The Weather Wire

 

April 2009                                                                                                            Volume 17 Number 04

 

Contents

 

 

 
·   Severe TRW Warning
 

·   Drought Monitor

 

·   March

    Summary

 

·   March Stats

 

·   April Preview

 

·   Sunrise/Sunset

 

·   Snow Totals

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March 

Avg High - 56.6

Avg Low - 27.0

Snow - 13.8"

Season Snow - 30.7"

Precipitation - 0.83"

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

April

Avg High - 60.9

Avg Low - 34.2

Avg Snow -  9.1"

Avg Precip - 1.93"

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Skyview Weather 

2350 N Rocky View Rd

Castle Rock, CO 80108

 

Phone: (303) 688-9175

Fax: (303) 380-3338

 

E-mail:    

tim@skyview-wx.com

 

We’re on the Web!

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

 

Copyright 2009

Skyview Weather

New Severe Thunderstorm Warning Definition

Becoming effective this summer is a new definition of a Severe Thunderstorm.  Below is the previous definition:

Severe Thunderstorm:  A thunderstorm which produces tornadoes, hail 0.75" or more in diameter, or winds of 58mph or more (50kts).

The NEW Severe Thunderstorm definition:

Severe Thunderstorm:  A thunderstorm which produces tornadoes, hail 1.0" or more in diameter, or winds of 58mph or more (50kts).

Obviously the only change is the size of the hail so how will this impact us here in Colorado?  Well, most of our thunderstorms here in Colorado become "severe" by definition strictly by the size of hail alone as we receive more hail here along the Front Range than any other populated area in America.  The second most common reason for severe thunderstorm warning is winds and third, tornadoes.  Since hail is the most common reason for NWS issuing Severe Thunderstorm Warnings here in Colorado there will likely be less warnings issued on a daily basis.  This is good in the sense that in theory there will be less watches and warnings issued and the ones that do get issued will be taken more seriously.  We will see how this goes as old habits are hard to break and in the past some warnings have been issued on borderline storms even with the 0.75" criteria.  With less watches and warnings there should be less confusion on exactly where the most severe weather is occurring.

Some of the downfalls of this definition change is that there can be damage done with storms below severe criteria.  Minor hail damage can occur with hail less than 1.0" in diameter and is typically minor damage, but damage none the less.  Combine winds of less than 50mph with hail less than 1.0" in diameter and wind blown hail can cause even greater damage, although typically to one side of the object.  Overall I believe this warning change will help eliminate the borderline issued warnings in the past and allow the strongest storms with the greatest threat to life and property to be brought to the forefront.       

Drought Update

Areas of drought have spread across much of eastern Colorado as well as northwest Colorado as a result of our precipitation deficit year to date. 

The map below shows forecasted temperature deviances for April 2009. As can be seen, it is expected that all of Colorado to have above normal temperatures for the month of April 2009. 

The map below shows forecasted precipitation deviances for April 2009.  Normal precipitation is anticipated for all of Colorado March 2009.

Some improvement in drought conditions is expected along the Front Range of Colorado during the April to June time period.

March Summary

March of 2009 was a continuation of the warm and dry weather from February until the last week of the month.  The average high was 56.6 degrees and the average low was 27 degrees, both were above normal resulting in a monthly mean of 41.8 degrees which is 2.2 degrees above normal.  Up until the blizzard on the 26th there was only 0.12" of precipitation for the entire month.  Thankfully the last week of March brought much needed snow and precipitation.  Snowfall for the month ended up at 13.8" which is above normal, but the water content was low resulting in a monthly deficit of nearly half an inch.  The month was rather windy with an average speed of 11.6mph and two days with gusts of 50mph or more reported at DIA.  Don't let the above normal snowfall for the month of March fool you as we are continuing to fall further into drought along the Front Range.

March Stats

TEMPERATURE (IN DEGREES F)

 

 

 

 

 

 

AVERAGE MAX

56.6

NORMAL

53.7

DEPARTURE

2.9

AVERAGE MIN

27.0

NORMAL

25.4

DEPARTURE

1.6

MONTHLY MEAN

41.8

NORMAL

39.6

DEPARTURE

2.2

HIGHEST

78 on the 22nd

LOWEST

10 on the 28th

 

 

 

 

 

 

DAYS WITH MAX 90 OR ABOVE

0

NORMAL

0.0

DAYS WITH MAX 32 OR BELOW

1

NORMAL

2.8

DAYS WITH MIN 32 OR BELOW

23

NORMAL

24.3

DAYS WITH MIN ZERO OR BELOW

0

NORMAL

0.5

 

 

 

 

 

 

TEMPERATURE RECORDS

 

Record high of 74 on the 2nd

Record high minimum of 47 degrees on the 2nd

Record high of 76 on the 4th

 

 

 

 

 

HEATING DEGREE DAYS

 

 

 

 

 

 

MONTHLY TOTAL

711

NORMAL

788

DEPARTURE

-77

SEASONAL TOTAL

4768

NORMAL

5277

DEPARTURE

-509

 

