3/2/2019 – Saturday/Sunday Snow Storm Rolling In!

Winter Weather Warnings/Advisories as of 8AM 3/2/2019

Weather warnings/advisories for the Palmer Divide and front range foothills as of 8AM 3/2/2019

The only changes to the advisories and warnings as of this morning is the inclusion of the Winter Weather Advisory for most of Eastern Colorado. We will be watching this closely, if the NWS believes there is a high probability of over 6 inches of snow accumulation over the Palmer Divide… we may see this upgraded to a warning.

You can see Douglas County/ Castle Rock specific weather warning details on our page here.


Our Forecast and What To Expect

Expected Snowfall (through Sunday evening)

*These are our forecast numbers and may not always match the NWS official forecast numbers*
  • Castle Rock and surrounding areas
    • 4-8 inches
  • Parker, Lone Tree, Highlands Ranch areas
    • 4-8 inches
  • Elbert, Elizabeth, Kiowa
    • 3-6 inches *locally higher amounts, especially in Western Elbert county*
  • Larkspur, Monument
    • 4-9 inches
  • Woodland Park, Palmer Lake, W. Colorado Springs Foothills
    • 5-10 inches *Woodland Park area may see over 10 inches in some areas*

 

WPC and our snow forecast amounts as of 3/2/2019 8AM

Timing

  • Fog and low clouds will prevail Saturday morning as the storm begins to set up. Light snow showers will be possible
  • By after 12PM snow intensity should start to fill in. Currently modeling has the heavier stuff starting around 12-2PM across the Palmer Divide
  • Heaviest snow looks to fall between 4PM and 12AM Sunday
  • Lingering snow showers possible into Sunday morning and early afternoon

Potential Impacts

  • Due to the cold temperatures expect roads to become slick quickly
  • Heavy snow in some areas will cause visibility and traction issues
  • Extremely cold temperatures into Sunday will keep roads icy

Models

The nice thing about this storm is that this morning we are seeing model agreement (to some degree but we won’t be too picky) for snowfall. Most models fit nicely into our ranges we had been thinking yesterday but with a slight uptick. That information combined with the fact that we are seeing a ton of moisture streaming in and the fact that extremely cold temperatures could boost snow/liquid ratios… we slightly upped our snowfall total forecast for some areas since yesterday.

  • GFS
    • 5.0 inches
  • Euro
    • 4.0 inches
  • Nam3K
    • 4.0 inches
  • HRRR
    • 5.8 inches

As of the writing of this post, more of the lower resolution models are coming in for the morning and are pretty much staying close to these predictions.


Summary

So, another interesting day on tap. I’d recommend you finish up your plans and start looking at heading home by mid afternoon. When the snow does move in this afternoon, some areas will see some fast and furious snowfall accumulation so be ready for that!

May have one or two more small updates today if things look to change, otherwise this storm is looking on track right now. Stay safe, stay warm and be prepared this afternoon!

 

3/1/2019 – Weekend Storm Update – Have’s and Have Nots

Current Weather Watches/Warnings/Advisories

NWS has issued Winter Storm Warnings and Winter Weather Advisories for this storm

Winter Weather Advisory

...WINTER WEATHER ADVISORY IN EFFECT FROM 9 AM SATURDAY TO 11 AM
MST SUNDAY...

* WHAT...Snow expected. Total snow accumulations of 4 to 7 inches
  expected.

* WHERE...Boulder and the western suburbs of Denver, Denver,
  Castle Rock and Greeley.

* WHEN...From 9 AM Saturday to 11 AM MST Sunday.

* ADDITIONAL DETAILS...Plan on slippery road conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving.

Winter Storm Warning

...WINTER STORM WARNING IN EFFECT FROM 9 AM SATURDAY TO 11 AM MST
SUNDAY...

* WHAT...Heavy snow expected. Total snow accumulations of 6 to 12
  inches expected.

* WHERE...The Southern Front Range Foothills.

* WHEN...From 9 AM Saturday to 11 AM MST Sunday.

* ADDITIONAL DETAILS...Plan on slippery road conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Storm Warning for snow means severe winter weather
conditions will make travel very hazardous or impossible. If you
must travel, keep an extra flashlight, food and water in your
vehicle in case of an emergency.

Please be aware, Castle Rock is not under the Winter Storm Warning. Only the western parts of Douglas County in the foothills.

