Historic Freeze, Some Snow – Storm Update – 10/09/2019

A historic storm is slated to move into the area starting Wednesday evening and night as an unusually strong “arctic” air mass will move into Colorado. No doubt about it, this is some of the coldest air I’ve seen in October during Colorado and I’ve lived here for awhile! I’m going to change up the layout of my weather posts a bit; we will talk about the important “need-to-know” stuff first and the analysis will be after that.

Watches/Warnings/Advisories – as of 1PM 10/9/2019

Wednesday afternoon

***Red Flag Warning***

Elbert/Central and East Douglas Counties Above 6000 Feet-
Southeast Elbert County Below 6000 Feet/South Lincoln County-
357 AM MDT Wed Oct 9 2019

...RED FLAG WARNING REMAINS IN EFFECT FROM NOON TODAY TO 6 PM MDT
THIS EVENING FOR WIND AND LOW RELATIVE HUMIDITY FOR THE PALMER
DIVIDE AREA AND SOUTHERN LINCOLN COUNTY...

* Affected Area...Fire Weather Zones 241 and 247.

* Winds...Southwest 10 to 20 mph with gusts up to 30 mph.

* Timing...Wednesday from Noon through 6pm MDT.

* Relative Humidity...As low as 8 percent.

* Impacts...Conditions will be favorable for the rapid ignition,
  growth, and spread of fires.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions
are either occurring now....or will shortly. A combination of
strong winds...low relative humidity...and warm temperatures can
contribute to extreme fire behavior.

Wednesday Evening through Thursday Morning

***Freeze Warning***

Including the cities of 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,
Bennett, Byers, Deer Trail, Leader, Agate, Hugo, Limon, Matheson,
Forder, Karval, Kutch, Punkin Center, Akron, Cope, Last Chance,
and Otis
418 AM MDT Wed Oct 9 2019

...FREEZE WARNING IN EFFECT FROM 10 PM THIS EVENING TO 9 AM MDT
THURSDAY...

* WHAT...Sub-freezing temperatures as low as 20 expected.

* WHERE...Northeast and East Central Colorado, including the
  Denver Metro area.

* WHEN...Freezing temperatures as early as 10 PM Wednesday.

* IMPACTS...Frost and freeze conditions will kill crops, other
  sensitive vegetation and damage unprotected outdoor plumbing.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold. To prevent
freezing and possible bursting of outdoor water pipes they should
be wrapped, drained, or allowed to drip slowly. Those that have
in-ground sprinkler systems should drain them and cover above-
ground pipes to protect them from freezing.

Around the State

Keep in mind if you are travelling or have outdoor plans. There are several snow/travel/temperature related warnings and advisories out. Many areas in the mountains have Winter Weather Advisories for tough travel conditions.  Several plains locations have Freeze Watches or Freeze Warnings out.

Forecast/Hazards/Timelines/Impacts (The Need to Know Planning Stuff!)

Impacts

  • Extreme cold
    • Wind chill temperatures in the single digits are pretty much a certainty. Air temperatures will be in the low to mid teens across most of the Palmer Divide. New model data shows many areas across the Palmer Divide will see wind chills near zero.
    • Prepare any outdoor plumbing, drain above ground sprinklers. If you can’t drain them be sure to cover with blankets. The ground will still be relatively warm so it’s not imperative that sprinkler systems be blow out just yet. Ensure host faucets are disconnected.
  • Snowfall/Travel Impacts
    • Likely there will be some impacts to Thursday  commute. Be prepared for extra time for travelling on Thursday. There’s a potential for an impact on Thursday evening’s commute if snow falls a bit longer and roads remain icy. Expect travel to take a bit longer around the Palmer Divide and Denver Metro area on Thursday in general.
    • FLASH FREEZE! – Super concerned that initially warm roads will flash freeze with the moisture and cold air moving in. These events can cause the road to ice over in a matter of minutes. Be super cautious on Thursday!

Timing

  • Wednesday
    • Will be warm during the day. Windy conditions, high temperatures and low dewpoints will mean fire conditions will be high.
    • Models currently have the cold front moving through sometime between 6-10PM. Expect strong winds and rapidly dropping temperatures when that happens.
  •  Thursday
    • Thursday morning commute most likely to be impacted but evening commute could be impacted.
    • Snowfall looks most likely on Thursday morning into early Thursday afternoon. Models still disagree on the overall timing but we will keep an eye on it.
  • Friday
    • Ice and snow may still be possible into Friday morning.
    • Travel impacts may linger for the Friday morning commute.

 

Snowfall

Our original snowfall forecast range. This hasn’t changed since we first posted it.

Pinpoint snow totals, no changes here either. Note that most of these areas end up on the lower range or in the middle of our forecast range.

