Severe Weather Season is Around the Corner! Time to start Preparing!

As many of you know (or not but now you will) Mountain Wave Weather is an officially designated NOAA Weather Ready Nation Ambassador. What does that mean exactly? It means we work with local businesses, residences and everyone in between to be prepared for severe weather.

The goal of the WRN Ambassador initiative is to foster innovative, stronger collaborations across government, non-profits, academia, and private industry to help make the nation more ready, responsive, and resilient against extreme environmental hazards.

Now that you know, stay tuned for some very interesting articles thorughout the month of April on Colorado’s severe weather, how to be prepared and what to watch for!


April 3, 2019

Safe place selfie at 11:11AM!

Do you know where your safe place is for severe weather? (Hint: it may be different depending on the threat!)

If there was one extreme weather preparedness action you want your loved ones to take, what would it be? For many, that one action is to know ahead of time where their safe place is located. On April 3rd, 2019, at 11:11am local time, please join the National Weather Service and its Weather-Ready Nation Ambassadors to take a “selfie” and post with the hashtag #SafePlaceSelfie.

Here are some helpful suggestions:

  • Think about the hazards in your area where you would need to know where safe places or evacuation routes are located.
  • Get creative! Storm shelters, safe rooms, and basements are all good safe places from tornadoes and strong winds, but think of other scenarios or hazards that may require other safe places.
  • What other preparedness actions make your safe place even safer? Having a NOAA Weather Radio? Emergency Kit? Family Communications Plan?
  • Encourage family, friends, and your social media network to post their #SafePlaceSelfie. Tag someone on your post and ask them, “Where is your safe place from extreme weather?”

I’ll have more information about this up tomorrow here on Mountain Wave Weather with some suggestions based on specific severe weather threats we see here in Colorado. Stay tuned!


Lightning Safety – It’s Thunderstorm Season!

 

We see the most lightning fatalities with outdoor activities and sports.

Did you know Colorado reports on average some of the highest numbers of lightning fatalities in the U.S.A.? We can probably chalk that up to our tendency to be outdoors a lot during the summer, but it also comes down to surprise thunderstorms in the mountains that can often find people in exposed, high altitude terrain with little options for shelter.

Speaking of which, should you be caught in the hills or mountains and a thunderstorm approaches, here’s some handy tips.

If you find yourself above treeline in a thunderstorm, you’re already in a bad situation… but these tips can help a bit.

Face it, if you’re in a highly exposed area with no time to get to shelter, you’ve already found yourself in a bad situation. It’s best to pay attention to the weather and make plans to take shelter as soon as you hear thunder.

Easy to remember this; when thunder roars, go indoors! If you can hear it… you are close enough to the storm to be hit by lightning!

Stay tuned for more severe weather discussion and preparedness tips in the coming days and weeks!

 

3/22/2019 – Fri Evening/Sat Morning Storm Update

Severe Weather Possible for SE Colorado

SPC Day 1 Severe Wx Outlook

Today will feature a large variety of weather across Colorado. The first thing that came out this morning is the Storm Prediction Center outlook and has far Southeastern Colorado under a marginal risk for severe weather. This means that a few storms may become strong or severe but we aren’t expecting a widespread severe weather event.

SPC severe hail probabilities

SPC severe wind probabilities

The main threats with a lot of these storms that become strong or severe will be large hail and damaging winds. Hail will be possible with stronger storms along the Palmer Divide but it is not expected to reach severe levels for many areas. The lower atmosphere is simply not going to get warm enough to support large amounts of severe storms. The instability will establish and that will help storms develop with heavy rain and potentially areas of heavy snow.


Palmer Divide Snow

Honestly, this will be a tricky forecast folks. I have a good feeling the models don’t have a decent handle on temperatures and thusly who sees snow and how much of it sticks. I’ll start out by saying from a snow accumulation standpoint this storm looks nothing like the last, temperatures will be too warm for many areas to see decent snow accumulation…even along the higher elevations is questionable.

