The Official 2009-2010 Denver winter weather thread

[VoodooCadillac]

Steady, moderate rain started in Fort Collins around 5:00 PM. Temp has dropped from mid-40's to 37 at the moment, so the change over to snow may come earlier than expected.

Still scheduled to fly out of DIA at 1:00 PM tomorrow. We've attempted to bump flight to earlier time slot - but airline isn't allowing that with paying exorbitant fees. Our worst fear is a moderate snow storm - not hard enough to close the airport - but bad enough to wreak havoc on the flight schedules. So we're hoping for a crazy, epic storm so we'll just get a credit for a flight at a future date.

[VoodooCadillac]

Rain changed over to moderate, wet snow around 7:45 PM.

[SCMedic]

Broomfield the snow is coming down hard!! Half inch on the grass and street is filling in.

[Dencolo]

Just starting the changeover to snow on the SW side of town. Earlier than anticipated. Check out the latest WSW...crazy!

A WINTER STORM WARNING REMAINS IN EFFECT FROM MIDNIGHT TONIGHT TO
6 PM MDT THURSDAY.

SNOW WILL BECOME WIDESPREAD THIS EVENING AND CONTINUE INTO THURSDAY.
SNOW WILL BE HEAVY AT TIMES ESPECIALLY WEDNESDSAY AND WEDNESDAY
NIGHT. SNOWFALL ACCUMULATIONS WILL RANGE FROM 12 TO 24 INCHES WITH
UP TO 3 FEET POSSIBLE IN FAVORED UPSLOPE AREAS IN THE FOOTHILLS. NORTH
TO NORTHEAST WINDS AT 15 TO 30 MPH WILL PRODUCE EXTENSIVE BLOWING
AND DRIFTING SNOW IN OPEN AREAS.

[SCMedic]

Really impressed with the early change over and how huge these flakes are. Coming down HARD. Hard to see at times coming home from Boulder. This isn't even the upslope yet!

[SCMedic]

2" down, streets filling in. Huge baby goblins falling from the sky! Love the local news forecasting 6" through Thursday. Idiots.

[PTPatrick]

Yeah...already about an inch or so here in Denver. Changeover was precisley 7:45 downtown. Definately an early start. Question is will it end earlier than thought. GFS QPFs are a little lower than previously, as are NAM, not sure what thats about as they both still have the storm going until thursday evening. I have trouble believing that 36-48 hrs of light to heavy snow in Denver will yeild anything less than 16 inches. I have a feeling we could wake up to more than the 3 inches forecast for overnight if things keep up.

[PTPatrick]

Interestingly enough neither GFS nor NAM really think it will snow much overnight, even though it is accumulating as we speak. The time for nowcasting as arrived as this thing really aint behaving quite according to plan. I didnt expect heavy snow until tomorrow afternoon but we are already getting it.

This reminds me of the 2006 storm. Everybody went to work that day expecting a little snow come (brunt was not supposed to hit until afternoon/evening) and about only 2-4 inches for the workday...had to leave at lunch with 10 inches on the ground and helter skelter roads. That storm really hit about hit 6 hours ahead of schedule and ended about 6 behind schedule.

WSW language: SNOW...HEAVY AT TIMES WILL DEVELOP WEDNESDAY MORNING AND CONTINUE
INTO THURSDAY. TOTAL SNOWFALL ACCUMULATIONS OF 10 TO 18 INCHES ARE
POSSIBLE...WITH UP TO 24 INCHES IN THE DENVER AREA. NORTH WINDS AT
15 TO 30 MPH WILL PRODUCE AREAS OF BLOWING AND DRIFTING SNOW.

[SCMedic]

This is a little more moisture with the initial front. Winds aren't easterly yet and low isn't in position for heavy upslope. I think this adds to the duration and snow totals.

[PTPatrick]

Just checked cams and it looks like 36 from 104th to Boulder is pretty nasty...plenty of accumulation on the highway with some spots only with tire tracks. Of course this burst could stop soon and melt before the real deal comes it. Also just noted some yellows on the radar over DIA.

[PTPatrick]

about 3.5 inches so far of wet snow downtowan. Looks pretty wet, already sagging lots of tree branches.

[SCMedic]

Had 4.5 here on the deck at 5am. Snow just finally picked up again, as it looked like the initial surge from the front dried out around 3am or 4 based on radar. This is the beggining of the upslope finally starting!