 

Analysis (The Weather Nerd Stuff)

Snowfall amounts have decreased slightly with nearly all models but are still within our original range so we won’t make a whole lot of changes to our forecast except to say that most areas will see on the lower side of what snowfall ranges we’ve predicted.

Lets’ take a look at some models!

Euro

GFS

Canadian (GEM)

Why do we still look at low res/long range models? They are still useful for watching for patterns and don’t forget that just like all weather models their accuracy is notably higher in these shorter timeframes. We see a great deal of consistency between the models in terms of snowfall amounts for the plains, front range and Palmer Divide. The discrepancy still exists in the mountains, so while that’s normally worth watching… The only model showing significantly higher amounts in the mountains is the Canadian and based on what I know of that model’s behavior with this storm, I’m not going to pay it too much attention.

Luckily for us the higher resolution and regular more running NAM 3K is now in range. This model runs every 3 hours or so and is great at picking up finer details in a storm system, but remember it is still subject to the same rules and biases as the longer range, lower resolution models.

As you look at this Nam3K image you can see it’s pretty in line with the other models as to snowfall amounts but what else do you notice?

I’ve highlighted in subtle yellow the snowfall bands this model is picking up on. A few things to remember about snowfall bands (AKA jet induced snowfall bands)

  • Models such as the Nam3K can tell you whether these are likely or not
  • They cannot tell where they will form
  • They cannot tell how strong they will be
  • They cannot tell how quickly they move or whether they stall over an area.

Banded snowfall means that some very specific areas could “bust high” on snowfall. This means your exact location could see higher snowfall (2-5 inches) and a mile away could see almost nothing. Snowfall bands are incredibly tricky and mean usually a forecast will hold for 90% of the people in your area… but 10% may get dumped on.

I don’t see any evidence of a huge snowfall event for any areas right now based on how warm the ground will be and how moisture starved storms like this usually are. Still some areas may see an hour or two of very intense snowfall under those bands so keep that in mind!

The cold front will move through Wednesday evening…

Let’s talk about temperatures real quick, because that is the feature that will make this storm historic. We’ll use data from the Nam3K…

 

Thursday 6AM low temperatures

6AM Friday low temperatures

Keep in mind, for a lot of our area record low territory is around 15 degrees. We look like we will either tie or break that pretty handily. Here’s where it gets a bit more interesting… let’s look at apparent temperatures (wind chill or what it will feel like on your skin)

This is the run for 6AM Friday. Note that any of the white areas along the Palmer Divide are wind chill values at or below zero. This is historic for this time of year!

Summary

So our forecast is still largely on track. If you’re getting excited about snow, cool! But it won’t be a big storm as far as snow is concerned. Like we discussed the frigid temperatures will really be the main story of this storm system.

The Euro ensembles seem to be in the ballpark of our snowfall forecast as well, always good to see.

Anyways, make sure everything is prepared for the cold by this evening. We will post any more storm updates as needed so be sure to keep an eye out for those!

Late Week Storm Update – 10/07/2019

Our late week storm system is becoming a bit more clear but we still have some unanswered questions that we should get answers to in the next 24 hours or so. Some of the longer and mid range models have shown some consistentenchy but we are still a bit further away before some of the higher resolution models come into play. That’s when we begin to see some of the nuances show up for storm systems.

As usual we’ll start with any weather watches/warnings/advisories issued as of the writing of this post (I think more will be coming, but we will address those as they come out.)

Watches/Warnings/Advisories (as of 6PM Mon Oct 7, 2019)

***Fire Weather Watch*** – Includes Palmer Divide

South and Southeast Grand/West Central and Southwest Boulder/
Gilpin/Clear Creek/Summit/North and West Park Counties Above
9000 Feet-Grand and Summit Counties Below 9000 Feet-
Central and Southeast Park County-
Jefferson and West Douglas Counties Above 6000 Feet/Gilpin/Clear
Creek/Northeast Park Counties Below 9000 Feet-
Elbert/Central and East Douglas Counties Above 6000 Feet-
Southeast Elbert County Below 6000 Feet/South Lincoln County-
558 PM MDT Mon Oct 7 2019

...FIRE WEATHER WATCH REMAINS IN EFFECT WEDNESDAY AFTERNOON FOR
WIND AND LOW RELATIVE HUMIDITY FOR THE CENTRAL AND SOUTHERN
MOUNTAINS...MIDDLE PARK...SOUTH PARK AND THE PALMER RIDGE|...

* Affected Area...Fire Weather Zones 212...213...214...216...
  241 and 247.

* Winds...Southwest 10 to 25 mph with gusts up to 50 mph.

* Timing...Wednesday from Noon through 6pm MDT.

* Relative Humidity...As low as 12 percent.

