Hot temperatures through the weekend followed by snow on Tuesday
Thursday, September 3, 2020
Temperatures are already near eighty degrees early this sunny Thursday afternoon in Steamboat Springs as we continue to recover from the cool start to the work week. Temperatures are expected to soar toward ninety this dry Labor Day weekend, followed by a dramatic cold front that may bring snow down the the Yampa Valley floor on Tuesday.
A ridge of high pressure currently over the West Coast will move over our area through the Labor Day weekend, with temperatures forecast to soar ten to fifteen degrees above our average of 76 F. But the dry air will keep our cool nights around, and with an average low temperature of 39 F, we could see several more days of fifty degree intra-day, or diurnal, temperature swings.
Enjoy the summery weather because wintry weather is forecast for Tuesday. As in snow, perhaps down to the valley floor! A chunk of cold air currently moving southward from the North Pole will merge with a Pacific system moving over the top of the ridge of high pressure and bring a strong cold front through our area around Monday night. The current timing will be fortuitous for what is expected to be a big travel weekend, as right now it is likely that most travel should be completed by the time the weather excitement begins.
So while we will be ten to fifteen degrees above average ahead of the cold front over the weekend, leading to record to near-record temperatures, we may be twenty to thirty degrees, or more, colder behind it. While it is not that unusual to see fifty degree temperature swings between the high and low of the day, especially in late summer, it is more unusual to see forty to fifty degree temperature swings between days, which we may approach if the storm evolves as current predicted. And I suspect that we may set some sort of two-day record for the largest temperature swings within a day and between consecutive days, though will have to leave that up to the climatologists to document, if such a record even exists.
It does appear, however, that while Labor Day will be dry and mostly sunny with increasing winds from the northwest, we may see the high temperatures dip a bit from the weekend ahead of the front. So we may not see a fifty-fifty degree intra-inter-day swing by Tuesday, but it may be of more of the forty-forty degree variety.
So according to the current forecast timing, we should wake up to quite the change Tuesday morning. At this point, I would guess we’ll see snowflakes in town, and accumulating snow on the mountain by Tuesday night. There is disagreement among the weather forecast models, as expected, with the European ECMWF more consistent in forecasting a wetter system further west than the Amercian GFS. In fact, the ECMWF cuts the storm off from the jet stream and forms an eddy over the Four Corners region (a so-called Four Corners low), and this may keep cool and unsettled weather around through the rest of the work week. The American GFS, on the other hand, ends the storm by midweek with warmer, but still below average, dry weather forecast for the rest of the work week.
My next regularly scheduled weather narrative on Sunday afternoon will be quite interesting, and I’ll certainly have more details on this upcoming mercurial weather event.
Weak cold front tonight followed by strong cold front Monday night
Sunday, August 30, 2020
Sunny skies are over the Steamboat Springs area this Sunday noon behind the showery day on Saturday, where areas within the city limits picked up between a third and a half inch of precipitation. Most of this occurred just before 5 pm as a line of storms moved through, accompanied by wind gusts of fifty miles per hour at the Bob Adams airport.
A weak cool front is forecast to move through tonight followed by a second strong cold front on Monday night, finally bringing some below average temperatures on Tuesday. But temperature rebound on Wednesday and stay warm through most of the weekend before another cold approaches around the end of weekend.
This afternoon, we should see breezy westerly winds ahead of the fairly dry and weak cool front tonight, with high temperatures once again above our average of 78 F.
High temperatures on Monday should cool a bit and be in the seventies behind the first front, but we’ll see another round of breezy westerly winds ahead of the second front for Monday night. This front is the real deal, and will be accompanied by some moisture, so expect a showery night with some snowflakes at the highest elevations.
Tuesday should have hints of fall, entirely appropriate for the first day of meteorological fall, with high temperatures five or so degrees below average. The cool-down will be brief though, as the still-strong sun will quickly modify the air mass and bring high temperatures on Wednesday back above average.
