The Weather Wire

 

February 2007                                                                                                            Volume 15 Number 02

 

Contents

 

∑   Snow Cover Record

 
∑   Weather Bites

 

∑   Drought Monitor

 

∑   January

    Summary

 

∑   January Stats

 

∑   February Preview

 

∑   Sunrise/Sunset

 

∑   Snow Totals

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

January 2007

 

Avg High 31.8

Avg Low 9.8

Snow - 15.9"

Season Snow - 59.5"

Precipitation - 0.55"

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

February

Avg High 47.2

Avg Low 19.1

Avg Snow -  6.3"

Avg Precip - 0.49"

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Skyview Weather 

2350 Rocky View Rd

Castle Rock, CO 80108

 

Phone: (303) 688-9175

Fax: (303) 660-0548

 

E-mail:    

tim@skyview-wx.com

 

Weíre on the Web!

http://www.skyview-wx.com/

 

Copyright 2006

Skyview Weather

Snow Cover Record???

 We have had a lot of people ask where we stand in the record books for snow cover on the ground.  Below you will find the official standings as far as the number of days with snow cover and what place it ranks.  Right now we sit at 4th place and tomorrow with continued snow cover we will establish this season in 3rd place.  From the NWS Boulder's website:

...DENVER'S CONSECUTIVE DAYS OF SNOW COVER CONTINUES...
...
47 CONSECUTIVE DAYS...ONE AWAY FROM 3RD PLACE...

IF IT SEEMS LIKE THERE HAS BEEN SNOW ON THE GROUND FOR AN UNUSUALLY LONG PERIOD OF TIME THIS SEASON...IT'S TRUE.  AS OF MONDAY...FEBRUARY 5TH...47 CONSECUTIVE DAYS OF MEASURABLE SNOW COVER IN DENVER HAS BEEN RECORDED.   47 CONSECUTIVE SNOW COVERED DAYS REMAINS AS 4TH  MOST CONSECUTIVE SNOW COVERED DAYS IN DENVER AND NOW IS ONLY 1 AWAY FROM 3RD PLACE.   IT STILL LOOKS LIKE THIS CONSECUTIVE TREND WILL CONTINUE EVEN IF DAY TIME TEMPERATURES CLIMB ABOVE FREEZING.  OVERNIGHT LOW TEMPERATURES WILL STILL BE BELOW FREEZING AT LEAST THROUGH THE END OF THE WEEK.  SOME MELTING IS EXPECTED THROUGH MID WEEK, BUT REFREEZING WILL OCCUR EACH MORNING.    MEASURABLE SNOW IS DEFINED AS HAVING AT LEAST ONE INCH OF SNOW ON THE GROUND WHICH IS MEASURED NEAR THE FORMER STAPLETON INTERNATONAL AIRPORT.

THE LONGEST STRETCH OF CONSECUTIVE DAYS WITH MEASURABLE SNOW COVER IN DENVER WAS 63 DAYS FROM NOVEMBER 26TH 1983 THROUGH JANUARY 27TH 1984.  THAT RECORD SETTING PERIOD WAS MAINLY THE RESULT OF THE THANKSGIVING WEEKEND BLIZZARD THAT DUMPED 21.5 INCHES OF SNOW OVER A TWO DAY PERIOD.  IN FACT...MOST OF THE SIGNIFICANT PERIODS OF SNOW COVER BEGAN WITH A MAJOR WINTER STORM JUST LIKE THE DECEMBER 20-21 2006 BLIZZARD.  ALSO NOTE HOW MOST OF THESE LONG STREAKS BEGAN IN OR NEAR THE MONTH OF DECEMBER...WHEN THE DAYS ARE SHORTEST AND THE SUN ANGLE IS LOWEST .

HERE IS A LIST OF THE TOP 10 PERIODS OF CONSECUTIVE SNOW COVER IN DENVER...