* Impacts...Conditions will be favorable for the rapid ignition,
  growth, and spread of fires.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Fire Weather Watch means that critical fire weather conditions
are forecast to occur. Listen for later forecasts and possible
Red Flag Warnings.

Jackson County Below 9000 Feet-
Larimer and Boulder Counties Between 6000 and 9000 Feet-
West Jackson and West Grand Counties Above 9000 Feet-
South and East Jackson/Larimer/North and Northeast Grand/
Northwest Boulder Counties Above 9000 Feet-
558 PM MDT Mon Oct 7 2019

...RED FLAG WARNING REMAINS IN EFFECT FROM 10 AM TO 6 PM MDT
TUESDAY FOR WIND AND LOW RELATIVE HUMIDITY FOR THE NORTHERN
MOUNTAINS...NORTHERN FOOTHILLS AND NORTH PARK...
...RED FLAG WARNING IS CANCELLED FOR WIND AND LOW RELATIVE
HUMIDITY FOR THE NORTHERN MOUNTAINS...NORTHERN FOOTHILLS AND
NORTH PARK...

The National Weather Service in Denver has cancelled the Red Flag
Warning for today. A Red Flag warning will remains in effect for
Tuesday afternoon.

* Affected Area...Fire Weather Zones 211...215...217 and 218.

* Winds...Southwest 10 to 20 mph with gusts up to 35 mph.

* Timing...Tuesday from 10am through 6pm MDT.

* Relative Humidity...As low as 4 percent.

* Impacts...Conditions will be favorable for the rapid ignition,
  growth, and spread of fires.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions
are either occurring now....or will shortly. A combination of
strong winds...low relative humidity...and warm temperatures can
contribute to extreme fire behavior.

Latest Analysis

As usual, let’s take a look at a few model products. (You can click on these images to make them larger for better viewing)

GFS 48 hour accumulated snowfall through 3PM Friday

 

Euro 48 hour accumulated snowfall through 3PM Friday

Canadian (GEM) model 48 hour accumulated snowfall through 3PM Friday

Note: the Canadian models (GEM) was the one I threw out yesterday because it was showing crazy snowfall amounts. Given the forecast data and other models I considered it an outlier for yesterday’s data, but it has come more in line today. What are these telling us?

For starters, they are all getting pretty close on their solutions, nearly all models are showing some snow accumulation for the front range foothills, plains and Palmer Divide with varying amounts based on location. We can see there’s a sharp cutoff which may be models picking up on warmer ground conditions (despite the frigid temperatures) or subtle shifts in the storm track. Unfortunately these lower resolution models can’t show us fine details on storm track shifts, that’s why we are eagerly waiting for shorter range/ higher resolution models tomorrow.

My biggest concern… and I only need one model to show this (others have varying degrees of cold temperatures but when the EURO is consistent with something I pay attention!)

TEMPERATURES!

Euro surface temps @ 6PM Thursday evening

Euro surface temps @ 3AM Friday morning

The temperatures shown above are Apparent Temperatures, so they are what it will feel like to exposed skin based on air temperature, humidity content and winds. As you can see, they are showing extreme cold Thursday night and into Friday morning. I’m especially concerned about the central, southern and eastern sections of the Palmer Divide.

When we see a snapshot of forecast air temperatures at Monument Hill we see verification of extreme cold.

 

Temperatures in the low teens to upper high digits is in record setting cold territory for this time of year folks. Models show several hours of Hard Freeze conditions meaning plants, animals and exposed plumbing will all have a tough time with the temperatures with this storm. Take Tuesday and Wednesday to prepare yourself, any plants you want to save and any animals (especially those that don’t have winter coats on yet) for this arctic blast.

Planning/ Preparation

Impacts

  • Extreme cold
    • Wind chill temperatures in the single digits are possible. Air temperatures will be in the low to mid teens across most of the Palmer Divide. Some select areas in Northern El Paso County may see wind chills near 0 degrees!
    • Prepare any outdoor plumbing, drain above ground sprinklers. If you can’t drain them be sure to cover with blankets. The ground will still be relatively warm so it’s not imperative that sprinkler systems be blow out just yet. Ensure host faucets are disconnected.
  • Snowfall/Travel Impacts
    • Possible impacts to Thursday morning and/or Thursday evening commutes. Be prepared for extra time for travelling on Thursday.
    • FLASH FREEZE! – Super concerned that initially warm roads will flash freeze with the moisture and cold air moving in. These events can cause the road to ice over in a matter of minutes. Be super cautious on Thursday!

Timing

  • Wednesday
    • Will be warm during the day. Windy conditions, high temperatures and low dewpoints will mean fire conditions will be high.
    • Models currently have the cold front moving through sometime between 6-10PM. Expect strong winds and rapidly dropping temperatures when that happens.
  •  Thursday
    • Thursday morning and/or Thursday evening commute could be impacted.
    • Exact timing details are still a but uncertain, some models have a Thursday morning, or Thursday evening event… some have a full day Thursday event. Stay tuned for updates on this.
  • Friday
    • Ice and snow may still be possible into Friday morning.
    • Travel impacts may linger for the Friday morning commute.