Here’s a quick timeline of what to expect:

Timeline

  • Thunderstorms possible after 12-2PM, initially precipitation will be rain. Small hail will be possible with stronger storms
  • Expect rain to transition to snow in the evening/overnight hours. Roads will be warm so not expecting a major impact to the evening commute but conditions will be wet
  • Overnight all snow will fall mainly along the Palmer Divide and especially East into Elbert County. Again, with warm temperatures there is a lot of mixed data on how much snow actually accumulates.
  • Storm looks to begin moving out in the early morning hours of Saturday. Expect clearing on Saturday morning.

Nam3k Model Snapshots:

Nam3k Precip Type Snapshot at 6PM

Nam3k Precip Type Snapshot at 8PM

Nam3k Precip Type Snapshot at 10PM

 

Snowfall

**Biggest chance for snow accumulation over-performance is in the higher elevations of Elbert and El Paso County

 


Tornadoes?

A lot of folks have heard from someone (no idea who…) that there is a potential for tornadoes along the front range of Colorado tomorrow. Not sure who is saying that but they may need to go back to school… the atmosphere just wont’ be supportive for such things. Here’s the SPC tornado probability…

SPC tornado probabilities

If I were a storm chaser I honestly wouldn’t be chasing anywhere near Colorado today… even that 2% probability in Texas is marginal at best.

0-1KM Bulk Wind Shear

 

0-6KM Bulk Wind Shear

Both images above are from around 9PM, but the entire afternoon and evening look similar to everything above. The low level wind shear (0-1KM) is what you look for in tornadoes and there really isn’t much going on near the front range and along the Palmer Divide. You’ll notice the best shear is out to the East of Colorado and South into Texas. Texas seems to see the best chance of severe weather today, Colorado’s is marginal at best… definitely a day I wouldn’t storm chase. There are a ton of other factors to look at when forecasting severe weather, if there’s any interest I may do an article or video on it!

So all in all, a tricky forecast. If temperatures trend colder we will see more snow accumulation, if they trend warmer we will see less snow accumulation. I’ll try to do some quick posts on Facebook to let everyone know if I’m seeing anything interesting going in either direction so keep an eye out for that!

Euro ensembles estimated snowfall through 6PM Saturday.

If the Euro’s not excited about a storm… I’m usually not either. The wild card here is the instability in the atmosphere (can produce strong bands of convective snow) and the temperatures. Models don’t always pick up on that too well… even the super accurate Euro. Should be fun to watch!

Hope everyone stays warm and dry tonight, looks like a wet and sloppy spring storm, but the good news is nowhere near as bad as the blizzard last week!

 

Spring is Here! All Aboard for the Weather Roller Coaster!

It’s been a quiet week here at Mountain Wave Weather, mainly because I needed a bit of a break after the blizzard and because the weather itself has been pretty quiet.  Not only that, a large part of the week has been spent fighting off the pop up social media “meteorologists” picking up on every single model blip and forecasting the next “monster snowstorm.”

For the record, there is no scientific proof or data that we will see another massive snowstorm in the next 7-10 days let alone the season. If that changes we will let you know but right now anyone predicting such a storm is being irresponsible and inaccurate, so keep that in mind!


Unsettled Weather Expected over Next Week or So

Let’s get back to the fun stuff, just because there’s no “monster snowstorm” in our forecast doesn’t mean we don’t have a decent chance at wet weather for the next week or so.

Next Storm System – Friday Night/ Saturday Morning

Models have been picking up on this for a few days now, you probably haven’t heard a ton about it because it doesn’t look all that impressive. That being said, we will keep an eye on it because this time of year temperatures can play a big part of what we see out of any storm (in terms of snowfall) and this time of year models struggle with forecasting the temperature/precipitation type link very well.

Nam3K Surface Map around 6PM Friday

The front end of the storm has pretty decent warm and instability so wouldn’t be surprised if we get the first organized thunderstorms of the year. The low isn’t especially well organized though and the track is not the same as our last storm so we don’t expect major impacts with this one as of right now.

