Nothing New – Just Another Cold February

February 2015 Central Iowa Climate Review

Temperaturestable1

Stating the obvious here, but the month of February 2015 was a very cold month as the state of Iowa averaged 14.0°F which was a whopping 10.0°F below normal (See Figures 1 & 2). This resulted in the 10th coldest February out of 143 years of state climate records (See table to the right). The majority of the month, Iowa remained in northwest flow aloft which led to a very persistent cold pattern. In fact, there were only 5 days in which the statewide average temperature was above normal and that occurred from the 6th to the 10th (See Figure 3). The 5th was the first of several very cold air masses to settle into the region as low temperatures bottomed out in the double digits below zero with the coldest temperature of -25°F at Elkader. The coldest temperature of the month, as well as for the winter, was -30°F at Stanley on the 27th and Elkader on the 28th of February. 18 of the 28 days in February, there were stations that recorded temperatures of zero or below zero. In fact, Waterloo was below zero for a total of 105 hours and 7 minutes and only above freezing for 42 hours and 46 minutes during the entire month! Waterloo only had 4 days when the maximum temperature rose above 32°F and recorded 9 days when the average daily temperature was at least 20 degrees colder than normal. The last 3 days of the month, Waterloo was at least 30 degrees colder than its average daily temperature (See Figure 4). Waterloo shattered its record low temperature on the morning of the 27th as it plummeted to -24°F breaking the previous record of -14°F set back in 1897. Mason City also set a new record on the 27th with a low temperature of -18°F breaking the previous record of -12°F set in 1899. Mason City also only had 6 days of the month above normal. Des Moines was below normal for average daily temperatures from the 12th to the end of February and was 9.5°F below normal for the month.

Figure 1: Statewide average temperature for February 2015.
Figure 1: Statewide average temperature for February 2015.

Figure 2: Statewide average temperature departure from normal for February 2015.
Figure 2: Statewide average temperature departure from normal for February 2015.

Figure 3: Statewide average temperature departure from normal for February 6-10, 2015 shows the warmest period during the month.
Figure 3: Statewide average temperature departure from normal for February 6-10, 2015 shows the warmest period during the month.

Figure 4: Statewide average temperature departure from normal for February 2015 shows the coldest period of the month.
Figure 4: Statewide average temperature departure from normal for February 2015 shows the coldest period of the month.

Precipitation

The statewide average precipitation was 1.14 inches which was just barely above the normal 1.05 inches for February (See Figure 5). This is the 62nd wettest February among 143 years of records. Along with the bitter cold month, Iowans endured the 11th snowiest February on record (out of 128 years). The statewide average snowfall was 12.6 inches or 5.8 inches above normal (See Figure 6). However, if we compare February 2015 to other recent years, it still ranks behind 2008 (15.8 inches), 2014 (14.9 inches) and 2010 (14.4 inches). The snowiest February on record, in Iowa, is 1962 with a monthly statewide average of 22.2 inches.

There were two main events (no not wrestling) that brought the majority of the precipitation in February. The first snow event was during the Super Bowl Sunday on the 1st and was a continuation from the snow that began on the January 31. The statewide average snow for the entire event was 8.5 inches and much of the state was covered with 6 to 16 inches of new snow (See Figure 7). The NWS office in Johnston recorded 14.2 inches and the Des Moines Airport received 11.6 inches from the storm. This storm was the largest snow event, in the state of Iowa, since the week of December 23-27, 2009 (See Figure 8). A light snow event affected southern Iowa on the 4th where 3 to 6 inches accumulated along and south of Highway 34 to the Missouri border (See Figure 9). Otherwise, no widespread precipitation affected the state until the 25th when much of the state, except the southwest, received anywhere from 1 to 6 inches. The higher amounts were in north-central to northeast Iowa with Calmar coming in with the highest total of 7.9 inches (See Figure 10). One positive from the month of February was the deep snow pack for much of central to southern Iowa was depleted during the brief warm up between the 6th and 10th. Des Moines had 10 inches of snow depth on the 2nd but carried an inch or a trace from the 9th through the remainder of the month. Northern Iowa, the snow pack was depleted some during the aforementioned warmup but them was replenished with the snow storm on the 25th.

Figure 5: Statewide average precipitation percent of normal for February 2015.
Figure 5: Statewide average precipitation percent of normal for February 2015.

Figure 6: Statewide average snowfall percent of normal for February 2015.
Figure 6: Statewide average snowfall percent of normal for February 2015.

Figure 7: Total snowfall from January 31 to February 1, 2015 snow storm.
Figure 7: Total snowfall from January 31 to February 1, 2015 snow storm.

Figure 8: Total snowfall from December 23-27, 2009.
Figure 8: Total snowfall from December 23-27, 2009.

Figure 9: Total snowfall from February 4, 2015 snow storm across southern Iowa.
Figure 9: Total snowfall from February 4, 2015 snow storm across southern Iowa.

Figure 10: Total snowfall from February 25, 2015.
Figure 7: Total snowfall from February 25, 2015.

Much of the statewide statistics are courtesy of State Climatologist Harry Hillaker and you can find additional statewide information here: http://www.iowaagriculture.gov/climatology/weatherSummaries/2015/pms201502.pdf

Blog Post by Kenny Podrazik – NWS Des Moines