Area Forecast Discussion

KEY MESSAGES

- Near-critical to critical fire weather conditions are expected across mainly NNW portions of the area on Wednesday. A Red Flag Warning has been issued from 12-8PM for areas along/west of a Genoa-Kearney-Beaver City line. Wind gusts near 40 MPH will be possible.

- More widespread fire weather concerns return for Thursday, as relative humidity drops quickly behind a passing frontal boundary. This frontal boundary will also be the focus for storms during the afternoon-evening hours...which may impact eastern portions of the area. Some strong-severe storms will be possible.

- Spotty precipitation chances continue through the end of the week and upcoming weekend...with models suggesting Sunday may be the best chance for more widespread precipitation. Lot of time to iron out details however and see how models trend.

DISCUSSION

Issued at 358 PM CDT Tue Apr 21 2026

Currently through tonight...

Dry conditions continue to reign today...with satellite imagery showing plenty of sun across the region. Looking aloft...upper air data shows west-northwesterly flow in place as ridging slides east through the Plains...set up between broad troughing off the East Coast and a larger scale low pressure system moving onto the coast of northern CA/southern OR. At the surface, the first half of the day saw most spots with light/at times variable winds with a weak surface boundary draped across the area. This afternoon, low pressure/troughing over the High Plains is helping to pull that boundary northward...with more ESE to the north ahead of the front, more gusty southerly winds to the south. Temperatures have worked out fairly well, with most in the mid-upper 80s. Do have spots where relative humidity values have dropped to/below 20 percent...but with the winds remaining generally lighter (though there has been an occasional gust near 20 MPH), critical fire weather conditions haven't been an issue.

This evening through tonight, no notable changes were made to the dry forecast. Not expecting changes with the surface pattern, we remain east of the main area of sfc low pressure, which will keep winds southerly through the night...speeds around 10-15 MPH, can't rule out some gusts near 20 MPH in spots. The southerly flow will continue to transport better moisture northward, with dewpoints in the 50s spreading across more of the forecast area with time. Overnight lows tonight are mild, dropping into the low-mid 50s (normal lows this time of year are in the mid 30s-low 40s).

Wednesday...

Overall, models haven't show any notable changes for Wednesday...still looking to be another day of well above normal temps, this time with stronger winds. In the upper levels, flow across the Central Plains is turning more southwesterly as that larger low pressure system moves further inland...becoming more centered over portions of MT by early evening. At the surface, low pressure continues to deepen ahead of this system...with models showing a strengthening dryline extending through western portions of SD-NE-KS. A tightening pressure gradient will bring stronger southerly winds throughout the day...with gusts near 35-40 MPH possible, especially for WNW portions of the area. Forecast calling for similar highs for most locations, well into the 80s for some...little more uncertainty across SSE areas, where there may be more lower level clouds lingering longer into the day than in other spots. After collab with neighboring offices, the main change to the forecast for Wednesday was with the issuance of a Red Flag warning, for areas roughly along/west of a line Genoa-Kearney-Beaver City, NE. There are some uncertainties...mainly with dewpoints and how far they drop with mixing through the day. Forecast is on the lower side of things for dewpoints/relative humidity in that area...have RH values falling into the 17-25 percent range, confidence in winds is higher...that NWrn area has the best potential to reach critical fire weather conditions.

Later in the afternoon, this surface dryline off to our west is expected to be the focus for isolated to scattered thunderstorm development, some of which could be strong-severe. The big questions for our area lie in the finer details...exactly where does that dryline initially set up/strengthen...and can any activity maintain itself long enough to impact our CWA. The further west that boundary ends up, the lower the chances of impact on us...but there are a few models that inch things further east...thus the SPC Day 2 Marginal Risk area remaining over our far west. Large hail/damaging winds would be the main threat...and would likely be a short-lived threat.

Through the overnight hours...can't rule out some scattered showers and weaker storms passing through the area as that main upper low/trough push further east. Based on some models recent trends, feel that current forecast PoPs are too broad in nature...have 20 percent chances all the way through our KS counties. Some models keep us dry and focus things just off to the north.

Thursday...

By the time 12Z Thursday rolls around...models aren't in too bad of agreement showing upper level low pressure having moved into eastern portions of Montana...with a SSW extending trough axis int the UT/CO border area. At the surface, models also in good agreement showing the main surface frontal boundary looks to be knocking on the door of our western-most counties. Through the rest of the daytime- evening hours...question number 1 is tied to that surface frontal boundary's progress through the forecast area. There have been and continue to be slight, but important, differences between models (even run to run for some) with the timing of that progress...as we get mid-late afternoon, that front will be the focus of thunderstorm development. Some models remain consistent that at most storms affect roughly the HWY 81 corridor...others have trended more toward/stayed with a earlier (more like early-mid afternoon), further west development (closer to HWY 281). It'll be interesting to see how models trend, now that we'll be getting further into a timeframe where more hi-res models are available. Ahead of the front, could have MUCAPE values exceeding 2000 j/kg...with deeper layer shear of potentially 30-40 kts. SPC Day 3 Slight Risk remains over portions of the area east of HWY 281. Any initial discrete storms look to form into more of a line fairly quickly...and the main severe threat also looks to make a overall quick exit to the east, even the slowest/western models have us clear by mid-evening.

Along with the storm threat, there is also a fire weather threat behind the surface front. Gusty west-northwest winds are expected to accompany the front...along with a drier airmass and increased mixing, dewpoints look to fall into the teens-20s. Forecast relative humidity values below 20 percent have the potential to be fairly widespread...but like the storm chances will depend on the eastward progress of that front. With the expected gusty winds, it's looking likely a fire headline will be needed for Thursday...just a matter of how much of the area will be included.

Friday and on...

For the end of the week, models continue to show the main area of upper level low pressure shifting into central Canada...keeping some spotty precipitation chances around mainly Friday night into Saturday. As we get into Sunday...another shortwave disturbance that starts the weekend out in CA slides ENE out onto the Plains...and models continue to be on the aggressive side with the potential coverage of precipitation. 12Z ECMWF ensembles showing a roughly 30- 50 percent probability of 1 inch more, mainly near/north of the NE- KS state line...GEFS is lower. Will see how things trend in the coming days...but that would be some very welcome moisture. Spotty precip chances continue into the start of the new work week...not much confidence in things that far out.

Following highs in the 70s-low 80s on Thursday...cooler highs are expected through the weekend. Highs Fri-Sun generally range from the low-mid 60s north to low 70s in the south.

AVIATION /00Z TAFS THROUGH 00Z THURSDAY/

Issued at 645 PM CDT Tue Apr 21 2026

For KGRI/KEAR Airports:

Significant weather: Low level wind shear (LLWS) tonight, very strong southerly surface winds on Wednesday.

Tonight: VFR. Main concern will be development of 35-40kt LLWS between 03Z-05Z at both sites. This LLWS should persist through about 09Z, then weaken. Sfc winds overnight will be out of the SE-S at around 8-13kt. Confidence: High.

Wednesday: VFR. Southerly surface winds will quickly ramp up during the AM, becoming downright windy for the afternoon. Expect peak winds during the afternoon to be (at least) around 21-27kt sustained, with gusts up around 35kt. Not expecting much for cloud cover. Strong S winds will likely persist for at least another 6 hours beyond this valid TAF period, though probably just a bit lower than the previous afternoon. Confidence: High.

GID WATCHES / WARNINGS / ADVISORIES

NE...Red Flag Warning from noon to 8 PM CDT Wednesday for NEZ039>041-046-047-060-061-072-073-082. KS...None.