 

Snowfall

It’s a bit early yet but I’ll post a very preliminary snowfall forecast. Expect this to change (possibly drastically) over the next 24-48 hours. You’ll notice I’m a bit more conservative than some of the news outlets and other sources online. I still am waiting to see how the warm ground is going to play out… models don’t always estimate that well and can sometimes over-do snowfall because of it. The other wildcard here is that strong winds may end up negating the warm ground factor… for all of that we will have to see how the models play out in the next day or two.

Estimated snowfall through Thursday Evening/ Friday Morning. Preliminary, this will change!

Summary

Quite the little storm we have setting up for October. The huge temperature contrast is going to be a shock for a lot of people so be ready for that. I don’t quite know yet if the snow will be a big impact, seems like the biggest impact will be the temperatures and wind.

If you have agriculture interests on the Palmer Divide, be ready to move animals inside during the storm. I know mine don’t have their coats in yet so the frigid temperatures may cause problems.

As always, stay tuned for further updates. I’ll be sure to post more as we get more data in, like all storm systems this is a rapidly evolving situation so expect some forecast changes over the next day or two based on new data.

That being said; as of right now we are highly confident on the frigid temperatures. We are moderately confident on snowfall of some sort and low/moderate confidence on snowfall accumulations on the ground.

Thanks and stay tuned!

 

First Snow, First Freeze Next Week? – 10/5/2019 Update

Quite a bit of weather news to talk about for the Palmer Divide and the upcoming week. Cool temperatures tonight means some areas will see frost through the morning and smoke from the Deckers fire will continue to pump smoke into some of the areas West and Southwest of Colorado Springs. Additionally, we will talk about the big news item from the weekend; the chance for our first snow of the season and the potential for the first freeze and hard freeze of the season.

Let’s get started!

First… A Quick Update on Warnings/Advisories

***Frost Advisory***

North and Northeast Elbert County Below 6000 Feet/North Lincoln
County-
Southeast Elbert County Below 6000 Feet/South Lincoln County-
Including the cities of Agate, Hugo, Limon, Matheson, Forder,
Karval, Kutch, and Punkin Center
321 PM MDT Sat Oct 5 2019

...FROST ADVISORY IN EFFECT FROM 3 AM TO 9 AM MDT SUNDAY...

* WHAT...Low temperatures between 32 and 38 will result in areas
  of frost.

* WHERE...North and Northeast Elbert County Below 6000
  Feet/North Lincoln County and Southeast Elbert County Below
  6000 Feet/South Lincoln County Counties.

* WHEN...From 3 AM to 9 AM MDT Sunday.

* IMPACTS...Frost could kill sensitive outdoor vegetation if
  left uncovered.

***Air Quality Alert***

...AIR QUALITY HEALTH ADVISORY FOR WILDFIRE SMOKE FROM 800 AM
SATURDAY UNTIL 900 AM SUNDAY...

A Little History…

Records are officially kept in Denver so that’s what the history books will say. Castle Rock’s dates may not fit these exactly but they’re in the ballpark. Due to our higher elevation on the Palmer Divide we tend to experience frosts/freezes/snowfall events a tad earlier than Denver does.

Still, it’s always cool to see these dates and compare in previous years, as well as this year as to where/when our first freeze and snowfall hits. Speaking of which, here’s a couple of fun articles to reference from last year…

First Snowfall Forecast 2018

Palmer Divide Fall Primer


Freeze/ Hard Freeze Chances

Models are in agreement that we’ll see much colder weather but you’ll see they are miles apart on how warm or cold it will ultimately get. The Euro shows extremely cold temperatures (For what it’s worth I think the EURO has overdone both snowfall and cold temperatures) so keep that in mind!

Euro Temperature forecast at 3AM Friday morning

GFS temperature forecast at 3AM Friday morning

The GFS shows warmer overall temperatures. As you’ll see below, the temperature difference above will show why there is such a difference in the snowfall forecasts below.


Snowfall Chances

I’m going to post some weather models. As always, at this time-frame these are far enough out that you shouldn’t pay attention to the amounts whatsoever. It’s too early to tell those details, instead focus on the pattern…

Euro 48hr Accumulation forecast by 3AM Friday morning

GFS 48hr Accumulation forecast by 3AM Friday morning

At this time I’m just posting the GFS and Euro. There are a couple of other long ranges I look at but ended up throwing them out because I didn’t like the solutions. What can we see from these models?  Beleive it or not, the Euro is going a bit higher on snowfall than the GFS (surprise!) This (and the other models I did not include) still show a considerable amount of uncertainty on snowfall amounts but most models are showing at least *some* snow from this storm.

