Colorado Front Range Blizzard Potential

[Tony Laubach]

I got up this morning to eyeball the severe weather potential this weekend and saw snow in the forecast for the Front Range here in Colorado... possibly a lot of snow!

Check out this morning's AFD from the Denver/Boulder NWS office...

I'm not going to jump the gun on any forecasting of snow amount as of yet, as my first thought of all this would be for it to be too warm across the Urban Corridor for any real snow to fall; at least in terms of even HALF of what we saw in the March 2003 blizzard. It definately looks like it could shape up to be a helluva precip maker for our area as the models are showing the system moving very very slowly off to the east, which would leave us in moist, upslope flow for at least 48 hours. If it were to get cold enough down here and snow half an inch per hour for 48 hours, that's good snow! I suppose one could say the potential is there, but I'm highly skeptical of anything close to the March 2003 blizzard.

A little timeline; during the March 2003 Blizzard, I saved all text products starting Saturday afternoon; the snow started Monday night (60 hours out). Here, snow's expected to start Saturday night, so I'll do the same just in case, saving text products of this event if it does pan out. Here's a small quote from the AFD issued in 2003 on Saturday afternoon in regards to the upcoming storm...

I LIKE THE DETAILS OF THE ETA AND WILL GO WITH THEM...WITH TWO CAVEATS. THE FIRST IS THE TEMPERATURES ON THE PLAINS. THERE IS WARM ADVECTION IN THE LOW TO MID LEVELS THROUGHOUT THE EVENT...BUT THE SURFACE EMPERATURE GRADIENT SHOULD TIGHTEN WITH SOME COOLING DOWN LOW EVENTUALLY. BOTH THE ETA AND GFS MAINTAIN A BROAD RADIENT WITH WARM TEMPERATURES WEST OF THE SURFACE TROUGH ALL THE WAY THROUGH THE EVENT. THERE SHOULD BE COOLING ON THE WEST SIDE OF THE TROUGH EVENTUALLY...WHICH WILL PRODUCE SNOW IN MOST PLACES BY TUE NIGHT. THE FAR NE CORNER MAY HOLD OUT INTO WED. SECOND ISSUE IS WHETHER TO BELIEVE THE SNOW AMOUNTS IN THE ETA. THE AVN GIVES STORM TOTALS OF 15 TO 20 INCHES FROM CHEYENNE TO DENVER AND OUT TO LIMON. THE ETA HAS STRONGER DYNAMICS FOR LONGER AND HAS NOT YET MOVED THE SYSTEM OUT WHEN IT ENDS WED AFTERNOON. IT SHOWS 35 TO 45 INCHES IN DENVER WITH 8 TO 20 INCHES ON THE MIDDLE PLAINS AND JUST AN INCH IN THE NE CORNER. THERE ARE GOOD REASONS THE ETA CRANKS OUT THIS MUCH...BUT IT SEEMS PRUDENT TO MENTION THAT KIND OF A STORM AS A POSSIBILITY RATHER THAN A LIKELIHOOD AT THIS TIME. SOMETHING LIKE THE OCTOBER 1997 STORM SEEMS TO BE A FAIRLY GOOD PROBABILITY. FOOTHILLS WILL GO NUTS ON WED IF THE ETA IS RIGHT. SNOW MODEL RUN BASED ON THE ETA SUGGEST STORM TOTALS OF 3 TO 6 FEET FROM OROGRAPHIC COMPONENT...THEN YOU HAVE TO ADD THE SYNOPTIC SCALE STUFF. ENOUGH SAID.

Awaiting what is being said with this afternoon's AFD and how the models continue to evolve this particular situation over the next 24 hours. As I said earlier, I have a very difficult time buying into this just yet, but I'm also sorry to say that if it looks as if 2 feet or more of snow will fall around here, I'm likely to enjoy that and its rarity and back out of chasing those days... we'll see.

Park your forecasts and discussions here in regards to this... right now, I'm pulling double duty trying to work chase plans AND watch a potential snow storm! :lol:

 

[Robert Dewey]

Man that's awesome... Nothing like catching thunderstorms (and hopefully tornadoes), and then have a nice snowstorm. The good thing about late season snowstorms is that they tend to be rather quick hitting, and then in a few days you're back in the 70's...

 

[Tony Laubach]

Still hanging at the back of the 12z run of the ETA, but check out the precip forecasts for the 72 and 84 hour....

http://www.rap.ucar.edu/weather/model/eta7...hr_sfc_prcp.gif

http://www.rap.ucar.edu/weather/model/eta8...hr_sfc_prcp.gif

That's over 3 inches... assuming 8 to 1 snow ratios, that's pushing two feet in that 24 hour period, not counting anything that may be forecasted beyond the model...

