Saturday PM Palmer Divide Storm Update

Not many major changes to what we are seeing tonight based on new data coming in. A lot of the mid and shorter range models are coming in and have dropped snow totals just ever so slightly across the area.

Snow banding is possible so some areas may over perform while others under perform.

As we’ve been saying all along, the way this storm system is moving in (the direction and moisture content) is not conducive to a major snow storm along the front range. The biggest impacts will be the cold temperatures the areas sees on Sunday and into Monday morning.

Still, we can’t discount a few quick bursts of moderate snow overnight tonight and combined with the much colder temperatures could make some areas a bit tricky for travel. The jet stream is overhead and as we’ve seen that can do crazy things to our snow totals for certain areas. Expect some areas to see slick roads overnight into Sunday especially South and West of Denver. The foothills should still see decent amounts of snow so I’d expect the travel conditions to be a bit trickier up that way.

Updated Timing, Impacts and Snowfall Amounts

Timing

  • The front is moving through Denver and Southward towards the Palmer Divide as of about 7:30PM
  • Expect precipitation to start as rain but may quickly change over to snow this evening
  • Snow will continue through the night and into the morning hours Sunday
  • Snow looks to end by 12PM on Sunday from the North to South

 

Impacts 

Roads

  • Light to moderate travel impacts across Denver and the Palmer Divide
  • Moderate travel impacts for the foothills and areas of Western Douglas County

 

Temperatures

  • Temperatures will be below freezing as the front moves through
  • Sunday will see highs in the upper 20’s to low 30’s
  • Sunday night into Monday morning, lows will be in the teens to lower 20’s for most areas. Some areas may even see single digits

 

Snowfall

  • Castle Rock, Parker, Lone Tree, Castle Pines, Sedalia / Central and Western Palmer Divide
    • 3-6 inch range still looks in play here
  • Southern Palmer Divide (Monument and nearby areas)
    • 2-4 inches looks like the most likely range for these areas
  • Eastern Palmer Divide (Limon, Elizabeth, Elbert)
    • 2-4 inches looks likely in these areas, towards the lower end of that range as  you get East towards Limon

 

Remember, the Winter Weather Advisory is still in effect from 8PM Saturday through 12PM Sunday for the Palmer Divide! (eastern areas towards Limon excluded)

Any updates I’ll be sure to pass along, also you can ask any questions or pose any thoughts on Facebook.

Stay warm and stay safe everyone!

 

Cold Blast – Accumulating Snow Coming This Weekend

Click the image for up to date Castle Rock Weather Alerts

Finally Starting to Feel Like Fall

Castle Rock high and low temperatures vs. average since Oct 1, 2018

Temperatures have been running well below normal for the past few days, we haven’t seen average or above average temperatures in Castle Rock since October 5. That’s great news after how warm September was and even better news is that we’ve seen a bit of moisture as well. After the cold temperatures abate a bit on Friday and Saturday another blast of cold air and a chance of snow makes its way into the area. The good news for snow fans is that it looks very likely we will see decent snow accumulation with this weekend’s storm!

Storm Setup and Analysis

Here’s a quick look at conditions on Saturday; a strong trough is expected to dip out of Canada and move into Colorado. Behind this trough is a whole boatload of cold air that has been pooling over Canada for some time now. That means we expect very cold temperatures to accompany this storm system. While this is not a favorable track for large amounts of snow, many models are showing enough moisture for accumulating snow along the front range.

Palmer Divide Weather | Castle Rock Weather | Snow Storm | Snow Totals | Storm Forecast

Estimated snowfall by late Sunday

The image above shows the most likely expected snowfall accumulation through late Sunday (50th percentile or probabilistically the most likely snowfall amount based on data today.) You can see areas along the foothills and areas over the Palmer Divide generally have snowfall totals pegged in the 4-6 inch range.

The SREF ensembles show a 6.42 inch mean at Centennial Airport and a 5.53 inch mean at Monument Hill. Those numbers are pretty consistent with what we see above and with some of the modeling.

