Updated Monday, 3/17, 9:50am – The National Weather Service has cancelled the Heavy Snow Warning for the Denver metro area.  Light snow early this morning should come to an end in most areas by late this morning and little additional snow accumulation is anticipated.  We should see gradual warming with dry and seasonal temperatures at least until Friday. 

Updated Monday, 3/17, 6:00am, Heavy Snow Warning Remains in Effect – Well, thus far the storm hasn’t quite shaped up as it was expected to, at least in the Denver metro area.  The one component that is really missing for heavy snowfall is a good, strong upslope wind.  Upslope winds have a northeasterly / easterly component and are what typically is required for us to see big snows and that just hasn’t happened – at least not enough of one.  Things started out strong yesterday evening with some good snow falling around 8:00pm but it didn’t last long.

Western Kansas on the other hand appears to be bearing the brunt of the storm with a mix of blowing snow and thunderstorms.  Indeed, our lightning detector was picking up a number of strikes out there during the 5:00am hour although that has since dissipated.

Looking at the rest of today, we do still remain under a Heavy Snow Warning until 3:00pm although if things don’t change, that could be lifted sooner.  Radar does show moisture coming up from the south of the metro area and forecasts still call for an additional 3 to 5 inches possible this morning.  However, with the temperatures staying near freezing, much of that will melt rather than accumulate. 

Updated 3/16, 5:15pm – It is looking more and more like this storm will be a reality.  The National Weather Service has upgraded the advisory to a Heavy Snow Warning that goes into effect at midnight tonight and runs through 3:00pm tomorrow.  Current projections are still a bit flakey and show that we will receive anywhere from 4 to 12 inches of snow by the time the storm moves out tomorrow afternoon.  As is typical in Colorado and especially with spring storms, we could even see sunshine by the end of the day tomorrow.

A heavy snow warning means severe winter weather conditions are expected or occurring. Significant amounts of snow are forecast that will make travel dangerous if not impossible. Only travel in an emergency. If you must…keep an extra flashlight…food…and water in your vehicle in case of an emergency.

3/16/08, 4:27am, Snow Last Night, Heavy Snow Warning In Effect For Tonight – Thornton woke up to a bit of a surprise this morning with some of the white stuff on the ground – just shy of half an inch at ThorntonWeather.com.  The forecast did say there was a chance but it was pretty slim so it wasn’t really expected.  It is a typical spring snow with lots of good moisture in it so it is welcome.  We should be mostly dry for most of the daylight hours today but the structure of the system is such that some thunder could be heard today – a bit of a herald of the spring thunderstorms that will be coming soon.  Heading into late afternoon and this evening things will change. 

The Pacific storm we have been waiting for is on its way and the National Weather Service has issued a Winter Storm Watchthat goes into effect late tonight and runs through Monday morning.  The track of this system is still a bit uncertain so the forecasts and models are hedging their bets a bit.  🙂   Current models are across the board for precipitation totals and locations so it is tough to say what we are going to end up with.  At the current time we would expect Thornton to see 3 to 7 inches of snow by the time the storm moves out tomorrow. 

Remember that a Winter Storm Watch means there is a potential for a hazardous winter event in and close to our area.  Significant snow accumulations may occur that could impact travel.  Tomorrow morning’s commute could be a bit ugly so plan on leaving for work early. 

Colorado in the spring!  Quite an array of weather across the state ahead for the coming days.  The northern and central mountains are getting pounded with snow where Winter Storm Warnings are in effect through Friday night.  One to two feet of snow is expected up there as our record snowpack continues to build.

On the Front Range, while the statewide snowpack is still well above-average, Denver is about 5 inches behind for the seasonal winter average and about 9 inches below the monthly average.  However, we have a pretty active weather pattern expected for the next week that could eat away at that deficit.  March is usually our snowiest month so the potential is there for some good storms in the coming weeks. 

Scattered rain and snow showers are possible throughout today and this weekend.  The big storm we were hoping to see Sunday night and into Monday looks to be pushing south into New Mexico but will cause us to be a bit unsettled through Tuesday at least.  Stay tuned to ThorntonWeather.com for the latest! 

We’re in the typical rollercoaster weather pattern that we usually see in the spring.  Tuesday was beautiful with a high of 68 degrees in Thornton.  Today will be a bit cooler as we reach 62 or so and that cooling trend should continue into the weekend.  A small disturbance could bring some minor snow accumulations to the area on Friday. 

