Posted by: Curtis Utley, Jefferson County Extension
Unless you have been living under a rock you will have noticed that we have been experiencing abnormally warm and dry weather this fall, and the long-range forecast looks to promise more of the same. In fact, NOAA reported:
Native rocks which one could be proud to live under
...NOVEMBER 2017...DRIER AND MUCH WARMER THAN NORMAL...
AFTER AN OCTOBER WHICH EXPERIENCED A WIDE TEMPERATURE RANGE WITHIN
THE MONTH, NOVEMBER 2017 RECORDED A FAIRLY NARROW RANGE IN
TEMPERATURE DUE TO LACK OF EXTREME COLD. TWO DAILY HIGH TEMPERATURE
RECORDS WERE SET IN NOVEMBER. THE HIGH ON THE 26TH REACHED A RECORD
SETTING 74 DEGREES WITH 81 DEGREES REACHED ON THE 27TH. THE HIGH OF
81 DEGREES ON THE 27TH ALSO ESTABLISHED AN ALL TIME MONTHLY HIGH
TEMPERATURE RECORD FOR NOVEMBER. THE HIGH OF 81 DEGREES ON THE 27TH
EXCEED THE PREVIOUS MONTHLY HIGH TEMPERATURE OF 80 SET ON BOTH THE
6TH OF THE MONTH IN 2006 AND THE 16TH OF THE MONTH IN 2016.
AS FOR PRECIPITATION, NOVEMBER 2017 LANDED SHORT OF THE MONTHLY
AVERAGE AS PREDOMINANT STRONG WEST TO NORTHWESTERLY FLOW ALOFT
PROVIDED FOR FREQUENT BOUTS OF DRY DOWNSLOPE FLOW ALONG THE NORTHERN
FRONT RANGE. A FEW WEAK COLD FRONTS PUSHED THEIR WAY INTO NORTHEAST
COLORADO DURING THE MONTH, HOWEVER WITH LIMITED MOISTURE ASSOCIATED
WITH EACH ONE, ONLY LIGHT PRECIPITATION AMOUNTS WERE RECORDED. A
STRONG AND FAST-MOVING DISTURBANCE, WHICH PASSED ACROSS SOUTHERN
WYOMING AND NORTHERN COLORADO LATE IN THE DAY OF THE 17TH, PUSHED
RAIN SHOWERS ONTO THE LOWER ELEVATIONS AND GAVE DENVER THE HIGHEST
PRECIPITATION FOR THE MONTH WITH 0.23 ON THE 17TH.
AS THE THANKSGIVING HOLIDAY APPROACHED, A LARGE RIDGE OF STABLE HIGH
PRESSURE BEGAN TO DEVELOP OVER THE SOUTHWEST UNITED STATES ON THE
21ST. THIS STABLE RIDGE PERSISTED ACROSS THANKSGIVING AND INTO THE
NEXT WEEK WHILE KEEPING THE REGION AND DRY WITH WELL ABOVE AVERAGE
AND EVEN RECORD SETTING TEMPERATURES.
TEMPERATURES:
THE AVERAGE TEMPERATURE AT DENVER INTERNATIONAL AIRPORT FOR THE
MONTH WAS 45.3 DEGREES F, WHICH IS 7.0 DEGREES ABOVE NORMAL. THIS
NOW RANKS AS 10TH WARMEST NOVEMBER`S SINCE TEMPERATURES RECORDS
BEGAN IN 2017 1872. THE WARMEST NOVEMBER ON RECORD OCCURRED IN 1949
WITH AN AVERAGE MONTHLY TEMPERATURE OF 50.9 DEGREES F. THE COLDEST
NOVEMBER ON RECORD WAS OCCURRED IN 1880 WITH A MONTHLY AVERGAE OF
22.0 DEGREES.
TEN WARMEST NOVEMBER`S IN DENVER WEATHER HISTORY SINCE 1872:
50.9 1950
47.2 1999
46.2 1933, 1914
45.9 1981, 1927
45.6 1910, 1917
45.5 1917
45.3 2017
TEN COLDEST NOVEMBER`S IN DENVER WEATHER HISTORY SINCE 1872:
22.0 1880
28.9 2000
29.7 1985
31.5 1929
32.3 1952
32.5 1889
32.8 1972
33.0 1886
33.1 1872
33.3 1979
PRECIPITATION:
PRECIPITATION FOR THE MONTH OF NOVEMBER AT DENVER INTERNATIONAL
AIRPORT WAS 0.29 INCHES, WHICH IS 0.32 INCHES BELOW THE NORMAL OF
0.61 INCHES. THERE WERE 3 DAYS WITH MEASURABLE PRECIPITATION DURING
THE MONTH. 0.23 INCHES OF PRECIPITATION FELL ON THE 17TH, WHICH IS
THE GREATEST DAILY AMOUNT FOR THE MONTH.
