Sunrise 5:21 AM   Sunset 8:05 PM Moonrise 3:55 AM   Moonset 3:56 PM

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FXUS66 KOTX 041140 AFDOTX

Area Forecast Discussion National Weather Service Spokane WA 440 AM PDT Sat May 4 2024

SYNOPSIS
It will be mild today with highs in the 60s and low 70s while bands of rain spread into central Washington. Rain will be widespread on Sunday as a slow moving low moves through the Pacific Northwest. As the low pulls out of the region, look for cool, showery, and brisk conditions Monday and Tuesday. Warmer and drier weather will likely arrive late next week.

DISCUSSION

Today through Monday afternoon: The start of the weekend will be mild, cloudy, and breezy thanks to a low pressure moving towards northern California. Along with that, rain chances increase in central Washington through the morning into the afternoon hours.
Eventually chances for measurable rain spread into Eastern Washington this evening and overnight.

Model disagreement is quite high still for the wrap around precipitation band Sunday morning in eastern Washington. There is a 60% chance of greater than 0.10 of an inch of rain from midnight through noon Sunday. 3-7 am Sunday appears the most favorable time for the deformation band to move through Spokane, although some models indicate a light rain lasting through much of the day.
Unsurprisingly, ensemble members with less rain warm temperatures up slightly faster during the morning. There is a 75% chance of temperatures not exceeding 45 degrees through noon Sunday. While the rain will be beneficial for dryland farmers in the Palouse and West Plains after a dry April, outdoor activities on Sunday will be dampened by the rain and cooler temperatures.

Monday will feature cooler temperatures compared to the norm, accompanied by showers and localized windy conditions. The departing low pressure system from the weekend will set up a tight westerly pressure gradient across the Cascades on Monday, resulting in gusty winds. According to ECMWF ensembles, wind gusts up to 35 mph are anticipated on Monday, with 50-70 percent of ensemble members forecasting gusts of 35 mph or higher across eastern Washington.

Monday night through Tuesday night: Brisk and showery. Northwest flow aloft prevails over the Inland NW as the slow moving low tracks into MT and a secondary weaker trough brushes in from the Pacific. Showery precipitation decreases Monday evening while brisk westerly winds persist through the night. A surface trough over eastern WA keeps pressure gradients packed, leading to wind gusts of 35-40 mph are possible in the lee of the Cascades and Palouse. The winds relax slightly Tuesday morning and shift from the west to northwest by the afternoon hours with higher gusts returning again across central WA into the Palouse. Showery conditions redevelop Tuesday afternoon and evening although with less coverage and mainly for extreme eastern WA into north ID.
Snow level take a dip during the overnight hours with light snow accumulations in the central Cascades, Blue mountains, and Panhandle mountains. It will on the cool side with daytime temperatures in the 50s to lower 60s and overnight lows in the mid 30s to lower 40s. db

Wednesday through Saturday: Drier and warmer. An upper level ridge builds over the eastern Pacific and builds inland. Still can anticipate a threat of showers over north Idaho for Wednesday, but trending less coverage for Thursday as drier and more stable conditions arrive. Winds decrease and shift from the north and east. Under lighter winds, the more noticeable change will be warmer temperatures reaching the 60s to lower 70s on Thursday and in the 70s to lower 80s by Friday into Saturday. /rfox.

AVIATION
12Z TAFS: Mid to high level clouds will continue to increase across the Inland NW and gradually lower this afternoon and evening as bands of precipitation move up from the south. Light rain is expected across the Cascades by the morning hours on Saturday with rain at KEAT by 16Z with local MVFR ceilings. South and easterly winds will pick up with the front approaching. KPUW- KGEG- KCOE will see the potential for gusts up to 25 kts into Saturday morning with the easterly pressure gradient tightening up. Rain bands will increase across KLWS, KPUW, KCOE to KGEG after 05Z.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence for VFR conditions through Saturday night except for at KEAT where confidence is moderate. The HRRR/NBM model guidance for KEAT indicates a 60% chance ceilings lower down to 3 kft. Chances for MVFR ceilings expand early Sunday morning to KLWS, KPUW, and KGEG.
/rfox.

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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 70 42 50 39 58 36 / 10 60 90 80 40 20 Coeur d'Alene 68 45 51 39 53 36 / 10 30 90 80 70 30 Pullman 66 39 46 37 52 35 / 10 90 90 80 60 40 Lewiston 72 46 56 43 61 41 / 10 90 90 80 60 30 Colville 68 42 59 38 59 34 / 20 20 60 80 70 40 Sandpoint 66 45 53 39 55 38 / 10 20 70 80 80 50 Kellogg 66 46 50 40 49 38 / 10 20 70 90 90 60 Moses Lake 69 45 61 41 62 38 / 30 70 100 40 10 0 Wenatchee 63 49 62 44 59 41 / 70 60 90 30 20 10 Omak 68 48 69 43 62 38 / 30 30 40 40 20 10

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

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