Chances for rain continue during the upcoming week
Thursday, July 22, 2021
The skies have clouded over this Thursday mid-afternoon with the mid-eighties temperatures observed earlier in the afternoon decreasing to the upper seventies in the areas of town lucky enough to see a few drops of rain, like the mountain area. The monsoonal plume of moisture is forecast to remain over our area this week, with chances for precipitation remaining modest through the weekend and the beginning of next week before increasing, perhaps substantially, for the end of the work week.
A ridge of high pressure is currently centered over the Four Corners region and extends into the central Canadian Plains. An eddy, which I first talked about in last week’s weather narrative, is currently in west Texas while a storm from the Gulf of Alaska is located near the northern Alberta - Saskatchewan border. The eddy to our south is forecast to move across the Desert Southwest through the weekend and up the West Coast next week while the Canadian storm is forecast to deepen as it moves toward the Northeast next week.
The monsoonal moisture plume located on the western side of the ridge of high pressure will meander around through the week as the ridge deforms and jiggles around. Furthermore, the moisture content of the plume will vary as weather features pass near it (like that eddy and a possible tropical storm well to the south next week), leading to a somewhat low-confidence forecast in the days where we will see the best moisture over our area, even though each day of the coming week will see some chances for showers.
Right now, modest chances for precipitation, similar to the last few days, will persist into the weekend before decreasing around the start of the work week and then increasing again, perhaps substantially, near the end of the work week. There is uncertainty in the forecast as soon as tomorrow as we will see some winds from the north on Friday as that Canadian storm flattens the ridge of high pressure and allows it rebuild to the west. While it is not clear if some drier air lurking to our northwest will invade the area and decrease shower chances, it does appear we will see some smoke from the Morgan Creek fire infiltrate town, according to the latest NOAA smoke plume model.
While areas to our south are far more likely to see precipitation this weekend, we could see drier weather if we see more of the dry air from the northwest, perhaps with some smoke from the Morgan Creek fire, or wetter weather if the flow from the south and southwest wins out.
Regardless of what happens during the weekend, it appears we will see slim, but not negligible, chances for precipitation to start the work week as the ridge of high pressure amplifies to the northwest and shifts the monsoonal moisture plume to the west. This is short-lived, however, as another Gulf of Alaska storm is forecast to move eastward and push the ridge of high pressure back to the east around midweek.
Not only will this shift the monsoonal moisture plume towards our area, but the plume may be enriched by some sort of tropical storm that injects some moisture into the flow from well to the south, though that is very uncertain as this time. But at least it looks like increasing precipitation chances after the start of the work week, with some storms becoming increasingly likely to produce periods of moderate to heavy rain.
And the American GFS, which produces a sixteen day forecast four times a day, has the wet pattern continuing into the first week of August as increasingly fast flow from the west pushes the ridge of high pressure eastward and keeps the monsoonal moisture plume on the backside of the ridge overhead. Stay tuned to my next regularly scheduled weather narrative on Sunday afternoon where I hope to have a better idea of our precipitation chances for next week.
Increasing rain chances this week
Sunday, July 18, 2021
Sunday is shaping up to be a hot day in the Steamboat Springs area as temperatures are already just above 80 F this Sunday noon. Less clouds than the last few days means upper eighties for today and likely the low nineties for tomorrow before we see a good chance of showers on a cooler Tuesday as a surge in monsoonal moisture moves overhead. Shower chances for the rest of the upcoming week are entirely dependent upon the vagaries of the location of the monsoonal moisture plume, though it is likely that at least some of the days will be favored for precipitation.
A ridge of high pressure centered over the central Rockies is sandwiched between areas of low pressure over the Gulf of Alaska and the Northeast. The ridge is forecast to amplify through Monday, keeping hot temperatures of five to ten degrees above our average of 82 F for the next two days with almost no chance for precipitation. Additionally, we may see some winds out of the north or northeast this afternoon which may briefly transport some smoke from the Morgan Creek wildfire into our area, though smoke concentrations predicted by the NOAA smoke model are quite light.
But this changes on Tuesday as some energy ejects out of the Gulf of Alaska low pressure area which reduces the amplitude of the ridge and tilts it to the east. This allows the monsoonal moisture plume associated with the southerly flow on the backside of the ridge of high pressure to move over our area for increased precipitation chances and decreased temperatures closer to average. And unlike the last couple of days, the showers are more likely to produce brief periods of moderate to heavy rain as the lower atmosphere moistens.
