The Official 2009-2010 Denver winter weather thread

[Dencolo]

Never like having to rely on the GFS, but it's something to look forward too....

From Denver AFD

FRONTS DROPPING ACROSS NORTHEAST COLORADO TUESDAY AND WEDNESDAY. GFS
FORECAST TEMPERATURE AT 700 MB IS -9 DEGREES ON WEDNESDAY...IF RIGHT
HIGH TEMPERATURES WILL STRUGGLE TO REACH THE MID 40S UNDER UPSLOPE
CONDITIONS. HAVE LOWERED MAX TEMPS A BIT ON WEDNESDAY. POPS WILL
INCREASE...AND THIS COULD BE THE FIRST SNOWFALL IN THE LOWER
ELEVATIONS OF THE SEASON. IF ECMWF AND 18Z DGEX ARE RIGHT...MUCH OF
THE COLD AIR WILL STAY NORTH OF US....SO STAY TUNED.

[Dencolo]

RECORD EVENT REPORT
NATIONAL WEATHER SERVICE BOULDER, CO
705 AM MDT FRI OCT 2 2009

...NEW RECORD LOW TEMPERATURE FOR DENVER...

AT 555 AM THE TEMPERATURE AT DENVER INTERNATIONAL AIRPORT DROPPED TO
26 DEGREES. THIS SETS A NEW RECORD LOW FOR OCT 2. THE OLD RECORD WAS
30 DEGREES SET IN 1999 AND 1959.

Looks like we're a llitte ahead of schedule....

Earliest Date of First Freeze: September 8, 1962
Latest Date of First Freeze: November 15, 1944
Average Date of First Freeze: October 7th
First Freeze Last 8 Years:
October 13, 2008
October 8, 2007
September 18, 2006
October 5, 2005
October 14, 2004
September 14, 2003
October 4, 2002
October 5, 2001

[Dencolo]

From Denver AFD, looks like next weekend could be interesting. At least the 2 major models are starting to come into agreement:

THE NORTHERN BRANCH IS STILL LOOKING LIKE THE DOMINANT FEATURE LATER IN
THE WEEK. THIS IS STILL SLATED TO BRING AN INITIAL PUSH OF COOLER
AIR ACROSS THE FORECAST AREA THURSDAY...AND THEN ANOTHER STRONGER
COLD FRONT BY LATE FRIDAY OR FRIDAY NIGHT. THIS NEXT SHOT IS COLD
ENOUGH TO BRING THE THREAT OF SNOWFALL TO THE ENTIRE FORECAST
AREA...AND THE GFS IS FINALLY COMING AROUND TO THE ECMWF SOLUTION OF
THE LAST 2 DAYS AS WELL.

[PTPatrick]

Was just looking at that discussion when I got home from work. I checked out the GFS and its definately trended much deeper and has -10 line ( have struggled to get below the 0 line) dipping into N colorado by sunday night. Looks like GFS has widespread post-frontal QPF (albeit the light variety), most likely in the form of snow or flurries/drizzle, occuring from saturday morning through nighttime. Of course everything is subject to change. I would love to get my hopes up but the 6-7 day time frame lately has proven quite wrong for this area on GFS. If it is still advertising by tuesday evening, I might get excited Of course the agreement with the Euro (and even the Candian, cuz I checked it) does give me a little hope

[SCMedic]

Looking better and better for a Friday night snow event! Heck, an inch or two would be great!

[Dencolo]

The whole weekend looks rather cold with several chances of snow. Check out the potential Sunday morning....

http://www.nco.ncep.noaa.gov/pmb/nwprod ... _144.shtml

[SCMedic]

Looking good. Each discussion brings colder temps, and now the mention of all snow, instead of a rain/snow mix. Whooo!

[SCMedic]

Now the mention of rain/snow chances Thurs and snow Thurs night. Looks like we could truly have an active weekend.

LONG TERM...MODELS CONTINUE TO DEVELOP THE COLDER AND UNSETTLED
PATTERN FOR THE SECOND HALF OF THE WEEK AS A COUPLE COLD FRONTS DROP
SOUTH OVER THE STATE AND POTENTIAL IS IMPROVING FOR THE SEASONS
FIRST SNOWFALL OVER THE LOWER ELEVATIONS.



For Thurs:

MODELS HAVE ALSO
TRENDED TOWARD A SLIGHTLY WETTER AIRMASS ALONG WITH UPSLOPE FLOW SO
HAVE BUMPED THE POPS FROM SLIGHT CHANCE TO CHANCE...AS THE NAM STILL
WANTS TO DISSIPATE THE MOISTURE ONCE IT COMES OVER THE CHEYENNE
RIDGE. 700 MB TEMPS LOWERING TO -4 TO -8C BRINGING THE CHANCE OF
SNOW MIXING IN WITH RAIN OVER THE PLAINS.