For what it’s worth, the Euro ensemble blend is showing much less snow than the operational model posted above.

So at this point safe to say snow is *POSSIBLE* but I’m not even putting it yet in the likely category. We will have to get a few more details over the next few days as to how this storm sets up. If I had to give it a probability I’d say with tonight’s data the chance for seeing snow is around 20-30%. This probability will either rise or fall depending on what other data we get in this week.

Wrapping it Up

As you can see above, the model data we have right now doesn’t really tell us a lot of anything with any certainty. This is why I caution people on what their weather app says or what one of the local news stations or social media weather sites say. I’m excited about the potential of our first snow of the year, I’m not trying to be a stick in the mud, but I’ve built MountainWave Weather on no hype, level headed and accurate forecasting. That’s not about to change, which is why I don’t get too excited about things unless there’s something to get excited about.

Here’s what we know at this point:

Chance for Freeze/Hard Freeze

LIKELY – I’d put the probability of this around 50-70% with model data tonight. That’s relatively high for this far out so that’s why we have a bit more confidence in this.

Chance for First Snowfall

POSSIBLE – I’d put the probability on this around 20-30% right now. Most models show snow but there’s still a ton of uncertainty about if the temperatures line up with the moisture and snowfall amounts. So I’d say this is still a bit up in the air.

Remember, all forecasts are fluid. We will get better data in the coming days and the probabilities outlined above will shift. Basically what I’m saying here is (shameless plug) stay tuned for more details in the coming days!

 

 

High Winds Possible over Next 48 Hours – Palmer Divide – 09/27/2019

A powerful storm system is setting up to impact the Pacific Northwest and Northern plains and Rockies this weekend. A ton of moisture and cold air funneling into the area means that many places in Washington, Idaho, Montana and Wyoming could see historic snowfall (for September.)

If you have any travel plans in or around that area, expect heavy impacts from heavy snow accumulations and strong winds.

Speaking of Strong Winds…

Colorado as a whole will relatively little impact from this storm in terms of snowfall. Our higher mountain peaks along the Continental Divide may be lucky enough to see a dusting but most snow amounts in Colorado’s high country will remain under 1 inch.

The big impact we will see around here will be the wind! Colorado will be caught in between the strong trough to our North and a relatively stout high pressure system to our South. What does that mean? When you are caught between two strong circulations the pressure gradient that results often means strong winds are a sure thing.

 

We will expect to see high winds establish over the Palmer Divide on Saturday morning. Keep in mind, the graphics below are wind gusts, so we’d expect sustained winds to be in the 20-30mph range with gusts up to the amounts shown below.

Nam3k forecast wind gusts Saturday morning around 8AM

As we move into Saturday afternoon more areas will see the wind pick up.

Nam3k forecast wind gusts Saturday evening around 6PM

The strong winds will continue Saturday night and into Sunday morning. Sunday throughout the day things will really ramp up with the foothills and plains getting in on more of the action.

Nam3k forecast wind gusts Sunday afternoon around 3PM

Another Concern…

With the warm temperatures we will experience, the high winds, low humidity and how dry we’ve been fire danger will be a major concern. Several Fire Weather Watches have been issued this afternoon. Details below…

...FIRE WEATHER WATCH IN EFFECT SUNDAY AFTERNOON FOR WIND AND LOW
RELATIVE HUMIDITY FOR MIDDLE AND SOUTH PARKS...SOUTHERN
FOOTHILLS...PALMER DIVIDE AND PLAINS EAST AND SOUTH OF DENVER...

...FIRE WEATHER WATCH IN EFFECT MONDAY AFTERNOON FOR WIND AND LOW
RELATIVE HUMIDITY FOR MIDDLE AND SOUTH PARKS...SOUTHERN
FOOTHILLS...PALMER DIVIDE AND PLAINS EAST AND SOUTH OF DENVER...

* Winds...South 20 to 30 mph with gusts up to 45 mph.

* Timing...Sunday afternoon, then again on Monday afternoon

* Relative Humidity...As low as 14 percent Sunday, 12 percent on
  Monday.

* Impacts...Conditions may be favorable for the rapid ignition,
  growth, and spread of fires

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Fire Weather Watch means that critical fire weather conditions
are forecast to occur. Listen for later forecasts and possible
Red Flag Warnings.

This Fire Weather Watch includes the entirety of the Palmer Divide so be mindful of that Sunday and Monday. If you see smoke report it immediately and if you have any plans to set anything on fire (for whatever reason) consider holding off until another time.