Our Forecast (As of this post) and What To Expect

Expected Snowfall (through Sunday 12PM) *Preliminary, keep checking back for changes!*

*These are our forecast numbers and may not always match the NWS official forecast numbers*
  • Castle Rock and surrounding areas
    • 3-7 inches
  • Parker, Lone Tree, Highlands Ranch areas
    • 4-9 inches
  • Elbert, Elizabeth, Kiowa
    • 2-6 inches
  • Larkspur, Monument
    • 4-8 inches
  • Woodland Park, Palmer Lake, W. Colorado Springs Foothills
    • 5-10 inches

Timing

  • Light snow shower were already being reported in several areas as of after 12PM Friday
  • Snow shower activity will continue and be spotty in nature through Friday night into Saturday morning
  • Thunder and graupel/ convective snowfall is possible Friday afternoon/evening
  • Widely scattered snow showers into Saturday morning (most of heavier snow action remains North of Denver)
  • Snow intensity and coverage should pick up by the afternoon hours on Saturday for the Palmer Divide
  • Heavy snow in some areas will be possible Saturday evening into Saturday night
  • Lingering snow showers could continue through Sunday morning but should be light as the day goes on.

Potential Impacts

  • Likely travel impacts will be slick roads with some accumulating snow on road surfaces
  • Highest travel impacts look like Saturday evening/night and overnight into early Sunday
    • Stay tuned in case the storm position changes and thus the impact area

Summary

Another very complex and constantly evolving storm system, but that’s been the name of the game so far this year. I’m not super excited about higher snowfall totals out of this storm just yet… model data is not strong that areas South of Denver will do super well… but we shall see!

Here’s 2 of the WPC forecast for snowfall…

25th% or slightly less than expected snowfall prediction by WPC

50% or expected (most likely) amount of snowfall from WPC

The reason I show both graphics above is because my forecast falls somewhere in between these. I’m concerned the track of the storm and how long it ends up setting up along the front range. There are a lot of “timing” complexities that need to come together for higher end snowfall totals and given the data I’m seeing today it is slightly more likely the snowfall ends up on the lower end of the ranges for the Palmer Divide.

Still, we can’t rule out heavy snowfall banding and the potential the storm track shifts; meaning we very well could bust high on this one too… but only in very localized places. (Those darn heavy snow bands have a way of mucking up forecasts for some localities.)

Take my forecast above as a preliminary guideline; snow in some form will be likely and cold temperatures Saturday through Monday are a dead lock. Be prepared for slick driving conditions and remember to take warm clothes if you will be out and about!

Stay tuned, we will update the forecast as we get more data in!

2/28/2019 – Weekend Storm On the Way?

After somewhat quieter weather and even a warm day here and there, our pattern is about to shift again! So what does that mean for us in Castle Rock and along the Palmer Divide? Here’s what we are watching over the next 24-72 hours:

Temperatures

A large blob of arctic air is slated to move down from Canada into the Central United States this weekend and with it the weather pattern in our area will become more unsettled.

 

Models don’t have a ton of agreement on how far West this cold air makes it or how intense it gets for a lot of Colorado. We won’t mention specifics on temperatures just yet as we don’t have the details just yet; but plan on much colder temperatures starting on Saturday (thinking 30’s or 20’s for daytime highs) and lasting through at least Monday. I would imagine the colder air may arrive a bit later on Saturday so it’s possible that the first half of Saturday doesn’t start off to chilly, but gets rapidly cooler as the day goes into the afternoon an evening hours.

Snowfall Chances

With the arrival of the colder air we expect to see a shift in the weather pattern as well. With that will come the chance of snow showers along the front range again. I don’t know if I see a ton of snowfall for the Palmer Divide on Friday and earlier Saturday. I suspect (given modeling data right now) better chances of snow will set up later Saturday with the unsettled pattern remaining with more snow chances through the weekend into next week.

Here’s a snapshot of the Nam3K for Saturday 5PM… what do you notice?

Did somebody say snowbands?

As you can see from the above image, the dreaded snowfall bands make an appearance on this model. The other models support this feature developing as well, so that’s something to watch out for. As you know, this can make the snowfall forecast tricky for a lot of areas,

Does the above mean Douglas County and Denver get pounded with heavy snow? Absolutely not! I emphasize this in nearly every post because a lot of folks like to take these models as gospel. All models can  do accurately  istell us is that conditions are favorable for heavy snow bands… they CANNOT tell us where they will set up or how intense they will be. We just don’t have the technology for that yet!

What to Expect

Like many snow forecasts, this one is likely to change based on subsequent data and model runs. Be sure to keep on eye on your favorite local, reliable weather source for updates!

Timing

Expect snow to start sometime later in the day Saturday. Models show anywhere from after 12PM to after 6PM… stay tuned for a better timeline as we get more data in.

Snowfall

A bit early for exact amounts as models still don’t agree. GFS is showing a much more favorable storm track as compared to the Euro… the NAM is somewhere in the middle so we don’t have great agreement yet to be able to put together a more specific snow forecast. Expect to have better details on that probably later in the day Friday.

I will say this though, there is strong evidence of heavy snowfall banding across many of the models. If your area ends up under those, expect the POTENTIAL for decent snowfall amounts. So be ready for that!