Another thing I've seen with the ETA is its calling for snow as the precip type; again, hard to put faith in this this far out, but its showing potential. Definately worth keeping an eye on.. I'm still very skeptical, though... hard to swallow this just yet.

 

[Mark Farnik]

I sure hope this storm pans out. We had .20 hundredths of an inch of rain and 8 inces of snow with a moisture content of .30 hundredths to get a grand total of a half inch from the blizzard we had out here last Thursday that missed Denver. That was nice, but the damn howling winds on Tuesday evaporated most of that moisture off :evil: . I really hope we get a good dose of rain and/or snow. It would be very beneficial and very welcome.
On another note, the 2:30 WFD from the Denver NWS contained unusual wording for this time of year. Here is the excerpt I found most interesting.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER CO 230 PM MDT
THU APR 7 2005
LONG TERM...FRI NGT-SUN MDLS CONTINUE TO SHW ABUNDANT MOISTURE AND PCPN ACRS ERN SLP MTNS AND IN AND NR ERN FTHLLS ON SAT NGT AND SUN AS CLOSED UPR LO MOVES NEAR 4 CORNERS AND ACRS NRN NM INTO TX PANHANDLE. HVY SNW IS LIKELY IN THE FRONT RANGE MTNS AND ERN FTHLLS. RAIN MAY WELL CHANGE TO SNW OVR URBAN CORRIDOR BUT TEMPS MAY TOO WARM FOR A LOT OF ACCUMS EXCEPT ON TREES AND GRASS. STILL TOO FAR OUT TO MAKE A GUD CALL ON RAIN VS SNW. RAIN WILL BE MIXED WITH SNW OVR HI PLAINS. A SHT WV IN ADV OF SYS WILL MOVE ACRS AREA ON FRI AFTN AND EVE. WILL KEEP ISOLD TSTMS IN FCST. STG DYNAMICS IN ADV OF MAIN SYS ON SAT AFTN AND EVE MAY ALSO TRIGGER SCT TSTMS... A FEW OF WHICH MAY BE SVR OVR NERN PLAINS.

They are a little vague about the snowstorm potential, you think? :wink:
But the thing that caught my eye was the last line. I zoomed over to the SPC to correlate, and sure enough, in their Day 3 outlook, it said:
...CENTRAL PLAINS...

LATE EVENING MODEL GUIDANCE APPEARS REASONABLY CONSISTENT WITH
EARLIER RUNS DEPICTING A STRONG UPPER SPEED MAX AND ASSOCIATED LOW
DIGGING SEWD ACROSS THE GREAT BASIN TO A POSITION OVER NRN NM BY THE
END OF THE DAY3 PERIOD. EXIT REGION OF EJECTING SPEED MAX SHOULD
ENHANCE CONVECTIVE POTENTIAL OVER THE CNTRL HIGH PLAINS AFTER
10/00Z. LOW LEVEL TRAJECTORIES WILL BECOME MORE FAVORABLE FOR
TRANSPORTING MODIFIED MOISTURE INTO THIS REGION THUS STRONG TO
PERHAPS SEVERE THUNDERSTORMS COULD DEVELOP ACROSS ERN CO INTO WRN
KS. IF UPPER TROUGH SLOWS AND DIGS FARTHER SOUTH...WHICH IS A
VIABLE SCENARIO...PROBABILITIES FOR SEVERE STORMS MAY NEED TO BE
ADJUSTED INTO PORTIONS OF THE TX/OK PANHANDLES.

Sorry about getting so off topic from the possible snowstorm, Tony, but it would be unusual for the severe storms to pan out. We usually don't see our first severe wx in NE Colorado till about the 25th-30th of April. Maybe it will be like the March 2003 Blizzard; remember when that tornado was videoed touching down at Byers the afternoon before the storm started with the temps in the low 50's? 8) With the right dynamics and moisture available, this storm could pull a similar stunt: some isolated severe cells on Saturday afternoon, and then a snowstorm Sunday into Monday! The prospects excite me very much! Colorado weather is absolutely awesome. :twisted:

 

[Tony Laubach]

Hehehe.. well, so much for that excitement.. back to chasing Sunday and Monday! :lol:

 

[Eric B'Hymer]

Does this mean that you are trekking to kansas again. If so i'll email you my number. I'll be in Wichita Sunday because i was asked to be on a stormchaser panel at the KWCH weather expo Sunday afternoon at 1pm or 1300 whichever you prefer. Not sure how long i'll be there and i still need to look at the models yet. It sounds as if sundays system will be similar to last tuesdays. We will see.

