739 FXUS66 KOTX 140929 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 229 AM PDT Wed Aug 14 2019 .SYNOPSIS... Dry with temperatures near normal into early next week. Only limited shower and thunderstorm chances will be found around the mountains. Northwest to northerly upper level flow is expected Thursday, and will last into the weekend. This will result in a slight chance of showers and possibly a few lightning strikes for the Idaho Panhandle mountains. && .DISCUSSION... Today through Thursday: A modest upper level jet will be over the region. There will be moisture in place and satellite shows moisture at upper levels producing cirrus clouds across much of the region early this morning. Surface dew points will also be in the mid 40s to lower 50s, so moisture also continues to remain at lower levels as well. The upper level jet will shift a bit slightly to the south with weak energy entering the northern mountains of eastern WA and the ID Panhandle for this afternoon. This will be followed by an upper level shortwave that will dig in over the region for late tonight into early Thursday. Instability will be a limiting factor for convection both this afternoon and overnight. There will not be enough cooling aloft with either shortwave to get too excited about thunderstorm development. What will be working in its favor today will be the destabilization at lower levels in the atmosphere, but that will only be enough for an isolated chance of thunderstorms over the higher terrain. The cold pool aloft with the shortwave overnight will cool down to around -14 celsius at 500 mbs. That doesn't appear to be enough to destabilize mid levels of the atmosphere to generate elevated thunderstorms. I'm confident that there will be a lot of ACCAS cloud cover, but I think the wave will be too weak to get enough vertical development for thunderstorms. The shortwave trough overnight will be exiting to the east by Thursday afternoon, thus will be moving through at the wrong time to tap into surface based instability. The Central Panhandle Mountains looks to see a chance for afternoon thunderstorms Thursday, but most of the convection will be over into western MT. /SVH Thursday night through Saturday...A Rex Block over the eastern Pacific will promote northwesterly flow aloft downstream over the forecast area Thursday night through Saturday. Even though there will be some moisture enbedded in this flow...this orientation is not known to be a significant precipitation producing pattern. Thus during this time frame expect some transient high clouds at times...temperatures about or slightly below normal for this time of year...and a ghost of a chance of mountain showers or a stray afternoon thunderstorms mainly near the Canadian border. There will also be a daily squeeze of breezy winds through the Cascade gaps during the early evening hours but minimum RH values do not look like they will reach critical values. Sunday through Tuesday...Ensemble 500 mb mean heights on all the available latest global models are in good agreement in digging a strong trough out of northwestern Canada oriented east to west spearing into the Gulf of Alaska and pinching off the upstream Rex Block. This will allow flow over the northwestern US to become more zonal and westerly and at this time no shortwave disturbances are detectable in this flow which suggests a generally dry forecast but with a continued chance for breezy conditions especially near the Cascades. Until some appreciable southwest flow becomes established...maybe way out on Tuesday or so...there will be no compelling reason to expect any significant warm up beyond the normal 80s readings for this time of year. /Fugazzi && .AVIATION... 06Z TAFS: A dry westerly flow is expected for the TAF sites into Wednesday with VFR conditions at all TAF sites. Sustained winds should remain generally at or below 10 kts through the period. For Wednesday afternoon the atmosphere will destabilize over the northern mountains as a weak system clips the area possibly triggering a few showers or thunderstorms. JW && .PRELIMINARY POINT TEMPS/POPS... Spokane 85 57 83 55 82 54 / 0 0 10 0 0 0 Coeur d'Alene 83 55 82 54 80 53 / 10 0 10 0 0 0 Pullman 84 53 81 51 80 49 / 0 0 10 10 0 0 Lewiston 90 63 89 61 88 60 / 0 0 10 10 0 0 Colville 90 46 91 47 88 46 / 10 0 0 0 10 10 Sandpoint 82 51 81 51 79 49 / 10 10 10 0 10 10 Kellogg 80 58 78 57 77 56 / 0 0 20 10 0 0 Moses Lake 91 58 90 55 88 55 / 0 0 10 0 0 0 Wenatchee 89 64 88 62 87 62 / 0 0 10 0 0 0 Omak 88 60 89 60 88 60 / 10 0 10 0 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$