NUMBER OF DAYS                                               INCLUSIVE DATES

63 DAYS....................................NOVEMBER 26 1983 - JANUARY 27 1984
60 DAYS....................................DECEMBER 1 1913  - JANUARY 29 1914
48 DAYS....................................DECEMBER 24 1982 - FEBRUARY 9 1983
47 DAYS AND COUNTING....DECEMBER 21 2006 - FEBRUARY 5 2007
43 DAYS....................................DECEMBER 19 1973 - JANUARY 30 1974
39 DAYS....................................NOVEMBER 21 1992 - DECEMBER 29 1992
38 DAYS....................................DECEMBER 24 1987 - JANUARY 30 1988
35 DAYS...................................JANUARY 2 1949   - FEBRUARY 5 1949
33 DAYS....................................DECEMBER 17 1918 - JANUARY 18 1919
27 DAYS...................................JANUARY 28 1989   - FEBRUARY 23 1989

The question now is how far into the record books can we expect to go???

We need another 17 days of snow cover of at least an inch to set the all time record for consecutive days with snow cover.   So how is the weather outlook  for snow cover to continue.

The next 2-3 days will not help us attain that record.  Temperatures for the 6th, 7th and 8th of February will stay well above normal.  Well into the 50s for the 6th then well into the 40s for the 7th , then back into the lower 50s on the 8th.  After this bit of a warm streak colder temperatures and a bit of light snow is expected for the weekend.  After a bit of a chill down its back to the 40s for next week.

What this tells us is that we are a sure but to break the 48 days to register this winter in third place.  With some warm days on tap and not much in the way of snow it is doubtful at this point that we will make it to second or first.  However, we are guessing that not many people really want to see the record broken!

Weather Bites...

A new feature that will appear from time to time in the Weather Wire.  We will look at current weather events across the United States and the world and add in some detail and explanation.

Tornadoes rip through central sections of Florida.

Strong tornadoes caused heavy damage across 4 counties in central Florida.  Some of these storms as strong as F4ís leveled homes and buildings as a strong cold front pushed through the southern US and into central Florida.  The Fujita scale rules from F0 the weakest to F6 the strongest.  F6 tornadoes can have winds exceeding 300mph, while F0ís produce winds on the order of a dust devil. 

Florida does not typically see strong Tornadoes so was this unusual for the sunshine state?  Most of the year Florida remains covered in warm tropical air.  Great for thunderstorm development, but not for tornadoes.  Typical tornadoes for Florida are in the F0 to F1 category.   The big tornadoes that we see in the central plains can reach F4 to at times F6.   The conditions that make up the big tornadoes include warm moist tropical air moving up from the south, cool to cold Canadian air moving down from the north and dry warm air pushing in from the desert southwest.  It is the combination of 2-3 different air masses and a fairly strong cold front that give us the monster storms we see on the plains.  Florida does not typically see these conditions because of itís location in warm tropical air most of the year.

There is however one time of the year where we can get the conditions necessary for strong tornadoes in Florida. Winter.  During the winter months cold fronts do make it across Florida, bringing with them cold air from the north to clash with the warm tropical air that typically sits over Florida.  Florida does miss out on most of the winter cold fronts as they typically stall out to the north over the southern states, but the strong arctic outbreaks that we see from time to time during some winters will push cold air all the way south into Florida.  When this happens we get the necessary ingredients for strong thunderstorms and strong tornadoes.  Cold arctic air clashes with the warm tropical air over Florida and this combination produces stronger tornadoes.

Now while not typical for Florida to see strong tornadoes, it is not unusual during the winter months to produce the conditions necessary for moderate to strong tornado development.

Drought Update

Little change, or perhaps improvement, in overall drought conditions across Colorado occurred in January.

The map below shows forecasted temperature deviances for February 2007. As can be seen,  above normal to normal temperatures are expected for Colorado for February 2007.

The map below shows forecasted precipitation deviances for February 2007.  Normal precipitation is expected for Northern Colorado for February 2007, with above normal precipitation forecast for Southern Colorado for February 2007.

As can be seen in the below map, drought improvement is forecast for portions of  Colorado through April.

