Strong to Severe Storms in the Upper Midwest; Bering Sea Low Continues to Impact Southwest Alaska

Scattered severe thunderstorms are possible Thursday across central and eastern Minnesota, Iowa, and western Wisconsin. A few tornadoes, isolated very large hail, and damaging winds may occur. In southwest Alaska, a Bering Sea low continues to cause strong winds, significant rainfall, and high seas, with further impacts expected Friday into the weekend from a North Pacific storm. Read More >

...A STATISTICAL PREVIEW OF DENVER`S APRIL WEATHER...

APRIL IN DENVER IS CONSIDERED A TRANSITION MONTH SIMILAR TO MARCH, HOWEVER IT’S WARMER WITH A BIAS TOWARD RAINFALL AND SEVERE WEATHER INSTEAD OF SNOW. LIKE MARCH, APRIL OFTEN PROVIDES A WIDE VARIATION OF WEATHER AND TEMPERATURE RANGES. FOR OUTDOOR ENTHUSIASTS, A DEEP SNOWPACK OFTEN REMAINS AVAILABLE AT HIGHER ELEVATIONS WHILE WARM SPRINGLIKE TEMPERATURES IN THE 80'S CAN BE EXPERIENCED AT LOWER ELEVATIONS.

FAST CHANGING WEATHER IS COMMON IN APRIL OVER THE DENVER METRO AREA AND EASTERN PLAINS. WHEN CANADIAN COLD FRONTS OCCASIONALLY CLASH WITH RELATIVELY WARM AND MOIST GULF MOISTURE, SEVERE WEATHER TYPICALLY ENSUES. WITH SOME OF THE MORE ORGANIZED PACIFIC TROUGHS OF LOW PRESSURE, SEVERE WEATHER OFTEN STRIKES AHEAD OF SIGNIFICANT SNOW STORMS. THE MONTHLY NORMAL SNOWFALL TOTAL CAN BE OFTEN REACHED WITH A SINGLE STORM SYSTEM LASTING FROM 1 TO 3 DAYS. IN ADDITION, WHETHER THE PRECIPITATION IS RAIN OR SNOW, APRIL'S NORMAL PRECIPITATION DOUBLES THAT OF MARCH'S.

DENVER'S MONTHLY MEAN TEMPERATURE FOR APRIL IS 47.4 DEGREES (1981-2010 AVERAGES) AND IS DENVER'S 6TH COLDEST MONTH OF THE YEAR BEHIND DECEMBER, JANUARY, FEBRUARY, NOVEMBER AND MARCH RESPECTIVELY. APRIL STARTS THE MONTH WITH A NORMAL HIGH OF 58 DEGREES AND ENDS WITH A NORMAL HIGH OF 66 DEGREES. FOR LOW TEMPERATURES, THE MONTH BEGINS WITH A NORMAL OF 30 DEGREES AND FINISHES WITH A NORMAL OF 37.

THE WARMEST TEMPERATURE EVER RECORDED DURING THE MONTH OF APRIL, SINCE RECORDS BEGAN IN 1872, WAS 90 DEGREES ON THE 30TH DAY OF 1992. APRIL'S COLDEST TEMPERATURE EVER RECORDED IN DENVER WAS -2 DEGREES AND OCCURED ON THE 2ND DAY OF 1975.

APRIL: DENVER'S TOP 10 COLDEST (MEAN TEMPERATURES):

38.8 DEGREES 1920

40.5 1997

41.0 1883

41.1 1873

41.4 1957

41.7 2013

42.2 1945

42.3 1984

42.5 1999

42.6 1918

APRIL: DENVER'S TOP 10 WARMEST (MEAN TEMPERATURES):

56.4 DEGREES 1981

56.3 1946

55.5 1930

55.3 1943

54.8 1992

53.8 1881

53.6 1954

53.3 2012

53.3 1888

53.2 1948

FOR DENVER'S NINE MONTH SNOW PERIOD OF SEPTEMBER THROUGH MAY, APRIL RANKS AS THE 5TH SNOWIEST MONTH AND ACCOUNTS FOR APPROXIMATELY 13 PERCENT OF THE ANNUAL SNOWFALL OF 53.8 INCHES. DENVER NORMALLY COLLECTS 6.8 INCHES OF SNOW IN APRIL BASED ON AVERAGES FROM FORMER STAPLETON INTL AIRPORT (1981-2010 AVERAGES). AT LOWER ELEVATIONS, INCLUDING THE EASTERN PLAINS, FRONT RANGE AND METRO DENVER, APRIL STORMS VARY WIDELY WITH RESPECT TO PRECIPITATION TYPE. PRECIPITATION FROM PACIFIC STORM SYSTEMS CAN COME IN THE FORM OF RAIN DURING DAYLIGHT HOURS WHICH THEN TRANSITIONS OVER TO SNOW IN THE EVENING HOURS AS TEMPERATURES COOL.

