textproduct: Glasgow

DISCUSSION

KEY MESSAGES: 1) Milder temperatures will continue over the next couple of days.

2) Low clouds and freezing fog is expected through Friday.

WEATHER PATTERN OVERVIEW: A large high amplitude ridge will continue over the western U.S. and influence NE Montana with mild and dry weather conditions. There will be a sharp gradient along a backdoor cold front with much of the northeast half of the CWA seeing lows each day in the single digits to teens and highs in the 20s and 30s. Meanwhile, lows over the Little Rockies and south of Fort Peck Lake will be in the 20s and low 30s with highs in the mid 30s and 40s each day.

This will allow for snowpack to melt and drag the moisture up over the front for continued freezing fog and low stratus. While extent, intensity, and timing beyond tonight are not well known, fog and low stratus does look to hang on in one form or another through at least Saturday morning.

Ridge pattern looks to intensify Saturday night into Sunday with a drier airmass entering the area. A cold front also arrives Monday and should also help to clear some long term fog and low stratus out of the area.

FORECAST CONFIDENCE & DEVIATIONS: Main deviation from NBM was in visibilities which do not appear to be matching up to satellite coverage well. Used a "Majority Rules" ensemble on visibility for much more accurate numbers to observations for the next 12-18 hours which also includes Hi-Res CAMs ensemble data in addition to the NBM-GLAMP non-ensemble data set.

Even with that said, confidence beyond 12-18 hours in intensity and placement remains low.

GAH

AVIATION

LAST UPDATED: 0930Z

FLIGHT CAT RANGE: Airport Shutdown - VFR

DISCUSSION: Fluctuating ceilings and visibility with freezing fog through the TAF cycle. Flight cats could lower down to near airport shutdown at times. Intensities and placement is highly variable and low confidence continues in these elements.

WIND: Light and slowly veering from west to east behind the front this morning into the early afternoon. East at less than 10 kts through the late afternoon and into tonight.

GAH

GGW WATCHES/WARNINGS/ADVISORIES

Dense Fog Advisory until 10 AM MST this morning for Central and Southeast Phillips-Central and Southern Valley-Daniels-Dawson- Eastern Roosevelt-McCone-Northern Phillips-Northern Valley- Prairie-Richland-Sheridan-Western Roosevelt-Wibaux.