However, weather forecast models are not in complete agreement, even among themselves, in the exact location of this monsoonal moisture plume, with the latest run of the European ECMWF backing off on precipitation chances on Tuesday. While areas to our south are more certain to receive moisture, our northern location means we are more dependent upon the vagaries of the exact plume location.
More of the same continues through the rest of the work week, with precipitation possible but hardly certain as that Gulf of Alaska storm is forecast to move eastward in a couple of pieces and cross the British Columbia coast around midweek before trekking across the Canadian Plains for the weekend.
This will substantially interact with the ridge of high pressure over the central Rockies, changing the location of the monsoonal moisture plume, which may be beneficial for continued precipitation chances, or not. Interestingly, that eddy I talked about in the last weather narrative is still forecast to break away from the area of low pressure over the Northeast around Tuesday and meander westward across Texas before it is trapped under the ridge of high pressure over the central Rockies. This may or may not eventually move over our area around next weekend, with substantially increased precipitation chances if it does.
It is not unusual for an uncertain precipitation forecast during our monsoon season, but the North American Monsoon seems well established which means there are at least chances for precipitation for our area. And for what its worth, the American GFS strengthens the monsoonal signature over our area after next weekend and heading into August. Stay tuned to my next regularly scheduled weather narrative on Thursday afternoon to see if this monsoon signal persists and for a better idea of precipitation chances for next weekend.
Skies dry and temperatures warm through the weekend and next week
Thursday, July 15, 2021
After a sunny morning in the Steamboat Springs area, temperatures have reached just above eighty degrees this Thursday mid-afternoon with skies clouding over as approaching storms bring the chance of precipitation. Moisture will decrease and temperatures will increase through the weekend and next week with an interesting possibility of significant precipitation emerging around next weekend.
A broad and modest ridge of high pressure is currently centered over the Rockies with areas of low pressure over the Gulf of Alaska and Hudson Bay. Both areas of low pressure are forecast to deepen and elongate to the south and southwest through the weekend and most of the following work week. Winds from the southwest ahead of the Gulf of Alaska area of low pressure will bring warmer and drier air inland which is forecast to amplify the ridge of high pressure over the Rockies through midweek before nudging it to the east through the rest of the work week.
This means warming temperatures and a drying atmosphere for our area, with shower chances persisting but decreasing through Saturday. There will be enough moisture for the possibility of brief moderate to heavy rain through Saturday under the stronger storms, but there is also a chance that we will see more wind than rain as the atmosphere dries.
The comfortable temperatures below our average of 82 F these past two days will be long gone by Sunday as temperatures rise into the upper eighties with almost no chance for precipitation. And this trend continues into the work week as precipitation chances become nil and high temperatures rise further with nineties likely.
A meterologically very interesting pattern may emerge early in the work week that could bode well for significant precipitation over our area by around next weekend. Weather forecast models have the southern end of the elongating Hudson Bay area of low pressure forming an eddy that is forecast to drift under the eastward moving ridge of high pressure through the work week. The evolution of this pattern is still up for debate, but it is possible that the eddy, which will be relatively moist if it maintains its forecast trajectory across the southern states, will be caught in the clockwise circulation around the high pressure system.
Furthermore, the positioning of the ridge of high pressure to our east will direct moisture to our south northward in a classic North American monsoon pattern, and this may further moisten the eddy as it treks around the western periphery of the ridge. There are several moving pieces that may contribute to the possibility of rain over our area for next weekend, but even if we don’t see that eddy, chances for precipitation will increase solely from the monsoonal push of moisture. Stay tuned to my next regularly scheduled weather narrative on Sunday afternoon where I hope to have more clarity on how this interesting weather pattern may unfold.
Near average temperatures with shower chances this week
Sunday, July 11, 2021
Temperatures around eighty degrees are over the Steamboat Springs area this Sunday noon under smokey skies from the recently ignited Morgan Creek wildfire 15 miles north of town. The excessive heat observed recently will be absent this week as a series of Pacific storms bring a chance of showers to our area starting Tuesday afternoon, with Wednesday likely bringing the highest probability of precipitation for the upcoming week.