Nam3K around midnight Saturday morning

As the low moves through and cold air swings aroudn the back side of the storm system, we will see some decent upslope.  A setup like this favors the Palmer Divide pretty well in terms of upslope, the big question will be how cold does it get and with that how much snow actually sticks and accumulates?

Fore brevity’s sake I won’t post images of every model but here’s a quick run down of what they’re thinking as of today:

Euro – 3-5 inches, targets Palmer Divide from Castle Rock to Elizabeth (central Douglas County to central Elbert County)

Nam3K – 1-4 inches, targets primarily Palmer Divide locations East of Castle Rock

GFS – 0-3 inches, mainly South of Castle Rock and East of Castle Rock

So as you can see, there’s not great agreement on any of these. The more accurate Euro model is predicing higher snowfall amounts especially for the Palmer Divide, so we will see if it is picking up on something the others aren’t.

Weather Into Next Week

Here’s a few things that jump out at me or warrant keeping an eye on as we go into next week. Keep in mind, the further out we go into time the more likely the forecast can change…

500mb Friday/Saturday storm

You’ll notice the setup looks similar to our “blizzard” storm that we had this week in terms of where this low sets up in Colorado. The big difference is that it is nowhere near as organized and doesn’t undergo any rapid intensification. Bomb Cyclone 2.0 this storm is not!

500mb noon on Tuesday

The week sees Colorado largely among “zonal” East/West flow. This generally means mountains continue to see snow as long as storms keep riding that track. For us East of the divide, this usually means we don’t have a good shot at any significant precipitation events. We do tend to see precipitation sneak over the divide on occasion with these setups but nothing large scale. I’d expect a decently nice week with a few shots of light precipitation here and there… wouldn’t be surprised to see some of the warmer days we’ve had in awhile in the middle of the week.

GFS 500mb next Friday March 29 timeframe

This is one that caught my interest a bit… a pretty strong low pressure system sets up over the plains late next week. This one I’ll be watching throughout the week next week, remember the GFS is horrible on accuracy this far out so while this looks intriguing it’s nothing to fret about at this point in time. Remember, a million little things have to go right for us to see another storm like last week and no model is going to get those details 7+ days out.

Wrapping it Up

Looks like a typical spring week in Colorado; decent chances to see thunderstorms, snow here and there and temperatures ranging in the daytime from the 40’s to possibly the 70’s. Buckle up folks, it’s springtime and it’s always a fun ride in Colorado!

 

Blizzard Warnings Hoisted for Strong Storm – Updates 3/11/2019

Watches/Warnings/Advisories for the Palmer Divide

A pretty significant storm is shaping up along the front range and Northeastern Colorado. A high impact “spring blizzard” type storm will move into the area Wednesday and bring with it heavy snow, strong winds and dangerous travel conditions. Here’s the latest:

Current watches/warnings/advisories for the Palmer Divide region as of 5PM 3/11/2019

Blizzard Warning

...BLIZZARD WARNING IN EFFECT FROM NOON WEDNESDAY TO 6 AM MDT
THURSDAY...

Including the cities of Castle Rock, Elbert, Fondis, Kiowa, Larkspur, Briggsdale, Grover, 
Pawnee Buttes, Raymer, Stoneham, Brush, Fort Morgan, Goodrich, Wiggins, Bennett, Byers, 
Deer Trail, Leader, Agate, Hugo, Limon, Matheson, Crook, Merino, Sterling, Peetz, Akron, 
Cope, Last Chance, Otis, Julesburg, Ovid, Sedgwick, Amherst, Haxtun, and Holyoke

* WHAT...Blizzard conditions expected. Total snow accumulations
  of 6 to 12 inches expected. Winds gusting as high as 65 mph.

* WHERE...Portions of east central and northeast Colorado.

* WHEN...From noon Wednesday to 6 AM MDT Thursday.

