OTX Forecast Discussion

000 FXUS66 KOTX 300026 AFDOTX

Area Forecast Discussion National Weather Service Spokane WA 426 PM PST Thu Jan 29 2026

KEY MESSAGES

SYNOPSIS

A milder and wetter pattern is expected through the week with periods of lowland rain and high mountain snow. The forecast trends drier by early next week.

DISCUSSION

Thursday night through Monday: The Inland Northwest will remain in a mild and progressive weather pattern over the next couple of days as persistent troughing in the northeast Pacific keeps the region in a mild southwestrly flow aloft. A weak frontal system will approach the Washington coast tonight and bring light precipitation to eastern Washington and north Idaho. Temperatures across the Inland Northwest have warmed above freezing with high confidence for precipitation to fall primarily as rain for the region. The exception will be across the Methow Valley and the upper northern valleys where model soundings reveal minor differences in the thermodynamic profile, introducing some in the exact precipitation type. Given models generally warm these locations a little too quickly, there is moderate confidence for precipitation to initially fall as freezing rain or snow tonight. A shortwave trailing behind the front will bring another shot at precipitation Friday afternoon, though confidence is higher by then that temperatures will be warm enough to support all rain across the lowlands. Snow levels are forecasted to rise between 5500 and 6500 feet Friday afternoon with 1 to 3 inches of high mountain snow.

Models are in good agreement for an upper-level ridge to amplify over the Inland Northwest on Saturday as deep closed low moves into the NE Pacific. The upper-level ridge over the Inland Northwest may be strong enough to keep most of the region dry Saturday into Sunday as the front associated with the low weakens. Its not until Sunday afternoon and evening when precipitation chances increase to 40-60% across the mountains and 30- 50% across far eastern Washington as a trailing shortwave moves inland.

Tuesday through Thursday: Model ensembles are in excellent agreement for an upper-level ridge to strengthen over the Western US, though there is some uncertainty in the exact placement. Ensembles are depicting this ridge to be rather strong with 500mb heights nearing the 98th to 99th percentile when compared to climatology. This would result in yet another period of dry conditions. With a true push of dry air or winds, this suggests the ridge may be accompanied by persistent low stratus and/or fog as well. /vmt

AVIATION

00Z TAFS: Radar shows light showers moving through the Idaho Panhandle, moving out of the area within the hour. There will be a break from 00-03Z, which is when the next wave of precipitation moves through. With temperatures rising, models all favor rain as the main precipitation type. Lingering rain at COE has resulted in a prevailing -RA but may not last through 03Z. Ceilings have currently improved to VFR with the exception of COE/EAT, but will drop back down to MFVR/isolated IFR with the incoming rain. HREF/REFS guidance favors MVFR/IFR ceilings through the rest of the forecast period. There is good model agreement on 60-80 percent chances of rain during the 09-15Z period for GEG, SFF, and COE, resulting in prevailing -RA in the TAFs. EAT’s prevailing rain will start earlier, at 03Z and lasting through 09Z. There is more uncertainty in rainfall for MWH, PUW, and LWS, with only a 10-30 percent chance of rain periodically through 00Z tomorrow, leading to rain being exclusively mentioned in only PROB30 categories. There is good HREF/REFS agreement on visibilities staying mostly at 6SM and above apart from a small time period at MWH.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence in precipitation type being rain. Low to moderate confidence in rainfall at MWH, PUW, and LWS with lower PoPs not supporting predominant rainfall. An alternate scenario for these sites could be the need for amendments putting -RA as prevailing. High confidence in prevailing rain showers at GEG, SFF, COE, and EAT. High confidence in ceilings degrading back down to MVFR/IFR. Moderate to high confidence in visibilities staying mostly at 6SM or higher. /AS

Confidence descriptors: Low - Less than a 30 percent chance Moderate - 30 to 70 percent chance High - Greater than a 70 percent chance

For additional probabilistic information for NWS Spokane airports,please refer to the Aviation Dashboard on our webpage: https:/www.weather.gov/otx/avndashboard

OTX WATCHES/WARNINGS/ADVISORIES

WA…None. ID…None.

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