 

[Mark Farnik]

Hey Tony,
don't throw in the towel just yet. This just in from the Denver WFO (minus a few hours):

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE DENVER CO
419 PM MDT FRI APR 08 2005

...STRONG SPRING STORM HEADING TOWARDS COLORADO...

.A MAJOR SPRING STORM WILL TAKE SHAPE SATURDAY NIGHT AND SUNDAY AS
LOW PRESSURE INTENSIFIES ALONG THE NEW MEXICO AND COLORADO BORDER.
THIS STORM HAS THE POTENTIAL TO PRODUCE SIGNIFICANT SNOWFALL ACROSS
THE FRONT RANGE FOOTHILLS...URBAN CORRIDOR...AND PALMER DIVIDE LATE
SATURDAY NIGHT AND SUNDAY. AT THIS TIME THERE IS THE POTENTIAL FOR
ONE TO TWO FEET OF SNOW IN THE FOOTHILLS...AND UP TO A FOOT OVER THE
URBAN CORRIDOR...MAINLY FROM FORT COLLINS SOUTHWARD INTO DOUGLAS
COUNTY. NORTH WINDS WILL ALSO INCREASE WITH GUSTS UP TO 35 MPH WITH
BLOWING SNOW AND POOR VISIBILITIES EXPECTED. FURTHER EAST...THE RAIN
WILL TURN OVER TO SNOW SUNDAY MORNING...SNOW AMOUNTS WILL BE A BIT
MORE LIMITED. DEPENDING ON THE EXACT TRACK OF THE STORM...SNOW
AMOUNTS COULD BE EVEN HIGHER THAN NOTED ABOVE.

STAY TUNED FOR THE LATEST STATEMENTS ON THIS POTENTIALLY DANGEROUS
LATE SEASON STORM.

Yes indeed, I think we're in for a lovely early spring winter storm over north central and northeastern Colorado! Blowin' and snowin' , that is music to my ears (note to the Storm Gods: make it strong enough and last long enough so there willl be no school Monday, plleeeaaassse!) :twisted: Looks like you may have to cancel your Sunday chase plans... that is, unless you want to try and take the Storm Tracer (that is it's name, isn't it) out in a freakin' blizzard trying to get to your target area in Kansas and wind up getting stuck in Byers or Limon... :roll: Your call, buddy. Whatever you decide to do, stay safe and take care of yourself. Maybe you can watch the little snow tornadoes that spin up as the wind and snow blasts around your house...

 

[Tony Laubach]

Mark,

I humbley agree... there was a 12 hour period in which things tapered down a bit, and I quickly jumped the gun of disbelief and shrugged it off. Now I have seen that I was wrong. Let me still publically say I have my reservations still for a variety of reasons, but at the same time, am preparing to see 1 to 2 feet of snow over the Metro area.

My chase plans at this time remain up in the air; while not as high as they were yesterday due to not only the snowstorm, but the potential to chase a squall line in Kansas.

I've got my forecasting hands full today, but the snowstorm is definately back into the scheme of things!

 

[Charles Kuster]

Our (Leadville, Colorado) snow is supposed to start tonight. However, I don't think we are going to get a ton of snow. Whenever Denver gets a lot of snow we usually get very little. The National Weather Service is predicting 8-12 inches of snow for tonight, but last weekend they forecasted 6-10 inches and we got .7". :shock: I hope we get something but I don't think we will. I hope you and Mark get a good snow storm down there!

make it strong enough and last long enough so there willl be no school Monday, plleeeaaassse!

That would be lucky! I wish that would happen up here but Leadville has never cancelled school for a snow storm.

 

[Mark Farnik]

Hello all,
I was up in Fort Collins today and was driving home with my mom and sister when I saw a flicker in the east as we crossed over I-25. Could it be...yes. It was lightning, and the whole way home there was almost constant lightning, all of it sheet or cloud to cloud, strangely enough. It gets stranger. When we turned off on Weld County Road 127 (one mile west of New Raymer) we ran into a nasty thundersnow. The snow was coming so hard and fast my windshield wipers were having a hard time keeping up and the roads were very sloppy... needless to say, unloading groceries while lightning flickers all around you, thunder cracks and wet, gloppy snow pelts you is not fun. :evil: The air temperature at 10:00 p.m. was 37 degrees and falling. I've been sitting in my porch watching the lightning from a few cells off to my southeast, and is has been fairly constant the whole evening. Only in Colorado can you get thunderstorms in the evening, and then by morning have a raging blizzard (as this could well be) in full swing. You gotta love it! 8) 8)