textproduct: Glasgow

KEY MESSAGES

- If fires were to develop this week, smoke could potentially produce light haze in our region.

- Overcast skies, possible precipitation, and low temperatures anticipated this weekend and into Monday.

- Weekend precipiation will primarily be rain, with chances for snow peaking Sunday night.

DISCUSSION

An upper-level ridge over the western US will result in high temperatures that are 5 to 15 degrees above normal and relatively dry conditions today. If fires were to develop nearby, the HRRR and RAP anticipate smoke potentially producing light haze in our region.

The ridge will gradually decay as the week progresses and an upper-level low and its associated trough exit the Aleutian region and dig over the PNW. The weakening ridge will result in temperatures decreasing marginally through Thursday. A slight rebound in temperatures will occur Friday as the weakened ridge crests over NE Montana.

The warmth will not last. The ridge will quickly exit eastward Friday night as the aforementioned PNW low digs as far as Point Conception between Saturday and Monday mornings. The subsequent amplified trough will produce strong cold air and moisture advection into the CWA behind an approaching front. Overcast skies, possible precipitation, and low temperatures anticipated this weekend and into Monday.

Precipitation chances begin late Saturday with rain showers as daily high temperatures decrease and winds increase significantly behind frontal passage. Temperatures will continue diving into Sunday, with highs in the 40s, nearly 20 degrees below normal. Snow may be possible overnight Sunday. If snow occurs, totals are anticipated to be less than an inch; melt will occur quickly.

Cooler and wetter conditions are expected to persist through Monday before beginning beginning to rebound Tuesday. However, forecasts beyond Saturday become less certain due to ensemble inconsistencies. Additionally, model guidance suggests the upper- level ridge to the east will become quasi-stationary, potentially stalling trough propagation. This may result in cooler/wetter conditions lasting longer than currently expected.

FORECAST CONFIDENCE & DEVIATIONS:

- No changes from NBM.

- There is moderate to low confidence (30-50%) in frontal timing Friday night/Saturday morning.

- There is high confidence (70-90%) in warmer temperatures through Friday and cooler temperatures this weekend.

- There is moderate to high confidence (50-80%) in any precipitation occuring between Saturday night and Monday morning.

AVIATION

LAST UPDATED: 1830Z

FLIGHT CAT RANGE: VFR

DISCUSSION: FEW/SCT mid-to-high clouds through this afternoon. SCT/BKN low-to-mid clouds will develop early this evening and persist overnight. Clearing will occur tomorrow morning, with FEW/SCT low-to-mid clouds through the rest of the 24-hour forecast period.

WINDS: Light and variable through the bulk of the forecast period at most stations. NW winds at 06 to 12 kt at KSDY and KGDV this afternoon, becoming light and variable this evening and NE at 05 to 10 kt by tomorrow morning.

GGW WATCHES/WARNINGS/ADVISORIES

None.