Parts of a storm currently riding over the top of a ridge of high pressure in the Gulf of Alaska will mix with some cold air currently over the Canadian Plains and may graze our area on Thursday morning. While the brunt of the cold air will be east of the Divide, we could see a chilly Thursday morning that would make it the coldest of the week, especially if we see clear skies.
But again, temperatures will quickly warm under mostly sunny skies, so expect the warm, above average highs to persist into the following weekend. There is some agreement among the longer-range weather forecast models that another Pacific storm will round the ridge of high pressure over the Gulf of Alaska and bring another cold front through our area around Sunday. Early indications are this front would be colder than the one coming this Monday night, but dry and windy, so stay tuned to my regularly scheduled weather narrative on Thursday afternoon where I’ll have more details.
Hot and showery weather ahead of our first cold front around Sunday night
Thursday, August 27, 2020
Temperatures in the mid-eighties and partly cloudy skies are over the Steamboat Springs area this Thursday mid-afternoon. We’ll see continued hot temperatures through the weekend, with afternoon and evening showers possible until the first cold front of the season passes through northern Colorado around Sunday night. And as if to highlight the coming of meteorological fall on Tuesday, the first of September, there may be some snowflakes at the highest elevations of Colorado around Sunday and Monday nights as we finally see temperatures drop to below average for a couple of days.
Currently, a ridge of high pressure over the central and southern Rockies is surrounded by rapidly weakening hurricane Laura to the southeast, storms to our north and a dry area of low pressure over northern California. Monsoonal moisture traveling northward along the western side of the Rockies ridge will remain over our area through the weekend, and portions of the storm to our north and then northern California will combine with the moisture for the chance of afternoon and evening storms. While most of the rain should be light and showery, there is the possibility of brief moderate to heavy downpours around the strongest cells.
A big pattern change comes to our area around Sunday night with the arrival of our first cold front of the season. A storm currently in the Gulf of Alaska is forecast to mix with some cold air from the North Pole and shift our winds to be from the current southwest to the west on Sunday and the northwest by Monday. There may be enough moisture around for some snowflakes at the highest elevations of Colorado, though it is not clear if that happens Sunday night and/or Monday night when a trailing wave passes through.
The most noticeable effect on our weather will be the much cooler temperatures on Monday and Tuesday, with lows in the thirties, below our average of 41 F, and highs falling from five to ten degrees above our average of 78 F before the first front to five to ten degrees below average after the front. Much drier air and breezy northwesterly winds will then invade our area as a stable ridge of high pressure builds over the Gulf of Alaska, keeping this pattern going through the work week.
And while daytime temperatures will warm back towards average starting around midweek, several waves of energy traveling along the eastern side of the ridge look to periodically mix cold air from northern Canada and keep cool morning temperatures in the thirties. After such a hot summer, next week should certainly have hints of fall.
The ridge of high pressure over the Gulf of Alaska is forecast to amplify by next weekend, which might enable Pacific energy traveling over the top of the ridge to again mix with cold Canadian air and bring another cold front through our area around the end of the following weekend or early the next work week.
I should have a better idea of whether we see any snow-dusted peaks early in the coming work week by my next regularly scheduled weather narrative on Sunday afternoon.
Moisture increases this week
Sunday, August 23, 2020
Another hot and hazy day is in store for Steamboat Springs this Sunday with the temperature already up to 84 F on this mostly sunny Sunday noon. Moisture from the southwest is forecast to increase over our area starting tomorrow and lasting for about a week. We need to make the best of what moisture will be available though, as it appears our first cool front, currently forecast for just before the first day of meteorological fall, September 1, will sweep any moisture over our area to the east.
A ridge of high pressure currently centered over the Four Corners will be suppressed to the south and nudged eastward over the upcoming week by a series of storms moving through the Gulf of Alaska and eventually the northern U.S. While the remnants of former-hurricane Genevieve look to skirt north of our area, the southwesterly flow on the western side of the ridge of high pressure will bring monsoonal moisture from the Mexican Plateau over our area. Unfortunately, it may also transport smoke from the Pine Gulch fire near Grand Junction and the Grizzly Creek fire near Glenwood Springs back to the region.
