Category Archives: Climatology

NOAA: Increased Flood Risk, Minimal Drought

Yesterday NOAA released its spring drought and flood risk predictions and in it are some good and bad news for Colorado. 

Beware of the dangers of flooding!First, the good news.  With the extraordinary amount of snow the mountains have experienced this winter, the chances of drought are negligible for most of the state.  The southeastern corner of Colorado however could see some risk.

Second, the bad news.  With all that snow comes a risk of flooding.  The danger could be especially great if we experience a warmer than normal spring and the mountain runoff occurs too quickly.  Most of the state, with the exception of the northeast corner, runs above normal risks of flooding this spring.  Locations in the mountains of Colorado have 150 to 200 percent of average water contained in snowpack leading to a higher than normal flood potential.  Flooding is the number one weather killer in the country so everyone needs to be aware of the dangers this presents! 

For more information, please see NOAA’s report here.

2008 Spring Drought Outlook     2008 Spring Flood Danger Outlook

NOAA: Coolest Winter Since 2001 for U.S. & Globe

A cold winter!This week NOAA’s National Climatic Data Center announced that from December 2007 to February 2008 temperatures across the United States and the globe were their coolest since 2001.  In the contiguous United States, the average winter temperature was 33.2°F which ranks it as the 54th coolest winter since national records began in 1895.  Globally, the combined land and ocean surface temperature was the 16th warmest on record for the period.

In terms of precipitation, as everyone here in Colorado knows, large swaths of the country experienced at or well-above normal levels of precipitation.  Indeed, some basins here in Colorado were in excess of 150% of normal.  Record February precipitation in the Northeast helped make the winter the fifth wettest on record for the region. New York had its wettest winter, while Pennsylvania, Connecticut, Vermont, and Colorado to the West, had their second wettest.

The charts below give a good view of both temperature and precipitation for the winter.  You can also view the NCDC’s complete summary on their website here.

Winter Temperatures     Winter Precipitation

March 2008 Weather Preview Now Available

March 2008 PreviewMarch in Denver typically means frequent and rapid weather changes. The days grow longer and we start enjoying more sunshine and sometimes summer-like weather. However, on occasion arctic air masses can still force their way south into Colorado dropping temperatures quickly and markedly.  Occasional thunderstorms do start to happen in March as well.

To see what to expect in the coming month, click here to view our March 2008 Preview.

Dry winter forecasts? Buried in the snow!

Dry winter?  Not here!An interesting article in the Denver Post today talks about how the forecasts for a dry winter have been way off the mark (thus far).  Even as recently as a month ago NOAA was saying that La Nina was going to wreak havoc and dry things out severely.  Yet today the mountains continue to have an amazing amount of snowpack with every basin well above normal. 

Meteorologist Klaus Wolter told the Denver Post that recent failures of their predictions may be traced to climate change.  Wolter said, “So we have two years in a row here where the atmosphere does not behave as we expect.  Maybe global changes are pulling the rug out from underneath us. We may not know the answer for 10 years, . . . but one pet answer is that you should get more variability with global change.”

 There it is!  You knew it was coming!  If all else fails, blame global warming!  🙂 

In all seriousness, assuming things continue as they have been, the concern now shifts not from drought but to possible flooding this spring.  Emergency planners are keeping a close eye and a fast run-off could not only lead to a loss of good, usable water but it could also cause a lot of problems. 

Despite the mountains of snow in the mountains, here on the plains we haven’t been quite as fortunate.  In the metro area, the historical seasonal average through the end of February is 39.6 inches of snow.  As of this morning (2/14), thus far this season ThorntonWeather.com has recorded 33.0 nches and the National Weather Service puts the official Denver measurement at 35.5 inches.  This puts us below average but there are still 15 days left in this month to catch up. 

 Please click here to view the entire Denver Post article:  Dry winter forecasts miss mark.

Snow on its way Wednesday evening. Warnings issued.

Snow in the forecast.Updated 2/13/08 @ 4:10pm.  A Snow and Blowing Snow Advisory has been issued and is in effect from midnight tonight until 5:00pm Thursday.  A blowing snow advisory means that winds and blowing and drifting snow will reduce visibilities sufficiently to make travel difficult.  Please continue to visit our site for the latest on the approaching storm.  If you haven’t, you may wish to sign up for our weather alert and report system to receive the latest information delivered directly to your inbox.

