Weather Lookup

Key Messages

- seasonably warm conditions on wednesday, followed by a warming trend thursday through saturday pushing temperatures into the upper 80S to mid 90S.

- widespread critical fire weather conditions on saturday.

- elevated fire weather conditions on sunday.

Synopsis

Near-average high temperatures in the 80S to near 90 degrees will last through wednesday before an upper-level ridge shifts into the inland northwest, boosting highs back into the upper 80S to mid 90S late in the week. A strong cold front on saturday will drive strong surface winds and low humidity across the region, creating widespread critical fire weather conditions. Temperatures cool by 8-10 degrees on sunday, though fire weather conditions will remain elevated.

Discussion

Tuesday afternoon and evening: an upper-level trough over the gulf of alaska will eject a shortwave inland, pushing a dry "cold" front across the region late tuesday afternoon. Tight pressure gradients will maintain west to southwest winds through the cascade gaps, across the waterville plateau, into the columbia basin, and up the okanogan valley through tuesday evening. Expect sustained winds around 15 to 20 MPH and gusts of 30 to 35 MPH, decreasing around 8PM to 10PM. In the wake of the front, precipitable water (PWAT) values will fall to 40 to 60 percent of normal. Fortunately the frontal passage will be late enough that cooling temperatures in the evening will help mitigate a drop in relative humidity during the period of elevated winds. However, minimum rhs will trend drier by wednesday afternoon, dropping into the low to mid teens for most locations. Cooling behind the front will be minimal, with high temperatures on wednesday only dropping a degree or two compared to tuesday, remaining in the mid to upper 80S.

Wednesday through friday: quiet conditions prevail wednesday with light winds. Upper-level ridging expanding north from the desert southwest will initiate a warming trend thursday and friday, driving afternoon high temperatures back into the upper 80S to mid 90S. An incoming shortwave will will create localized breezy conditions across central washington thursday afternoon with sustained speeds of 10 to 15 MPH and gusts to 25 MPH. The shortwave will also support a low (5 to 10 percent) chance of thunderstorms over the blue mountains and central idaho panhandle, though the best moisture and dynamics for thunderstorm development will be further southeast.

Saturday through monday: saturday continues to be the primary focus of the next seven days. An upper-level low offshore of british columbia will swing inland, driving a strong dry cold front through the pacific northwest and positioning an impressive upper-level jet (120+ KTS at 200 mb) directly over the area. Model guidance continues to trend upward with surface wind forecasts. Probabilities for wind gusts exceeding 40 MPH have risen to 70 to 100 percent across the columbia basin, waterville plateau, blue mountains, and lewiston-clarkston valley. Over the waterville plateau where the strongest winds will be focused, the national blend of models indicates a 50 to 70 percent chance of gusts exceeding 50 MPH. These impressive winds combined with minimum rh values in the upper teens to low 20S will bring widespread critical fire weather conditions.

Following the frontal passage, a sharp cooldown will limit highs on sunday to the mid to upper 70S, around 10 degrees cooler than on saturday. West winds will decrease some compared to saturday but will remain breezy, with sustained speeds of 10 to 20 MPH and gusts of 25 to 35 MPH. A shortwave ridge of high pressure moves in on monday, bringing temperatures back into the low to mid 80S with light winds forecast across the region. /fewkes

Aviation

06Z tafs: primarily VFR conditions will continue through the taf period. HRRR smoke shows a plume of surface smoke moving into the spokane area overnight, potentially reducing visibility to 5sm or less. Smoke from oregon will continue to move into southeast washington and the southern id panhandle as well, resulting in visibility reductions to 6sm at kpuw and klws. Winds will be light on wednesday with speeds less than 10 knots.

Forecast confidence and/or alternate scenarios: low confidence in MVFR visibilities at kgeg/ksff from wildfire smoke.

----------------------- 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