GFS expected snowfall Sunday by end of storm

Given the much colder temperatures I say snow accumulation is a good bet if everything else pulls together well. As you can see there is still a bit of discrepancy between some of the models for the snow totals at lower elevations but the overall image is pretty consistent. The foothills and mountain areas stand to see the best snowfall amounts while over the Palmer Divide we will see slightly more than Denver and areas to the North and East.

Speaking of temperatures, they’re going to be downright frigid!

 

What To Expect

  • Friday and the first half of Saturday will be quite nice with decent temperatures and mostly clear skys.
  • Snow will move in late on Saturday most likely in the evening hours past 4PM
  • Snow will continue overnight saturday into Sunday
  • Snow looks to end by about 12PM on Sunday
  • Extremely cold temperatures will set in Sunday night into Monday morning
  • Expect most areas along the Palmer Divide to see accumulating snow in the 3-6 inch range
  • Largest travel impacts look to be later Saturday night into Sunday morning

 

Keep the things listed above in mind and know that timing and snow totals still have time to shift. We will have another update as more data comes in!

Stay tuned!

 

Weather Pattern Change Ahead

After several weeks of well above average temperatures and incredibly dry conditions, it looks like we may finally see a fall weather pattern change on the horizon!

Ridge of Doom is Breaking Down!

For the past several weeks a high pressure ridge has been fairly efficient at keeping warm dry air over Colorado and keeping the storm track away from us. Signs that this is changing are beginning to appear as early as today. 500mb (upper air pattern) shows a trough digging into the Western United States and pushing the ridge responsible for our stagnant weather pattern eastwards.

In simplest terms, this means warm and dry air will dominate the weather pattern for the Eastern U.S. but things in the west will be changing! The trough to our west will finally allow cold air pooling in Alaska and Canada to make its way down to the western and central part of the U.S.

Is Snow in our Near Future?

You’ve no doubt heard the hype already on a lot of weather websites, social media platforms and TV stations; but snow early next week is looking like a sure thing for the mountains of Colorado… and yes the possibility exists even for the front range to see something as well, but as with a lot of these early season storms; the devil is in the details!

GFS Precipitation type and intensity for Sunday 6PM

Looking at some of the longer range (read: less accurate in this time frame) models we see a strong upslope signal showing itself on Sunday and into Monday. The trough should be fairly efficient at bringing cooler air and moisture into the area. But, just like a lot of our “fall/winter” type storms; exactly where and how things set up will make all of the difference.

Don’t get too excited about snow flying around Castle Rock just yet, but this is something to definitely keep an eye on over the next few days. Here’s a few things we will be watching:

  • Cooler and more unsettled pattern for the rest of the week into the weekend is looking very likely
    • Expect cooler temperatures and precipitation Wednesday and again over the weekend
    • Snowfall is not expected along the Palmer Divide for the next 3-4ish days.
  • Weekend has a reinforcing shot of cold air and may be able to tap into decent moisture
    • Where the trough sets up will determine moisture availability and upslope possibility
    • Will the air be cold enough for snow? We think it is a strong possibility but may be too warm for much to stick
    • Timing! Some models shows this stuff cranking by mid-day Saturday while others hold off until later Sunday into Monday

So obviously, still a lot of unanswered questions that need to flesh out in the next few days.

For now, anticipate cool and unsettled weather for the next 5-7 days beginning with a cold front late in the day Wednesday. Be prepared to move sensitive vegetation indoors this weekend and possibility of needing to cover above ground irrigation equipment if it’s not already drained late in the weekend (think Saturday night – Monday night timeframe)

We do not yet have answers on if it will snow (50% probability at this time) and/or what the impacts will be, stay tuned for further updates on that information!


Obligatory Snowfall Model for Late This Weekend

You all know I hate sharing snowfall models this far out… the reason I’m doing it right now is I just want to show you all what models are picking up on as of this morning.

