11/19/2008 Weather

11/19/2008 Weather Discussion: Two distinct storms are tracking toward the PNW. We should begin to feel the effects of the first tomorrow and then again on Friday night/Saturday. These storms have the potential to drop some wet heavy snow on the mountains by the weekend. Long-term models have a lot of inconsistency in them so I have low confidence on what will happen after the weekend. Stay tuned. Forecast from Wednesday 4pm Thursday 4am Precipitation Lt .10 in. Water trace in. Snow Temperatures Low 30 High 34 Winds 5-10 E Forecast for Thursday 4am to 4pm Precipitation .25 in. Water 2-4 in. Snow Temperatures Low 28 High 32 Winds 5-10 W/SW TRENDS AND TIMING Precipitation: The main push of moisture should reach the mountains around mid day tomorrow and increase later in the evening. The precipitation could start out as rain but is expected to turn to snow after 4pm. Snow should taper off early Friday morning with some lingering showers. The next similar system is currently timing out to arrive later Friday night or early Saturday morning. Freezing levels: The temps will be the decider through this. Freezing levels are expected to drop to 4000’ by tomorrow afternoon and then drop to 3500’ over night. A repeat of this pattern is expected with Friday’s system (warm to start then cooling) Winds: Strengthening *east winds are expected to remain in place until the front officially passes sometime tomorrow. Winds will then shift to a westerly flow. This pattern will repeat itself on Friday/Saturday. Models are showing some potential for some windy periods associated with these storms. *Fun weather fact: East flow - there are 3 main things that make wind. Temperature changes, pressure differences and the spin of the earth. (Coriolis effect) When there is high pressure east of the Cascade crest and low pressure to the west, wind will move from high pressure to low pressure thus producing east flow through the Pass. East flow can save us from the rain monster by drawing cool air from the east and lower surface temps – This may be the case tomorrow.