2011/2012 Denver Winter Weather: Maybe this year!

[SCMedic]

With our first fall cold front dropping through on Weds and snow levels falling to 10k feet, I figured it was a good time to start the Winter Weather thread for the front range.

Someone kill a chicken or something so we can see some flakes this year!

[PTPatrick]

Ha! you read my mind. Its not looking goood...another La Nina winter...just when I thought the last one fizzled. its like wack-a-mole. Hopefully it wont be as strong as last winters and wont effect our snow chances much. Either way I am ready for some cold weather and cloudiness!

[SCMedic]

Looks like the snow level could be down as low as 8k in the heavier front range rain as the upslope gets fairly deep tonight. Should see 1-2" across the metro area(rain).

Long term models give us a much weaker La Nina than last year. I'd be willing to bet we can't have LESS snow than last season.

[zephyr99]

Speaking of LaNina years and snowfall in Denver:
2010-2011: 22.8"
2007-2008: 46.3"
2000-2001: 58.3"
1999-2000: 45.6"
1998-1999: 44.5"
1995-1996: 50.3"
1988-1989: 50.1"
1984-1985: 55.2"

Of note snowfall measurements were taken at Stapleton until June of 2008, then measurements were taken from DIA afterwards. So 2010-2011 was the first LaNina year with DIA as the station. Definitely dry years, but not record breaking.

[Dencolo]

GFS been pretty consistant in some coolor wetter weather at the end of next week. I'll go ahead and predict some snow for the foothills for next Friday!

From morning AFD:

THE LONG RANGE MODELS ARE HINTING AT SOME CHANGES COMING LATER NEXT
WEEK AND INTO NEXT WEEKEND BUT STILL BEYOND OUR DAY 7 RANGE. STILL A
LOT OF INCONSISTENCIES IN RUN TO RUN IN REGARDS TO TIMING BUT EXPECT
A GRADUAL COOLING OFF PERIOD WITH INCREASING CHANCES OF SHOWERS. AT
LEAST SOMETHING TO TALK ABOUT.

[Dencolo]

Still looking for some colder weather to move in. From this morning's AFD:

STILL LOOKING AT A PATTERN SHIFT BY LATE IN THE WEEK AS A STRONGER
DISTURBANCE MOVES INLAND OFF THE WEST COAST AROUND THURSDAY. MOST OF
THE BIGGER CHANGES WILL BE BEYOND THE DAY 7 FORECAST WITH CERTAINLY
COOLER TEMPERATURES AND A BETTER CHANCE OF SHOWERS RETURNING. LONG
RANGE MODELS STILL SHOWING CONSIDERABLE DIFFERENCES WITH THE
EUROPEAN SOLUTION DEVELOPING A CLOSED LOW OVER COLORADO ON FRIDAY
WHILE THE GFS HAS A MORE OPEN AND PROGRESSIVE SOLUTION. EVEN THE GFS
ENSEMBLE MEMBERS ARE QUITE VARIED WITH A FEW OF THE MEMBERS SHOWING
A CLOSED OFF SYSTEM. INDEED IF THE SYSTEM DOES CLOSE OFF SOMEWHERE
TO THE WEST OR SOUTHWEST OF COLORADO THEN OUR CHANCES OF INCREASES
PRECIPITATION WILL BE GREATER. STAY TUNED BUT WOULD FAVOR THE SLOWER
AND MORE AMPLIFIED EUROPEAN SOLUTION GIVEN THE HIGHLY AMPLIFIED
PATTERN.

[SCMedic]

Still looking for some colder weather to move in. From this morning's AFD:

STILL LOOKING AT A PATTERN SHIFT BY LATE IN THE WEEK AS A STRONGER
DISTURBANCE MOVES INLAND OFF THE WEST COAST AROUND THURSDAY. MOST OF
THE BIGGER CHANGES WILL BE BEYOND THE DAY 7 FORECAST WITH CERTAINLY
COOLER TEMPERATURES AND A BETTER CHANCE OF SHOWERS RETURNING. LONG
RANGE MODELS STILL SHOWING CONSIDERABLE DIFFERENCES WITH THE
EUROPEAN SOLUTION DEVELOPING A CLOSED LOW OVER COLORADO ON FRIDAY
WHILE THE GFS HAS A MORE OPEN AND PROGRESSIVE SOLUTION. EVEN THE GFS
ENSEMBLE MEMBERS ARE QUITE VARIED WITH A FEW OF THE MEMBERS SHOWING
A CLOSED OFF SYSTEM. INDEED IF THE SYSTEM DOES CLOSE OFF SOMEWHERE
TO THE WEST OR SOUTHWEST OF COLORADO THEN OUR CHANCES OF INCREASES
PRECIPITATION WILL BE GREATER. STAY TUNED BUT WOULD FAVOR THE SLOWER
AND MORE AMPLIFIED EUROPEAN SOLUTION GIVEN THE HIGHLY AMPLIFIED
PATTERN.

I don't think there is going to be enough cold air for our first snow with this storm, but it's a start. Let's hope it pans out.

[SCMedic]

Wouldn't be surprised to see some wet flakes mixed in late tonight and tomorrow. A few of the oultliers (NAM) show accumulating snow all the way out to DIA. Don't think that'll be the case, but with evap cooling in the dry subcloud layer, could see temps cold enough for flakes. Heavier bands could produce too as they pull down cold air from up high.