Keep in mind with this image: It is not a forecast, it is very early and preliminary, these numbers WILL change higher or lower as we get more data in and get closer to the storm’s arrival.

GFS total accumulated snowfall from now through Sunday 6PM

This is also why I caution about anyone trying to forecast we definitely will or will not have snow next week. This model was showing 4-8 inches of snow for the Palmer Divide last night and this morning’s run shows 0!

 

El Nino 101: What is El Nino?

What Is the El Nino Southern Oscillation? (ENSO)

For most people they hear the word “El Nino” and know that it means big shifts in the weather pattern for Colorado (whether from being here long enough or hearing it from the local TV Weather people> But many don’t know exactly what “it” means exactly or the mechanisms behind it.

The El Nino Southern Oscillation is a periodic weakening or reversal of trade winds stretching across the Pacific Ocean from South America to Australia. This allows a redistribution of warm and cold water which in turn affects the atmosphere above the ocean as well. This means big changes in weather patterns for the tropics and subtropics along with areas further North and South.

To measure the El Nino Southern Oscillation sea surface temperatures are monitored in different “Nino” regions. To make a long story short, this area stretches roughly between Australia and South American along the equator; roughly between 120E and 80W lines of longitude and between 0-5 degrees North and South latitude.

There are 3 different “phases” of the El Nino Southern Oscillation that occur based on what the observed sea surface temperatures are for a period of 3 months and I’m sure you’ve often heard about them.

Neutral

A neutral phase of ENSO means warm water and air is pushed across the ocean towards Australia. Cooler water “upwells” from deep beneath the ocean along the South American coast.

The neutral state is the normal phase of ENSO, it is neither an El Nino or a La nina. In this pattern wind blows from East to West along the Equator pushing warm moist air and warm ocean water across the ocean towards Australia.  As the warmer water at the upper layers of the ocean is pushed away from the coast of South America, cooler water from deeper in the ocean rises to take its place. This is a process called upwelling and is very important to many forms of oceanic life along the coast of South America.

During the neutral phase of ENSO, warmer water tends to flow towards Australia while cooler water upwells of the coast of South America.

It’s also important to note that during a neutral ENSO phase, the trade winds push the warmer water West but this also effects the atmosphere along the equator.  This normal phase of trade winds and high and low pressure  circulation is called the “Walker Circulation.” It’s illustrated in the image above but here’s another to help visualize:

The trade winds that blow across the ocean circle back North and circle around towards North America. This West to East wind over N. America is what influences our storm track across the United States. So as you can imagine, when these trade winds and circulations get disrupted it has big implications for our weather.

So what does that mean for temperature and precipitation patterns for the U.S. during a neutral phase? Basically we’d expect to follow along climate normals through the season. We should see normal temperatures, normal snowfall and normal precipitation through a period of neutral conditions. We know however; this is not always the case as there are other things that can influence our weather.

During neutral conditions the U.S. tends to see colder winters across the Northern and Central United States with drier conditions to the South and close to normal temperatures.


El Nino

The warm phase of ENSO means a weakening or shifting of prevailing  (trade)winds that allows warm water to pool against the South American coast. This can mean a disruption of weather patterns in the Pacific which can in turn influence the weather in the U.S.

When we say an El Nino is setting up or occurring we are referring to the warm phase of ENSO. In this pattern the trade winds pushing from East to West across the equator break down or even reverse in some cases. This allows warmer water to pool against the South American coast while colder water upwells against Australia.

During December 2015 we were seeing one of the strongest El Nino’s recorded. Notice the extremely warm water across the Equator towards South America and the average to below average temperatures near Australia and to the North of Australia.

Sea surface temperatures increase along the South American coast and sea surface temperatures drop in and around Australia. This means areas of increased convection (shower and thunderstorm activity) for South America and less for Australia. It is not uncommon for Australia to see severe drought conditions and South America to see extreme flooding conditions.

