Area Forecast Discussion
Issued by NWS Spokane, WA
Issued by NWS Spokane, WA
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743 FXUS66 KOTX 150459 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 959 PM PDT Fri Jun 14 2024 .SYNOPSIS... Breezy to gusty winds along with isolated thunderstorms and rain showers are expected Saturday afternoon and evening. Snow will be possible down to 5000 feet. Temperatures will trend cooler into early next week with the potential for frost in colder pockets Sunday and Monday morning. Showers and thunderstorms, mainly in the mountains will be possible each afternoon through midweek. && .DISCUSSION... Friday and Saturday: Breezy southwesterly winds have infiltrated the region following this morning`s passage of a dry cold front. Fire weather concerns will remain elevated this afternoon and evening due to the combination of 20 to 30 mph wind gusts and relative humidity percentages in the low 20s. As a center of low pressure tracks eastward through the Inland Northwest, chances for precip will increase tonight into tomorrow. Cold air advection will drop snow levels down to between 4000 and 5000 feet tomorrow through Sunday morning. Higher mountain passes including Stevens, Sherman, and Washington have a 60 percent chance of seeing light snow between 5 AM tomorrow and 5 AM Sunday, though accumulations and impacts will be minimal due to warm ground temperatures and the high sun angle this time of year. Those recreating in mountain areas should plan ahead for light snow and prepare accordingly. Tomorrow`s winds will be slightly stronger than today`s with gusts upward of 40 mph expected for the eastern slopes of the Cascades, the Wenatchee area, exposed areas of the Columbia Basin, the West Plains, and the Palouse. In addition to gusty winds, convective showers and isolated thunderstorms are in the forecast for tomorrow afternoon and evening. An unstable atmosphere will allow any thunderstorms that develop to produce lightning, brief downpours, and small hail. By tomorrow night, showers will dissipate and skies will begin to clear, which should enable the surface to radiate heat away rather efficiently. As a result, Sunday morning will be the coldest morning of the forecast period. Lows will be in the 30s to low 40s regionwide, and patchy frost will be likely for sheltered northern valleys. /Fewkes Sunday through Thursday: The Northwest will remain under the influence of an upper-level trough throughout the period. This will equate to cooler than normal temperatures, periods of showers and some thunderstorms, and on a positive note, no significant wind events. An anomalously cool low will be over the area Sunday into Monday before ejecting into to the east around Tuesday. Sunday will start off cool with potential for patchy frost across the sheltered mountain valleys and Upper Columbia Basin. At this time, probabilities for temperatures of 34F or cooler are between 30-60 for locations like Deer Park, Colville, Republic, Priest Lake, Ione and 10-20% around Wilbur, Davenport, St Maries. There will be a shield of clouds coming in from the north around sunrise; if this can arrive earlier, probabilities could trend lower. Afternoon heating Sunday afternoon will destabilize the atmosphere with widely scattered showers and a few thunderstorms largely in northern and central WA Sunday afternoon then shifting into Idaho and Eastern WA Monday. Dynamic forcing will be also be stronger Monday as the low begins to eject leading to higher rainfall totals along the ID/MT border. CPC has W MT outlined for potential heavy rainfall for June 17-18 so probabilities for the heavier rains in Idaho has decreased at this time. Precipitation amounts will be not be particular heavy but a few localized areas could pickup over a quarter of an inch. The main energy of the trough will fill and drift east early next week but a baggy trough will persist over the PacNW. Temperatures will slowly return to near average with a 20-30% chance for afternoon convection each afternoon across the northern mountains. These cells will be the slow moving variety forming over the higher terrain producing pockets of a tenth or slightly more. Rainfall amounts will be spotty. Thinking we will finally push temperatures to normal or mid to upper 70s by Wednesday and upper 70s to mid 80s by Thursday. /sb && .AVIATION... 06Z TAFS: Winds will remain steady overnight with stronger winds and scattered showers in the forecast for Saturday. Winds will increase through the morning and peak in the aftn with sustained speeds 15-25kts with gusts 28-35kts. All TAF locations will be windy Saturday. Lighter winds will stretch across northern WA and ID. Winds will come down during the evening, but still remain elevated. Showers look best to develop across northern WA/ID, but cannot rule out -shra for GEG/SFF/COE/PUW. Thunder with these showers is possible, with a high enough threat to mention it for the COE TAF. FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: There is high confidence in continued VFR conditions through 06z Sunday. Smoke may move into LWS impacting visibility, but confidence is low. However left what was in previous TAF of 6sm. ----------------------- 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 50 64 39 64 41 65 / 0 50 10 10 10 30 Coeur d`Alene 47 61 38 60 40 64 / 0 70 20 10 10 30 Pullman 46 59 36 60 38 57 / 10 40 10 0 10 40 Lewiston 52 69 44 68 46 70 / 10 30 10 0 10 40 Colville 44 62 33 60 36 67 / 10 90 30 50 30 40 Sandpoint 45 59 37 57 38 62 / 0 90 40 40 30 40 Kellogg 48 56 40 58 42 57 / 0 80 30 20 10 50 Moses Lake 51 69 40 68 45 72 / 0 20 10 10 10 10 Wenatchee 51 66 45 66 48 70 / 0 10 10 10 10 10 Omak 49 69 40 66 44 74 / 10 60 10 40 20 20 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$