Past IEM Features tagged: dec
Above Freezing in December
26 Dec 2024 05:37 AMTemperatures have been mild overnight with much of the state at or above freezing at 5 AM this morning. The featured chart presents the frequency by hour for the temperature being at or above 32°F during December for Des Moines. The diurnal signal is clear with the lowest frequencies happening during the early morning hours before whatever meager daytime heating that does exist can start to raise near surface air temperatures. For most hours of the day, being below freezing is more common than not. The overnight frequencies are all around 1/4 of the time or higher, so having such temperatures isn't necessarily all that rare for this time of the year.
Voting:
Good: 10
Bad: 2
Tags: dec
December Precip vs Snow
23 Dec 2024 05:30 AMToday's featured chart checks in on the relationship between December total snowfall and precipitation for Ames. The 2024 total so far is highlighted in red and indicates a below average precipitation with below average snowfall. There isn't really a strong relationship between these two as not all precipitation events during December produce snowfall. The current forecast for the rest of 2024 does have a few chances of liquid and frozen precipitation, but nothing till after Christmas.
Voting:
Good: 9
Bad: 2
Abstain: 3
Tags: dec
December Hours of 40+
19 Dec 2023 05:30 AMOur brief bout with colder temperatures is being replaced by an extended stretch of above average temperatures with low temperatures for this upcoming weekend forecast in the low 40s for some parts of the state! The featured chart looks into the number of hours spent at or above 40 degrees during December for Des Moines. This year's total is already well above a simple long term average and it appears the upcoming accumulation will push us dangerously close to the maximum shown on the plot during 2006. The hope for any white ground covering in time for Christmas seems very slim at the moment.
Voting:
Good: 11
Bad: 0
Tags: dec
40+ in December
06 Dec 2018 05:34 AMAir temperatures were about as warm as they have been over the past two weeks on Wednesday with values briefly at 40 degrees during the afternoon hours for Des Moines. The featured chart looks at the hourly frequency of having a 40+ degree temperature during December. The afternoon odds are about one in four to five days, which is about right for having one day so far five days into December. Unfortunately, it will be at least five more days until we perhaps may see as warm of temperatures again.
Voting:
Good: 7
Bad: 0
Tags: dec
December Hours of 50+
20 Dec 2017 05:34 AMTemperatures were very mild again on Tuesday with highs well into the 40s and even some 50s over Iowa. Some places, like Ottumwa, were able to enjoy a hour or more of temperatures in the 50s. How common are hourly temperatures in the 50s for December? The featured chart looks into that using period of record data for the site during December. The top chart provides the total number of hourly temperature reports at or above 50 degrees and the bottom report shows the average and 2017 totals by hour of the day. Our total this year is below totals from a number of recent years, but still well above average. Unfortunately, it would not appear likely that these totals will be added to for the rest of the month as much colder weather will arrive soon.
Voting:
Good: 4
Bad: 0
Tags: dec
December Precip Hours
24 Dec 2015 05:40 AMWednesday was yet another wet December day over much of Iowa with rainfall totals approaching an inch for a swath of the state. The featured chart displays the number of hourly observations by month with measurable precipitation reported for Des Moines. The total hourly reports for December is the highest on record, according to the unofficial archive maintained by the IEM. It is also interesting to see that this month's total is higher than any other month this year! More chances for precipitating storms are in the forecast, so the total will likely be added to.
Voting:
Good: 30
Bad: 15
Abstain: 13
Tags: dec precip
Beating December 1889
11 Dec 2015 05:38 AMFor Des Moines, the warmest December on record was way back in 1889. This December has certainly started off warm with yet another very warm day in Iowa on Thursday. The featured chart looks at the chances that this December could top the previous one. The method simply appends each previous year's Dec 11 - 31 period onto the end of this years Dec 1 - 10 period and computes the average temperature. None of these scenarios are able to top 1889, but a few of them come very close!
Voting:
Good: 40
Bad: 18
Abstain: 13
Tags: dec
Snow vs Precip Totals
31 Dec 2014 07:25 AMWhile snowfall totals for Des Moines were rather paltry this December, the total precipitation was close to long term average for the month. The featured chart compares the total snowfall vs precipitation for the month of December for Des Moines. The precipitation total includes melted snowfall. Most of the snowfall this month has been confined to northern Iowa. The forecast to start the new year only has a chance of snow for this coming weekend.
Voting:
Good: 34
Bad: 18
Abstain: 20
Tags: dec
December extreme days
31 Dec 2010 06:03 AMThanks to a powerful push of warm and moist air on Thursday, temperatures soared and topped out at 61 degrees for Des Moines, which is two degrees short of a record. This high temperature was more than two standard deviations warmer than the average high (two sigma). The featured chart presents the combination of two sigma days against the average high and low temperature for December. The green symbols and lines are the values for 2010. The symbols are offset slightly for readability. The chart shows what one may intuitively expect, that cold months have a number of very cold days and vice versa. This year shows up as a somewhat rare combination of having a below average month along with an above two sigma warm day (yesterday).
Voting:
Good: 53
Bad: 24
Tags: dec
Another cold December
20 Dec 2010 05:53 AMThe featured chart presents the Iowa average December temperature along with a 30 year moving average. Five out of the past six years have seen well below temperatures, but nothing compared to 2000 or 1983. The moving average shows that the general trend has been for colder Decembers. Clicking the image will give a view back to 1893.
Voting:
Good: 25
Bad: 3
Tags: dec
Hope after a cold start
09 Dec 2010 05:50 AMThe start of December has been on the cold side with an average of just 20 degrees for Ames so far. The featured chart presents some hope for warmer weather comparing the first 8 days of December versus the remaining 23. The cold starts most frequently see warmer weather for the remaining period, but only a few are above the overall average (blue dash). The far outlier to the left in the image was 2005, where the average temperature was only 6 degrees for the first 8 days of December. Thankfully, above freezing temperatures are expected today and tomorrow.
Voting:
Good: 17
Bad: 6
Tags: dec