Quick Summary

  • Colder this weekend, especially later in the day Saturday
  • Snowfall most likely later Saturday into Sunday morning (at this time)
  • Heavy snow bands look likely, this means be prepared for bursts of heavy snow in localized areas and possible travel impacts

 

Stay tuned, we will be tracking this storm system and will have more updates as we get more meaningful data!

 

Storm Snowfall Totals – February 23, 2019

Here’s a quick look at the snow totals from our latest storm! The storm system behaved pretty much as expected with many of the Palmer Divide locations ending up within or very close to our forecast range. Hope everyone had a safe night, was able to get off the roads before things got nasty and stayed warm!

Data from The National Operational Hydrologic
Remote Sensing Center

NWS Officially Reported Totals for Cities Along and Near the Palmer Divide

CountyLocationSnow Accumulation.Source
Arapahoe2 SW Centennial8.5public
Arapahoe3 E Cherry Creek Reserv8trained spotter
Arapahoe3 N Foxfield8public
Douglas1 NNW Lone Tree7.5cocorahs
Douglas2 SE Chatfield Reservoi7.2trained spotter
Douglas2 SSW Castle Rock4.6cocorahs
Douglas3 SW Ponderosa Park5.1cocorahs
Douglas2 E Parker4.6cocorahs
Douglas3 SSW Highlands Ranch7cocorahs
Arapahoe2 SSW Aurora8.5cocorahs
Arapahoe2 ESE Foxfield6.5cocorahs
Arapahoe1 SW Greenwood Village7.5cocorahs
Arapahoe2 WSW Buckley Afb8.5cocorahs
Arapahoe3 N Cherry Creek Reserv6.8cocorahs
Douglas3 S Castle Pines4.1trained spotter
Douglas3 NW Parker6.2trained spotter
Elbert1 NW Ponderosa Park5.5trained spotter
ArapahoeGreenwood Village7.8public
Douglas3 NNW Parker5.5public
Arapahoe4 S Bennett4.5trained spotter
Elbert9 NE Ponderosa Park5trained spotter
ArapahoeSoutheast Aurora5public
Arapahoe2 N Highlands Ranch7.5trained spotter
Arapahoe4 S Arapahoe Park8.2trained spotter
Arapahoe4 NNE Foxfield7.7public
Arapahoe4 ESE Foxfield5trained spotter
Arapahoe1 SE Littleton7.8trained spotter
Arapahoe2 SSW Arapahoe Park7public
Arapahoe3 SE Aurora8trained spotter
Arapahoe3 WSW Aurora7trained spotter

Overall a pretty good forecast for a very tricky storm! Look for clearing conditions on Saturday with a bunch of quieter weather days ahead for this week. Temperatures will warm up and hopefully we can get rid of some of the snowpack still hanging around on the higher elevations of the Palmer Divide.

Cheers everyone, have a great weekend!

 

Banded Snowfall will Make or Break this System

Winter Weather Watches/Warnings/Advisories (as of 12PM)

Front range and Palmer Divide now included in latest Winter Weather Advisory

Winter Weather Advisory (4PM Friday  – 8AM Saturday)

Cities/Areas Included

The Northern Front Range Foothills-
The Southern Front Range Foothills-Fort Collins-
Boulder and the western suburbs of Denver-Denver-Castle Rock-
Briggsdale-Greeley-Fort Morgan-Byers-
Including the cities of Estes Park, Glendevey, Nederland,
Red Feather Lakes, Bailey, Central City, Evergreen, Georgetown,
Idaho Springs, Westcreek, Fort Collins, Hereford, Loveland, Nunn,
Arvada, Boulder, Golden, Lakewood, Longmont, Aurora, Brighton,
City of Denver, Denver International Airport, Highlands Ranch,
Littleton, Parker, Castle Rock, Elbert, Fondis, Kiowa, Larkspur,
Briggsdale, Grover, Pawnee Buttes, Raymer, Stoneham, Eaton,
Fort Lupton, Greeley, Roggen, Brush, Fort Morgan, Goodrich,
Wiggins, Bennett, Byers, Deer Trail, and Leader

Hazards

Plan on slippery road conditions. The hazardous conditions could impact the evening commute.
A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving.

Winter Storm Watch (11PM Friday– 11PM Saturday)

Cities/Areas Included

Including the cities of Yuma, Wray, Burlington, Arapahoe,
Cheyenne Wells, St. Francis, Bird City, Atwood, Oberlin, Norton,
Goodland, Colby, Hoxie, Hill City, Sharon Springs, Oakley,
Quinter, Grinnell, Grainfield, Tribune, Leoti, Benkelman,
Culbertson, Trenton, Stratton Ne, Palisade, and McCook

Hazards

Heavy mixed precipitation possible. Total snow accumulations of 4 to 6 inches and ice accumulations
up to around a tenth of an inch will be possible. Winds could gust as
high as 55 mph.