TEN WETTEST NOVEMBER`S IN DENVER WEATHER HISTORY SINCE 1872:
3.21 INCHES 1946
2.67 INCHES 1991
2.63 INCHES 1983
2.13 INCHES 2015
1.95 INCHES 1922
1.93 INCHES 1886
1.88 INCHES 1975
1.74 INCHES 1908
1.69 INCHES 1972
1.68 INCHES 1881
TEN DRIEST NOVEMBER`S IN DENVER WEATHER HISTORY SINCE 1872:
TRACE 1949, 1901, 1889
0.01 INCHES 1939
0.03 INCHES 1917
0.04 INCHES 1905, 1904
0.05 INCHES 2003
0.07 INCHES 1903
0.08 INCHES 1920, 1874
NO THUNDER WAS OBSERVED AT DENVER INTERNATIONAL AIRPORT AND
4 DAYS WITH DENSE FOG WITH A VISIBILITY AT OR BELOW 1/4 MILE DURING
THE MONTH. THE PEAK WIND GUST OF 52 MPH FROM THE NORTHWEST OCCURRED
ON THE 1ST.
While attending the Rocky Mountain Regional Turfgrass Association Conference and Trade Show last week my colleague, Carol O’Meara and I were lamenting the fact that landscapes along the Front Range are going to suffer if the dry warm weather continues through the winter. Both of us planned on watering our landscapes a little, over the weekend, to prevent winter-kill from desiccation.
I also received a few calls last week from landscape maintenance companies concerned about protecting customer’s lawns from turfgrass mites which can kill drought-stressed turf in the winter months. This morning I decided to inspect the turfgrass outside of my office for mite activity and sure enough, I found clover mites actively feeding on the turf close to a south-facing retaining wall. Without natural winter precipitation or winter watering it is likely the clover mite population will explode and cause enough feeding damage to the quasi dormant turf to kill it out right.
 |
| Southwest facing retaining wall |
 |
| Active Clover mites |
Clover mites and Bank’s grass mites are cool-season pests of turfgrass along the Front Range and have caused economic damage to landscapes in the past and will kill turf this year too unless susceptible aspects of lawns receive irrigation or natural precipitation. To learn more about turf mites, check out the factsheet http://extension.colostate.edu/docs/pubs/insect/05505.pdf
What does that mean? Damage caused by these cool-season mites is always most severe on south or west facing slopes (aspects) or on the South or West sides of evergreen trees, shrubs, buildings, walls, and fences, so focus your winter watering efforts on those areas of your lawn specifically. To learn more about winter watering, check out the factsheet http://extension.colostate.edu/docs/pubs/garden/07211.pdf
 |
| South facing slope with mite damage |
 |
| South facing side of a blue spruce |
 |
| West facing slope with mite damage |
Check for mite activity in your lawn by swiping a white sheet of paper over the lawn. Turn the paper over and examine it for small red streaks; the streaks represent crushed mites. If found, know that your lawn at that specific location is in peril and you should water. If the paper has lots of streaks, consider spraying that aspect with an insecticidal soap to knock back the population of mites then begin watering. To learn how to check for mites, watch this video
Next spring, if you notice the south and west aspects of your lawn are not greening-up with the rest of your lawn, check the margins of the damage with a clean sheet of white paper. If you find streaks, begin watering.The areas of turf that have not greened up by April are probably dead and should be re--sodded, reseeded or, consider mulching those areas and planting western natives in those locations. To learn more, check out this factsheet http://extension.colostate.edu/docs/pubs/garden/07241.pdf or this Plantalk script http://planttalk.colostate.edu/topics/lawns/1517-sodding-lawn/ . A little water now may save you the cost of replanting, and a lot of water next spring to re-establish your turf.
 |
| Small red streaks are crushed mite bodies and indicate activity |