Thursday, April 20, 2017
A cold Gulf of Alaska storm is currently on our doorstep, and some showers have popped up today in advance of the main storm. While snow levels are currently near 9500′, temperatures will drop this evening and bring snow to the Yampa Valley floor overnight. I would expect to see accumulations on the grassy surfaces by the morning of an inch or two, with a more substantial 4-8” at the higher elevations.
Cool and moist northwest flow will follow for Friday and Saturday. Showers, most likely snow even at the valley bottom, will be heaviest through Friday night, with an additional inch or two expected at the higher elevations.
Decreasing moisture on Saturday will limit the showers, but seasonably cool and still unstable northwest flow will make them most likely in the afternoon.
Sunday should be a spectacular day as temperatures warm under a transient ridge bringing mostly sunny skies.
However, a strong and progressive Pacific jet stream containing several embedded waves will move that ridge of nice weather eastward, with the first weakening wave bringing a chance of light showers by Monday afternoon.
Behind that, a stronger wave moves over the Steamboat Springs area on Tuesday, bringing heavier precipitation and the chance of snow down to the valley floor again.
It does not appear there will be much of a break in the weather as the strongest wave in this series moves across the central Rockies on Wednesday. Additional energy will keep the cool and wet weather around for the rest of the work week, with impressive precipitation accumulations likely across all of Colorado by week’s end.
The timing and details of these waves in the fast Pacific jet stream are notoriously difficult to predict, and I expect changes to the forecast for my next update on Sunday or Monday.
Monday, April 17, 2017
An energetic and progressive Pacific jet stream will send several waves of energy over the Steamboat Springs area this week, with breaks in the weather appearing between the storms on Tuesday and Thursday.
The first weak wave is currently moving across the Montana - Wyoming border and has brought breezy conditions with some clouds today.
Meanwhile, a strong storm in the Gulf of Alaska has mixed with some cold air leaking westward from a relatively persistent late-season Hudson Bay vortex. Tuesday looks to be a warm and dry day before some energy ejects from the Gulf of Alaska storm and grazes northern Colorado Tuesday night. Several inches of snow are possible above 9000′ overnight and into Wednesday morning, with rain showers likely for the Yampa Valley.
Thursday should be an in-between day with some light rain showers possible before additional upstream energy from the Pacific dislodges the cold Gulf of Alaska storm and moves it across the Great Basin during the day.
There is a fair bit of uncertainty for Friday and Saturday with respect to the storm’s structure and its southern extent, but we will be cold enough for snow down to the valley floor on Friday and likely Saturday as well. The storm is forecast to move across our area in several pieces, with the heaviest snow currently expected overnight Thursday into Friday morning, with significant accumulations possible at the higher elevations. Unsettled and cool weather will persist for Friday and Saturday, with a trailing wave increasing the likelihood of stronger snow showers later Saturday.
A warm and dry Sunday is advertised by the models ahead of another possible quick-moving storm for Monday.
Thursday, April 13, 2017
A powerful storm from the Gulf of Alaska has crossed the West Coast, and temperatures in the Steamboat Springs area will be much above normal today as breezy southwest flow ahead of the storm carries warm air over the Rockies. However, the storm will be deflected to our northwest and move over the northern Rockies as the western ridge flattens over the next two days. Some cooler air will be dragged over our region on Friday and Saturday, and there may be enough moisture for some clouds both days.
Behind the grazing storm early in the weekend, skies will be sunny and temperatures above normal again for Sunday as the western ridge rebuilds.
The weather will turn unsettled by Monday as a still energetic Pacific jet stream carries waves of energy over the continental U.S. There may some showers on Monday afternoon as the first relatively weak wave of many moves over our area under seasonable temperatures.
While Tuesday looks to be a warm and dry day ahead of the next Pacific wave, cold air from a persistent Hudson Bay vortex will slide southwestward toward the Gulf of Alaska at times over at least the following week, reinforcing storms originally formed in the Pacific. The fast westerly flow aloft combined with uncertainty regarding the southward and westward extent of the cold air from the Hudson Bay makes for an uncertain forecast beyond mid-next week.
While the details are uncertain, models agree that a cold storm will move over our area after midweek, with snow possible down to the valley floor.
Monday, April 10, 2017
An easy forecast for me to make means tranquil weather over the Steamboat Springs area this week. The still active Pacific jet stream will drive a weak and dry wave across the Great Basin later Tuesday, briefly interrupting a steady warming trend already in progress and possibly bringing some clouds for later Tuesday and early Wednesday.
Concurrently, a powerful storm develops in the Gulf of Alaska and makes landfall along the West Coast around midweek. Our temperatures will rise to above normal on Thursday as breezy southwest flow ahead of the storm carries warm air over the Rockies. However, the storm will be deflected to our northwest and then move north of our area as the western ridge holds strong. Some cooler air will be dragged over our region on Friday and Saturday, and there may be enough moisture for some clouds both days, and even a stray shower Friday afternoon.
Behind the grazing storm early in the weekend, skies will be sunny and temperatures above normal again for Sunday and Monday as the western ridge rebuilds.
Friday, April 7, 2017
A moderate atmospheric river event is currently pounding California again and will push the western ridge responsible for the warm and dry weather over the Steamboat Springs area eastward on Saturday. Breezy winds today will increase on Saturday ahead of the precipitation which will start as soon as Saturday afternoon.
The storm will come in two main pieces, with energy ejecting ahead of the storm bringing the possibility of some thunder by Saturday afternoon in windy conditions with snow levels above 9000′ or so. Precipitation will be showery, with some showers capable of producing periods of localized moderate to heavy precipitation.
The main cold front looks to push through our area after midnight on Saturday as the parent storm travels across the Colorado - Wyoming border, dropping snow levels to the valley bottom by Sunday morning. But a promising storm has become less promising over the last few model runs as a further-north storm track and quickly eroding moisture limit the accumulations. Due to the likely variable nature of the precipitation, especially during the first part of the storm, I would guess 1-4” by Sunday morning with another 1-4” during the day as cool and unsettled weather continues in the favorable northwest flow behind the storm.
Drying and seasonable temperatures are expected for Monday. The midweek storm from the last forecast is now expected to only graze our area on Tuesday, keeping our area dry and dropping temperatures a bit.
Another western ridge builds behind the weak storm, bringing warming temperatures by Wednesday and much above normal temperatures by Thursday.
Another powerful Gulf of Alaska storm is forecast to cross the West Coast around Thursday. However, the higher sun angles of Spring will bolster the western ridge, weakening the Gulf of Alaska storm as it moves eastward across the great Basin on Friday. Right now, only light and relatively warm showers are expected later Friday before the western ridge rebounds for the Closing Weekend. However, the models are struggling the interaction between Pacific energy and the western ridge, and I expect the forecast for Closing Weekend to evolve over the next week.