You can visit the National Weather Service for more watch and warning information outside of the Palmer Divide region.

We also have a warnings page set up for Castle Rock here.


A Tough Forecast – Model Mayhem!

If you’ve been following this storm on TV or social media you’ve seen a ton of different forecasts for this storm. There’s a reason behind that: uncertainty. Depending on which streams of data and models you’re looking at you’ll see vastly different results of what is expected out of this storm.

Here’s a look at some of the major models:

The European model is not too impressed with this storm. This bears some weight as it is one of the more accurate models, but not as high of resolution and isn’t run as often.

The GFS has impressive snowfall amounts, but places a lot of that well East of Denver and the Palmer Divide

Nam3K has heavier snowfall over the Palmer Divide

HRRR shows similar results to the Nam3K. It shows banded snowfall with higher amounts across the Palmer Divide.

A few things to note here when reading these models:

  • The GFS and Euro are lower resolution and only run a few times per day, so they can lag behind other models in picking up trends
  • The Euro is one of the most accurate, for us to get a big storm and for that model to miss it within 24 hours would be rare… but it can happen
  • The Nam3K and HRRR are higher resolution models that are run several times a day so they can pick up on weather changes quicker

Discrepancy = Uncertainty

When models don’t agree, that means there is a lot of uncertainty. It means that you have to monitor things as the storm moves into the area and you can expect several changes (maybe even significant changes) to a forecast in the few hours before the storm. That will be the case here, this forecast most likely won’t be the final product we release about this storm. It may have several iterations, so stay tuned.

Below are the snowfall range probabilities from the NWS, this should give you an idea of how likely any range is in an area close to you:

For cities in Douglas, CO county
LocationSnow Amount PotentialChance of Seeing More Snow Than
Low End
Snowfall
Expected
Snowfall
High End
Snowfall
>=0.1″>=1″>=2″>=4″>=6″>=8″>=12″>=18″
Castle Rock, CO24797%92%82%49%19%5%0%0%
Deckers, CO12497%88%63%9%0%0%0%0%
Franktown, CO13696%91%80%47%18%4%0%0%
Highlands Ranch, CO23698%93%81%43%13%2%0%0%
Larkspur, CO13696%91%79%44%15%3%0%0%
Monument Hill, CO14796%91%81%52%21%5%0%0%
Parker, CO13797%92%82%51%23%7%0%0%
Roxborough Park, CO24798%94%86%55%25%8%0%0%
For cities in Elbert, CO county
LocationSnow Amount PotentialChance of Seeing More Snow Than
Low End
Snowfall
Expected
Snowfall
High End
Snowfall
>=0.1″>=1″>=2″>=4″>=6″>=8″>=12″>=18″
Agate, CO24799%97%91%61%30%11%0%0%
Elbert, CO24797%93%85%56%25%7%0%0%
Elizabeth, CO14695%89%79%45%14%2%0%0%
Kiowa, CO24796%92%83%56%27%9%0%0%
Kutch, CO13796%89%77%47%23%8%0%0%
Matheson, CO23899%97%90%60%32%13%1%0%

Our Forecast (As of this post) and What To Expect

Expected Snowfall (through Saturday 12PM)

*These are our forecast numbers and may not always match the NWS official forecast numbers*
  • Castle Rock and surrounding areas
    • 3-7 inches
  • Parker, Lone Tree, Highlands Ranch areas
    • 3-7 inches
  • Elbert, Elizabeth, Kiowa
    • 3-7 inches
  • Larkspur, Monument
    • 4-8 inches
  • Woodland Park, Palmer Lake, W. Colorado Springs Foothills
    • 4-9 inches

Timing

  • Expect snow to begin after 2-4PM on Friday
  • Heavier snow showers are most likely between 6PM Friday and 3AM on Saturday
  • Snow showers should diminish by mid-morning on Saturday
  • **Largest chance of a travel impact will be 6PM Friday – 3AM on Saturday**
  • Friday’s evening commute may be impacted

Potential Impacts

  • Likely travel impacts will be slick roads with some accumulating snow on road surfaces
  • Friday evening and Saturday morning travel may be impacted
    • Stay tuned in case the storm position changes and thus the impact area

Remember one Thing!

Storms with snow bands are incredibly difficult to forecast. If the snow bands sets up further North or South, many of us along the Palmer Divide could come away with little to nothing. Unfortunately models can’t tell us where or how intense these bands set up, they can only show us that they will be possible. Stay tuned, because as we get later into Friday I imagine this forecast will change more!

Final Word

I’ve seen a few comments online related to forecasts like this “we have no idea what’s going to happen” and “you’re just giving a large range to cover your ass when you’re wrong.” We do the best we can with the data we have and the knowledge we’ve gained, but it doesn’t mean every forecast will be right.