Looking a bit further ahead, big changes could be in store for Sunday night and into Monday.  We are currently tracking a major Pacific storm system that is working its way west and if it tracks over the state, significant snowfall could result.  This far out the models are pretty inconsistent – some show it hitting us, others show it tracking much farther south into New Mexico. 

Updated, Sunday, 3/2/08 @ 4:20pm – The storm has pretty much passed to the south of the Thornton area at this time.  The NWS says they will keep the Snow & Blowing Snow Advisory in effect until 8:00pm but there is little cause for concern on our side of town.  Any lingering showers should be confined south of I-76 and I-70.  Look for clearing skies tonight and a cool but decent day tomorrow.  Our next chance for precipitation should be into Wednesday but at this time that doesn’t look like it will amount to much. 

Updated, Sunday, 3/2/08 @ 2:00pm – After a bit of a lull things started picking back up for a while.  Winds continue to blow quite a bit and more snow is falling.  As previously mentioned, it is difficult to measure with how much it is blowing and drifting.  The National Weather Service guidelines say to take an average and pretty much make a “best guess” so that is what we do – call it 4.1″ of snow thus far today. 

Areas south continue to get the worst of the storm, particularly from Park and Jefferson counties east through Douglas and Elbert counties.  Blizzard conditions exist in these areas and do stretch north into eastern Adams county and to Limon.  Travel is not advised in these areas.

Radar does seem to indicate that the storm is slowly moving out and we should start seeing a decrease in intensity on the north side of town in the next couple of hours. 

Speaking of blizzards…  As of yet, this storm has not been classified as an official one – at least in the metro area.  By National Weather Service definition, a blizzard has winds of 35mph or greater and blowing snow that reduces visibilities to 1/4 mile or less for more than 3 hours.  Today, while the wind has been nasty, speeds have  been a bit erratic and we haven’t  had the sustained speeds to meet the definition.  Further, snowfall rates for the most part haven’t caused that severe of visibility issues.   Areas south and east of Denver however do appear to meet the criteria.

Updated, Sunday, 3/2/08 @ 8:40am – Fast and furious would be a good description of this storm.  The wind is the biggest thing right now causing drifting.  In our area depending on where you measure you can have anywhere from 1/2″ to 5″ which makes it pretty difficult to get an accurate measurement.  Radar does currently show that the worst of the storm has passed us by so it should continue to taper off although the wind will be with us for a while. 

Below are a few pictures we took at around 6:40 this morning as the worst of the snow was falling.

Updated, Sunday, 3/2/08 @ 5:25am – The storm is here!  Snow has started falling in the north Thornton area just in the last 15 minutes.  Coupled with it are extremely high and dangerous winds.  The winds started building about an hour ago as the storm approached and reached a crescendo just before 5:00am when we recorded a ThorntonWeather.com record wind gust of 46mph.  This shatters the old record of 40mph.  Current average windspeeds are above 30mph which is quite high.

Radar is showing the front moving south across the area and conditions should continue to deteriorate as we get closer to sunrise and as the morning progresses.  Please rememeber that there is a Snow & Blowing Snow Advisory in effect until 8:00pm tonight.  A snow and blowing snow advisory means that visibilities will be limited due to a combination of falling and blowing snow. Use caution when traveling, especially in open areas.

Saturday, 3/1/08 @ 11:00pm – At 9:51pm tonight the National Weather Service issued a Snow & Blowing Snow Advisory for much of central Colorado and the central and northern mountains.  This goes into effect at 5:00am Sunday through 8:00pm.  Areas affected do include the Denver metro area.  Current models are indicating a stronger than expected upslope with this storm which will help slow it down as it moves through the area. 

Rain and snow showers could start to appear after 2:00am, changing to mostly snow by dawn.  By the end of the day Sunday we could see between three and five inches of snow in Thornton.  However, the ground is pretty warm thanks to the nice weather in recent days so a lot of it won’t stick.  The wind could cause some minor drifting and higher accumulations.   The south metro area and the Palmer Divide could see some significant accumulations and driving conditions will deteriorate quickly so if you are heading that way, please be aware.

This is of course quite a change compared to today (Saturday) when DIA reached a new record high for this date of 74 – the old record was 73.  Up north in Thornton we were a bit warmer with a high of 75.7.  We hope everyone enjoyed the warmth because change is coming!  🙂