Summary

  • Strong winds will be likely across the Palmer Divide Saturday, Sunday and Monday.
    • Be sure to tie down or shelter anything that can be picked up and tossed
    • From what we can see with models so far, winds look Southwesterly so if you’re driving along highways be careful as gusts can tend to blow lightweight and high profile vehicles around.
  • Fire Danger will be extreme
    • The strong winds, low humidity and warm temperatures mean any fires that start will grow rapidly
    • Call 911 and report smoke immediately, the quicker a fire can get under control the better the chance of it not spreading and getting out of hand.

 

Pay attention to the weather forecast, I’ll have any updates as needed over the next couple of days!

 

Fall is Here! A Look at the next 7-10 Days – 09/23/2019

Astronomical fall has finally arrived as of 1:50AM this morning and luckily for us it will start feeling a bit more like fall around here… after today. Monday looks to continue our trend of warm, above average temperatures but there are signs that the heat is coming to an end! Unfortunately, it has also been dry and while we see chances of moisture here and there in the medium range outlooks, not a whole lot of it looks too promising.

Temperatures

Temperatures overall will remain warm for the first part of the week so we will still continue to feel like summer for at least a little bit. We do see signs of a storm system dropping temperatures by the end of this week and towards the weekend. All eyes are on a stronger signal for cooler temperatures and possibly moisture going into the early/mid part of next week. Below is the forecast temperatures from the Euro model and is a pretty good representation of what you should expect in lower elevation areas of the Palmer Divide.

Centennial Airport Euro Model forecast temperatures through Weds. Oct. 2

The next graphic is for the Monument Hill area and is a good representation of the higher elevation areas of the Palmer Divide. As expected, temperatures at higher elevations will remain a bit cooler but keep a close eye on that system next week as we could see a period of freezing overnight temperatures in locations around or above 7,000 feet in elevation.

Monument Hill Euro Model forecast temperatures through Weds. Oct. 2

Precipitation… any snow in the forecast?

Unfortunately the moisture situation doesn’t look stellar over the next 7-10 days for especially the Eastern part of the state. That doesn’t mean we will see absolutely nothing, it just means that whatever we do see looks pretty hit or miss and not a whole lot of quantity of moisture.

Drought conditions are slowly beginning to return to Colorado with mainly the mountain areas and Southwest part of the state seeing the biggest effects. That said, if conditions verify as I expect them too, I wouldn’t be surprised to see some of these drought conditions expanding Eastward to the front range and along the Palmer Divide in the near future.

The thing to remember is that September is generally a dry month, so the fact that we’ve been dry for the past few weeks is not unusual in and of itself. What doesn’t help is the crazy heat we’ve had to deal with… more on that later but September could go down in the history books as the warmest September on record for Colorado.

As far as moisture, let’s take a look at some models…

GFS total precip for next 10 days

Above is the GFS precipitation expected through Wednesday October 9 and as always since this is a longer range look don’t get hung up on exact numbers and locations. Instead look at the higher level pattern the model shows; moisture right up along the continental divide with some chances for moisture in the  mountain areas as well. Southwestern Colorado may benefit from decent moisture which will help out their drought situation, at least a little bit. The most concerning thing is the dry signal East of the Divide…

GFS precipitation anamoly for next 10 days

In fact, in the 10 day anomalies you can see most of the state will end up below normal, even though there will be chances for moisture it won’t be enough to keep us around average. This graphic basically means that even though we recieve some chances of moisture in the next 10 days, if you take that amount and put it up against the average (what we normally see over the next 10 day period) we will end up below average.

And this signal doesn’t just show up on the GFS… the Euro is similarly dry for the next few days as well and especially with drier conditions East of the divide.

Euro total precip for next 10 days

Euro precipitation anomaly for next 10 days

So as you can see, both  models are picking up on similar signals in the near future but as the Euro tends to do better at longer ranges we tend to lean towards that one. Interesting to note, the Euro keeps us a bit drier than the GFS does so that will be something to watch.

Summary

So what should you expect over the next 7-10 days? Expect a week of fall in Colorado; you will see everything from near record-setting heat to days that barely break the 70’s. We like to call it the roller coaster!

From a precipitation standpoint, really the best shot looks like next monday-wednesday timeframe. I want to caution that since that is more than 7 days out at this point, take it with a grain of salt and just keep an eye out for forecast updates. Yes, it would be cold enough to snow at higher elevations over the Palmer Divide in the night-time hours but I won’t get too excited about it until I get better evidence that this storm system lines up and produces moisture first.

So not yet calling for the first snow down here… but keeping a close eye on early to mid next week!

 

SPC Upgrades Today’s Severe Weather Risk – 09/08/2019

Today’s Severe Weather Outlook

The Storm Prediction Center upgraded much of the front range to a “Slight” severe weather risk from marginal this morning. While this still doesn’t mean most of the area will see widespread severe weather, we do tend to notice when they upgrade in Colorado.

