Sunrise 5:29 AM   Sunset 7:58 PM Moonrise 1:36 AM   Moonset 9:05 AM

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FXUS66 KOTX 300345 AFDOTX

Area Forecast Discussion National Weather Service Spokane WA 845 PM PDT Mon Apr 29 2024

SYNOPSIS
Scattered showers will continue into Tuesday. Winds will decrease tonight with the potential for frost expanding across the mountain valleys through Wednesday morning. A warming trend through the rest of the week into the weekend. Weather conditions will remain unsettled for the rest of the week with a weather system moving in off of the eastern Pacific on Thursday and another one over the weekend.

DISCUSSION
Evening update: The mid level disturbance responsible for today's convection is beginning to shift out of the area with a couple remaining bands of showers stretching from the Palouse and Camas Prairie up towards Lookout Pass as of 830 PM. Radar was also showing some showers up near Lauier and Northport. As this system continues to push east shower activity will continue to be on the decrease. The evening POP's were adjusted based on radar trends. The showers helped cool the lower level considerably this evening with many areas across northeast Washington and the Idaho Panhandle already down into the upper 30s to low 40s as of 8 PM. Expect frost in many areas of Eastern Washington and north Idaho Tuesday morning.

Another low pressure system near Vancouver Island will drop southeast towards the south WA coast tonight. Bands of snow showers will continue to rotate north into Stevens Pass tonight where a Winter Weather Advisory remains in place through 2 AM PDT. The focus of more persistent snow showers for the Cascades will shift south of Stevens Pass Tuesday morning as the main energy from the low slides into southern Washington and northern Oregon. JW



AVIATION
00Z TAFS: A weather system passing through into the early evening will continue to promote scattered showers and gusty west winds.
Heavier showers will continue to produce small hail or graupel along with an isolated lightning strike. This evening with the loss of daytime heating shower will dissipate along with the gusty winds. On Tuesday another round of showers will develop as the atmosphere destabilizes but less in coverage compared to today.
Isolated thunderstorms may also develop, but the main threat will be over the higher terrain of SE Washington (Blue Mountains), and up over NE Washington around Republic and Colville. Mainly VFR conditions are expected, except for KPUW/KCOE from near 12-18z Tuesday with the HRRR showing near a 60% chance of MVFR conditions.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: There is about a 30% chance of blowing dust across the Columbia Basin into the early evening, including at MWH. Confidence in visibility dropping below 7 miles is low so did not include mention in TAF. Confidence is also low that thunderstorms will impact terminals through early this evening and also Tuesday afternoon. JW

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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 31 53 34 58 36 60 / 0 20 10 10 10 20 Coeur d'Alene 30 50 33 55 36 59 / 10 30 20 30 10 20 Pullman 31 48 32 53 34 57 / 50 40 20 30 20 30 Lewiston 36 56 37 61 39 62 / 40 40 30 20 10 30 Colville 25 54 30 61 33 61 / 40 40 10 20 10 30 Sandpoint 29 50 34 53 36 58 / 20 40 20 50 20 40 Kellogg 32 45 34 48 36 56 / 60 50 30 70 20 40 Moses Lake 34 59 34 66 38 62 / 0 10 0 0 10 20 Wenatchee 38 57 38 63 41 59 / 10 20 0 0 10 20 Omak 32 58 35 66 41 64 / 0 20 0 0 10 20

OTX WATCHES/WARNINGS/ADVISORIES
ID...None.
WA...Winter Weather Advisory until 2 AM PDT Tuesday for Western Chelan County.

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