 

 

 

 

 

COOLING DEGREE DAYS

 

 

 

 

 

 

MONTHLY TOTAL

0

NORMAL

0

DEPARTURE

0

YEARLY TOTAL

0

NORMAL

0

DEPARTURE

0

 

 

 

 

 

 

PRECIPITATION (IN INCHES)

 

 

 

 

 

 

MONTHLY TOTAL

0.83

NORMAL

1.28

DEPARTURE

-0.45

YEARLY TOTAL

1.00

NORMAL

2.28

DEPARTURE

-1.28

GREATEST IN 24 HOURS

0.63" on the 26th

DAYS WITH MEASURABLE PRECIPITATION

5

 

 

 

 

 

SNOWFALL (IN INCHES)

 

 

 

 

 

 

MONTHLY TOTAL

13.8

NORMAL

11.7

DEPARTURE

2.1

SEASONAL TOTAL

30.7

NORMAL

51.3

DEPARTURE

-20.6

GREATEST IN 24 HOURS

7.8" on the 26th

GREATEST DEPTH

7.0" on the 27th

 

 

 

 

 

 

WIND (IN MILES PER HOUR)

 

 

 

 

 

 

AVERAGE SPEED 11.6

PEAK WIND GUST

53mph on the 21st and 22nd from the S and SW

 

 

 

 

 

 

MISCELLANEOUS WEATHER

 

 

 

 

 

 

NUMBER OF DAYS WITH THUNDERSTORMS

0

NORMAL

0

NUMBER OF DAYS WITH HEAVY FOG

3

NORMAL

1

NUMBER OF DAYS WITH HAIL

0

 

 

PERCENT OF SUNSHINE

67%

NORMAL

69%

 

 

 

April Preview

April is normally our transition month coming out of winter into Spring with a wide variety of weather ranging from downright hot to freezing cold with thunderstorms or even a blizzard.  The average highs are now in the 60s and the average low for the month is just above freezing.  April is the 3rd snowiest month of the year, averaging 9.1", but snow typically does not stay on the ground for long.  As far as total precipitation goes, 1.93" is normal, but even with the active weather so far this month up to the 9th there is only 0.06" so far at DIA.  Storms are moving through, but the position of these storm systems are favoring surrounding areas and not the Front Range in particular.  This trend will likely continue resulting in April of 2009 ending up below normal in both precipitation and snowfall.  Temperatures however may actually be below normal due to the active storm track bringing increased cloud cover and cooler air.

DENVER'S NOVEMBER CLIMATOLOGICALLY NORMAL

(NORMAL PERIOD 1971-2000)

 

 

TEMPERATURE

 

 

 

AVERAGE HIGH

60.9

AVERAGE LOW

34.2

MONTHLY MEAN

47.6

DAYS WITH HIGH 90 OR ABOVE

Less than 1

DAYS WITH HIGH 32 OR BELOW

Less than 1

DAYS WITH LOW 32 OR BELOW

11

DAYS WITH LOWS ZERO OR BELOW

Less than 1

 

 

PRECIPITATION

 

 

 

MONTHLY MEAN

1.93"

DAYS WITH MEASURABLE PRECIPITATION

9

AVERAGE SNOWFALL IN INCHES

9.1"

DAYS WITH 1.0 INCH OF SNOW OR MORE

3

 

 

MISCELLANEOUS AVERAGES

 

 

 

HEATING DEGREE DAYS

524

COOLING DEGREE DAYS

2

WIND SPEED (MPH)

10.0mph

WIND DIRECTION

South

DAYS WITH THUNDERSTORMS

2

DAYS WITH DENSE FOG

1

PERCENT OF SUNSHINE POSSIBLE

67%

 

 

EXTREMES

 

 

 

RECORD HIGH

90 on April 30, 1992

RECORD LOW

-2 on April 2, 1975

WARMEST

56.4 in 1946, 1981

COLDEST

38.8 in 1920

WETTEST

8.24" in 1900

DRIEST

0.03" in 1963

SNOWIEST

33.8" in 1933

LEAST SNOWIEST

0.0" in 1888, 1930, 1943, 1992
 

Sunrise/Sunset (Jul - December Denver area)

               JAN               FEB               MAR             APR                MAY              JUN
_______________________________________________________________________________
     sr - ss     sr - ss     sr - ss     sr - ss     sr - ss     sr - ss
 01  0721-0446 | 0707-0518 | 0632-0551 | 0643-0723 | 0600-0753 | 0534-0821  01
 02  0721-0447 | 0706-0519 | 0631-0552 | 0642-0724 | 0559-0754 | 0533-0822  02
 03  0721-0448 | 0705-0521 | 0629-0553 | 0640-0725 | 0557-0755 | 0533-0822  03
 04  0721-0449 | 0704-0522 | 0628-0554 | 0638-0726 | 0556-0756 | 0532-0823  04

