Thursday, May 8, 2014
An expanding ridge over Hudson Bay has pushed its eponymous vortex westward into the Canadian Plains, providing a source of cold air that has fed into today’s passing storm and produced non-accumulating snow showers in the Yampa valley this morning. This pool of cold air will again be drawn into the next storm currently making landfall in the Pacific northwest as it approaches our area, creating moderate to heavy precipitation by Sunday.
Until then, showers will continue today and increase towards sunset as the limited daytime heating continues to destabilize the atmosphere. A quick moving and low amplitude ridge should clear the showers later tonight and tomorrow morning before waves of energy ejecting out of the incoming storm allow showers to redevelop Friday afternoon.
Saturday may also start out relatively nice as breezy southwest flow moves over our area ahead of the advancing storm to our west. The cold front is predicted to move through our area Saturday afternoon or evening and will eventually bring significant precipitation to all of Colorado by Sunday. Any rain in the valley should turn to snow during the night as precipitation ramps up and continues at moderate to heavy levels during the day Sunday. Accumulations on the hill will likely be over a foot by Monday morning, especially at the higher elevations, though accumulations in the valley will be limited by warm ground temperatures and any small warming seen during daylight hours.
Monday will start quite chilly before additional waves of energy and cool air from the Hudson Bay vortex will regenerate much lighter showers by Monday afternoon. Earlier model runs had warming and drying by midweek, but as happened many times this year, we will be susceptible to continued showers and cool air surges during the workweek as waves rotate around the west side of the pesky Hudson Bay vortex.
Thursday, May 1, 2014
A ridge currently centered along the west coast is moving east towards our area and will bring warm and dry conditions that will persist into the new workweek. Several waves spinning around the Hudson Bay vortex will stay well to our north and east tomorrow and Saturday, but flatten the ridge, keeping temperatures around seasonal levels. There may be enough moisture and instability for afternoon clouds and a few thunderstorms, though this activity will be isolated. The ridge regains some of its lost amplitude by Sunday after these waves pass leading to unseasonably warm temperatures that will last at least through Monday.
However, this warm and dry weather will end around midweek when another wave forecast to make landfall in the Pacific northwest on Sunday begins to influence our area. The European ECWMF now agrees with the American GFS model with the early evolution of the storm, leading to warm and windy conditions ahead of this storm for Tuesday. Both models now have cold air from the Hudson Bay vortex entering the storm on Tuesday, but the American GFS continues to pour cold air into the backside of the storm leading to another prolonged cool and wet period from Wednesday through at least part of next weekend. The European ECMWF currently does not show this additional energy entering the storm and keeps it fast moving and through the area by Thursday.
Confidence that a storm will be over our area around midweek is high, but the details are uncertain. My inclination is to believe the cool and wet pattern advertised by the GFS as that model seems to be better handling the Hudson Bay vortex and its interaction with energy entering the west coast from the Pacific.
Tuesday, April 29, 2014
An additional 4” has fallen since yesterday afternoon at the top of the Steamboat ski area leading to a storm total of about 9”. The higher elevations of the central Rockies did best as Loveland reported 2 feet in the last 3 days!
Showers should continue today and last through tomorrow as additional waves of energy and cool air rotate around the west flank of the Hudson Bay vortex. In the last blog post, model forecasts had this continuing through the workweek but it now appears the ridge will build eastward enough to keep most of this energy just to our north and east. The end result is drying and and warming temperatures for Thursday and Friday, though Friday may be a bit cooler as models keep the cool air lurking just to our north.
Another Pacific storm forecast to make landfall in the northwest early in the weekend forces this ridge to amplify over our area. Dry air and likely unseasonably warm temperatures will make for a beautiful weekend that will likely persist for Monday as well.
However, the interaction between this Pacific storm and the Hudson Bay vortex still looks to occur beginning over the weekend and will strengthen the storm, bringing showers into our area sometime on Tuesday in increasing southwest flow. The American GFS model advertises another active period of weather starting midweek as the storm moves over our area and lasting through the following weekend, though the European ECMWF has a less amplified and quieter solution.
Sunday, April 27, 2014
The Steamboat powdercam is showing about 5.5” up top this afternoon with a temperature of 19F, though I had only trace amounts of snow on my deck this morning as the precipitation fell mostly as rain last night. Even though this impressive spring storm is east of us, we will continue to be affected by this storm this entire week as its eastward motion is impeded by additional waves of energy and cold air from the persistent Hudson Bay vortex digging into its western flank. Indeed, the eastern two thirds of the country will soon be affected by this enormous storm.
For our area, a trailing wave from the Pacific northwest will bring another round of showers and cooler temperatures during the day tomorrow and tomorrow night. Snows will continue to accumulate at higher elevations on the hill though the valley precipitation will be either rain or non-accumulating snowfall.
Showers lessen on Tuesday, though they don’t end, and will pick up again Wednesday as a wave rotating around the west side of the Hudson Bay vortex brings another round of cool air and showers. Earlier model runs had the west coast ridge building over us by Wednesday, but the cold air moving southward from Canada will prevent this from happening. In fact, further surges of cold air are now advertised for Thursday and Friday as well, keeping the west coast ridge to our west and showers over our area.
Concurrently, a Pacific storm approaches the coast around the end of the workweek, interacting with and destroying the west coast ridge. There is model uncertainty during the weekend with regards to how much interaction there is between this Pacific storm and energy along the western flank of the Hudson Bay vortex, though both the American and European model keep unsettled weather over our area. The European ECMWF model has more cool air entering the Pacific storm, which may allow temperatures to warm briefly ahead of the storm during next weekend, while the American GFS keeps this storm weaker, but forecasts cool and unsettled conditions in the moist northwest flow through the weekend.
Even though details are likely to change, unsettled weather continues to be forecast into the following week, as the earlier advertised active spring weather continues into the foreseeable future.
Tuesday, April 22, 2014
Two storms will affect our area in the following week, with clouds and moisture from the first storm currently overspreading our area. Showers will continue through the day today and grow heavier later this afternoon when surface temperatures are highest. The cold front associated with the first storm will bring rapidly falling temperatures and snow levels by early tomorrow, though accumulations at higher elevations will be modest at best due to the storm’s quick movement. Showers will persist in the seasonally cool and showery weather before clearing by later Wednesday ushers in a cool start to Thursday.
Thursday and Friday look to be warm and pleasant before the next colder, moister and generally far more impressive storm makes landfall on the west coast on Friday. Our area will be affected from Saturday through early next week as clouds and winds increase ahead of the storm on Saturday. A strong cold front brings sharply colder temperatures and precipitation by later Saturday afternoon or evening.
Sunday will be cool and showery before the storm is re-energized by an influx of cold air from the persistent Hudson Bay vortex on Monday, increasing showers and further lowering snow levels. There is model uncertainty as to how much cold air is dragged into the system, and this will determine how long the storm will be in our proximity and whether we see snow in the valleys. Mountain elevations, however, are likely to see significant snows. Current forecasts predict rapid warming and drying by midday Wednesday and lasting for a few days before more unsettled weather approaches our area in this very active and productive spring.