The Weather Wire
October 2007 Volume 15 Number 10
Avg High 80.1
Avg Low 50.0
Snow - 0.0"
Season Snow - 0.0"
Precipitation - 0.54"
Avg High 66.0
Avg Low 35.9
Avg Snow - 4.1"
Avg Precip - 0.99"
Definitions for Selected Winter Weather Watches and Warnings:
�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.
�A WINTER STORM WARNING IS ISSUED WHEN HEAVY SNOW IS OCCURRING OR WILL DEVELOP IN THE NEXT 18 HOURS. THE HEAVY SNOW WILL BE ACCOMPANIED BY WIND GREATER THAN 15 MPH AND BLOWING SNOW.
�A HEAVY SNOW WARNING IS ISSUED WHEN HEAVY SNOW IS OCCURRING OR WILL DEVELOP WITHIN THE NEXT 18 HOURS. WINDS ARE EXPECTED TO BE LESS THAN 15 MPH DURING A HEAVY SNOW WARNING.
�A BLIZZARD WATCH IS ISSUED WHEN BLIZZARD CONDITIONS ARE POSSIBLE IN THE NEXT 12-18 HOURS.
�A BLIZZARD WARNING IS ISSUED WHEN THE FOLLOWING CONDITIONS ARE EXPECTED FOR AT LEAST 3 HOURS: SUSTAINED WINDS OF 35 MPH OR GREATER CONSIDERABLE FALLING AND/OR DRIFTING SNOW LOWERING VISIBILITIES TO LESS THAN 1/4 MILE.
�A WIND CHILL WATCH IS ISSUED WHEN WIND CHILL WARNING CRITERIA ARE POSSIBLE IN THE NEXT 12 TO 18 HOURS.
�A WIND CHILL WARNING IS ISSUED FOR WIND CHILLS OF AT LEAST -25 DEGREES ON THE PLAINS, AND -35 DEGREES IN THE MOUNTAINS.
�A SNOW ADVISORY IS ISSUED WHEN GENERAL SNOW ACCUMULATIONS ARE EXPECTED:
�BETWEEN 4 AND 8 INCHES IN 12 HOURS IN THE MOUNTAINS...AND BETWEEN 3 AND 6 INCHES IN 12 HOURS AT LOWER ELEVATIONS.
�A SNOW AND BLOWING SNOW ADVISORY IS ISSUED WHEN FALLING SNOW IS ACCOMPANIED BY BLOWING SNOW TO CAUSE TRAVEL PROBLEMS DUE TO LOWER VISIBILITIES AND DRIFTING SNOW.
�A BLOWING SNOW ADVISORY IS ISSUED WHEN WIND BLOWN SNOW WILL OCCASIONALLY REDUCE VISIBILITIES AND CREATE A HAZARD FOR TRAVELERS.
�A DENSE FOG ADVISORY IS ISSUED WHEN WIDESPREAD FOG WILL REDUCE VISIBILITIES TO 1/4 MILE OR LESS.
�A WINTER WEATHER ADVISORY IS ISSUED FOR FREEZING DRIZZLE OR A MIX OF PRECIPITATION TYPES (SUCH AS SNOW AND SLEET) THAT WILL IMPACT TRAVEL CONDITIONS.
�A WIND CHILL ADVISORY IS ISSUED WHEN WIND AND TEMPERATURE COMBINE TO PRODUCE WIND CHILL VALUES OF 18 DEGREES BELOW ZERO TO 25 DEGREES BELOW ZERO.
�THERE ARE OTHER NWS ADVISORIES, BUT THEY ARE RARELY USED HERE IN COLORADO. TO SEE ALL THE WINTER WEATHER WATCHES, WARNINGS, AND ADVISORIES VISIT:
Most of Colorado continued to see dry conditions, with little improvement in drought conditions along all borders of the state. With a dry September conditions will be deteriorating if we continue to experience below average precipitation. October is a relatively dry month for all areas of the state, but by November the western half of the state should see a significant increase in precipitation.
The map below shows forecasted temperature deviances for October 2007. As expected temperatures are anticipated to be near average through the month.
The map below shows forecasted precipitation deviances for October 2007. Normal precipitation is expected for Eastern Colorado for October 2007, though southwestern areas of the state look to receive below normal precipitation..
As can be seen in the below map, little overall change is anticipated for much of Colorado through December. Areas to our north such as Idaho, Montana and western Wyoming will see improving drought conditions as they have been experiencing drought now for up to 10 years in some locations.
September of 2007 was a very dry month with only 0.54" reported at DIA. This was 0.60" below the normal of 1.14". As a whole much of the Front Range was very dry with the exception of extreme northern Jefferson County and Boulder County as an isolated area of heavy rainfall deposited over an inch of rain in the area. Temperatures were above normal both for average highs and lows. Temperatures in both cases were 2.7 degrees above normal. With the warm and dry weather there was abundant sunshine throughout the state. September is usually the month with the most available sunshine and this month was abnormally sunny with 87% possible sunshine. Normal is 74% so hopefully you were able to get outside and enjoy the beautiful sunny and warm weather. There were 7 thunderstorms observed at DIA which was 3 above normal, unfortunately these storms did not produce much in the way of rainfall. Besides being a dry and relatively warm month with abundant sunshine there were no records set and climatologically last month did not rank in the top 10 for any categories including temperature and precipitation.
October is the first full month of fall and if we have not experienced any snow in September usually we will get the first snow out of the way in October. Only 14 years on the climatological record has there not been any measurable snowfall here in Denver, so the odds are very good that we will certainly see some snowfall sometime towards the end of the month. As we all know, Halloween has a history of being cool, wet or snowy and there is no reason to think this year will be any different.
October is also known for extreme temperature differences with a record high of 90 and a record low of -2. October of 1969 set many long standing records including the coldest, snowiest, and most precipitation on record. October of 1969 tallied 31.2" of snow which is nearly half of a normal winter. We will not experience an October like that this year as temperatures will most likely end up just above normal for the month and precipitation will most likely be near normal as we have a few weeks left for incoming storm systems to produce some rainfall or the seasons first snowfall for many locations.
Sunrise/Sunset (Denver area)
May 2007 to Sept 2007