I’m not trying to cover my bases or anything of that sort. My role as a meteorologist is to communicate what is most likely to happen, what could potentially happen in a worse case scenario and make sure people are prepared for all scenarios. Additionally, I feel that if we make a forecast like this one it’s a disservice to say IT WILL SNOW 3-7 INCHES. Without any gauge of uncertainty, that doesn’t tell anyone a lot of useful information. It’s much more useful to say, “3-7 is the most likely range but considerable uncertainty remains in our data, so we could see more or less depending on how the storm sets up so be prepared for a larger snowfall/impact event just in case.” That’s the reality of weather in Colorado, it’s unpredictable but that’s what makes it oh so fun!

Cheers, stay warm and stay safe tonight!

 

Storm Setup Tricky over Next Few Days

Another set of weather disturbances is set to impact the state starting as early as Thursday afternoon and evening and it does appear that the front range will again see a slight impact from these storms., but it will become clear quickly which areas of Colorado will see the major impacts.

All winter weather warnings and advisories are confined to the mountains as of this afternoon.

Given what the models and forecasts are showing for this storm, I’m not highly confident the front range will see any major warnings with this storm. I could see an advisory issued for some areas that could see an icing concern (I’ll explain that below.) We’ll keep an eye on this to see if anything changes.


Thursday-Friday

There could be impacts from this storm along the Palmer Divide and Northeastern Colorado, but not necessarily from snowfall accumulation. Some of the latest model soundings a picking up on an interesting setup in the atmosphere with the arrival of the first wave of this storm…

Don’t get too wrapped up in the details about what a Skew-T is or does, just look at our explanation below

The above image is from a forecast sounding from the NAM3k model for tonight around 11PM-midnight. Keep in mind, some models say precip will have already been falling for a bit of time by the time this sounding is forecast. The key takeaway here is the setup of temperature/dewpoint with height and the presence of easterly winds for upslope.

Notice the warm air aloft (red line moving from left to right) above the surface, this is a layer of warm air over a temperature inversion. So depending on how shallow the moisture is with upslope we would see liquid precip (rain) from in this area and fall. It then falls through a cold layer at the surface, at first glance you’d be thinking snow though right? Not so fast, the saturated layer of cold air will make it difficult to completely freeze before it hits the ground, instead the rain may become supercooled (in a liquid state but temperature below freezing) as it falls. As we know, this stuff remains liquid until it contacts a surface and then instantly turns to ice. Fascinating stuff but may cause some very icy conditions in some areas.

As you can see above, any variation in how large that warm layer is can make a big difference in what precipitation type you see. Being at a higher altitude, sometimes the warm layer isn’t as well established along the Palmer Divide so we could see snow or sleet instead.

What to Expect

Expected Snowfall (through Friday 12PM)

*These are our forecast numbers and may not always match the NWS official forecast numbers*
  • Castle Rock and surrounding areas
    • 0-2 inches – be aware of ice accumulation!
  • , Parker, Lone Tree, Highlands Ranch areas
    • 0-2 inches – be aware of ice accumulation!
  • Elbert, Elizabeth, Kiowa
    • 0-2 inches – be aware of ice accumulation!
  • Larkspur, Monument
    • 0-2 inches – be aware of ice accumulation!
  • Woodland Park, Palmer Lake, W. Colorado Springs Foothills
    • 1-3 inches – be aware of ice accumulation!

Overall, not an impressive storm as far as snowfall is concerned.

Timing

  • Precipitation will begin Thursday evening
  • Some areas will start as rain, others as snow depending on elevation
  • Nearly all areas have the potential for freezing rain

 

Impacts

Be prepared for slippery road conditions for the morning commute where freezing rain falls.

Expect a light to moderate impact on driving conditions

Freezing rain means some roads will be covered in ice that could be nearly invisible. Plan on these tricky conditions for Friday. Freezing rain chances are higher as you go North of the Palmer Divide into Denver.


But Wait… There’s More!

Another wave will move in late Friday and into Saturday, this storm will similarly have a chance to bring light snow accumulations across the front range into Saturday morning.

We will have a post up regarding the next wave of this storm on Friday near mid-day!

 

Next Decent Chance for Snow Comes Early Next Week

By and far the winners of the snowfall lottery this past week have been the mountains of Colorado. A weather feature often called an “atmospheric river” or sometimes the “Pineapple Express” has set up the past several days over the Western U.S. This feature is known for bringing incredible amounts of moisture inland to California, Arizona, Nevada, the Pacific Northwest and Western Colorado.

Image courtesy of Weather.US

The good news is that our mountains in Colorado benefit considerably when this type of pattern establishes. Copious amounts of moisture combined with a strong jet stream produces strong upslope and lifting due to instability created by the jet overhead. We often see a similar effect over the front range with the jet overhead and upslope that has led to several of our banded snowfall events this year.

