Thursday, September 10, 2020
Partly sunny skies and a temperature of fifty degrees are observed in the Steamboat Springs area early this Thursday afternoon. The storm that produced the winter-like weather and strong winds on Tuesday should finally pass over our area through tonight, leaving sunny skies and warming temperatures in time for the weekend. The seasonable weather then turns hot and dry for the following work week.
That was quite the windstorm on Tuesday, with many trees down in the neighborhoods around the base of the mountain and at least one flattened stop sign in the Eagleridge area. A 56 mph gust was observed at the Bob Adams airport Tuesday morning, and the NWS public summary indicated sustained winds of 48 mph at the top of Mt Werner and 54 mph winds somewhere in Steamboat Springs.
Similar to the Routt County Blowdown in October of 1997, I’m guessing that strong easterly winds formed a mountain wave over the Continental Divide, which then broke on the lee side of the Park Mountain Range, similar to an ocean wave breaking on a beach. This created very strong and localized gusts of winds that seemed to occur in a hopscotched pattern around the neighborhood.
Additionally, the storm brought snow to the higher elevations, with about 4” at the remote SNOTEL measuring site on Buffalo Pass north of town. Rabbit Ears Pass was closed for a time Tuesday morning due to blowing snow and dangerous conditions, though the Rabbit Ears SNOTEL showed no accumulations, likely since the wind blew the snow off the measuring pad. And we did see snowflakes in town, though accumulations were confined to elevations just above the Yampa Valley floor.
The storm that brought these conditions to our area is currently located over northwest Colorado, and is forecast to pass overhead tonight and vacate our area by Friday afternoon. But we will see two chances for precipitation, first later this afternoon and this evening in the southwest flow ahead of the storm and then again Friday morning in the favorable moist and unstable northwest flow behind the storm, with some snow likely at the higher elevations.
There may be enough sun by Friday afternoon to push our temperatures into the sixties, which is about ten degrees below our down-trending average of 74 F, with nighttime temperatures around freezing tonight, which is about five degrees below our average of 37 F.
A ridge of high pressure is then forecast to build over the west for the weekend and the following work week, bringing dry air, sunny skies and warming temperatures, with high temperatures moving from the low seventies on Saturday to upper seventies on Sunday to around the low eighties for the work week.
Longer range weather forecast models agree that a storm loitering well off the coast of California will merge with a wave of Pacific energy and moisture traveling though the Gulf of Alaska and form a stronger storm that may affect our area around the following weekend, though they disagree on the timing and strength. Stay tuned to my next regularly scheduled weather narrative on Sunday afternoon for more details on that possibility, and be sure to enjoy the return of our summery weather.
Sunday, September 6, 2020
The headline is not hyperbole! After several days of well-above average temperatures in Steamboat Springs, including a 90 F reading at the Bob Adams airport this past Saturday, we will be going to bed after a summery Monday and waking up to a snowy Tuesday!
The temperature in Steamboat Springs is currently 78 F on this Sunday noon, on its way into the mid-eighties, which is around ten degrees above our average high of 75 F. More warm, but increasingly windy, weather is expected for tomorrow before an unseasonably strong and winter-like cold front blasts through Colorado Monday night.
We should see snowflakes in town with accumulations of an inch or two on grassy surfaces and foliage by Tuesday night possible, so be sure to shake your trees to prevent limb damage. Temperatures during the day Tuesday should be around forty degrees below Monday, with a hard freeze almost certain by Wednesday morning. Unsettled weather and below-average temperatures look to stick around through Thursday before we dry out and temperatures return to more reasonable levels heading into next weekend.
Currently, a Pacific storm that has traveled over the top of a ridge of high pressure in the Gulf of Alaska is mixing with some cold air originally sourced from the North Pole, and will bring a strong cold front through the northern Rocky Mountain states on Labor Day. The cold front will leave most of Monday unaffected for our area, except for strong pre-frontal winds from the west. So fire danger will remain elevated through the day before the front is expected to blast through overnight. Luckily, the bulk of the long Labor Day weekend travel should be completed before the wintry weather arrives.
But travel will likely become difficult over the mountain passes on Tuesday as wet heavy snow should overcome the warm road surfaces and create areas of slush and limited visibility at the higher elevations, and maybe even briefly at lower elevations. And as bad as it will be west of the Continental Divide, more significantly snow east of the Divide and unprepared drivers will likely make the roads down to and possibly within the Front Range treacherous, including the I-70 corridor.
So after high temperatures in the forties during the day Tuesday, Tuesday night will be bone-chilling cold, with the current forecast for our zone from the Grand Junction weather office indicating lows in the 5 to 15 F range! That sounds a bit aggressive to me, but be prepared for a hard freeze Wednesday morning with low temperatures in the teens.
The weather forecast models have struggled with the placement and speed of this storm over the last week, with the latest nod going to the European ECMWF as it looks like the storm will cut off from the main jet stream and form an eddy over the Four Corners region, as suggested by some earlier and more recent iterations of that model.
This eddy, or so-called Four Corners low, is forecast to slowly move northeastward through Thursday, keeping cool and unsettled weather over our area for another couple of days. While precipitation is expected to mostly subside by Wednesday, we may see another round of precipitation wrap around the northern side of the storm for Thursday. And while this will likely be rain at the lower elevations, higher elevations may continue to accumulate snow. Combined with the cold temperatures, all persons recreating or hunting in the higher elevations need to be prepared for winter-like weather from Tuesday through Thursday.
The sun is still high in the sky, so it will do a good job of modifying the air mass starting Wednesday, even in the presence of clouds. Obviously, more clouds mean cooler temperatures, so the longer the storm lingers the cooler it will be, but right now I would expect high temperatures in the fifties on Wednesday, sixties by Thursday and seventies by Friday.
The sun should return for the weekend, perhaps as soon as Friday, as temperatures return to normal to above normal. Still warmer and dry weather is currently advertised for the following work week. I’ll have a synopsis of at least the first part of this impressive winter-like storm for my next regularly scheduled weather narrative on Thursday afternoon.
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.