textproduct: Glasgow

KEY MESSAGES

- An upper-level trough will produce precipitation tonight through Monday.

- Cooler, near average temperatures are to be expected this forecast.

DISCUSSION

An upper-level trough is digging over the western US. Subsequent moisture-ladden SW flow with aloft will produce precipitation tonight through Monday. Embedded minor perturbations within the flow may cause localized areas of greater precipitation. Polar air associated with the system will cause colder temperatures this weekend.

Rain totals this weekend have been trending higher compared to previous model runs. At least 0.5" of rain is expected across the CWA. Snow is possible Sunday night, but warm ground temperatures will prevent any accumulating snowfall from sticking, the only exception being the Little Rockies.

The trough will eventually split as a cut-off low develops over the Four Corners region, where it will remain quasi-stationary through Wednesday morning.

Model agreement deteriorates significantly from this point onward. There is little confidence in weather conditions Thursday and Friday.

FORECAST CONFIDENCE & DEVIATIONS: Confidence is increasing that the precip on Saturday through Monday evening will bring more than expected amounts of precipitation, though given warm ground temperatures and marginal thermal profiles, below average confidence exists on snow as a precipitation type, timing of any changeover, or any accumulation, save for the higher terrain such as the Little Rockies.

Deviations in QPF are trending higher versus prior model runs.

Confidence is also below average on precipitation chances later in the week as ensembles show increasing spread at larger time scales. It is possible the low tracks too far to the southeast for anything significant, other than increasing clouds and light precipitation. Will be monitoring in the coming days for any trends.

FIN/DON

AVIATION

LAST UPDATED: 2144Z

FLIGHT CAT RANGE: MVFR for KOLF, KGDV and KSDY. MVFR, IFR at times, for KGGW

Discussion: VFR transitions to MVFR as ceilings lower into tonight. Expect ceilings of 9,000 ft down to 6,000 ft by this evening. KGGW may have overcast ceilings as low as 900 ft tomorrow morning. An advancing low pressure system will bring rain Saturday evening at KGGW and KOLF, which may cause decreased visibilities. An AIRMET is in effect until 12Z Sunday for icing (all stations).

Winds: Northerly winds and gusty conditions are expected to back NE. Winds will sustain at 10-15 kts throughout the forecast period.

Icing: Light, occasionally moderate, icing above 8,000 ft in western portions of the CWA. Expect moderate icing above 12,000 ft.

FIN/DON

GGW WATCHES/WARNINGS/ADVISORIES

None.