The Weather Wire
October 2009 Volume 17 Number 10
Avg High - 78.0
Avg Low - 48.9
Snow - 0.0"
Season Snow - 0.0"
Precipitation - 0.74"
Avg High - 66.0
Avg Low - 35.9
Avg Snow - 4.1"
Avg Precip - 0.99"
Winter Weather Definitions...
With winter looking like it will make a visit to Colorado this month it is time to review all the winter weather definitions since we will be seeing a lot of these over the coming winter months as higher than average snowfall is expected.
The National Weather Service issues many different types of watches and warnings during the winter months. Here is what they mean:
WINTER STORM WATCH:
A winter storm watch is issued when winter storm conditions are possible within the next 12 to 36 hours, but the timing, intensity, or occurrence may still be uncertain.
WINTER STORM WARNING:
A winter storm warning is issued when heavy snow is occurring or will develop in the next 18 hours. The heavy snow may be accompanied by wind and blowing snow.
A blizzard warning is issued when the following conditions are expected for at least 3 hours: Sustained winds of 35mph or greater with considerable falling and/or drifting snow lowering visibilities to less than 1/4 mile. Remember, snow does not necessarily need to be falling and dangerous wind chills are often observed during blizzard events.
WINTER WEATHER ADVISORY:
A winter weather advisory for snow is issued when these general snow accumulations are expected: Between 4 and 8 inches in 12 hours in the mountains. Between 3 and 6 inches in 12 hours at lower elevations, such as Denver Metro.
A winter weather advisory for snow and blowing snow is issued when falling snow is accompanied by blowing snow to cause travel problems due to lowered visibilities and drifting snow.
A winter weather advisory for blowing snow is issued when wind blown snow will occasionally reduce visibilities and create a hazard for travelers.
Below freezing temperatures are expected and may cause significant damage to plants, crops, or fruit trees in areas unaccustomed to freezing temperatures. Usually issued for first frost/freeze of season and again in spring for late frost/freezes.
HIGH WIND WARNING:
wind warning is issued for the following conditions: Sustained winds of
50mph for at least 1 hour, or gusts to 75mph for any duration in the
mountains and foothills. Sustained winds of 40mph for at least 1 hour, or
gusts to 58mph for any duration at lower elevations away from the
We as weather forecasters use different wording or terms when we describe a snow event. Whether it is just some flurries or a large winter storm we use different words that best suit the snow event that is expected.
- Light snow falling for short durations. No accumulation or light dusting
is all that is expected.
Rain drops that freeze into ice pellets before reaching the ground. Sleet usually bounces when hitting a surface and does not stick to objects. However, it can accumulate like snow and cause a hazard to motorists.
Rain that falls onto a surface with a temperature below freezing. This causes it to freeze to surfaces, such as trees, cars, and roads, forming a coating or glaze of ice. Even small accumulations of ice can cause a significant hazard.
Snow and or severe cold can be potentially life threatening and every year we see cold and snow related deaths.
Everyone is potentially at risk during winter storms. The actual threat to you depends on your specific situation. Recent observations indicate the following:
Frostbite is damage to body tissue caused by that tissue being frozen.
Frostbite causes a loss of feeling and a white or pale appearance in
extremities, such as fingers, toes, ear lobes, or the tip of the nose. If
symptoms are detected, get medical help immediately! If you must wait for
help, slowly re-warm affected areas. However, if the person is also showing
signs of hypothermia, warm the body core before the extremities.
When CAUGHT in a Winter Storm...
Do not eat snow: It will lower your body temperature. Melt it first.
IN A CAR OR TRUCK
in your car or truck. Disorientation occurs quickly in wind-driven snow and
Make yourself visible to rescuers:
Exercise from time to time by vigorously moving arms, legs, fingers, and toes to keep blood circulating and to keep warm.
AT HOME OR IN A BUILDING
Stay inside. When using ALTERNATIVE HEAT from a fireplace, wood stove, space heater, etc.:
and drink. Food provides the body with energy for producing its own heat.
Keep the body replenished with fluids to prevent dehydration.
Colorado sees it share of snow during the winter months. The best time to prepare for the next snow is now while the weather is mild and dry. Take an inventory of you winter supplies both for the car and the home and stock in items that you need. Be prepared and the winter snows will be a lot less bothersome this year.
With the widespread precipitation of the last several months, little areas of drought remain in Colorado, though some dry areas have developed in southestern Colorado.
The map below shows forecasted temperature deviances for October 2009. As can be seen, it is expected that much of Colorado to have below normal temperatures for the month of October 2009, with eastern Colorado expected to have normal temperatures.
The map below shows forecasted precipitation deviances for October 2009. All of Colorado is expected to have above normal precipitation for October 2009.
Little in the way of drought remains in Colorado, with no changes expected.
September of 2009 was fairly quiet weather wise with most of the monthly precipitation falling between the 21st and 23rd of the month as a slow moving storm system brought rain and snow to the Front Range. DIA did not report any snow from this fall like system, but many foothill and Palmer Divide locations received the seasons first snow, generally an inch or less with higher amounts in the Jefferson, Boulder and Larimer County foothills. Precipitation fell short of normal for the second month in a row with only 0.74" reported at DIA with 1.14" on average. For the month ending in September the yearly precipitation now stands at 15.82" which is 3.63" above normal and assures that this year will feature above "normal " precipitation. Even with the stretch of cool weather towards the end of the month temperatures were above normal with an average high of 78 compared to 77.4 on average. Low temperatures averaged 48.9 compared to 47.3 degrees normally. The warmer overnight temperatures may have been held up by above normal cloud cover acting like a blanket and not allowing the daytime heat to escape overnight. The percent of possible sunshine was only 61% compared to 74% on average which is quite significant and indicates much more cloudiness than normal.
October of 2009 will likely bring the seasons first meaningful snowfall to many Front Range locations as the onset of fall has occurred. Already this month DIA has reported record low temperatures in the middle 20s and the trees sure seem to be changing early this year, especially the scrub oak and they are "typically" one of the last trees to change. Daylight loss becomes very noticeable in October especially after the time change and temperatures respond accordingly dropping 12 degrees from the average high of September. Overnight temperatures are frequently at or below freezing with 9 days on average per month. There can certainly be some beautiful fall weather in October with 72% of possible sunshine which makes October one of the sunniest months of the year. Large variations in temperatures and weather conditions are common in October with thunderstorms and blizzards both possible just days or hours apart. Skyview Weather believes that this October will feature colder than normal temperatures and above normal precipitation with a couple bouts of snow likely.
Sunrise/Sunset (Jul - December Denver area)
May 2009 to October 2009