Weekend:

THE NEXT FRONT WILL ARRIVE AROUND FRIDAY NIGHT AS A JET ON THE
BACKSIDE OF THE TROUGH PUSHES SOUTH TOWARD THE STATE. THIS FRONT
LOOKS TO HAVE SLIGHTLY COLDER AIR BEHIND IT COMING STRAIGHT OUT OF
THE ARCTIC AS THE TROUGH STAYS OVER THE CENTRAL US KEEPING THE COLD
NORTHWESTERLY FLOW ALOFT. HAVE ADDED IN MORE CHANCES OF ALL SNOW
THROUGH THE WEEKEND. MAX TEMPS COULD STRUGGLE TO GET OUT OF THE 40S.

[PTPatrick]

I still WANT to get excited but GFS has all the QPF hung up over the Cheyenne area through the whole period. So far there is still very little continuity other than the cold is coming. The question is how much precip with it. last night GFS had a nice bit of snow here for Thursday night but thats gone down considerably, and like I said, the Friday-Sunday time period it is keeping most of the QPF north. Its so aggrevating with the switching back and forth. If its any consolation the Canadian has some QPF for THursday night and then again towards Saturday morning. So there is certainly still hope.

[SCMedic]

Hmmmm.. Pretty dissapointing to hear your view. Seems local mets and NOAA are more bullish with this upcoming couple of systems. Hell, local mets are even calling for snow, and I've seen them put "partly cloudy" up with a WSW.

[SCMedic]

Thurs 18Z on the newest GFS run...


Sat at 00Z.. Same run.

[Dencolo]

Loveland (ski resort) is opening up tomorrow! A-basin on Friday. Earliest ski season opening in 40 yrs for Loveland - earliest opening for A-basin ever. It was nice to see Loveland win the opening battle for a change. I was starting to think A-basin was never going to lose.

On another note, I'm getting more bullish on some snow for Thursday in Denver. I don't think any of the upcoming systems will accumulate a ton of snow, but I'd be surprised if we didn't get at least some accumulation.

http://www.denverpost.com/extremes/ci_13498572

[PTPatrick]

I to after looking at models from this afternoon, feel Thursday night is the Metro area's best chance at seeing real accumulation. Having said that, I am expecting that Friday will be mostly dreary, and Saturday and Sunday will probably feature intermittent snow showers that dont accumulate much. Either way a "snowy" day in early october is pretty crazy. Cheyennes discussion is pretty bullish on the cold period, they are talking low teens for some of thier plain zones, which if that pans out I could easily see low 20s in the metro area. I think the Friday night to sunday night time period is just going to be one of those periods where we wont know when its going to snow until is as every model seems to have subtle differences that are making quite a bit of difference in QPF.

MEANWHILE...I was caught WAY off guard by the frost this morning. There wasnt even a freeze warning and it was 28 degrees. I had more frost than any of the previous freezes. Anyway, more watching and waiting...

[SCMedic]

Looks like the morning discussion is coming around to a snow event for Thursday afternoon/evening with what's looking like a stronger one on Friday night. Scattered snow showers around for sat/saturday night at this point. Curious to see if they come around to another short wave on Saturday like some of the models show. Looks like Game 3 will be a chilly/snowy one for me.

[Dencolo]

http://forecast.weather.gov/MapClick.ph ... 04.873&e=1

Looks like we'll get our first measurable snowfall tomorrow, October 8th. If so, that would be our earliest snowfall since 2001, and beat the average first snowfall by 11 days. And more may be in store this weekend. Nice!

Autumn First Snow Information
Earliest Date of First Snow: September 3, 1961
Latest Date of First Snow: November 21, 1934
Average Date of First Snow: October 19th
First Measurable Snow Last 8 Years:
November 14, 2008
October 22, 2007
October 18, 2006
October 10, 2005
November 1, 2004
November 5, 2003
October 25, 2002
October 5, 2001

[Dencolo]

They upped the snow chance to 70% for tomorrow - And now some freezing drizzle in the forecast for the weekend. Freezing drizzle/rain is not too common for Denver. Let's see if that pans out....

http://forecast.weather.gov/MapClick.ph ... 04.873&e=1

[PTPatrick]

Well, unfortunately its game time and there still isnt much model support for anything more than an inch with tonight or friday-sunday time frame. Actually very little QPF showing up on the models for the weekend(<.2 inches for the whole period). Seems like our best bet is a little dusting of fluffy snow, that will probably melt quickly because of ground temps. Not complaining, just saying. I will take any snow I can get, and I am trying to send good joo joo to the snow gods. We will just have to see. Should be nice to look out the window this evening and see a few flakes in the air, even if it amounts to zilch.

[VoodooCadillac]

FYI - live in Fort Collins - work in Cheyenne - commute 4 times a week. Left FC @ 6:45 this AM, ran into snow in Wellington, enough snow just south of the State Line to make I-25 snow covered and a little slick. About 1" of snow in Cheyenne @ 7:30 AM.

[PTPatrick]

Well, I suspect most of us have the same story to tell. Flurried/drizzled/ light snowed all day in Denver, nothing stuck. Ok I saw a little white on the north side of a tree, but thats about it. Moving on to tomorrow night.

[Dencolo]

Still getting some light flurries now on the southside. Temp right at 33.. Snow may move out just in time to start sticking, even though these flurries wouldn't amount to much.

Today the temp was just about 3-4 degrees to high, preventing accumulation. Saturday it looks like the temps will top out close to freezing. Now, will we get the precip????