January Summary

Denver registers 8th coldest and 8th snowiest on record.  The snow that began in December continued during January.  Not quite as much as in December, but still 15.9 inches of snow was recorded at the Co-op site near the former Stapleton Airport.  This was 8.2 inches above the 7.7 January normal and registers January 2007 as the 8th snowiest Denver January.  The snowfall now for the season, stands at 59.5 inches which is 26.2 inches above the normal for this period.  This 59.5 inch snowfall is more that we have seen in 7 of the past 8 seasons.  The average for a season in Denver is 61.7 inches.  The last time that that total was exceeded was during the 2002-2003 season when the total accumulated was 61.8 inches.  Some of the snow favored areas along the Front Range have exceeded 100 inches for the year and we still have our 2 snowiest months ahead.

Precipitation during the first month of the year stands at 0.55 inch.  This is only 0.04 inch above the normal of 0.51 inch, but does mark the second month in a row with above normal precipitation.

January 2007 finished as the 8th coldest January in Denver weather history.  The average temperature was only 20.8 degrees, which is 8.4 degrees below the monthly normal of 29.2 degrees.  In spite of being 8.4 degrees below normal, there were no temperatures records tied of broken.  All 31 days registered low temperatures below freezing and ranged from -8 degrees up to 30 degrees.  16 days had high temperatures below the freezing mark which is 10 above normal and had 4 days below zero which is right at normal.

January Stats

TEMPERATURE (IN DEGREES F)

 

 

 

 

 

 

AVERAGE MAX

31.8

NORMAL

43.2

DEPARTURE

-11.4

AVERAGE MIN

9.8

NORMAL

15.2

DEPARTURE

-5.4

MONTHLY MEAN

20.8

NORMAL

29.2

DEPARTURE

-8.4

HIGHEST

58 on the 10th

LOWEST

--8 on the 13th

 

 

 

 

 

 

DAYS WITH MAX 90 OR ABOVE

0

NORMAL

0

DAYS WITH MAX 32 OR BELOW

16

NORMAL

7

DAYS WITH MIN 32 OR BELOW

31

NORMAL

30

DAYS WITH MIN ZERO OR BELOW

4

NORMAL

4

 

 

 

 

 

 

TEMPERATURE RECORDS

 
 None  

 

 

 

 

 

 

HEATING DEGREE DAYS

 

 

 

 

 

 

MONTHLY TOTAL

1361

NORMAL

1111

DEPARTURE

250

SEASONAL TOTAL

3813

NORMAL

3597

DEPARTURE

216

 

 

 

 

 

 

COOLING DEGREE DAYS

 

 

 

 

 

 

MONTHLY TOTAL

0

NORMAL

0

DEPARTURE

0

YEARLY TOTAL

961

NORMAL

696

DEPARTURE

265

 

 

 

 

 

 

PRECIPITATION (IN INCHES)

 

 

 

 

 

 

MONTHLY TOTAL

0.55"

NORMAL

0.51"

DEPARTURE

0.04"

YEARLY TOTAL

0.55"

NORMAL

0.51"

DEPARTURE

0.04"

GREATEST IN 24 HOURS

0.18" on the 5th

DAYS WITH MEASURABLE PRECIPITATION

4

 

 

 

 

SNOWFALL (IN INCHES)

 

 

 

 

 

 

MONTHLY TOTAL

15.9

NORMAL

7.7

DEPARTURE

8.2

SEASONAL TOTAL

59.5

NORMAL

33.3

DEPARTURE

26.2

GREATEST IN 24 HOURS

6.1 on 21st-22nd

GREATEST DEPTH

14

 

 

 

 

 

 

WIND (IN MILES PER HOUR)

 

 

 

 

 

 

AVERAGE SPEED

10.4

       

PEAK WIND GUST

46mph from the W

 

 

 

 

 

 

MISCELLANEOUS WEATHER

 

 

 

 

 

 

NUMBER OF DAYS WITH THUNDERSTORMS

0

 NORMAL

 0

NUMBER OF DAYS WITH HEAVY FOG

4

 NORMAL

 1

NUMBER OF DAYS WITH HAIL

0

 

 

PERCENT OF SUNSHINE

76

NORMAL

71

 

 

 

February Preview

February has a reputation as a rather grim month in many parts of the country.  However, that is not usually the case in Denver.  Even though it may not be grim, it is still winter with below freezing temperatures occurring almost every night and on average, 6.3 inches of snow is recorded during the month.  February is Denverís 6th snowiest month.  February stands out as having relatively uneventful weather and joins September and October for the quiet months of the year.  February is a transitional month between occasional severe cold of mid-winter and the spring storms that are common along the Front Range.