Palmer Divide SPC outlook and storm threats

A slight risk doesn’t mean much in a lot of places, but in Colorado we’d storm chase a yellow risk area!

Today’s slight risk encompasses most of the front range from the Northern border down to about Pueblo. As far West as the foothills and reaching out to nearly the Colorado/Kansas border.

  • Main Threats
    • Hail: large hail will be possible with some of these storms, especially while they’re descreet and before they merge into a large line.
    • Wind: Largest threat today from these storms today is damaging wind gusts.
    • Tornadoes: Chances are very low but as we know, when storms start spitting out outflow boundaries and they converge we can see a random funnel cloud or landspout tornado. That’s what we will be looking for today.
    • Rain: some flooding may occur under heavier storms.
  • Timing
    • Palmer Divide locations to the west should be ready between 4-7PM
    • Locations in Elbert County and points East should be keeping an eye on the 5-9PM timeframe.

NAM3k forecast snapshot for around 7 PM tonight

 

Labor Day Weekend Outlook – 08/31/2019

A lot of folks will be travelling this week (especially to the mountains if yesterday’s traffic was any indication) and lots of camping and boating along with BBQ-ing will be in our near future. Luckily the weather this weekend looks to be absolutely outstanding… if you love heat anyways.

Record setting heat possible again this weekend with very low chances for any precipitation

Castle Rock and its surrounding areas will experience very warm temperatures throughout the weekend. Particularly Sunday and Monday temperatures will be running over 15 degrees above average!

Denver will threaten some of it’s record highs for the date.

For those of us at higher elevations in Elbert County it will be a bit cooler overall but still well above average. Here’s data from the weather station at the Monument/Elbert station

Forecast high and low temperatures for Monument Hill/Elbert station. (EURO model)

Notice for both areas it remains quite warm through next week with a cooldown possible by next weekend. We are after all, approaching fall so while the hot temperatures are here for now, we start to see a marked decrease in them especially as we get later into September.

Hope everyone has a happy and safe Labor Day weekend!

 

Colorado Monsoon 2019… Missing In Action?

After an abnormally cool and wet period the front range (and most of Colorado) has settled into a drier and warmer period for the month of July. As we move into July we typically see the monsoon establish across the southwestern United States and with it a uptick in rain and thunderstorms across Colorado.

The weather pattern has been strange this summer though, earlier rain and cool temperatures were not related to the monsoon, more with strong cold fronts and moisture from the Pacific Northwest. As we’ve seen the jetstream migrate North (as it often does this time of year) we’ve begun to dry out.

July 2019 Was Very Dry

Largely July was a very dry month for Colorado (some very select areas were exceptions as you can see with the graphic below) The lack of a monsoon pattern establishing meant widespread normal and above normal precipitation was lacking for a large majority of the state.

PRISM Climate Data (precipitation anomaly) for July 2018

A lot of the state experienced precipitation in the 50-70% of average category. This is not what we’d expect with a healthy monsoon setup.

Quick Note: But I’ve Been Hearing on the News…

I’m not exactly sure why certain TV meteorologists have been attributing a lot of ours storms in July and early August to the “monsoon.” The pattern simply hasn’t been there… you can argue it but the data above doesn’t lie.

August 2019 – Glimpses of the Monsoon?

Fret not though, we are seeing glimpses of a monsoon pattern shift in the near future… but there’s a catch…

While models are pointing to a monsoon type setup over the next week or two it doesn’t look all that healthy. The image above is the EURO model ensembles and shows while we see moisture from the gulf rotation around a high pressure over roughly Texas, the moisture advection is not terribly strong. In fact, there are still several key ingredients of a healthy monsoon pattern that just simply aren’t there.

Here’s a more ideal setup

So compare the two images above and it becomes clear that what we will see over the next 7-10 days looks weak at best. Not to say this is set in gospel (models are not 100% accurate remember) but it’s worth noting that the overall trend shows at least a slight uptick in moisture but not a strong monsoon setup.

What Does This Mean for the Palmer Divide?

The influx of moisture means we should see a bit more thunderstorm activity return to our area again over the next few days.  Not only that, but on those days the temperatures should cool a bit so we get a bit of relief from the heat but it should stay pretty warm overall.

Here’s the EURO Meteogram for temperatures at Centennial Airport for the next few days.

As always, add or subtract a few degrees from these depending on your elevation. The point here is you can see the cooler days above… those will be the best shots for thunderstorms with decent moisture.

With the influx of moisture and lift we will have to keep an eye on the Palmer Divide… our elevation and terrain makes us a bit of a bullseye for thunderstorm development under these conditions.

We’ll keep an eye on things over the next few days to couple of weeks to see if we can spot any significant changes in the weather pattern but for now it looks like more of the same!

