Area Forecast Discussion

KEY MESSAGES

- Periodic breezy winds with seasonably normal temperatures Sunday through Wednesday. Elevated to critical fire weather conditions Tuesday for central WA.

- Above normal temperatures return by Thursday with highs in the 90s.

- Critical Fire Weather expected for portions of the Inland Northwest Saturday August 1.

SYNOPSIS

Breezy winds will linger through Wednesday across Central Washington, resulting in elevated to locally critical fire weather conditions. Temperatures will stay cool to near seasonal normals in the 80s. Above normal temperatures return later next week in the 90s with continued dry conditions. Monitoring Saturday for a dry cold front passage of similar magnitude to yesterday.

DISCUSSION

Sunday through Wednesday: Dry and breezy conditions continue today through Wednesday as the overall pattern remains steady. Temperatures will remain near normal to slightly below normal in the 80s to low 90s. Tuesday looks to have the best potential for locally critical fire weather conditions on the Waterville Plateau, Upper Columbia Basin, and the southwestern portion of the Colville Reservation. A shortwave trough will brush through Vancouver Island and eject northeast towards central Alberta. A dry cold front will brush through central Washington and far northeast Washington Tuesday afternoon and evening bringing west/southwest winds around 10-20 mph with gusts up to 30 mph with relative humidities around 20- 30 percent. A Fire Weather Watch was considered for portions of central Washington Tuesday but confidence was too low in relative humidity and wind speeds hitting critical levels. There is a small chance (15%) of a shower at the Cascade crest Tuesday but no rain expected elsewhere. A more robust shortwave trough Thursday will migrate through northwest Oregon through southeast Washington bringing a 5-15% chance of thunderstorms to southeast Washington and the southern Idaho Panhandle in the afternoon and evening.

Thursday through Sunday: Temperatures Thursday and Friday will bounce back above normal in the high 80s to high 90s as high pressure strengthens in the desert southwest. Changes come Saturday as a dry cold front passage is set to occur through the day. Deterministic GFS and ECMWF guidance this morning have an upper level jet actually slightly stronger than yesterday around 110-120 kt. All of the ensemble clusters indicate at least a 95th percentile upper level jet moving through the region. There is a 40-80% chance of winds gusting 40+ MPH through the Columbia Basin and Waterville Plateau. This period will be very closely watched over the next several days for elevated to critical fire weather conditions. There is still decent ensemble spread for the pressure gradients across the region. Next Sunday looks cooler after the front passage with temperatures in the upper 70s to upper 80s. /Butler

AVIATION

18Z TAFS: VFR conditions will prevail. Winds Sunday afternoon in the Columbia Basin and Spokane area will peak around 10 kt. Winds will relax below 10 kt this evening except Wenatchee where Cascade gap winds will continue into the overnight hours. Smoke impacts are uncertain but KGEG-KSFF-KCOE-KLWS-KPUW are in a favorable area for local and regional wildfire smoke to reduce visibilities especially overnight into Monday.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: Low confidence in smoke reducing visibility at the TAF sites. This is the most impactful alternate scenario. Should smoke reduce visibilities, amendments will be issued.

----------------------- 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 56 87 57 86 56 86 / 0 0 0 0 0 0 Coeur d'Alene 57 86 58 86 57 86 / 0 0 0 0 0 0 Pullman 51 84 51 83 50 83 / 0 0 0 0 0 0 Lewiston 62 92 61 91 61 91 / 0 0 0 0 0 0 Colville 51 86 52 86 50 87 / 0 0 0 0 0 0 Sandpoint 53 84 54 84 54 84 / 0 0 0 0 0 0 Kellogg 55 83 55 83 55 83 / 0 0 0 0 0 0 Moses Lake 56 89 57 89 55 88 / 0 0 0 0 0 0 Wenatchee 63 89 63 86 60 88 / 0 0 0 0 0 0 Omak 60 90 59 90 56 89 / 0 0 0 0 0 0

OTX WATCHES / WARNINGS / ADVISORIES

WA...Air Quality Alert until 11 AM PDT Monday for Central Chelan County-Lower Garfield and Asotin Counties-Moses Lake Area- Northeast Blue Mountains-Northeast Mountains-Okanogan Highlands-Okanogan Valley-Spokane Area-Upper Columbia Basin-Waterville Plateau-Wenatchee Area-Western Chelan County-Western Okanogan County. ID...Air Quality Alert until noon PDT Monday for Central Panhandle Mountains-Idaho Palouse-Lewis and Southern Nez Perce Counties-Lewiston Area.