textproduct: Glasgow

KEY MESSAGES

- Warm and dry conditions are expected the next few days, peaking on Wednesday.

- A Red Flag Warning has been issued Monday for gusty NW winds expected with low relative humidity. A Lake Wind Advisory is also in effect Monday.

- The forecast becomes potentially wetter Wednesday night into the weekend with more scattered showers and isolated thunderstorms possible.

DISCUSSION

WEATHER PATTERN OVERVIEW:

Warming temperatures with dry weather prevails over the next few days. On Monday specifically, the next shortwave looks to approach from the north with a weak cold front. Gusty northwest winds are expected with strong boundary layer mixing aloft bringing pre-frontal warming and afternoon humidity readings below 20 percent. When combined with a low greenness index and strong NW wind gusts, heightened fire weather concerns are expected. Upper ridge builds into the area on Tuesday with lighter winds and dry weather.

On Wednesday the upper ridge axis moves through eastern Montana with the warmest day of 2026 so far expected. Some locations will likely have highs in the 90s with increased southerly flow, adding to ongoing fire weather concerns.

A more zonal flow pattern develops thereafter to moderate temperatures some and bring smaller synoptic ridge/trough couplets embedded in it. This will bring chances for showers and thunderstorms at times across the region through the weekend with possible wetting rains or even a marginal severe potential depending on whether it matches up with peak heating. Individual ensemble members continue to disagree on what day/time any given ridge/trough couplet moves through though.

FORECAST CONFIDENCE & DEVIATIONS:

Confidence is HIGH for warm and dry conditions through Wednesday. Confidence in critical fire weather conditions on Monday is HIGH as well, especially for the northeast zones.

Confidence is MODERATE for critical fire weather conditions on Wednesday. Confidence is LOW on thunderstorm and wetting rain chances starting Wednesday night.

-JEZ

AVIATION

LAST UPDATED: 1900Z

FLIGHT CAT RANGE: VFR.

DISCUSSION: Mid and high clouds move in tonight before clearing Monday morning behind a frontal passage.

WIND: SE to S at 5 to 10 kts, then shifting to the northwest between 14-17Z and strengthening to 15-25 kts with gusts around 35 kts.

EQUIPMENT: No obs from KSDY. TAF will be AMD NOT SKED until obs return.

FIRE WEATHER

Critical fire weather is expected Monday afternoon with a Red Flag Warning upgrade issued for all fire zones. Persistent periods of elevated fire weather will continue over the next several days. An upper ridge pattern brings warm/dry conditions along with occasional disturbances that cause gusty/shifting winds and isolated dry lightning potential later in the week.

A frontal passage on Monday will bring strong northwest winds with gusts to 45 mph into northeast Montana. With relative humidity down to around 15 percent likely, critical fire weather conditions are expected. Fire weather concerns are greatest across the eastern zones 120/122 where grassland fuels are critically receptive as ERCs are exceeding the 97th percentile. Western portions of zone 137 and zone 135 with some green up and more 100/1000 hour fuels are of less concern. The pattern the rest of the week remains warm and dry, presenting repeated elevated fire weather when winds pick up or shift. Wednesday is the next day of more concern with temperatures as high as the 90s, gusty southerly winds and RH as low as 10 percent. No opportunities for wetting rain exist through at least midweek.

-JEZ

GGW WATCHES/WARNINGS/ADVISORIES

Lake Wind Advisory from 9 AM to 9 PM MDT Monday for Central and Southeast Phillips-Central and Southern Valley-Garfield-McCone- Petroleum.

Red Flag Warning from 11 AM to 8 PM MDT Monday for Dawson/McCone/Prairie/Richland/Wibaux Counties-Fort Peck Reservation and Daniels/Roosevelt/Sheridan Counties-Northern Valley and Northern Phillips Counties-Southern Petroleum and Southern Garfield Counties-The Little Rockies-The Lower Missouri River Breaks including the Charles M Russell National Wildlife Refuge.