 

Independence Day 2019 Weather Outlook

As is typical this time of year, we will start off the day very nice, sunny and cool. We will quickly see temperatures warm up in the afternoon and with it will come our daily chance for showers and thunderstorms. Here’s a quick update of what to expect today:

Severe Weather Possible

SPC Severe Outlook as of this morning 7/4/2019

Severe thunderstorms will be possible across Northern, Northeastern and Eastern Colorado today. A marginal risk extends across the Palmer Divide meaning a stray severe storm is possible but most storms seen in the area will remain below severe limits. As you move Eastward into Eastern and Northeastern Colorado the risk is upgraded to slight, again meaning severe weather will be scattered in nature, but is a slightly higher chance than the green shaded areas.

Primary threats to watch out for with these storms:

  • Large hail
  • Damaging wind
  • Heavy Rain

–A slight risk of tornadoes exists, but mainly in areas well Northeast of Denver.

Temperatures – It’s Going to be a Scorcher!

HRRR predicted high temperatures for today

High temperatures for many areas along the Palmer Divide will top out in the mid to upper 80’s today. As you move lower in elevation things will heat up a bit more with lower elevation areas along the Palmer Divide (Lone Tree, Parker, Calhan, Simla) all seeing temps in the upper 80’s to low 90’s. Not the hottest temperatures we’ve seen this year, but you will definitely notice how toasty it is if you spend time outside this afternoon.

Make sure to drink plenty of water and sunscreen is a must today!

Afternoon Thunderstorms – Have a Plan to Move Inside

Models have pinpointed the 3PM-8PM timeframe as the most likely time we see thunderstorms along the Palmer Divide so keep that in mind. There is disagreement amongst the models as to how strong those storms get, as we know models can’t exactly pinpoint when or where a storm hits; they can only give us general areas to look out for.

Nam3K simulated reflectivity

The Nam3k shows weaker storms over Douglas and Elbert counties with a later timeframe, closer to 7-8PM.

HRRR simulated reflectivity at around 5PM

The HRRR shows storms firing as early as 3-4PM across the foothills and moving across the Palmer Divide by 4-6PM. 

HRRR simulated reflectivity at around 6PM

By 6PM this particular model has storms lingering along the I-25 corridor but notice the big storm in Elbert County. This setup will bear keeping an eye on because this model is showing a pretty significant storm out that way into the evening hours.

HRRR simulated reflectivity at around 9PM

By a bit later in the evening we should see a lot of the storms shift off to the Northeast. If these models verify they all have a pretty decent evening for the area after 9PM.

 

We will keep an eye on this throughout the day and be sure to pass along any updates. We will also forward along the 11AM SPC update if it looks like the severe weather area is shifting westward and closer to home.

Hope everyone has a happy and safe independence day, remember to keep an eye out for lightning this afternoon!

 

Major Weather Pattern Shift Arrives This Week – 06/24/2019

No doubt, June and Spring in general was colder and wetter than average for a lot of places in and around Colorado. In fact, several mountain locations saw significant snowfall this past week while the front range was buried in moisture, low cloudiness and severe weather.

The good news (for summer weather and warm temperature lovers) is we are spying a rather large weather pattern shift starting this week. For the past several months low pressure systems have been riding the jet stream across the mountain west into Colorado, this has made for very unsettled weather so far.

The change is becoming very apparent in a lot of long and medium range models:

GFS 500mb upper air pattern for Wednesday June 26, 2019 around Noon

As you can see from the GFS snapshot above, high pressure is beginning to establish to the Southeast of Colorado. This is something we tend to see in typical summertime patterns in Colorado. As such, we’d expect our weather to shift away from cold and unsettled, to hot and summer-like.

GFS 500mb upper air on Friday June 28, 2019

As we move into the weekend we see the ridge intensify and shift the jet stream and thus the storm track away from Colorado. Notice the trough moving into the Northwest? That feature will struggle to make it into Colorado so while we may see a slight chance of storms from it over the weekend (very small, think 10% or less chance)

Here’s  peak at the GFS forecast temperatures on Friday…

Notice that hot air making its way up into the middle part of the country… right about where the high pressure ridge establishes. Now keep in mind, this model shows at noon on Friday so these aren’t the “true” high temperatures… probably need to add a few degrees to the ones in Colorado at least.

For those of us closer to home along the Palmer Divide, the Euro Ensembles show a pretty toasty week and weekend across our area as well. The official station for our area is Centennial Airport, so if you are higher elevation than there (most of us are) maybe subtract a degree or two.

True Long Term Shift or A slight Reprieve Before Back to Cold and Unsettled?

Stay tuned for another post, now that summer is finally here I’ll be crunching the data and looking at some models to see if this is just a short term pattern swing or if summer is truly here to stay.

For now, enjoy the warm temperatures and generally dry conditions for the next 5-7 days!