In the image above, darker yellows and lighter reds indicate a foot or more of snowfall while the darker reds and browns indicate over 2 feet of snowfall… in just the last 72 hours. This is awesome news because the areas seeing the most snow in the Southwest are also the areas in the worst level of drought right now.


Where’s Our Snow?

Unfortunately for the Palmer Divide, setups like this create strong westerly or southwesterly flow which benefits the mountains with tons of snow but leaves our air drier and warmer. In most cases, we tend to see a lot of classical downslope events in our area with these types of patterns.

If you need any more proof of that, just remind yourself of the wind we’ve seen the past few days and the warm temperatures. We’ve seen nearly 3 feet of snow at our place melt in just a couple of days!

The thing with the “Pineapple Express” setup is that it rarely is good for snow along the front range. The only times I’ve seen it work out for us is when it is further South and hooks up with a strong cold front and upper level disturbance coming out of the North… this is very rare.

Fear not though, because as we know… weather patterns are fluid and always changing. As the “atmospheric river” begins to break down and move East, it will open our storm track up just a little bit in the coming days.


Scoping the Next Storm

I did say that our storm track will shift a bit over the next few days and with it chances for snow along the front range. Sadly though, I don’t see any major storms in our future at this time. The pattern is shifting again back to Northwesterly flow aloft setup that we’ve seen most of the winter. This means we could see more quick hitting storms that move through and drop bits of snow here and there.

GFS anticipated snowfall accumulation through 5PM Tuesday

While there is the chance of on and off snow/rain showers over the weekend across the front range (and I suspect some areas will see light bits of precip here and there) the next decent chance comes around Sunday/Monday. The GFS pictured above is the model that’s most excited about this storm maxing out at 3.5 inches, but since we are so far out I caution to read all of those numbers with a huge grain of salt. We won’t get any specific details until we get closer to the storm and get in range of higher resolution models.

All we can determine from a model this far out is an overall “theme” and the theme we are seeing here is colder and unsettled to begin the week next week.

For what it’s worth the EURO is not terribly excited about this storm either.

There’s on interesting pattern I can see in both models above… can you spot it?

The dry slots along the front range and Palmer Divide scream DOWNSLOPE! Now each models has its differences on where and when that sets up but we can’t ignore it… downsloping conditions will  be efficient at eroding snowfall and may shift where the snow falls/accumulates based on the surface winds.

Again… too early for much more details than that. But if you want to follow along forecast this one with us, I’d recommend to keep an eye on the models over the next few days and especially how it develops winds at the surface over the next few days.


The Takeaway

Not much more details on our next storm than what we presented above. Just keep in mind to plan for the POTENTIAL for a storm early next week and right now it doesn’t look too major. As we know that can change quickly so we will be watching over the next few days to see how it evolves and will pass along any updates as needed.

Cheers!

 

Afternoon Storm Update for 2/6-2/7, 2019 Storm

The picture on this storm is becoming a bit clearer as we get more data in. This will be another tricky forecast (I’ll discuss why a bit further down the page) but basically most areas along the front range won’t see a whole ton of snow out of this. Some very specific areas will have the chance to bust high on the snowfall forecast again, that combined with quick bursts of snow and some wind means travel conditions will likely be tricky for the commute Wednesday night.

Here’s the latest updates as of 1PM today:

NWS Weather Alerts (Updated as of 1PM 2/5/2019)

Winter Storm Warnings for the mountains are up for hazardous travel conditions due to heavy snow, strong winds and snow accumulation. For the front range of Colorado, a Winter Weather Advisory is in effect for primarily travel difficulties.

Winter Weather Advisory (12PM Wednesday– 5AM Thursday)

Cities/Areas Included

Including the cities of Estes Park, Glendevey, Nederland,
Red Feather Lakes, Bailey, Central City, Evergreen, Georgetown,
Idaho Springs, Westcreek, Fort Collins, Hereford, Loveland, Nunn,
Arvada, Boulder, Golden, Lakewood, Longmont, Aurora, Brighton,
City of Denver, Denver International Airport, Highlands Ranch,
Littleton, Parker, Castle Rock, Elbert, Fondis, Kiowa, Larkspur,
Briggsdale, Grover, Pawnee Buttes, Raymer, Stoneham, Eaton,
Fort Lupton, Greeley, Roggen, Brush, Fort Morgan, Goodrich,
Wiggins, Bennett, Byers,

Hazards

Plan on slippery road conditions. The hazardous conditions will impact the evening commute. The cold
wind chills as low as 25 below zero could cause frostbite on  exposed skin in as little as 30 minutes.
A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving.

