Weather Lookup

Key Messages

- scattered showers and isolated thunderstorms over southeast washington and the souther to central idaho panhandle this evening.

- warm temperatures thursday through monday with afternoon highs in the mid 70S to low 80S. Temperatures cool to near normal by the middle of next week.

Synopsis

Shower and thunderstorm chances return to the forecast over southeast wa and the central id panhandle thursday evening into friday. Afternoon temperatures will be warm wednesday through monday with highs in the 70S to low 80S, and overnight lows will fall into the 40S to low 50S.

Discussion

This afternoon through saturday: an upper level low pressure system will track from eastern oregon today into eastern idaho by saturday. Moisture pushing north ahead of this low will bring up moisture with up to a 50% chance of showers across the southeast portion of the forecast area through this evening. Mid level lapse rates also steepen with an isolated thunderstorm threat with these showers as well. Best instability will generally be over the higher terrain of the blue mountains in northeast oregon to the clearwater mountains in the southern idaho panhandle. Storms will then be moving into an environment that won't be as conducive for continuing to support thunderstorm development as the push further north into places like the the palouse to the silver valley. Decaying convection will still have the potential to produce at least occasional cloud to ground lightning strikes gusty outflow winds up 30 MPH, and brief heavy downpours. Latest convective allowing model guidance has weakened the potential outflow boundary produced by the convection this evening. It's not completely out of the question that blowing dust will occur with the winds, but chances look much less likely compared to what these models were indicating this time yesterday. Showers are expected to continue into the evening, but the convective potential will be decreasing as we lose the surface heating. As such, i expect shower coverage to be less over the southeast portion of the forecast area, and the potential for thunderstorms will rapidly decrease as well.

We won't be as unstable on friday and saturday as the low makes its march eastward across idaho. The fringes of the southeast portion of our forecast area will continue to see the potential for diurnally forced convection in near the camas prairie and in the st. Joe forest in the central panhandle mountains. Otherwise, it looks like we won't be unstable enough for convection to initiate off of the higher terrain further north and west, E.g. Over the palouse. Temperatures will remain warm and above average into the weekend. Cloud cover also will be on the decrease as the upper level pulls away.

Saturday night through thursday: good agreement among the model ensembles with a ridging of high pressure building in over the region into early next week. This will keep our temperatures warm with highs in the upper 70S to low 80S. Models also are generally in good agreement with the overall longwave pattern with troughing of lower pressure in the eastern pacific and ridging of higher pressure over the rockies. Where models disagree and uncertainty is introduced is how close in proximity the trough will be to the northwest region. The general consensus is that temperatures will be cooler starting tuesday into wednesday, but how much cooler is still very much up in the air. Right now it is 50/50 if we see cooler than average temperatures with an increased chance for showers, particularly over the cascades, or continue with a dry forecast with temperatures at or slightly above normal for thursday into friday next week. /svh

Aviation

18Z tafs: a low pressure system spinning over eastern oregon will spread scattered showers with a isolated embedded thunderstorms into southeast washington and the southern idaho panhandle today. Timing for showers and thunderstorms into klws looks to be mid to late afternoon into the evening hours (after 22Z). Instability parameters are less likely to support thunderstorms as far north as kpuw with chances decreasing to a 15% chance. Chances decrease further north and west into kmwh/kgeg/ksff/kcoe where spread mid to high level clouds from convection is all that is expected at these airport terminals. Thunderstorms will be capable of gusty outflows of up to 20-25 KTS and brief heavy downpours. Isolated showers in the vicinity of klws and kpuw will continue overnight, but convection is expected to weaken.

Forecast confidence and/or alternate scenarios: high confidence in VFR conditions. Low to moderate confidence for thunderstorms to impact klws and kpuw airport terminals this afternoon and evening. /svh

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

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