Updated 2/13/08 @ 7:00am.  It looks like the metro area will be in for snow this evening and into tomorrow.  We are expecting 3 to 6 inches in the Thornton area and the northern suburbs; higher accumulations will occur south with up to 9 inches across the southern metro area to the Palmer Divide.  Mountain areas could see up to a foot of snow. 

We’ll reach a high near 60 today but temperatures will drop rapidly as nighttime falls.  The storm is expecting to roll in from Wyoming and start hitting the Colorado border around 7:00pm, expanding to the Palmer Divide by 11:00pm.  Winds of 25 to 35mph are expected with the front so blowing snow will be a concern.  Evening rush hour today should at least be fine but tomorrow morning could be a bit dicey so please plan on leaving for work early and taking it slow.   Snow will continue Thursday morning and gradually diminish from north to south by Thursday afternoon. 

The National Weather Service has already issued Snow & Blowing Snow Advisories and Winter Storm Watches for some of the southern and central mountain areas.  These could be expanded as the storm develops. 

 Stay tuned to ThorntonWeather.com for the latest on this approaching system. 

Snowpack Continues to Grow

Snow in the forecast.

 The snowpack in the mountains continues to add up and we are having a great year as far as that goes.  The South Platte, which is crucial to many metro area water reserves including Thornton stands at 108% of normal. 

Colorado SNOTEL Snowpack Update Report
Based on Mountain Data from NRCS SNOTEL Sites
**Provisional data, subject to revision**
Data based on the first reading of the day (typically 00:00) for Tuesday, February 12, 2008
Basin
  Site Name
Elev
(ft)
Snow Water Equivalent Percent of
Current
(in)
Today’s
Average
(in)
Avg
Peak
(in)
Avg
Peak
Date
Today’s
Average
Avg
Peak
GUNNISON RIVER BASIN
Basin-wide percent of average 148  95 
UPPER COLORADO RIVER BASIN
Basin-wide percent of average 131  82 
SOUTH PLATTE RIVER BASIN
Basin-wide percent of average 108  66 
LARAMIE AND NORTH PLATTE RIVER BASINS
Basin-wide percent of average 110  70 
YAMPA AND WHITE RIVER BASINS
Basin-wide percent of average 115  76 
ARKANSAS RIVER BASIN
Basin-wide percent of average 169  108 
UPPER RIO GRANDE BASIN
Basin-wide percent of average 171  110 
SAN MIGUEL, DOLORES, ANIMAS AND SAN JUAN RIVER BASINS
Basin-wide percent of average 157  102 

Latest Snowpack Reports Continue to Hold Promise

Snowpack above normalSnowpack reports as of this morning continue to hold great promise for Colorado.  All of the major basins are above average with the exception of the South Platte.  Another major snowstorm is hitting the mountains today and yet another is forecast for Wednesday.  We can only hope this pattern continues and NOAA’s forecasts of a dry first quarter don’t hold true.

It would however be nice if some of that moisture would move out onto the front range and into the Denver area and the plains.  There is a chance for a bit of snow in the metro area tomorrow and again on Wednesday although right now it doesn’t look like they will amount to much.

Colorado SNOTEL Snowpack Update Report
Based on Mountain Data from NRCS SNOTEL Sites
**Provisional data, subject to revision**
Data based on the first reading of the day (typically 00:00) for Sunday, January 27, 2008
Basin
Site Name
Elev
(ft)
Snow Water Equivalent Percent of
Current
(in)
Today’s
Average
(in)
Avg
Peak
(in)
Avg
Peak
Date
Today’s
Average
Avg
Peak
GUNNISON RIVER BASIN
Basin-wide percent of average 132 72
UPPER COLORADO RIVER BASIN
Basin-wide percent of average 114 61
SOUTH PLATTE RIVER BASIN
Basin-wide percent of average 93 49
LARAMIE AND NORTH PLATTE RIVER BASINS
Basin-wide percent of average 99 54
YAMPA AND WHITE RIVER BASINS
Basin-wide percent of average 99 56
ARKANSAS RIVER BASIN
Basin-wide percent of average 148 80
UPPER RIO GRANDE BASIN
Basin-wide percent of average 150 83
SAN MIGUEL, DOLORES, ANIMAS AND SAN JUAN RIVER BASINS
Basin-wide percent of average 141 78

Storm Chaser Convention Coming to Denver

Storm Chaser Convention Coming to DenverFebruary 15th -17th Denver will play host to the 10th Annual National Storm Chaser Convention.  The event will be held at the Raddison Hotel at I-225 and Parker Road (3200 South Parker Road).  Most notably, the keynote speakers will be Dr. Josh Wurman and Sean Casey who appeared in the recently aired Discovery Channel special, Storm Chasers.  This is a great opportunity for weather enthusiasts to share storm stories, learn more about severe weather and storm chasing, see new weather gadgetry and hear from some of the experts in weather related fields. 

