Friday, May 12, 2017
A large storm currently off the British Columbia coast will be reinforced by an upstream Pacific wave moving over a ridge of high pressure centered in the Gulf of Alaska, forcing a series of cold fronts to move across the Great Basin this week. Earlier in the season, the cold fronts would have had more of an impact on the weather in the Steamboat Springs area, but now, the stronger warming associated with longer days and higher sun angles will reduce the strength of the fronts as they penetrate inland.
Ahead of the first cool front timed for Sunday, pleasant weather for today and Saturday may be interrupted by a chance of afternoon storms, most likely over the higher elevations.
While the bulk of the effects of the first cool front will be shunted to our northwest, we should see a few degrees of cooling for Sunday along with dry and breezy conditions.
Dry air will persist for Monday when a second wave, crossing the West Coast further south along southern California, brings another seasonable day with breezy afternoon conditions.
The dry air that was over our region on Sunday and Monday will be pushed southward by the front, bringing a chance of showers for Tuesday.
By Wednesday, the parent storm crosses the Pacific Northwest coast and moves into the Great Basin. There is model disagreement with respect to the storm’s strength and southern extent, but we may feel its effects as soon as later Wednesday when a stronger front with associated showers is advertised to push through our region.
Unsettled weather with much cooler temperatures is a good bet for at least Thursday and Friday as the the storm slowly moves across the Great Basin and over our area.
Monday, May 8, 2017
A storm currently near northern Baja will move slowly across the Desert Southwest tomorrow, bringing wet and cool weather to the Steamboat Springs area starting later Tuesday. Model forecasts show Tuesday night and Wednesday being the wettest period of the week, followed by clearing weather for Thursday and a return to warmer temperatures and the chance of afternoon storms heading into the weekend.
The wet weather Tuesday night is due to a wave of energy ejecting out of the approaching southwest closed low. Additionally, the Pacific jet stream is moving across the Canadian - U.S border, and a wave in that flow will drag a cool front through northern Colorado around then. This will interact with the closed low that is forecast to move across the Colorado - New Mexico border during the day Wednesday and enhance precipitation for Tuesday night and Wednesday.
By later Wednesday, the storm is forecast to be east of Colorado, bringing significantly drier weather for Thursday, though there is model disagreement as to whether there will be enough instability for showers later in the day.
A sharp ridge of high pressure builds over the Rockies behind the departing storm and ahead of a strong Gulf of Alaska storm that is forecast to elongate along the West Coast during the weekend. This will lead to warm mostly sunny days through early next week with the chance of afternoon storms, strongest on Friday as lingering moisture fuels the storms.
It appears the West Coast storm will eventually affect our weather sometime next week, though model disagreement with respect to its movement and strength makes the details uncertain.
Friday, May 5, 2017
The beautiful weather in the Steamboat Springs today will hang around for most of tomorrow before the current ridge of high pressure is nudged to our east by an approaching Pacific wave. This wave will split as it approaches the West Coast, with much of the energy diving south along the California Coast and forming a closed low pressure system cut off from the main jet stream.
Moisture and limited energy will eject over our area starting later tomorrow, bringing breezy southwest winds and afternoon clouds. The dry lower levels of the atmosphere will allow rain that falls to evaporate before reaching the ground (virga), bringing gusty afternoon winds in places.
By Sunday, the now well developed cutoff low will assume a relatively long-lived position along the California - Arizona - New Mexico border. As the lower atmosphere moistens, and more moisture and energy eject from the spinning low to our southwest, thunderstorm chances and coverage will increase for Sunday.
These cutoff lows are notoriously difficult to predict since there is no strong upstream forcing to move the storm along. The end result is that timing and position of precipitation is nearly impossible to get right this far out, and a slight southern shift in the storm southward would greatly diminish our precipitation chances while a shift further north would increase the chances.
That being said, current forecasts have the chance of afternoon storms for both Monday and Tuesday before the cutoff low lumbers eastward through most of the work week. Models have the storm more or less over Colorado around midweek, bringing cooler and much wetter weather to Colorado for Wednesday and some or most of Thursday.
A very complicated pattern then ensues, with interactions between additional Pacific energy approaching the coast, the cutoff low and even energy swinging back westward from an East Coast storm that developed from our storm this past Monday and Tuesday. While earlier in the week it looked like summer-like weather would return after the cutoff low moved east of us, more unsettled weather now looks more likely heading into next weekend.
Monday, May 1, 2017
Winter looks to be finally done with us by midweek, but not before another disturbance in cool northwest flow moves over the Steamboat Springs area on Tuesday. Showers will start in the morning and continue through the day, and though we may see the last snowflakes of the season in the Yampa Valley near the beginning of the storm and again near the end of the storm Tuesday evening, accumulating snows of 2-5” will be confined to elevations above 8000′.
If skies clear by Wednesday morning, temperatures will start out quite chilly with some moderate warming during the day that will bring temperatures towards average.
More pronounced warming will increase temperatures to above average on Thursday and even warmer summer-like temperatures are expected to last through the weekend as a deep and strong closed low that is cut off from the Pacific jet stream forms over southern California late in the weekend
It’s meteorologically remarkable that we flip from a long-lasting winter-like pattern to a summer-like pattern in a few short days, but the southwest flow ahead of the eventual southern California cutoff low will bring an increase in atmospheric moisture that will begin our thunderstorm season. These are expected as soon as Saturday afternoon, with coverage, intensity and duration increasing on Sunday and Monday as waves of energy eject out of the loitering cutoff low to our southwest.
It looks like we go from cold and wet to warm and wet as that cutoff low will continue to influence our weather during next week. There is model disagreement as to when that cutoff low moves east, but models have the storm moving near or over Colorado sometime during next week.