Area Forecast Discussion
Issued by NWS Spokane, WA
Issued by NWS Spokane, WA
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383 FXUS66 KOTX 160446 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 946 PM PDT Sun Sep 15 2024 .SYNOPSIS... Monday will be the warmest day of the week. Tuesday and Wednesday will be cooler with periods of rain over north Idaho and the eastern third of Washington. Gusty north winds down the Okanogan valley Monday will become breezy from the west on Tuesday and be more widespread across parts of central and eastern Washington. && .DISCUSSION... Tonight through Tuesday: Bands of light showers will continue to pass over southeastern WA and the ID Panhandle tonight as a center of low pressure rolls down the West Coast toward California. A few showers will linger over the L-C Valley and Camas Prairie tomorrow, but the rest of the region will remain dry with mostly clear skies and temperatures several degrees warmer than today`s. Northerly winds will pick up in the Okanogan Valley overnight tonight and into tomorrow morning due to the pressure gradient created by the low to our south. Winds will peak in the late morning tomorrow with gusts up to 35 mph expected. Blue skies and dry conditions will be short-lived with another low on track to drop down the coastline from the Gulf of Alaska on Tuesday, bringing temperatures back down into the upper 60s to low 70s and increasing chances for showers primarily over the Cascade Crest, the eastern third of WA, and the ID Panhandle. /Fewkes Wednesday through Sunday: We remain under the influence of a trough on Wednesday with the energy well to our south. Thursday onward there is the potential of a ridge setting up. There are some fairly large discrepancies as to where the ridge sets up, if at all. By Saturday the 100 member ensemble forecast is showing a 60/40 split of a ridge scenario vs a trough scenario. The ridge scenario is quite different with 30% of it showing the ridge off the coast, which creates more of a northwest flow for us and would keep showers perhaps going for northeast WA and the ID Panhandle. Another 30% shows the ridge further east over western WA which would be drier scenario. The trough scenarios have it located off the coast, they just disagree on the strength of the low. So, what`s in the forecast? Well daytime temps will be in the mid 60s to mid 70s and lows in the 40s. Through Friday the forecast is largely dry except for at the crest of the Cascades and parts of the ID Panhandle. Saturday and Sunday the threat of showers expands a bit to encompass most of the region, but the best chance for rain will be across the Cascades, extreme eastern Washington and the ID Panhandle. It looks like for the most part, central WA will continue to remain dry. Winds will be light with gusts not exceeding about 15 mph. /Nisbet && .AVIATION... 06Z TAFS: VFR conditions will prevail across Central and Eastern Washington into north Idaho. A large low pressure system over California and Nevada will continue to send mid and high clouds up into the region from the south. There is a 20% chance of showers into Monday for Pullman and Lewiston, otherwise dry conditions are expected. FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: There is a very small chance with a light upslope wind and a moist boundary layer of IFR stratus developing on the Palouse between 10z-17z. The HREF shows a 10-20% chance at KPUW, with confidence too low to include in the TAF forecast. JW && .PRELIMINARY POINT TEMPS/POPS... Spokane 52 78 48 71 48 73 / 10 10 0 20 10 10 Coeur d`Alene 49 78 50 67 49 69 / 10 10 10 40 30 30 Pullman 44 74 49 65 45 67 / 10 20 20 50 20 20 Lewiston 51 78 55 71 55 74 / 20 20 30 50 30 10 Colville 47 81 47 76 38 74 / 10 0 0 10 10 10 Sandpoint 49 76 48 68 46 66 / 10 10 10 50 40 30 Kellogg 49 74 50 65 51 62 / 10 20 20 70 50 50 Moses Lake 49 81 50 78 48 76 / 10 0 0 0 0 0 Wenatchee 54 81 56 76 56 76 / 0 0 0 0 10 0 Omak 54 82 48 81 51 80 / 0 0 0 0 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$