Marine Weather and Tide Forecast for Lewiston, ID

SYNOPSIS
On Saturday breezy to windy conditions will develop with the passage of a cold front. Little to no precipitation will occur with the front and dry conditions expected through at least the middle of next week. Temperatures cooling to near normal over the weekend.

DISCUSSION
Today and Sunday: A Low pushing through Central Canada will swing a dry cold front through the Pacific Northwest this morning. With very little moisture associated with front, the only area with possible precip chances is along the Cascade crest. The main features with the cold front passage are increasing westerly winds and the colder temperatures. The front will pass during the morning hours. Westerly winds will be sustained in the teens to low 20s mph with gusts into the mid 30s. The best areas for the winds are the upper Basin and Cascade ridges with 40-70% probability. The speeds not promote blowing dust potential but some isolated areas could be possible. Winds will wane by the evening hours. Daytime highs will be in the upper 50s to low 70s on Saturday and 50s and low 60s on Sunday. Overnight lows will be in the upper 20s and 30s for Saturday and 30s and low 40s on Sunday. Overnight patchy frost could impact any remaining gardens and sensitive seasonal plants.

Monday through Wednesday: A trough will be digging a low along to coast into California. The Low becomes cutoff and a split flow pattern develops over the Northwest. It will bring dry, warm pattern over the Inland Northwest. The region can expect warm daytime and cold overnight conditions. Winds will be generally calm except a brief period of breezy winds down the Okanogan Valley on Tuesday with gusts into the upper 20 mph range. Highs will be in the 60s. Overnight lows will be in the upper 20s and 30s. Overnight patchy frost could impact any remaining gardens and sensitive seasonal plants.

Thursday and Friday: The Low finally ejects northeast as a trough moves into the Pacific Northwest. It is bringing increased precip chances but amounts are not expected to more than a couple of hundredths. The probability of any precipitation to occur over the Cascade crest and in the Idaho Panhandle is between 30-40%. Snow levels dropping down to around 5,000 feet Thursday night. Highs will be in the 50s to low 60s.
Overnight lows will be in the upper 20s and 30s. /JDC

AVIATION
12Z TAFS: VFR conditions will prevail as a cold front passes through the region today. Easterly flow will become westerly with the front passage. Winds will be particularly breezy at KPUW sustained around 15-18 kts before decreasing in the evening.
Cold front passage will be in the late morning on Saturday between 15-18Z at KEAT and KMWH to early afternoon 18Z-22Z at KGEG/KSFF/KCOE/KPUW/KLWS. A brief period of low level wind shear is expected at KPUW between 15-17Z Saturday morning before westerly winds aloft are able to mix down to the surface.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence for VFR conditions.

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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

Preliminary Point Temps/PoPs
Spokane 65 35 60 39 58 37 / 0 0 0 0 0 0 Coeur d'Alene 63 35 60 39 59 39 / 0 0 0 0 0 0 Pullman 64 36 60 38 57 34 / 0 0 0 0 0 0 Lewiston 71 41 64 42 63 41 / 0 0 0 0 0 0 Colville 67 29 61 31 60 30 / 0 0 0 0 0 0 Sandpoint 61 32 59 37 59 36 / 0 0 0 0 0 10 Kellogg 61 36 59 39 61 39 / 0 0 0 0 0 0 Moses Lake 69 32 62 37 60 34 / 0 0 0 0 0 0 Wenatchee 66 36 61 43 60 42 / 0 0 0 0 0 0 Omak 68 33 62 38 61 38 / 0 0 0 0 0 0

OTX WATCHES/WARNINGS/ADVISORIES
WA...None.
ID...None.