Either way, enjoy. 70's coming back by Mon.

[Dencolo]

Some snow has accumulated on grass around town. Closest web cam I've seen to town with accumulating snow is 470 and I25. Not much here though on the SW side.

[SCMedic]

A few flakes mixed in for me up north during the day but nothing much at all. Maybe a brief changover. Rained and chilly all day. Looks like 70 and south did ok for accum. A little colder than expected changed things a bit. Warming back up for a week at least now.

[PTPatrick]

Well, it's only october 12th, and imalready bored with winter. I know it's early for much snow, but I feel like good fall cool days haven't even been around...except for last Saturday. And now were looking at 70s to 80 through the weekend. Needing a good snowy october day....but long range gfs looking ridgy through next 2 weeks.

[PTPatrick]

Snow is now in the Denver forecast...only 6 days left for it to fizzle into a dry windy cold front!

[SCMedic]

Models are actually in really good agreement for a solid frontrange setup. We'll see.

[PTPatrick]

Got to look at 12zgfs and Canadians...both would have a pretty good snow storm for the front range...probably on the order of 4-8 along I-25 and over a foot in foothills, Palmer divide. Looks later...with precip cranking late tuesday evening. Looks to me like rain, if any would be very brief, with most of the 1-1.5 inches of qpf as snow. If gfs really panned out i think 8-12 isn't out f the realm of possibility even in Denver. Of course all the usual October caveats will be in place, evaporative cooling, heavy wet snow, warm ground, etc,..which is why 4-8 seems more reasonable. Good thing bulk of now would be over night and looks relatively heavy, accum rates could be good.

Of course lots of time for this to change...but you gotta love a GFS 5 day forecast blizzard.

[PTPatrick]

Tonight's gfs is wetter and slower...widespread1.5 inch qpf, with up to 2 inches. If that wet could easily drop 20+ inches in the foothills.

[Dencolo]

About 4 days away and gfs still looking very wet. Now I think it's a safe bet we will see our first snow. The question is how much. Forecast highs for Wednesday are now in the mid 30's and gfs is now showing more of an all day event. I think the previous runs weren't as wet mostly due to the speed of the system.

[Dencolo]

12z GFS still looking strong. Here is an updated HWO

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL
COLORADO.

.DAY ONE...TODAY AND TONIGHT

DRY AND MILD CONDITIONS WILL PREVAIL.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

A SIGNIFICANT CHANGE IN WEATHER IS EXPECTED TO REACH NORTHEAST AND
NORTH CENTRAL COLORADO TUESDAY EVENING AND WEDNESDAY AS A STRONG
UPPER LEVEL DISTURBANCE MOVES ACROSS THE STATE. RAIN AND SNOW ARE
EXPECTED TO DEVELOP TUESDAY EVENING AND THEN CHANGE TO SNOW BY
WEDNESDAY MORNING. SIGNIFICANT SNOWFALL WILL BE POSSIBLE OVER THE
FRONT RANGE MOUNTAINS AND FOOTHILLS...ALONG WITH THE PALMER DIVIDE
AND I-25 CORRIDOR. STAY TUNED TO THE NATIONAL WEATHER SERVICE FOR
THE LATEST FORECASTS AND UPDATES CONCERNING THIS APPROACHING STORM
SYSTEM.

VERY COLD TEMPERATURES FOR LATE OCTOBER WILL ALSO ACCOMPANY THIS
STORM. HIGH TEMPERATURES ON WEDNESDAY MAY ONLY BE IN THE 30S ACROSS
THE PLAINS. LOW TEMPERATURES ON TUESDAY NIGHT AND WEDNESDAY NIGHT
MAY BE WELL BELOW FREEZING. MODERATING TEMPERATURES AND DRIER
WEATHER ARE EXPECTED THURSDAY AND FRIDAY.

[SCMedic]

Personally, I think the temp drop will be quick and we'll go all snow Tuesday evening. 2" of QPF across the board is pretty good. Even with low 10:1 snow to liquid ratios, warm roads and compaction, we should see at least 10-12" fall across the urban corridor. Whether or not we have 10-12" on the ground at any point is another story.

[PTPatrick]

I would agree, ground temps , and all other things being equal, we'd prolly be looking at a foot of snow in Denver...but as warm as it's been and will be tomorrow, just can't see it happening. I agree though most of that 1.25 of qpf should be snow. Will be interesting. Climo speaking it's snow time. I think if this forecast holds foothill locals could be digging out around 18 inches.


Looked back at the October '09 blizzard to try and make some comarisons...it dropped 15 inches at DIA which was from only about .7 inches of qpf at DIA. That storm gave me something on the order of 20 inches. Places in the foothills got 30+ inches. This looks much more brief. That storm lasted like 2 and a half days....if it was able to rack up 20 inches in downtown, snowing at that slow of a pace...maybe this one could do well since it looks heavy and fast. On the other hand... we had already had one small snow that month and a freak cold spell early in the month with teens, so ground would have been considerably colder. It was actually the second coldest October in history. This october has been pretty toasty.

[SCMedic]

That storm gave me 22" in my yard. Great storm. Models are trending colder max temps. I think if it starts hard and fast we could make up for that warm ground with coverage. Part of me is still waiting for it to fizzle after last years non-events.