Tracking This Week’s Possible Snow Storm (April 28-30, 2016)

Model guidance is continuing to suggest a very wet and soggy storm system to affect the area later this week and into this weekend. While this storm shows a lot of similarities to our blizzard we had just a couple of weeks ago there are some big differences as well. This storm is showing no signs we need to go raid the grocery stores as of this time.

  • Similarities
    • This storm has a ton of moisture, just like the last one it taps into gulf moisture and spins this into the state giving us ample up slope to produce precipitation
    • It is very slow moving. Many models have the affects of this storm being felt from Thursday this week into Tuesday next week
  • Differences
    • This storm looks to have trouble tapping into colder air form the North. This means more precip may fall as rain and snow may take longer to accumulate, diminishing overall totals
    • Because of the first point, temperatures will remain warmer overall. A single degree warmer or colder makes a huge difference in the spring-type storms
    • The storm track is slightly further South meaning we would see the best snow further South. Areas along the Palmer Divide and into Springs will see the most moisture, but elevation will play a key role in snowfall amounts

Model Guidance on Snowfall as of This Morning

(Again, not official forecasts. These are just a look at models at this time)

 

 

GFS (Long Range Model)

Storm Total Accumulation by Saturday April 30, 2016 12:00PM

The GFS shows snowfall along the front range
Thursday night into Friday and possibly
lingering into Friday. The amount shown
uses a 10:1 ratio but warm temperatures may
cut this amount down.

Using 10:1 Ratio: 3-6 inches of snow
Using 5:1 Ratio: 1-3 inches of snow

 

NAM (Medium Range Model)

Storm Total Accumulation by Saturday April 30, 2016 12:00PM

The NAM shows lesser snow accumulation
possibly due to a warmer atmosphere or
storms in the East robbing us of moisture and
dampening our upslope.

Using 10:1 Ratio: 1-3 inches of snow
Using 5:1 Ratio: 0-2 inches of snow

 

NAM4K (Short-Medium Range High Resolution Model)

Storm Total Accumulation by Friday April 29, 2016 12:00PM

The NAM 4K’s range only goes through Friday
noon at this point. It shows some of the finer
details with the storm and shows similar totals
to the other 2 models.

Using 10:1 Ratio: 1-3 inches of snow
Using 5:1 Ratio: 0-2 inches of snow

 

SREF Ensemble (Short Range Model Ensemble)

Storm Total Accumulation by Saturday April 30, 2016 6:00PM

The SREF is a combination of a bunch of model
runs. It generally has a better accuracy level
than just looking a single model (GFS,NAM,etc…)

This model shows a solution more in line with the
GFS and shows slightly higher snowfall
accumulation along the Palmer Divide
Predicted Snowfall (as an average between all
short range models): 6.17 Inches

 

Current Winter Weather Watches/Warnings/Advisories

WW_04272016_11AM_2

This watch does not include Central or Eastern Douglas County as of this time. Castle Rock is not included.

**Winter Storm Watch In Effect**

Timing

WINTER STORM WATCH IN EFFECT FROM THURSDAY EVENING THROUGH
FRIDAY EVENING

Cities/Areas Included

CAMERON PASS...
LARAMIE AND MEDICINE BOW MOUNTAINS...RABBIT EARS RANGE...
ROCKY MOUNTAIN NATIONAL PARK...WILLOW CREEK PASS...
BERTHOUD PASS...BRECKENRIDGE...EAST SLOPES MOSQUITO RANGE...
EAST SLOPES SOUTHERN GORE RANGE...EISENHOWER TUNNEL...
INDIAN PEAKS...KENOSHA MOUNTAINS...MOUNT EVANS...
WILLIAMS FORK MOUNTAINS...WINTER PARK...ESTES PARK...GLENDEVEY...
NEDERLAND...RED FEATHER LAKES...BAILEY...CENTRAL CITY...
EVERGREEN...GEORGETOWN...IDAHO SPRINGS...WESTCREEK...FAIRPLAY...
HARTSEL...LAKE GEORGE...SOUTH PARK

Snowfall

GENERALLY 10 TO 20 INCHES. FAVORED UPSLOPE
AREAS EAST OF THE CONTINENTAL DIVIDE WILL SEE THE MOST SNOW...
WITH TOTALS PERHAPS APPROACHING TWO FEET.

Impacts

ACCUMULATING SNOW ON BRANCHES AND POWER LINES COULD
LEAD TO TREE DAMAGE AND POWER OUTAGES. ROADS WILL AT LEAST GET
SLUSHY THURSDAY NIGHT AND FRIDAY NIGHT BUT DUE TO THE HIGH SUN
ANGLE DURING THE DAY ON FRIDAY THEY MAY NOT EXPERIENCE A LOT OF
ACCUMULATION DURING THE DAYLIGHT HOURS.

Summary

At this time there is no reason to panic with this storm. With what we are seeing now it looks like it will at worst be an inconvenience for folks below 7,000 feet in elevation on Friday and possibly Saturday. This storm does not look like it will produce the type of snowfall that will trap you in your house so no reason to run on the grocery stores.

We will continue to keep an eye on the forecast and relay any changes in forecast through the day Wednesday and Thursday regarding higher or lower snowfall amounts. Stay tuned!

 

John R. Braddock
Storm Chaser/ Amateur Meteorologist at Mountain Wave Weather
John R. Braddock is a NOAA/NWS Certified Storm Chaser and Amateur Meteorologist living in Castle Rock, Colorado. A graduate of Colorado State University with a Bachelor's in Computer Science and a Colorado native, he specializes in short range forecasting, severe weather and mountain weather dynamics.

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