During El Nino the weather in the continental U.S. can change too. Due to trade winds and circulations being disrupted, the positioning of high and low pressure systems, along with shifts in the jet stream can cause big changes for our weather. If you’re new to Colorado, you may not know but our bigger snow storms in Denver tend to come during El Nino years, so that’s something to keep an eye on!

El Nino effects on the U.S. largely depend on the strength of the event. During weaker events cooler air stays North and East while warmer conditions manifest during stronger events. Precipitation tends to favor California and southern parts of the U.S. during stronger events while dry conditions tend to show up during weaker events across the Central part of the country.


La Nina

During La Nina, stronger trade winds allow cool water upwelling to spread across the South American coast. The cold water pools and will spread across the Pacific and warmer water stays further West near Australia and New Zealand.

La Nina on the other hand refers to below average sea surface temperatures setting up across the South American Coast reaching further West across the Pacific Ocean. With this pattern the trade winds pushing from East to West across the equator strengthen substantially, which  allows colder water from upwelling to spread out across the ocean to the West of the South American Coast.

As recently as last winter we saw a La Nina event unfolding in the Pacific Ocean. In this image of sea surface temperature anomalies from January 2018 the cooler than normal water can be spreading from the South American coast across the pacific ocean along the equator.

Conditions in a La Nina pattern are basically the opposite of those found within an El nino. Colder water spreads across the ocean towards the West and warmer water stays pooled up against Australia and New Zealand. Just like with an El Nino, this pattern can disrupt normal weather patterns and can mean changes for parts of the U.S.

Just like during an El Nino, ocean and atmospheric circulations get disrupted and have effects on where high and low pressure sets up and even has effect on the jet streams. During La Nina events a lot of convection gets shifted towards Asia and Austrlia, where high pressure across the Eastern Pacific and towards the United States causes shifts in our weather as well.

During La Nina events the overall pattern features a drier and warmer than average Southwest while the Pacific Northwest, Northern tier of the country and the Midwest tend to be a bit cooler and wetter than average.


Quick Summary

I’ll wrap this up with a quick summary because I know this is a long article…

ENSO Neutral

  • Normal oceanic pattern of the El Nino Southern Oscillation. Warmer water is found further West with cooler water from up-welling tending to stay near the South American Coast of the equator.

 

El Nino

  • The warm phase of the El Nino Southern Oscillation. Weakening or disruption of trade-winds allows warmer than average water to spread across the Pacific Ocean. This warm water can also influence weather systems and atmospheric currents.

 

La Nina

  • The cold phase of the El Nino Southern Oscillation. Strengthening of trade-winds allows cooler than average water to spread across the Pacific Ocean. This colder than average water can also influence weather systems and atmospheric currents.

 


How Does ENSO Effect Colorado’s Weather?

This will be coming in our next article… we will deep dive into how shifts in ENSO have effected Colorado’s weather throughout the years and how we can identify patterns to help forecast what this year’s El Nino or Neutral event may be.

I’m putting together that information and will have some pretty nifty graphics and stats, so stay tuned for that in the next week or so!

Fall Weather Arriving Right on Schedule!

Scorching September

We’ve all heard from our local TV stations about how hot it’s been in Denver.

Courtesy of our friends at KDVR Fox 31 News.

We’ve seen 8-plus consecutive days in the 90’s for Denver, this is unusual and helps demonstrate how warm many areas along the front range have been. Some areas of the far Eastern plains even reached 100 degrees yesterday (September 18.)

I decided to dig up the data for Castle Rock and while I didn’t expect our weather data to show anything different from Denver… it was surprising just how far above average we’ve been this month.

September 2018 temperature data for Castle Rock, Colorado as of September 18

You can see in the graphic the charts all skew well above average for daily high, daily low and daily mean (average of daily high and low) temperatures. If the month ended today we would be an astounding 4.56 degrees above the 30 year average. Whether you’re a serious weather nerd or not, it’s not hard to understand that 4.56 degrees above average for the month is quite notable.

Fear Not! Things May Be Changing!