To learn more, please visit the National Storm Chaser Convention website at:  http://chaserconvention.com

State Lucky Thus Far – Dry Months Ahead According to NOAA

Dry Months Ahead?Klaus Wolter, a meteorologist affiliated with the University of Colorado and the National Oceanic and Atmospheric Administration continues to promise a dry winter.  In an article today in the Rocky Mountain News he says, “I think we should count our blessings. We got lucky” in regards to the amount of moisture the state has seen thus far.

According to Wolter, the La Nina weather pattern present in the Pacific will persist resulting in storms tracking north of our state.  The good news though is that snowpack thus far is above normal statewide and even if their predictions bear out, we should be okay come summer.  Here are the latest readings as of today:

           S N O W  -  P R E C I P I T A T I O N    U P D A T E 
  
              Based on Mountain Data from NRCS SNOTEL Sites 
                    As of MONDAY: JANUARY 14 , 2008 
----------------------------------------------------------------------------- 
STATE                                                      PERCENT OF AVERAGE 
  RIVER BASIN                                     Number   Snow Water  Accum 
                                                 of Sites  Equivalent  Precip 
-----------------------------------------------------------------------------
COLORADO 
  GUNNISON RIVER BASIN ......................... 11 of 13     144       137 
  UPPER COLORADO RIVER BASIN ................... 27 of 29     119       124 
  SOUTH PLATTE RIVER BASIN ..................... 15 of 15     105       101 
  LARAMIE AND NORTH PLATTE RIVER BASINS ........ 13 of 13     101       109 
  YAMPA AND WHITE RIVER BASINS ................. 17 of 19     102       111 
  ARKANSAS RIVER BASIN .........................  5 of  9     141       124 
  UPPER RIO GRANDE BASIN .......................  9 of 13     158       144 
  SAN MIGUEL, DOLORES, ANIMAS 
     AND SAN JUAN RIVER BASINS ................. 14 of 16     153       135

We of course hope the forecasters are wrong just like they have been about the last two hurricane seasons

Please click here for the full Rocky Mountain News Article. 

Hurricane Season Ends – Questions to Answer Though

Record low hurricane seaso for 2007The 2007 hurricane season officially ended on November 30th and in the Atlantic, a total of 14 named storms were produced, including six hurricanes, two of which became major hurricanes.  The good news is that only one hurricane, one tropical storm and three tropical depressions struck the United States so we escaped relatively unscathed.  This does however make one wonder about the accuracy of hurricane forecasts.  This is the second year in a row that predictions indicated above normal activity when the opposite turned out to be true. 

It is notable that as recently as NOAA’s August hurricane update they said: 

NOAA is predicting a very high likelihood (85% chance) of an above-normal 2007 Atlantic hurricane season, a 10% chance of a near-normal season, and only a 5% chance of a below-normal season, according to a consensus of scientists at the National Oceanic and Atmospheric Administration (NOAA) Climate Prediction Center, National Hurricane Center, Hurricane Research Division, and Hydrometeorological Prediction Center.

 There’s that word again – CONSENSUS!  Let’s take a look at the facts:

  • – The 2007 Atlantic hurricane season was below normal and tied for 2002 as the most inactive since the El Nino depressed 1997 season in terms of storm energy.
  • – The North Atlantic was not the only ocean that experienced quiet tropical cyclone activity. The Northern Hemisphere as a whole is historically inactive. How inactive? One has to go back to 1977 to find lower levels of cyclone energy as measured by the ACE hurricane energy metric. Even more astounding, 2007 will be the 4th slowest year in the past half-century (since 1958) .
  • – Fewest Northern Hemisphere hurricane days since 1977 – the 3rd Lowest since 1958 (behind 1977 and 1973).
  • – When combined, the 2006 and 2007 Atlantic hurricane seasons were the least active since 1993 and 1994.

ThorntonWeather.com has to wonder – If we can’t accurately predict short term climatological events such as hurricanes, how can those that make up a “consensus” accurately predict and gauge man-made climate change on a global scale? 

Click here to view NOAA’s 2007 hurricane season summary.