The Morgan Creek wildfire has ballooned in size from the initially estimated 5 acres Friday afternoon to almost 2000 acres. The cool front on Saturday morning likely contributed to the increase in fire size as breezy winds from the north accompanied the front. And while the temperatures cooled to around five degrees above our average of 81 F Saturday thanks to the cooler air mass, the winds from the north also transported smoke from the wildfire directly into town. The NOAA smoke plume model shows the current smoke abating by this evening before increasing again tomorrow before again decreasing by Monday evening.
The dominant ridge of high pressure responsible for the excessive heat that was over the West the last several weeks is under assault by a series of waves ejecting out of a strong storm currently in the Gulf of Alaska. The first such wave brought the cool front early Saturday while the next one will pass to our north Wednesday morning, but not before first leaving a piece of energy and moisture behind that will move over our area that afternoon.
The end result will be that today and Monday will be the warmest days of the upcoming work week with highs around five degrees or so above our average of 81 F and near nil chances for precipitation. The winds will shift to be from the north to be from the west starting Tuesday ahead of the Wednesday wave, which should help keep the wildfire smoke north of town.
The wind shift will bring some increased moisture overhead on Tuesday for a small chance of late day showers, though winds will be increasing on Tuesday and more so on Wednesday as the wave moves north of the state. While the increasing winds are bad news for the wildfire, that leftover piece of energy is forecast to move overhead later in the day Wednesday giving us the best chance of wetting rains for the upcoming week.
Precipitation chances look to decrease substantially on Thursday as some dry air behind the wave tickles our area though they are forecast to increase modestly by Friday as the dry air recedes for a day.
However, cold air from the North Pole is forecast to mix with that Gulf of Alaska storm during the second half of the work week and force it to elongate to the south off the West Coast. The increased flow from the southwest ahead of the storm will reinvigorate the ridge of high pressure over the West by the end of the work week leading to rebounding temperatures well above average and a general decrease in precipitation chances.
There is weather forecast model uncertainty for the following week as the American GFS wants to move the Gulf of Alaska storm inland and displace or deform the ridge of high pressure over the West while the European ECMWF keeps more of the storm off the West Coast. This is important for the development of the North American Monsoon as our area will depend upon that western ridge of high pressure being forced far enough east so that the southerly flow on the backside of the ridge can bring moisture to our south northward. I should have a better idea on whether this may occur in my next regularly scheduled weather narrative on Thursday afternoon.
Cooler temperatures for the weekend
Thursday, July 8, 2021
The Steamboat Springs area has seen periods of sun and clouds this Thursday morning with temperatures already in the mid-eighties as of noon. Another hot day is forecast for Friday before a dry cool front brings some relief from the heat for the weekend. While the following week starts hot again, a series of Pacific waves will bring increasing clouds and cooler temperatures with chances of precipitation starting on Tuesday.
A weak and compact storm just off the Washington coast will move across the northern Intermountain region on Friday, about twelve to eighteen hours later than forecast in my last weather narrative on Sunday. While we may see some brief showers today, the later arrival of the cool front means another hot day on Friday with temperatures again around ten degrees above our average of 81 F. Unfortunately, winds will be increasing ahead of the front on Friday, especially in the afternoon, and the dry air ahead of the front means even less of a chance of showers than today.
But relief from the heat arrives on Saturday as the cool front sweeps through our region Friday night. Expect temperatures to fall much closer to average under sunny skies as dry air moves overhead for a very pleasant Saturday. The dry air sticks around for Sunday and Monday with temperatures increasing a few degrees each day.
Meanwhile, a storm churning in the Gulf of Alaska will eject several waves early and late in the work week which are forecast to carry some moisture overhead, as well as encourage moisture from the southwest to move towards our area. While the American GFS is more enthusiastic about the moisture than the European ECMWF, we should at least see some clouds starting on Tuesday that will help hold our temperatures closer to, but likely still above, average.
Shower chances increase for Wednesday through Friday as subtle waves originally ejected from the Gulf of Alaska storm move overhead. Even if we don’t get the showers, at least clouds are a good bet, so expect more of the comfortable temperatures to persist through the work week.
Weather forecast models forecast the ridge of high pressure that had been over the West to reassert itself heading into the weekend and deflect any influences from that Gulf of Alaska storm to the north. This leads to another round of hot and dry weather for the weekend following the cooler and moister work week.
Enjoy what should be a quite comfortable weekend, and I’ll have more details about the unsettled weather for the following work week in my next regularly scheduled weather narrative on Sunday afternoon.