For the past several weeks a large ridge of high pressure has been dominating our weather pattern. This means hot air moving in from the West and Southwest and little to no storms in the area as our moisture gets shut off. The good news is we see some changes and the high pressure ridge looks to be shifting out of the area.

500mb upper air pattern

As the high pressure ridge moves East it will allow cooler air to spill in from Canada, thanks to low pressure troughs finally having the ability to establish to our Northwest and move across Colorado. This means more cold fronts will begin to show up in our future!

In fact, we will begin to cool down starting on Thursday! Here’s today’s forecast high temperatures and tomorrows (Thursday)

Forecast high temperatures for Wednesday September 19, 2018

Forecast high temperatures for Thursday September 20, 2018

What’s All This I Hear About Snow in Denver Next Week?

After the cool front moves through this week and cools our temperatures a bit, models are hinting at a stronger front moving through next week. I’d caution folks about reading too much into this at the moment as models are jumping around a lot on next week… as we all know models aren’t great at picking out details more than about 3-5 days out.

I pulled the specific time-frame the TV stations were ranting and raving about yesterday and saw that even as of this morning this particular model had shifted away from snow back to an all rain solution along the front range. There is still plenty of time for this to change and I fully expect it to wobble back and forth, but looking at the weather setup beyond just this one model… snow doesn’t look likely at this time.

So you’re saying there’s a chance?

Not to say it isn’t possible, the chance of snow isn’t 0… but the probability is a very low percentage. I’d say less than 5% with the data we are seeing now. Still, we will keep an eye on it over the next few days just in case things change.

Takeaways for Weather Over the Next 5-7 Days

  • Record setting heat will come to an end after Wednesday
  • Overall weather pattern shift means we will start to see more seasonable (read cooler) temperatures
  • A stronger cold front and associated storm system may bring us a bit of moisture towards the middle of next week
    • Yes, snow is possible… but very unlikely at this time
  • Beware TV Stations and Social Media sources that hype up snow next week… it’s way too early to tell, it’s unlikely and it’s ratings season!

 

 

Florence: Dangerous Storm Could Effect East Coast This Week

Hurricane Florence Update | NHC Forecast Cone

11PM Eastern Time forecast track from National Hurricane Center for September 9, 2018

Hurricane Florence is a storm we’ve been watching for a few days now… as we’ve seen models jump back and forth we advised caution and keeping an eye on this storm. It also wasn’t a bad idea to make preparations for this storm whether it be preparing to evacuate or to go to the store and get necessary supplies.

Sadly, it is looking more and more likely that Florence will impact the East coast of the U.S. between South and North Carolina. This storm is anticipated to undergo rapid intensification late Sunday and through Monday and Tuesday, current landfall projections are as a Category 4 storm.

 

Hurricane Florence Update | Spaghetti Models

Hurricane Florence model track plots as of 11PM Eastern Time on September 9, 2018

There are a few models that still take Florence back out to sea, but we’ve seen a lot more agreement on tracks taking the storm into the East Coast of the U.S. and especially in and around the Carolinas.

Our Advice

Although not Colorado weather related, we urge folks with friend and family in these areas to keep in touch with those folks. Urge them to prepare for this storm if they haven’t yet… if this storm landfalls as a Category 4 it will be very significant.

There are still slight chances the track shifts or the storm goes back out to sea but the models predicting that are becoming fewer and fewer.

Resources

 

Please feel free to share the above resources with friends and family… all are from the National Hurricane Center so they are reliable information.

We’ll keep an eye on the storm and pass any updates along this week!

Colorado Drought Update

Latest Drought Update

Current Colorado drought status as of 8/16/2018

The biggest change to Colorado’s drought status for the week was the expansion of severe drought conditions across a good portion of Western Colorado to include many mountain areas. Many mountain areas have experienced above normal temperatures most of the summer and have been very dry. The expansion of the severe drought status is an indication that these areas are becoming quite parched as we move towards fall.

