textproduct: Missoula

DISCUSSION

KEY MESSAGES:

- Quiet and Seasonable Weekend: Expect high pressure to bring dry conditions and a mix of sun and clouds.

- Messy Monday/Tuesday Commute: Pacific moisture returns early Monday, bringing a mix of valley snow and rain with moderate snow accumulations on mountain passes.

- Midweek Winds and Snow: A cold front Tuesday night into Wednesday will bring gusty winds and more organized snow showers to the region.

The Northern Rockies are currently under the influence of a building ridge of high pressure. This will result in a relatively quiet weekend across western Montana and north-central Idaho, with a mix of sun and clouds.

Monday and Tuesday:

The weather pattern shifts significantly as the ridge flattens and a moist Pacific system moves inland. Forecast models show high confidence in moisture spreading across the area starting Monday morning. Expect moderate snow for the mountain passes (Lookout, Lolo, Marias, Lost Trail), which may impact travel.

The forecast is more complex for valley floors. Initial precipitation Monday morning will likely start as snow, potentially creating a slick morning commute. As warmer air moves in during the afternoon, snow will transition to a rain/snow mix or plain rain.

North-central Idaho valleys below 4000 feet are expected to see mostly rain during this period as snow levels rise.

Wednesday and Thursday:

An upper-level dip in the jet stream and an associated cold front will sweep through late Tuesday night into Wednesday. This will usher in cooler air and increase atmospheric mixing.

Expect gusty westerly winds to develop behind the front. There is lower confidence in the exact wind speeds for Wednesday, as model solutions vary on the strength of the cold front. However, the trend toward windier and colder conditions for the middle of next week is well-supported.

Showers will become more organized, with the potential for snow banding which can lead to rapid visibility changes. Snow levels will drop back to the valley floors by Wednesday morning.

Showers will linger into Thursday morning, followed by a breezy afternoon.

Friday into Next Weekend:

Unsettled weather is likely to linger as weak disturbances move through the flow. While widespread heavy precipitation is not currently expected, daily chances for light snow or rain will continue, particularly for the higher terrain.

AVIATION

VFR weather conditions anticipated through the forecast period. Thickening mid-level clouds and a northeasterly pressure gradient will prevent surface saturation and fog development in most areas other than confined and isolated steep river valley locations. Ridgetop winds remain southwesterly at 10-20 knots. Mixing increases by 15-18z Sunday allowing 15-20 knot southerly surface gusts to mix down to terminals heading into the afternoon.

MSO WATCHES/WARNINGS/ADVISORIES

MT...None. ID...None.