textproduct: Aberdeen

KEY MESSAGES

- Light rain showers mid day today through this evening. Rainfall ranges from a tenth to a quarter inch.

- Colder air for the first half of the work week. Lows Tuesday morning close to freezing, but with clouds and a stiff northwest breeze temperatures should stay above 32. Much better setup for widespread frost/freeze conditions Wednesday morning with clear skies and light winds.

UPDATE

Issued at 1236 PM CDT Mon May 18 2026

Aviation discussion updated below for the 18Z TAFs.

DISCUSSION

Issued at 128 AM CDT Mon May 18 2026

Next wave coming up from the southwest brings in moisture mid-day today through the early overnight. Still mainly light rain/showers. QPF is just a tenth or two.

For Tuesday morning, we are faced with the prospect of cold advection enhanced winds, shallow cloud cover and NBM guidance proposing temperatures down to the freezing mark. Clearly not a setup for frost, but with 925mb temperatures around +1 to +2C between deterministic models, which is in alignment with the HREF mean that should put temperatures into the low/mid 30s. That said, the NSSL WRF, NAM NEST and HRRR have 925 temps down to 0C for various parts of the CWA. Latest NBM is a little warmer for lows, and now has just about everyone at 33F and warmer. No headlines/frost mention for Tuesday morning but it will get quite close to the freezing mark. Frost caddishness negated by these winds and clouds however.

Much more impactful drop in temperatures will be noted for Wednesday morning. During the day Tuesday, daytime driven cumulus evident in NAM BUFKIT profiles. While this is shallow (~5kft), cant rule out light rain showers/sprinkles. Regardless, cloud cover during the day will limit heating. Loss of daytime driven convection with temperatures only into the 50s and dewpoints in the low/mid 30s and surface high pressure overhead will leave us with a good setup for frost. 25th range across the CWA is 29-32 while the upper range is 32-35. Keeping frost mention at this time but still too early for any headlines.

The upper pattern features the current upper trough departure, with a second trough over the intermountain west. That puts us under a ridge for Wednesday - early Thursday. There's a negative tilt trough passage for Friday. Aside from the precipitation associated with this wave/surface low, there is a wide range in temperatures with a 10 degree spread in the 25th/75th for highs so a low confidence forecast to close out the work week. After that its zonal flow across the northwestern CONUS into the northern plains.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 1236 PM CDT Mon May 18 2026

Terminals KABR,KATY,KPIR,KMBG

Areas of -SHRA will move northeast into and through the region this afternoon and evening. VSBY may drop to MVFR in precipitation. CIGs will generally be MVFR, although forecast is for IFR at times in areas of precipitation and overall lower cloud cover potential during the evening hours.

ABR WATCHES/WARNINGS/ADVISORIES

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