The National Drought Summary also mentioned, “According to August 12 USDA reports, 59% of the pasture and rangeland in Colorado was in poor to very poor condition, and 42% of the topsoil was short or very short of moisture.”

Closer to Home

Palmer Divide region drought status as of 8/16/2018

Not much change from the past few weeks along the Palmer Divide. Most of the Northern sections remain abnormally dry with southern sections in the moderate drought classification. There are  few areas in Southern and Eastern Elbert County that have made it into severe drought, but this hasn’t changed in the past few weeks.

Why Are We Still in Drought?

Often folks have short memories when it comes to weather, the past few weeks most areas have seen rain fueled by the monsoon and some areas have seen quite a bit of it! The thing with drought is, it’s not a short term problem and there are no quick ways to knock out drought.

Let’s take a look at how July finished for precipitation in Castle Rock for example, when the monsoon started

When you go back and look a the data, July finished just slightly above average for precipitation, we’d certainly qualify that as a “good” monsoon pattern as it brought beneficial rain across the Palmer Divide. Many areas ended up way above average, but that was only one month. Drought does not form or dissipate in a period of one month (except in very rare circumstances.)

So the month of July finished slightly above average, that’s good! Let’s zoom out a little bit and take a look at the three month period between May and June this year…

Precipitation stats for Castle Rock from May 1 – July 31, 2018

Not terrible but overall precipitation was just a tad below average… so whatever our drought status was at the time, we didn’t receive enough to dent it but weren’t dry enough for it to become too much worse.

If we zoom out just a bit more and look at the entire year the picture becomes a bit more clear. Castle Rock is over 2.5 inches below average for the year. This doesn’t sound like much, but 2+ inches is a big deal.  When you look back at the beginning of the year especially, you can see how dry our winter and spring were. Spring being one of our wet times of the year; if we fall behind in March and April, it is difficult to make that up for the rest of the year.

Castle Rock recorded precipitation vs. average from 1/1/2018 – 7/31/2018

Speaking of March and April, when we look purely at snowfall for  snow year (September 1 – June 1), we can see more evidence of why we are still in drought status.

Snowfall statistics for Castle Rock from 2017-2018 snowfall season

Castle Rock was over 13 inches below average for snowfall last season. That combined with the overall lack of precipitation compounded our drought conditions and is a big reason why we are still seeing stress on vegetation, not to mention fires still going across the state.

By the way, for the snowfall season September 1, 2017 – June 1, 2018 Castle Rock was nearly 6 inches below average for precipitation. That is an enormous amount of missing water!

Any End In Sight?

Figuring out how long a drought will last is not an easy task, it requires a lot of long range forecasting and a bit of luck.  With an El Nino pattern brewing for us going into fall and winter, there is reason to be optimistic about our chances of a wetter than average fall and winter.

This is whole topic in and of itself and will coincide with our long range forecast for the Palmer Divide (looking at fall and winter conditions expected for 2018-2019) Stay tuned for that and we will have more details on that and if we think our drought will be broken anytime soon.

Wrapping It All Up

So remember, drought is a long term weather phenomenon. There is no quick start or end, it’s something that either builds or dissipates over a period of time. Our drought this year has been building since late 2017… with months and months of dryness a few weeks of rain in July is just enough to stop it from getting worse. It will take several months of above average precipitation to break us out of a drought, hopefully things pull together for us this fall!

Precipitation anomaly for Sept 2018 – July 2018. You can see how the worst areas of drought follow along the driest areas on this map.

Don’t forget to look at the big picture, July 2018 was quite wet, but overall for the past year we’ve seen many more abnormally dry months than abnormally wet months!

7/25/2018 – Monsoon Pattern will make for Active Weather Day

The 2018 summer monsoon pattern has firmly established itself across the Southwestern United States and with it moisture is being funneled into Colorado. Many areas have seen strong storms with hail and heavy, flooding rains over the past few days.

Castle Rock Weather | Colorado Weather | Summer Monsoon

The summer monsoon is a pattern that shepherds subtropical moisture into Colorado.