Expected Snowfall (through Wednesday 5AM)

*These are our forecast numbers and may not always match the NWS official forecast numbers*
  • Castle Rock and surrounding areas
    • 1-4 inches
  • Parker, Lone Tree, Highlands Ranch areas
    • 2-5 inches
  • Elbert, Elizabeth, Kiowa
    • 1-4 inches
  • Larkspur, Monument
    • 1-4 inches
  • Woodland Park, Palmer Lake, W. Colorado Springs Foothills
    • 1-4 inches

Timing

  • Snowfall may spread onto the front range late Wednesday morning
  • Heavier snow showers are most likely between 12PM and 6PM on Wednesday
  • Snow showers should diminish and be out of the area by 9PM or so
  • **Largest chance of a travel impact will be 12PM-8PM on Wednesday**

WPC most likely snowfall for this storm, it’s pretty in line with our forecast.

Impacts

  • Likely travel impacts will be slick roads with some accumulating snow on road surfaces
  • Wednesday evening looking likely to be impacted
  • Models as of this afternoon still favor areas around and North of Denver for more of an impact with less of an impact along the Palmer Divide.
    • Stay tuned in case the storm position changes and thus the impact area

Storm Synopsis

The turd in the punch bowl (excuse the expression) for this storm is thrown in when we look at the snowfall models coming out this afternoon.

Remember these…?

They’re back! Given the storm setup aloft and the fact that we can see banded snowfall on the models means some areas will not fall within their forecast snow range.

We can see pretty clearly on some of the higher resolution models that there will be bands of heavier snowfall along with this storm. Given the strong flow aloft out of the West and Northwest, this is something I’d expect even if the models didn’t pick up on it.

Here’s the big thing to remember about snowfall bands:

  • We can’t forecast where they set up exactly
  • We can’t forecast exactly when they set up (only a range)
  • We can’t forecast how intense they get
  • We can’t forecast how long they stick around

All we can tell you based on this information is that some areas will see higher snowfall amounts than what is forecast.

Banded snowfall setup; ours will be similar with this storm but snow bands will be more oriented SW to NE. (Credit: http://www.skyviewweather.com)

For what it’s worth models tend to be keeping the heavier snowfall bands in and around Denver and points to the North. That doesn’t necessarily mean a thing, just figured I’d point it out!

Summary

All in all, this storm will be like the past couple we’ve seen. With the jet overhead to enhance lift in very specific areas and moisture and up slope establishing with a cold front moving in; I’d expect this storm will be mainly just a headache for most folks.

Those that do get lucky enough to stick under those snow bands for awhile will graduate this storm beyond a headache to a pain in the rear.

We’ll be keeping an eye on this storm as we get more data into the evening. Probably expect at least one more post or two up late tonight and perhaps tomorrow morning if things start to change.

Stay tuned!

Batter Up! Next Storm System Rolls Into the Region on Wednesday!

After a period of quiet and somewhat tranquil weather, there is evidence our weather pattern may be shifting back to an unsettled period for a bit again heading towards the middle of the month. A new storm system pounding the state of California will begin to move towards Colorado.

The storm will hit the mountains with a ton of moisture and energy but the brunt of that will stay in the higher elevations. That being said, there is the potential for quick bursts of moderate to heavy snow that could cause some travel headaches primarily on Wednesday afternoon into the early evening hours. Here’s the preliminary information on this storm…

NWS Weather Alerts

Winter Storm Watches are in effect for the mountains. No weather advisories/warnings for the front range as of this evening.


Expected Snowfall (through Wednesday 11PM)

*These are our forecast numbers and may not always match the NWS official forecast numbers*
  • Castle Rock and surrounding areas
    • 1-3 inches
  • Parker, Lone Tree, Highlands Ranch areas
    • 1-4 inches
  • Elbert, Elizabeth, Kiowa
    • 0-3 inches
  • Larkspur, Monument
    • 0-3 inches
  • Woodland Park, Palmer Lake, W. Colorado Springs Foothills
    • 0-3 inches

WPC most likely snowfall for this storm, it’s pretty in line with our forecast.

Timing

  • Snowfall may spread onto the front range late Wednesday morning
  • Heavier snow showers are most likely between 12PM and 6PM on Wednesday
  • Snow showers should diminish and be out of the area by 9PM or so
  • **Largest chance of a travel impact will be 12PM-6PM on Wednesday**

 

Impacts

  • Likely travel impacts will be slick roads with some accumulating snow on road surfaces
  • Wednesday evening commute may be impacted
  • Models as of this evening are favoring the areas around and North of Denver for more of an impact with less of an impact along the Palmer Divide.
    • Stay tuned in case the storm position changes and thus the impact area

Not seeing any hints of a major storm, but we know how that has been this year. One thing we will have to keep an eye on is strong flow aloft, which means snowfall banding could be possible. If you end up under these snow bands the potential for the forecast to bust high will be increased.

Models are hinting at snowfall banding potential with this storm, but like I’ve said… they can show us the potential but not exactly when or where they will set up.

We will be keeping an eye on this storm as we get more data in on Tuesday along with the higher resolution and short range data coming in. Stay tuned!