* ADDITIONAL DETAILS...Travel could be very difficult or
  impossible. Avoid travel Wednesday afternoon and Wednesday
  night. Widespread blowing snow will significantly reduce
  visibility. Very strong winds could cause extensive tree damage
  and result in scattered to widespread power outages.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Blizzard Warning means severe winter weather conditions are
expected or occurring. Falling and blowing snow with strong winds
and poor visibilities are likely. This will lead to whiteout
conditions, making travel extremely dangerous. Do not travel. If
you must travel, have a winter survival kit with you. If you get
stranded, stay with your vehicle.

Winter Storm Watch

...WINTER STORM WATCH IN EFFECT FROM WEDNESDAY AFTERNOON THROUGH
WEDNESDAY EVENING...

The Southern Front Range Foothills-
Boulder and the western suburbs of Denver-
Including the cities of Bailey, Central City, Evergreen,
Georgetown, Idaho Springs, Westcreek, Arvada, Boulder, Golden,
Lakewood, and Longmont

* WHAT...Heavy snow possible. Total snow accumulations of 4 to 8
  inches possible. Winds could gust as high as 45 mph.

* WHERE...The Southern Front Range Foothills and Boulder and the
  western suburbs of Denver.

* WHEN...From Wednesday afternoon through Wednesday evening.

* ADDITIONAL DETAILS...Plan on slippery road conditions. Patchy
  blowing snow could significantly reduce visibility. The
  hazardous conditions could impact the afternoon and evening
  commute with rapidly deteriorating conditions by midday
  Wednesday.
 PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Storm Watch means there is potential for significant
snow, sleet or ice accumulations that may impact travel. Continue
to monitor the latest forecasts.

***Potentially High Impact Storm!***

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

Expected Snowfall (through Thursday 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
    • 5-10 inches
  • Parker, Lone Tree, Highlands Ranch areas
    • 4-9 inches (concerns about lower snow amounts among lower elevations due to warm air)
  • Elbert, Elizabeth, Kiowa
    • 6-12 inches
  • Larkspur, Monument
    • 6-12 inches
  • Woodland Park, Palmer Lake, W. Colorado Springs Foothills
    • 6-12 inches

Timing

  • The storm moves into the area Wednesday morning, precipitation may start out initially as rain depending on elevation
  • By noon on Wednesday the Blizzard Warning goes into effect. As we move into the afternoon hours snow and wind will pick up and road conditions will deteriorate
  • Highest impacts for travel look to be 12PM Wednesday through 6AM Thursday
  • Plan on impacted travel (roads and the airport) If you have flights at DIA pay close attention to cancellations

Potential Impacts

  • Areas within and immediately surrounding the Blizzard Warning area can expect the potential for road closures, power outages and property damage due to wind.
  • Ranchers and ag interests should take actions to prepare livestock and property from serious impact
  • This has the potential to be a high impact storm. Travel is not recommended later in the day Wednesday and into Thursday morning

 

Synopsis

As of Monday afternoon, everything still looks on track with this storm. We are cautiously optimistic that this one delivers a pretty good wallop to the Palmer Divide and NE Colorado. That being said, we will have to watch very closely in case this thing shifts or falls apart at the last minute. That’s something we will be keeping a close eye on through the day on Tuesday.

Here’s some models:

GFS 24 hour snowfall accumulation as of 6AM Thursday

The GFS has been bouncing around on this storm, anywhere from super excited to not expecting much at all. Since this tends to over and under react to a lot of short term changes, it’s something we watch for patterns and shifts but don’t put a ton of stock in just this one model.

GFS FV3 is a newer upgrade of the GFS model launched recently. It’s still in a testing phase but still fun to keep an eye on

NOAA’s newer upgraded GFS FV3 (stands for Finite Volume Cubed-Sphere dynamical core in case you wanted to know) is something we like to keep an eye on. It’s still in a bit of a testing phase so I haven’t been able to yet determine its accuracy vs the standard GFS or any of the Nam/Euro models. It’s still fun to look at… it’s a lot more excited about this storm than its older cousin.