 05  0721-0450 | 0703-0523 | 0626-0555 | 0637-0727 | 0555-0757 | 0532-0824  05
 06  0721-0451 | 0702-0524 | 0625-0556 | 0635-0728 | 0554-0758 | 0532-0824  06
 07  0721-0452 | 0701-0525 | 0623-0557 | 0634-0729 | 0553-0759 | 0532-0825  07
 08  0720-0452 | 0700-0527 | 0721-0658 | 0632-0730 | 0552-0800 | 0531-0826  08

 09  0720-0453 | 0659-0528 | 0720-0659 | 0631-0731 | 0551-0801 | 0531-0826  09
 10  0720-0454 | 0658-0529 | 0718-0700 | 0629-0732 | 0550-0802 | 0531-0827  10
 11  0720-0456 | 0656-0530 | 0717-0701 | 0628-0733 | 0549-0803 | 0531-0827  11
 12  0720-0457 | 0655-0531 | 0715-0702 | 0626-0734 | 0548-0804 | 0531-0828  12

 13  0719-0458 | 0654-0533 | 0714-0704 | 0625-0735 | 0547-0805 | 0531-0828  13
 14  0719-0459 | 0653-0534 | 0712-0705 | 0623-0736 | 0546-0806 | 0531-0829  14
 15  0719-0500 | 0651-0535 | 0710-0706 | 0622-0737 | 0545-0807 | 0531-0829  15
 16  0718-0501 | 0650-0536 | 0709-0707 | 0620-0738 | 0544-0808 | 0531-0829  16

 17  0718-0501 | 0649-0537 | 0707-0708 | 0619-0739 | 0543-0809 | 0531-0830  17
 18  0717-0502 | 0648-0538 | 0706-0709 | 0617-0740 | 0542-0809 | 0531-0830  18
 19  0717-0503 | 0646-0539 | 0704-0710 | 0616-0741 | 0541-0810 | 0531-0830  19
 20  0716-0504 | 0645-0541 | 0702-0711 | 0614-0742 | 0541-0811 | 0532-0831  20

 21  0716-0505 | 0644-0542 | 0701-0712 | 0613-0743 | 0540-0812 | 0532-0831  21
 22  0715-0507 | 0642-0543 | 0659-0713 | 0612-0744 | 0539-0813 | 0532-0831  22
 23  0714-0508 | 0641-0544 | 0658-0714 | 0610-0745 | 0538-0814 | 0532-0831  23
 24  0714-0509 | 0639-0545 | 0656-0715 | 0609-0746 | 0538-0815 | 0533-0831  24

 25  0713-0510 | 0638-0546 | 0654-0716 | 0608-0747 | 0537-0816 | 0533-0831  25
 26  0712-0511 | 0636-0547 | 0653-0717 | 0606-0748 | 0537-0816 | 0533-0831  26
 27  0711-0512 | 0635-0548 | 0651-0718 | 0605-0749 | 0536-0817 | 0534-0832  27
 28  0711-0514 | 0634-0550 | 0650-0719 | 0604-0750 | 0535-0818 | 0534-0832  28

 29  0710-0515 |                       | 0648-0720 | 0602-0751 | 0535-0819 | 0534-0832  29
 30  0709-0516 |                       | 0646-0721 | 0601-0752 | 0534-0820 | 0535-0831  30
 31  0708-0517 |                       | 0645-0722 |                      | 0534-0820 |                       31

 

 Snowfall

October 2008 to April 2009

City

Oct

Nov

Dec

Jan Feb Mar Apr

Seasonal Totals

Aurora (Central)

 0.0 7.6 12.3 5.8 2.6 11.5   39.8
Brighton  0.0 1.6 12.1 5.7 0.8 18.6    38.8
Broomfield  0.0 2.3 13.8 7.0 1.0 16.2    40.3

Castle Rock 4 NE

 0.3 12.0 9.7 6.6 3.2 15.3    47.1

Colorado Sprgs Airport

 TR 2.6 5.2 3.4 0.6 4.7    16.5
Denver DIA  TR 1.7 10.3 4.9 TR 13.8    30.7

Denver Downtown

 0.0 3.0 8.4 7.8 3.1 15.0    37.3

Golden

TR 9.3 19.5 14.9 3.5 18.8   66.0

Fort Collins

TR TR 10.5 5.8 4.1 12.2    32.6

Highlands Ranch

 0.0 13.9 9.7 8.9 6.0 20.9    59.4

Lakewood

 0.0 3.8 8.5 9.5 4.2 17.0    43.0

Littleton

 0.0 15.2 10.7 8.7 3.7 16.3    54.6

Parker

TR 9.3 14.5 12.4 3.2 13.1    52.5

Sedalia - Hwy 67

 TR 14.2 8.0 9.0 3.0 16.0    50.2

Thornton

 0.0 3.4 13.6 6.9 1.8 18.6    44.3

Westminster

 0.0 2.3 13.4 9.7 1.4 21.8    48.6

Wheatridge

 0.0 5.3 12.0 15.6 4.7 21.7    59.3