Blizzard Warning Issued for Palmer Divide and NE Colorado

Huge post with a lot of important information, please take this storm seriously and begin your preparations today!

NWS Weather Alerts

Castle Rock Weather | Palmer Divide Weather | Blizzard Warning | Snow Storm | Winter Weather Advisory

Latest weather alerts as of 12PM on Monday January 21, 2019

Blizzard Warning (8PM Monday – 11AM Tuesday)

Cities/Areas Included

Castle Rock-Fort Morgan-Byers-Limon-Akron-
Including the cities of Castle Rock, Elbert, Fondis, Kiowa,
Larkspur, Brush, Fort Morgan, Goodrich, Wiggins, Bennett, Byers,
Deer Trail, Leader, Agate, Hugo, Limon, Matheson, Akron, Cope,
Last Chance, and Otis

Hazards

Travel will be very difficult. Blowing
  snow could significantly reduce visibility. The hazardous
  conditions could impact the morning commute. Gusty winds could
  bring down tree branches.

Winter Weather Advisory (8PM Monday – 9AM Tuesday)

Cities/Areas Included

Arvada, Boulder, Golden, Lakewood,
Longmont, Aurora, Brighton, City of Denver,
Denver International Airport, Highlands Ranch, Littleton, Parker,
Eaton, Fort Lupton, Greeley, and Roggen

Hazards

Plan on slippery road conditions. Blowing
  snow could significantly reduce visibility, especially east of
  Interstate 25. The hazardous conditions could impact the morning
  commute.

Expected Snowfall (through Tuesday 12PM)

*These are our forecast numbers and may not always match the NWS official forecast numbers*
  • Castle Rock and surrounding areas
    • 3-7 inches, locally heavier amounts
  • , Parker, Lone Tree, Highlands Ranch areas
    • 2-5 inches
  • Elbert, Elizabeth, Kiowa
    • 4-10 inches
  • Larkspur, Monument
    • 4-10 inches, locally heavier amounts
  • Woodland Park, Palmer Lake, W. Colorado Springs Foothills
    • 4-10 inches

Timing

  • Snowfall looks most likely after 8PM on Monday
  • Heavier snow looks most likely from late Monday night through mid Tuesday morning
  • Models have the storm exiting the area by 12PM Tuesday

 

Impacts

Blizzard conditions are looking more likely across the Palmer Divide and Northeastern Colorado. Strong winds approaching 50mph will cause blowing and drifting snow as well as whiteout conditions. Travel will be dangerous.

Road closures will be possible

Expected worst impacts: Monday Night – Tuesday Morning

Most concerned about Palmer Divide areas East of Castle Rock and Northeastern Colorado.

If you must travel, please have a winter survival kit… I’ll post it again for reference.

Castle Rock Weather | Palmer Divide Weather | Winter Weather Preparedness | Winter Survival Kit

By the way, it’s always a great idea to have these items in your car when you need to be out driving in snow. As we know in Colorado a minor storm can turn into a major one very quickly, so be prepared!

Please stay aware of the forecast, significant uncertainty still exists on whether this will be a high or low impact event. We are urging folks to be prepared in case it does pan out to be a high impact event.


Storm Synopsis

Nam3k forecast storm track and precip type

There is still a lot of model disagreement between the North American models and the Euro. The NA models still show a storm track further north and at a quicker pace, this is why NWS has waited so long to see what this storm actually does. It’s easy to count this storm out with so many models calling it a bust for the front range of Colorado, but the problem is the Euro still takes the storm track South and slows it down a bit.

The Euro has been by and far, much more accurate than our own U.S. based models for several years now. While it still has the ocassional curve ball it misses (the last surprise storm) it doesn’t happen very often.

With all the uncertainty, we were waiting to see what track the storm started taking and something interesting started to happen as it was tracked on water vapor imagery…

The image above shows the approximate location of the low pressure center… the thing is it is a bit further South than many of the North American models were predicting. This southerly bias is what caused NWS to pull the trigger and issue warnings today. Now, could the storm still fall apart? Absolutely, but given we’d want a more southern track for a higher impact event and that’s exactly what we are seeing (so far) it seems like a good idea to at least get people prepared.

The next steps are to continue to watch this storm, if it wobbles any further North as it crosses Utah and the Colorado mountains we’d expect to see lesser impacts from this storm for Colorado’s front range. If it stays on track and biases more Southerly, we will be in business!

By the way, main part of a Blizzard warning is not how much snow we get, but the combination of snow (really any amount that can cause travel issues) and strong winds.

700mb winds for Tuesday morning

700mb winds will either be at surface or a bit above depending on your elevation but models have them absolutely screaming early Tuesday morning into about mid morning. Those red areas are up to 50mph so be aware blowing and drifting snow will be very likely with this storm.

That’s it for now, will be keeping an eye on it all day Monday, into Monday night and Tuesday morning. We will be sure to pass along any additional updates.