textproduct: Glasgow

DISCUSSION

KEY MESSAGES: 1) Milder temperatures will continue over the next couple of days though with a sharp gradient along a backdoor front.

2) Backdoor front will drag low clouds and freezing fog along the frontal boundary today into tonight.

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 snow pack to the southwest to melt and drag the moisture up over the front for freezing fog and low stratus in the east and northeast through at least Thursday and likely into Saturday morning, though extent, intensity and timing beyond tonight are not well known.

The ridge looks to flatten and slide east with enough ensemble guidance to leave in slight chance pops for Saturday night, especially near the Canadian border. That said, do not see marked shifts in temperatures at this time.

FORECAST CONFIDENCE & DEVIATIONS: No major deviations from NBM were observed.

Confidence in temps through Saturday are relatively high.

Confidence in placement and timing of fog is moderate today and low through Friday.

Confidence in forecast beyond Monday is low and ensembles have a wide variability in large synoptic features from here onward.

GAH

AVIATION

LAST UPDATED: 0830Z

FLIGHT CAT RANGE: VFR - Airport Shutdown

DISCUSSION: High to mid clouds will leave conditions VFR through about 13-15Z. Then a backdoor front will drag lowering clouds in from the northeast that will lead to progressively lower ceilings and then reducing visibility with freezing fog. Flight cats could lower down to near airport shutdown at times which could last at KGGW and KOLF through almost 21Z.

Confidence is low in how long the fog will stay beyond mid afternoon as ensembles do not have a firm grapple on visibilities beyond this point yet. There is a high chance that fog could return Wednesday night, but intensities and placement is highly variable and low confidence continues in these elements.

WIND: Light and slowly veering from W this morning to E around Noon behind the front. Remaining light and E to SE this afternoon through midnight. Becoming Variable early Thursday morning.

GAH

GGW WATCHES/WARNINGS/ADVISORIES

None.