Wednesday, February 26, 2014
Two storms undercutting the west coast ridge will influence our weather from Thursday through the beginning of next week. We received another big fat zero inches of snow last night, even as areas to our south received a couple of inches. I’m surprised we could not generate any lasting precipitation when the storm moved through just before sunset, but dry air quickly moved in and shut down the precipitation.
The first storm will bring clouds into our area by tomorrow, and precipitation may start as early as the afternoon. Though the winds are initially westerly, they veer to the northwest around midnight, and I expect our best snow will wait until then. I would expect 3-6” of heavy snow by Friday morning with an additional 3-6” during the morning hours and early afternoon, which will be reported Saturday morning. Precipitation will likely start as rain in the valleys before changing over to very wet snow later in the evening.
Snow will diminish or even end later Friday as a small ridge moves over our area between the two storms. Clouds will quickly increase again by midnight Friday as a far stronger storm situated around central California spreads warm temperatures and moisture over our area. I don’t believe we will get significant precipitation until we get a bit of cooling associated with some energy ejecting from the storm Saturday morning.
While these storm are progressing eastward, a very cold wave rotating around the persistent Hudson Bay vortex moves first over the Washington / Oregon region before it begins sliding east. As mentioned in the previous blog, the amount of cold air, if any, that interacts with the warm southern storm will greatly influence our weather. At this time, it appears most of the cold air will remain to our north and east and any interactions will be minimized, as forecast by the European model several days ago. Still plenty of time for that to change, though!
Current forecasts have this impressively wet storm staying to our south, likely bringing the heaviest precipitation to southern Colorado and New Mexico, though central Colorado will also receive significant accumulations. I expect less precipitation over our area, though these southwestern storm can sometimes surprise, especially if there is a convective component where cooler air aloft destabilizes the atmosphere and increases upward motion (similar to bubbles rising in a pot of heated water, though the rising motion in the pot is caused by heating the bottom of the pot as opposed to cooling the top of the pot).
The flow does turn to the northwest after the storm passes by Sunday afternoon, and showers from this storm are likely to continue through Tuesday. Any breaks in precipitation look to be short-lived as a wave traveling over a transient ridge building over our area brings upward motion, cooling and the chance for more showers on Wednesday.
Longer term, I see continued storminess at least through mid-March as the Hudson Bay vortex continues to torment the east and Midwest with cold and stormy weather while the west continues to experience relatively warm and wet storms from the Pacific.