Area Forecast Discussion
Issued by NWS Spokane, WA
Issued by NWS Spokane, WA
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498 FXUS66 KOTX 060223 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 723 PM PDT Sun May 5 2024 .SYNOPSIS... Rain showers will continue across the PacNW into Monday. As the low slides east, conditions will remain cool and showery and breezy. Warmer and drier weather will arrive late next week. Next weekend has the potential to deliver our warmest temperatures of the spring so far. && .DISCUSSION... Evening update to make adjustments to the precipitation forecast for the rest of tonight. Nothing too drastic with the band on the backside of the low that is pulling away. I did reduce the PRISM influence and this had the effect of lowering precipitation amounts a little bit over the mountains. I also removed a significant area of where we had thunderstorms in the forecast over northeast portions of Washington into the central and northern portions of Idaho. Model sounding profiles show a distinct cap between the 12 kft to 15 kft layer to the convection tomorrow afternoon that will make it difficult for these areas to see enough charge separation for lightning. Better chances will be over the far southeast portion of the forecast area from the Northeast Blue Mountains to the southern Idaho Panhandle. Otherwise, the forecast remains on track. Winds will be picking up tonight precipitation decreases from west to east. Stevens Pass, Washington Pass, and Lookout Pass will see the potential for light snow, but any accumulations are expected to be light and below advisory criteria thresholds. /SVH && .AVIATION... 00Z TAFS: The rain band extending from Sandpoint to Spokane to Tri Cities will pivot to the west this afternoon. That should bring several hours of ceiling and visibility improvements to Spokane, Coeur d`Alene, Pullman and Sandpoint. Radar trends and 12z model runs limit the westward progress to about Moses Lake and Grand Coulee. With drier downslope west winds in central WA, confidence is high that Wenatchee, Chelan, and Omak will remain VFR with little to no precipitation. Moses Lake and Ephrata will get some light rain, but may experience enough drying from the west to keep prevailing VFR until the rain band moves eastward this evening. Spokane, Coeur d`Alene, Pullman, and Lewiston can expect ceilings to lower as the band returns in the 00z-05z time frame before it moves east and gusty winds help to break up low ceilings after 06z. /GKoch FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: Confidence in ceilings and visibility within the band of rain is low. We are dealing with an axis of mid and low level moisture convergence favoring localized ceiling reductions to 1500 ft or less, but it is a relatively narrow band with a good deal of dry being advected from the west. With a good deal of variability in the MOS and HREF guidance, frequent amendments are anticipated to keep up with the changing conditions. /GKoch ----------------------- 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 41 57 35 59 37 63 / 100 50 20 10 0 0 Coeur d`Alene 42 54 35 55 37 60 / 100 70 40 30 10 0 Pullman 40 52 34 52 35 56 / 100 60 40 20 0 0 Lewiston 45 61 41 59 41 63 / 100 60 40 30 10 0 Colville 41 59 32 59 36 67 / 100 40 40 20 0 0 Sandpoint 42 53 36 53 38 58 / 100 80 50 50 10 10 Kellogg 39 49 36 48 37 54 / 100 80 70 70 20 20 Moses Lake 44 63 38 64 37 71 / 100 20 0 0 0 0 Wenatchee 44 59 41 59 40 69 / 10 20 0 0 0 0 Omak 43 64 36 64 38 72 / 80 20 10 0 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$