MUCH LIKE MARCH, SIGNIFICANT SNOW STORMS ARE ALSO POSSIBLE IN APRIL. DENVER'S 5TH BIGGEST SNOW STORM IN HISTORY OCCURRED IN 1885 AND BROUGHT A QUICK 23.0 INCHES IN LESS THAN 24 HOURS. FROM A MONTLY TOTAL SNOWFALL ASPECT, APRIL WEATHER PROVES TO BE VERY COLD AND UNSETTLED AT TIMES WITH MONTHLY TOTALS LANDING VERY MUCH IN-LINE WITH SNOWFALL AMOUNTS SEEN IN MARCH.

APRIL: DENVER'S TOP 10 SNOWIEST

33.8 INCHES 1933

32.0 1885

28.3 1920

28.2 1945

25.5 1957

54.4 1909

25.0 1907

24.8 1973

23.3 1935

20.4 2013

THE END OF THE WINTER AND ONSET OF SPRING ALONG THE FRONT RANGE AND HIGH PLAINS OCCASIONALLY EXPERIENCE EXTENDED DROUGHT-LIKE CONDITIONS. THESE DRY PERIODS ARE OFTEN ASSOCIATED WITH LA NINA PHASES OF THE PACIFIC OCEANIC REGION. LIKE MARCH, THE DRIEST APRILS USUALLY END THE MONTH WITH ABOVE NORMAL MONTHLY TEMPERATURES MAINLY DUE TO WINDY, CLOUD FREE, DOWNSLOPE WINDY DAYS COMBINED WITH WARMER NIGHT-TIME LOW TEMPERATURES.

APRIL: DENVER'S LEAST SNOWY

0.0 INCHES 1995, 1992, 1943, 1930

T 2002, 1969, 1946, 1925, 1915, 1910, 1889, 1888, 1887

0.2 1963

0.3 2006, 1965

0.5 2010, 1896

APRIL CAN BE CONSIDERED THE FIRST MONTH OF THE SEVERE WEATHER AND THUNDERSTORM SEASON IN THE DENVER AREA. TROUGHS OF LOW PRESSURE OFTEN USHER IN RELATIVELY COLD AIR ALOFT IN NORTHWEST FLOW. THIS CAN CREATE PERIODS OF INSTABILITY IN COMBINATION WITH SURFACE AIRMASS COLLISIONS OF COLD CANADIAN AIR AND MOIST GULF AIR. PRECIPITATION IN THE FORM OF SLEET AND SMALL HAIL IS ALSO COMMON WITH APRIL THUNDERSTORMS. AS WE MOVE INTO THE WARM AND CONVECTIVE MONTHS OF SPRING AND SUMMER, MONTHLY PRECIPITATION TOTALS BECOME A MEASURE OF INTEREST. DENVER'S SECOND WETTEST MONTH IN HISTORY OCCURRED IN APRIL, 1900. MAY 1876 was

APRIL: DENVER'S TOP 10 WETTEST

8.24 INCHES 1900

5.86 1999

4.95 1905

4.94 1885

4.13 1957

4.09 1933

4.07 1935

4.01 1942

3.95 1967

3.75 1914

APRIL: DENVER'S TOP 10 DRIEST

0.03 INCHES 1963

0.05 1878

0.23 2002

0.31 1880

0.32 2008

0.33 1996

0.34 1982

0.39 1908

0.40 1925

0.48 1955

...THE OUTLOOK FOR APRIL 2015...

WITH MARCH 2015 COMING IN WITH ABOVE AVERAGE TEMPERATURE AND BELOW NORMAL PRECIPITATION, THE SHORT TO MEDIUM RANGE MODEL INDICATE A PERSISTANT PATTERN OF QUICK MOVING PACIFIC STORM SYSTEMS PASSING ACROSS THE NORTHERN AND CENTRAL ROCKIES THROUGH THE FIRST 15 DAYS OF THE MONTH. LOOKING BEYOND THE FIRST 15 DAYS, THE CLIMATE PREDICTION CENTER'S LONG RANGE MONTHLY FORECAST INDICATES CONDITIONS TO TREND NEAR SEASONAL AVERAGES WITH NO SIGNIFICANT BIASES.

...APRIL STATISTICS...

...TEMPERATURES (1981-2010 NORMALS)...

AVERAGE HIGH........................... 61.5

AVERAGE LOW............................ 33.3

MONTHLY MEAN........................... 47.4

DAYS WITH HIGH 90 OR ABOVE............. 0 (<0.1)

DAYS WITH HIGH 32 OR BELOW............. 0 (0.3)

DAYS WITH LOW 32 OR BELOW.............. 13 (13.0)

DAYS WITH LOWS ZERO OR BELOW........... 0 (<0.1)

...PRECIPITATION...

MONTHLY MEAN........................... 1.71 INCHES

DAYS WITH MEASURABLE PRECIPITATION..... 9 (9.1)