The mild weather in February often gives Denver residents a false sense of spring.  About the time we get in that spring mood the big snowstorms of March and April arrive with more winter like weather.  Just a few years back the St. Patrickís Day blizzard lasted for 3 days and dropped 2-4 feet of heavy wet snow along the Front Range. 

DENVER'S FEBRUARY CLIMATOLOGICALLY NORMAL

(NORMAL PERIOD 1971-2000)

 

 

TEMPERATURE

 

 

 

AVERAGE HIGH

47.2

AVERAGE LOW

19.1

MONTHLY MEAN

33.2

DAYS WITH HIGH 90 OR ABOVE

0

DAYS WITH HIGH 32 OR BELOW

4

DAYS WITH LOW 32 OR BELOW

26

DAYS WITH LOWS ZERO OR BELOW

2

 

 

PRECIPITATION

 

 

 

MONTHLY MEAN

0.49"

DAYS WITH MEASURABLE PRECIPITATION

6

AVERAGE SNOWFALL IN INCHES

6.3"

DAYS WITH 1.0 INCH OF SNOW OR MORE

2

 

 

MISCELLANEOUS AVERAGES

 

 

 

HEATING DEGREE DAYS

892

COOLING DEGREE DAYS

0

WIND SPEED (MPH)

8.8

WIND DIRECTION

SOUTH

DAYS WITH THUNDERSTORMS

0

DAYS WITH DENSE FOG

1

PERCENT OF SUNSHINE POSSIBLE

2

 

 

EXTREMES

 

 

 

RECORD HIGH

77 DEGREES ON 02/27/2006

RECORD LOW

-25 DEGREES ON 02/01/195`

WARMEST

43.7 DEGREES IN 1954

COLDEST

17.6 DEGREES IN 1899

WETTEST

2.01" IN 1934

DRIEST

0.01" IN 1970

SNOWIEST

22.1" INCHES in 1912

LEAST SNOWIEST

0.03" 1970

Sunrise/Sunset (Denver area)

     Date

Sunrise

Sunset

     Feb 1  

07:08

17:18

     Feb 5

07:04

17:22

     Feb 10

06:58

17:28

     Feb 15

06:52

17:34

     Feb 20

06:46

17:40

     Feb 25

06:39

17:46

     Feb 28

06:34

17:49

 Snowfall

October 2006 to April 2007

City

Oct

Nov

Dec

Jan Feb Mar Apr

Seasonal Totals

Aurora (Central)

16.2 4.0 31.1 17.8       69.1

Castle Rock 4 NE

 22.5 5.5 49.8 22.2       100.0

Colorado Springs

6.1 3.5 8.3 6.6       24.3
Denver Stapleton  4.8 4.4 29.4 15.4       58.2

Denver Downtown

5.6 4.2 35.3 15.2       66.9

Golden

20.5 12.5 45.6 24.8       103.4

Highlands Ranch

19.0 5.0 42.0 24.8       90.8

Lakewood

13.3 5.0 32.0 18.3       68.6

Littleton

13.0 6.5 40.2 21.2       80.9

Louisville

 9.0 6.7 36.0 21.2       82.5

Parker

11.0 4.0 40.0 19.2       79.7

Sedalia - Hwy 67

13.0 4.5 38.8 28.0       94.8

Thornton

12.7 4.9 38.9 19.1       75.6

Westminster

13.9 5.3 40.4 21.5       81.1

Wheatridge

15.1 8.1 43.2 16.9       83.3