Scientific Forecaster Discussion
000 FXUS66 KOTX 222325 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 425 PM PDT Thu Jun 22 2017 .SYNOPSIS... The weather for the weekend will be quite warm. Afternoon temperatures on Saturday will likely reach the mid 80s to low 90s. Sunday and Monday will be even warmer with most lowland areas reaching the 90s. A return to cooler, more average temperatures are expected by the middle of next week, with breezy conditions possible late Monday through Tuesday. && .DISCUSSION... Tonight through Saturday: A high pressure ridge will build in over the next 48 hours. Strong subsidence and dry air will suppress cloud cover with clear and sunny skies. Temperatures will see a warming trend to above normal with widespread 80s Friday and mid 80s to low 90s by Saturday. /SVH Saturday Night through Monday: The upper level ridge axis shifts east into eastern WA which will keep temperatures rising. Sunday valley temps will heat up to upper 80s to mid 90s, with a few degrees of additional warming on Monday. Monday will be the warmest day in the 7 day forecast. These daytime temps are 14-18 degrees above average and overnight lows 5 to 12 degrees above average for this time of the year. Mostly clear skies are expected with some cirrus streaming in Sunday and Monday. Monday afternoon southwesterly winds start to pick up across the east slope into the Columbia Basin as the ridge gets pushed east. Monday evening and Tuesday: Lots happening these periods. The first is the models showing some energy moving up from the southwest Monday evening into Tuesday morning. Models have a very difficult time nailing down the specific track of these waves, but it looks to mainly impact southeast WA and the southern ID Panhandle. The GFS-that shows the strongest waves-has quite a bit of convective inhibition which would make it difficult for thunderstorms to get going. However given the pattern recognition have added thunder across extreme southeast WA and the southern ID Panhandle with the hopes of honning in on it better as the event approaches and the models can see better detail of timing and track. The second weather feature to watch is a low pressure system moving into Canada from the Gulf of Alaska. There are some pretty big model differences and the confidence in this portion of the forecast is quite low. The GFS has been consistent in digging that low down into our area on Tuesday while the ECMWF has been consistent with itself in keeping the low in northern BC and Alberta. Of course the models are consistent with themselves but totally different from each other! The Canadian seems to track the low right in the middle of the other two models. The Canadian as well as the EC keep the forecast dry. Wasn't confident to take out our slight chance showers across NE WA and north ID along the canadian border, but didn't increase our chance of precipitation. With the breakdown of the ridge and the low pressure moving somewhere to the north of WA, our winds will increase. Winds will pick up Monday evening and continue through the night and into Tuesday evening. They look to peak Tuesday late afternoon and early evening. The main area of concern is from the central east slopes of the Cascades east into the Columbia Basin and into the Palouse and Spokane area. The winds Monday will be a concern as RH values will be in the upper teens to near 20 percent. This will bring fire weather concerns to the Columbia Basin. Tuesday the winds will be slightly stronger, but temperatures should drop about 10 degrees and RH values should come up a bit. Wednesday and Thursday: Models are having trouble with what to do with the ridge to the west and whether or not to bring a cut off low into the region. Temperatures will remain at or above average for this time of the year. Low confidence on our chance of precip across extreme NE WA and north ID. /Nisbet && .AVIATION... 00Z TAFS: Dry northwest flow will bring VFR conditions to the TAF sites through the period. Locally gusty westerly winds will taper off early near KPUW & KLWS with light north/east winds overnight. Light winds will continue into Friday with speeds under 10kts. /rfox. && .PRELIMINARY POINT TEMPS/POPS... Spokane 50 82 55 87 59 91 / 0 0 0 0 0 0 Coeur d'Alene 46 79 50 84 54 89 / 0 0 0 0 0 0 Pullman 45 80 51 85 55 89 / 0 0 0 0 0 0 Lewiston 53 86 56 91 59 96 / 0 0 0 0 0 0 Colville 46 82 48 87 52 91 / 0 0 0 0 0 0 Sandpoint 43 79 45 84 49 86 / 0 0 0 0 0 0 Kellogg 44 78 49 83 51 88 / 0 0 0 0 0 0 Moses Lake 50 88 55 93 56 97 / 0 0 0 0 0 0 Wenatchee 55 87 60 92 62 96 / 0 0 0 0 0 0 Omak 51 86 55 91 55 94 / 0 0 0 0 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None.