Though hurricane Marco, currently in the Gulf of Mexico and soon-to-be-hurricane Laura, currently over the Dominican Rebublic are forecast to threaten the Gulf Coast through the work week, our area will not be seeing any moisture from these tropical storms. We will have to rely on much more modest monsoonal moisture for the next week, and can expect at least some clouds that will help reduce our forecast high temperatures to around five degrees above our average high of 79 F.
The moisture will also insulate the surface during the night, so expect much warmer low temperatures around ten degrees or more above our average low of 42 F.
Chances for rain increase starting on Monday afternoon, though showers associated with the early part of a monsoon surge usually yield more wind than rain as it takes a day or two for the lower levels of the atmosphere to moisten. In any event, none of the work week days look to produce significant accumulations, though storms that develop could produce brief but locally moderate to heavy rain. Additionally, the moister atmosphere makes it more likely that we may see some rainfall overnight as well.
Our best chance for significant rain will likely wait until later next weekend as one of the Gulf of Alaska storm mixes with some cold air from the North Pole, bringing our first cool front since spring through our area around the beginning of the following work week. There is a lot of variability in the forecast strength and southern extent of this storm, with the American GFS bringing the storm across in several pieces while the European ECMWF has a more coherent storm that passes through earlier.
But both increase rain chances on Sunday before the passage of the cool front, and both eventually have much drier air behind the front as the westerly flow severs the monsoonal moisture tap, with longer-range models keeping the dry air around through at least the next work week.
So for the upcoming week, hope for rain and minimal smoke, and I’ll have more details about our first impending cool front of the season on my next regularly scheduled weather narrative on Thursday afternoon.
Significant rain likely about a week away
Thursday, August 20, 2020
Temperatures in Steamboat Springs are in the lower eighties early this Thursday afternoon, on their way towards ninety. As was the case yesterday, we may see a storm or two later today that would produce more wind than rain, but rain chances become almost nil with continued hot weather through the weekend. This continues into the next work week before good chances for moisture arrive starting midweek.
A ridge of high pressure currently stands firm over the western states, with light winds from the northwest bringing a modicum of moisture over our area today, similar to yesterday. But the lower atmosphere remains very dry, so while there may be some drops of rain, gusty winds and possibly dry lightning are the most likely outcome around any storms that form.
A continuing series of storms in the Gulf of Alaska is forecast to move the ridge of high pressure eastward and over the Rocky Mountains through the weekend. The resultant more westerly flow will eliminate whatever mid and upper-level moisture has been around these past two days, and keep high temperatures five to ten degrees above our average of 80 F. Fortunately, the insulating effects of the moisture at night will be lost with the dry air so expect nighttime lows to return to around our cool average of 43 F.
Our best hope for significant moisture since mid-July appears around the following midweek as current Hurricane Genevieve, located near the southern tip of the Baja peninsula, travels northward along the West Coast. The eventual remnants of this hurricane will merge with the southward-expanding storm complex over the Gulf of Alaska, and we will see our winds switch to be from the southwest early in the work week, bringing moisture-rich tropical and subtropical air over the Colorado mountains as early as Tuesday afternoon.
The interaction between the eventual former hurricane and the Gulf of Alaska storms will be complex, with current weather forecast models indicating that some of the hurricane will move ashore early in the work week while some will be left behind to be absorbed by another wave approaching the West Coast. Eventually, this second wave will move over our area by the end of the work week or the following weekend with even better chances of wetting rains than earlier in the week.
While the light westerly winds will keep the smoke from the Colorado wildfires away from our region, we may see some smokey haze from the California wildfires at times through the weekend. And while the winds turning to be from the southwest by Tuesday should bring desperately needed moisture to our area, it may also allow smoke from the Pine Gulch fire near Grand Junction to our southwest and the Grizzly Creek fire near Glenwood Springs to our south to once again infiltrate the Yampa Valley.
I’ll have a better idea by my next weather narrative, scheduled for Sunday afternoon, of the details surrounding this increase in moisture for the mountains of Colorado and the possible reintroduction of smoke to our area.