[Dencolo]

Snow starting to pick up downtown, with streets becoming slushy. Should be an interesting commute home. Here comes a lot of 'green' on the radar!

http://radar.weather.gov/radar.php?rid= ... 1&loop=yes

[Portastorm]

Yeah, I was just on the http://www.cotrip.org website and enjoyed seeing the white stuff accumulate. Those of us in this part of Texas have to live vicariously through your weather (at least for now! ).

Hope your commute home isn't too crazy.

[solarlux]

I'm at work near the SW corner of the Denver metro area and am wondering if we'll get a facility closure. If the winds pick up, I'm guessing businesses will start closing up early. I'm not sure as to how the forecasters predict the wind levels though.

I noticed that the 15z RUC seems to trend the 500 mb low as slightly deeper than the NAM and perhaps moving a little more slowly. I wonder if this will have an effect on the storm impact.

[Dencolo]

Source: 9news.com As of 10 a.m. And if it's snowing at 1"/hr these #s will grow pretty fast...

Arvada 6.5"

Aurora 5.0"

Bailey 4.5"

Bergen Park: 9.0"

Boulder 6.6"

Brookvale 10.5"

Conifer 9.3"

Denver (Downtown) 3.5"

Estes Park 11.0"

Fairplay 6.0"

Fort Collins 6.0"

Louisville 6.0"

Nederland 18.0"

Parker 5.0"

From the NWS
1021 AM MDT WED OCT 28 2009

.NOW...
MODERATE SNOWFALL WILL CONTINUE OVER THE I-25 URBAN CORRIDOR THROUGH
NOON. SNOWFALL RATES WILL GENERALLY BE NEAR AN INCH AN HOUR. SOME
HEAVIER SNOWFALL IS LIKELY CLOSER TO THE FOOTHILLS WITH RATES OF ONE
TO TWO INCHES PER HOUR. ROADS WILL BE SLUSHY AND OR SNOWPACKED AND
SLIPPERY IN MANY AREAS...ESPECIALLY ON THE BRIDGES AND OVERPASSES
WHICH COULD BE ICY AND SNOW COVERED

[srainhoutx]

MESOSCALE DISCUSSION 2147
NWS STORM PREDICTION CENTER NORMAN OK
0113 PM CDT WED OCT 28 2009

AREAS AFFECTED...N CNTRL CO...SERN WY...WRN NEB PANHANDLE...EXTREME
SW SD

CONCERNING...HEAVY SNOW

VALID 281813Z - 290015Z

SNOWFALL RATES ARE EXPECTED TO INCREASE TO AROUND 1 INCH/HOUR WITH
LOCALIZED 2 INCH/HOUR RATES WITH UPSLOPE ENHANCEMENT.

SURFACE ANALYSIS SHOWS A STRONG SURFACE RIDGE WITH COLD AIR FROM
SERN WY INTO NERN CO WITH TEMPERATURES IN THE 20S F. MEANWHILE...LOW
PRESSURE CONTINUES TO DEEPEN TO THE S. PERSISTENT ISENTROPIC LIFT OF
AN EVER MOISTENING AIR MASS SHOULD RESULT IN AN EXPANDING AREA OF
SNOW FROM N CNTRL CO INTO SERN WY...EXTENDING NEWD INTO SWRN SD BY
00Z. MODEL CONCENSUS IS FOR 3 HR QPF RATES OF 0.20-0.30
IN/3HR...WHICH WOULD CORRESPOND TO AROUND 1 IN/HR SNOWFALL RATES. N
TO NE LOW LEVEL WINDS WILL LIKELY ENHANCE SNOWFALL RATES NEAR
FAVORABLY ORIENTED TERRAIN...PERHAPS AS HIGH AS 2 IN/HR LOCALLY.

..JEWELL.. 10/28/2009


ATTN...WFO...LBF...UNR...BOU...CYS...

[SCMedic]

That's big if it pans out.

[srainhoutx]

Here are some Denver area webcams http://www.dickgilbert.com/denvercams.htm

Going to bump up David's Cam Links.

[Dencolo]

Storm totals As of 2:30 p.m. Still coming down hard. I'm up to a foot of snow here....

Mead 7.0"
Littleton 12.0"
Idledale 20.1"
Barr Lake 5.5"
Fairplay 12.0"
Boulder 17.0"
Pinecliffe 24.0"
Wheat Ridge 10.6"
Golden 14.0"
Federal Heights 8.0"
Kittredge 14.3"
Conifer 20.0"
Arvada 9.0"
Louisville 12.0"
Westminster 12.0"
Nederland 18.0"