with this wave but looks to begin earlier, now beginning Thursday evening/night. Chances for precipitation will persist through Friday before exiting the area on Saturday. Latest deterministic guidance still shows the potential for some weak instability and is supported by the ensembles as they show a 40-60% chance for instability values to exceed 500 J/kg. The highest probabilities look to come on Friday, thus signaling that some claps of thunder are possible. Still looking at chances for rain transitioning to rain/snow on the backside of the system after a cold front passes through the area.

DISCUSSION

Issued at 1221 PM CST Mon Mar 2 2026

THIS Afternoon: Stratus continues over portions of IA/MN and far eastern SD this afternoon, though satellite suggests the cloud layer is quite thin. Temperatures have again risen into the 40s in most areas, cooler over the deeper snow pack from the weekend snow. Further west, we're seeing the development of light showers in the West River and Panhandle areas. This light rain will continue on an eastward path late this afternoon, but will be fighting a very pronounced dry layer centered around 850mb.

TONIGHT: Light rain/sprinkles will continue to move eastward through the evening hours tied to a stronger vort lobe along I-90. After the passage of this wave, soundings suggest that we'll lose ice in the atmospheric column, and with the continuation of very weak isentropic lift AOB 800mb we may begin to see drizzle develop into daybreak Tuesday. There remains some fluctuation in overnight temperature potential. Assuming we can warm into the upper 30s to lower 40s, expanding stratus after dark may help blanket the area and keep temperatures a few degrees above freezing and mitigate any icing potential. The deterministic NBM seems to be biased by the recent cold overnight periods with hourlies at or below the 25th percentile. With that said, have blended in more short term CAMs that keep hourlies near or just above freezing in most areas. Confidence remains high that QPF itself will be very light, with only a 30% probability of more than 0.10". Most may see only a couple hundredths.

TUESDAY: We'll continue to remain under the influence of mid-lvl vorticity into mid-day Tuesday, while the introduction of a light northerly wind AOA 800 mb should lessen the depth of the low-lvl moisture layer and gradually reduce the drizzle production potential south of I-90. Temperatures warm into the upper 40s to 50s in the afternoon. An upper trough will eject slowly eastward into the Mid- Missouri River valley Tuesday night and Wednesday, with weak channeling of low-lvl moisture and weak warm advection back to areas south of I-90 and towards Highway 20 overnight. This will continue or reintroduce the potential for drizzle to spits of rain into Wednesday morning. With temperatures again above freezing no impacts are likely.

WEDNESDAY: Mid-lvl heights begin to rise on Wednesday, and surface winds turn back to the south through the day. A thermal ridge will develop over the Dakotas and point towards the Arrowhead of Minnesota by Wednesday afternoon. Temperatures at the surface respond by jumping into the 60s west of the James River and 50s to the east.

THURSDAY-FRIDAY: Medium range models and their ensembles remain in strong agreement for the end of the week, pushing a long wave trough over the West Coast Wednesday into the Plains by Thursday and Friday. Closer to home, the initial response will be deeper lee- side troughing Thursday which will allow the thermal ridge to slide east, but also increase the southerly surface winds. While the airmass ahead of this trough is warm, ESAT tables would suggest that this airmass sits around the 90th percentile of climatology centered around early March. Meaning, at this point, the potential for records remains low Thursday and Friday. One thing to watch is the potential for any stratus to linger along or east of I-29, which would have a lowering impact on temperatures.

Regarding precipitation, this is where some slight deviations in guidance develop. Both EC/GFS/CMC show the potential for the long wave trough to split, with a positively tilted trough sagging eastwards into Friday, and energy at the base of the trough diving southward. This split, while uncertain, could deviate the moisture trajectory of this system. On the other hand, some guidance (mostly EC but some GFS members) does bring a more condensed area of vorticity northeastward, allowing at least some moisture and instability (~300-500 J/KG MUCAPE) to focus near the Tri- State area. The potential release of this instability may be the one key aspect of the forecast that could drive up QPF potential, which based on other ensemble solutions remains low. Probabilities of >0.1" have risen to near 80%, with probabilities of >0.50" much lower at 20- 30%. No matter what, this system does at least have the potential of producing more than a ground wetting rain by time it ends late Friday. This system also has hints of a separate deformation band trying to form over central SD that could turn into a rain/snow mixture depending on timing.

SATURDAY-MONDAY: Temperatures remain very warm heading into next weekend with no strong cold advection behind the passing trough Friday. Breezy southwesterly winds are likely next weekend, but especially on Saturday where the SPG increases quickly. Temperatures in the 50s and 60s are expected, with the current NBM forecast sitting closer to the 75th percentile of the ensemble solutions.

AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/

Issued at 1043 PM CST Mon Mar 2 2026

A few light rain showers persist late this evening near the Iowa/Minnesota border. Mid and high level clouds persist across the majority of the area with low level stratus developing across the Missouri River valley. This stratus is expected to expand north and eastwards throughout the night. The stratus looks to lower to IFR/LIFR levels as well. There could be some drizzle beneath the stratus though confidence is too low to include in a TAF. The stratus will stick around through the morning hours before lifting to MVFR levels and and somewhat breaking up for the afternoon timeframe. However, the stratus looks to fill back in during the evening timeframe to end the TAF period. The stratus looks to remain at MVFR levels for the end of the period but could sink lower, especially just after the period ends.

FSD WATCHES/WARNINGS/ADVISORIES

SD...None. MN...None. IA...None. NE...None.