Severe Weather Outlook for Wednesday

As with most storms the past few days, there is ample moisture and instability for stronger storms to pop up with a threat for heavy rain, wind, lightning and large hail. Be prepared to move indoors or take steps to protect property with any storms that form this afternoon.

Palmer Divide will be Focal Point Again

HRRR model around 5PM Wednesday July 25, 2018

Timing

  • Models have storms firing across the foothills by 2-3PM, we’d expect them to move Eastward along the Palmer Divide shortly after (thinking after 3PM)

 

Main Threats

  • Heavy rain and strong winds will be the most likely threats
  • There is a chance for storms to contain large hail
  • Frequent lightning means don’t get caught unprepared outdoors. Be ready to move inside or take shelter!

 

HRRR model reflectivity around 8PM

Please note! Models show an additional wave of storms moving through later in the evening around the 7-9PM timeframe.

Heavy Rain Possible Thursday

Monsoon Sneak Peak

Thursday, the high pressure ridge responsible for our hot and dry conditions shifts slightly to the West. This means good moisture from the Gulf of Mexico will make its way into Colorado. That combined with weak steering winds, means storms will move slowly and have the potential for heavy rain!

A Marginal Severe Weather risk encompasses the Palmer Divide and most of Eastern Colorado for Thursday.

Storm chances are in the 60-80% range today; I like those odds. Most folks will see beneficial rain today but due to the instability in the atmosphere we can’t rule out a very isolated severe storm.

Primary threats include:

  • Heavy rain/ flooding conditions
  • Strong winds
  • Lightning
  • Possibility of hail exists for short time periods

For those of us along the Palmer Divide, the best chance of seeing storms is in the 4pm-8pm range with additional storms possible until midnight. Please stay weather aware!

 

6/25/2018 – Palmer Divide Weekly Weather Outlook

The week ahead looks to transition back into a more summer pattern for Colorado and most of the Southwest and South. As the storm system responsible for our cooler air and rainy conditions departs off to the Northeast, a high pressure system moves in from the Southwest. High pressure generally means the storm track gets steered away from Colorado and hot, dry, desert air from the Southwest gets pushed into Colorado and the Southern and Western United States.

On the 500mb (upper level air) model below, we can plainly see the low off to the East and the high building in over SW Colorado. This model run is for Tuesday and subsequent model runs show this feature strengthening through Wednesday and Thursday.

Colorado Weather | Castle Rock Weather | Temperature Outlook | Colorado Front Range Weather | Mountain Wave Weather

Upper level ridge (high pressure system) seen building over Southwest Colorado for this model run on Tuesday June 26.

So what does this mean for our weather this week? Plainly put… it’s going to get very hot. Possibly some of the warmest temperatures we’ve seen in at least a year and possible a couple of years. Here’s a look at forecast high temperatures for Tuesday – Thursday this week.

Castle Rock Weather | Palmer Divide Weather | Summer Heat | Colorado Weather

Tuesday High Temperatures

Castle Rock Weather | Palmer Divide Weather | Summer Heat | Colorado Weather

Wednesday High Temperatures

Castle Rock Weather | Palmer Divide Weather | Summer Heat | Colorado Weather

Thursday High Temperatures

Toasty to be sure, but honestly I think the temperatures from this model for Wednesday and Thursday are a bit cooler than they will end up. A lot of the model ensembles show temperatures pushing or exceeding 100 degrees in Denver for Wednesday and Thursday. If that occurs, expect temperatures along the Palmer Divide to trend upwards a few degrees from what you see above as well.

Summary

Expect mild conditions on Monday as the ridge hasn’t quite built in yet. By Tuesday we begin to crank the heat up a bit but the hottest days will be Wednesday and Thursday by far. Chances for rain or thunderstorms look low (generally 10% or below) through Thursday.

If you have outdoor activities this week, stay cool and hydrated. Sunscreen will also be an absolute must!