NAM3K 24 hour snowfall accumulation

Nam3K is more excited about this storm as well. I love when the higher resolution comes into range as we can start to see some of the subtleties around where this model thinks the bigger snow will be.

Euro models expected snowfall

Finally the EURO, also pretty excited about this storm and one to always watch as it tends to be more accurate than the others. The main drawback is that it only updates a couple of times a day so it can miss short term changes.

A Historic Storm?

In a sense, if things set up this could be one for the record books. Some of the models are showing incredibly low pressure in the center of this storm system. In fact, what we see in the pressure with this storm is similar to the pressures we see in moderately strong hurricanes. This is why we are pretty confidence in a high wind event at the very least.

Like I’ve mentioned the past few days, hopefully everyone has taken this seriously and made preparations. I’m most concerned about people just East of Castle Rock into Elbert County and points East and Northeast.

Is there still potential that this storm does absolutely nothing? Yes, but it’s looking less and less likely. Still we will be watching closely because these big spring storms are often in the habit of throwing curveballs that could potentially upend our forecast completely.

Tune in tonight for a Facebook Live Stream discussing this storm!

One last thing, I’ll be doing a livestream tonight looking at some of this information and discussing it. I will also have some updated data to look at and general storm discussion. Don’t miss it!

Facebook Page for the Livestream

 

Large Storm Potential Next Week. Be Prepared!

If you’ve followed my site for awhile you know I present the weather very “level-headed” and don’t like to hype things. If there’s a serious event headed our way I’ll let everyone know! That’s why the information below is so important.

Large Storm Looks Likely… For Someone!

Euro mean level surface pressure anomaly snapshot 5AM Wednesday 3/13/2019

2 of our longer range, higher resolution models have been moving slowly closer to agreement on the setup for a significant storm next week. The GFS and Euro were originally far apart as of yesterday (GFS showing a non-event for this storm and Euro very bullish.) The movement has been towards a higher impact storm across both models, so that increases our confidence in this event.

GFS precip type and rate snapshot for Wednesday 11AM 3/13/2019

So, a large storm looks very likely. The questions we still have are pertaining to timing, storm track and intensity along with speed. There’s a few variables at play here we just don’t have the answers to just yet.

  • Storm track
    • Further North or South can mean different snowfall amounts in different locations
    • We’ve seen some big misses when the storm track wobbles at the last minute, so that’s something to keep an eye on
  • Timing
    • Trying to pinpoint when the worst of this storm will hit is elusive right now. This is to be expected as we are still quite aways out. Suffice to say the impact window is sometime between Tuesday and Thursday at this time.
  • Speed
    • For big snow out of this, we need the storm to stall for a decent amount of time. Too quick and the heaviest stuff will slide to the East, leaving us with little precip and mainly a lot of wind. This something we will have to keep an eye on.
  • Wild Card!
    • See all those thunderstorms on the GFS image above? Severe weather is likely in front of this storm along the warm sector. If those storms get too big or hang out too close to Colorado, they could rob this storm system of moisture for our upslope. We’ve seen this happen before and it will be something to keep a very close eye on.

What to do Ahead of this Storm

We can’t get too excited about this just yet because it could fall apart. That being said, we can’t ignore when models agree on a POTENTIALLY HIGH IMPACT STORM. It’s one of those things where it’s better to be prepared in case something does happen than unprepared and caught with a major storm.

Here’s what to keep an eye on the next couple of days:

  • Pay very close attention to the forecasts! We will keep you updated on what the storm is doing and what models and guidance are saying
  • National Weather Service is a great resource!
  • If you feel like you want to get prepared for this storm; get your errands and shopping done early on Sunday. I imagine the news stations will start to pick up on this and stores will be crowded later on Sunday and especially Monday and Tuesday.

**Understand that there is still possibility this storm does nothing… but there is equal the possibility it is a high impact event. That’s why I’m stressing folks begin to get prepared for this!

If you have ranching/ag interests, especially in Elbert County. Please begin making preparations for the possibility of a high impact event that could effect livestock.

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!